# embeddings_queue

created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 865e1e4b-5d04-44b6-915e-bbe7b62d0fbc
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 54, "full_page_content": "55 \n \napplications: \n6. The two keys can be applied in either order: \nM = D[PUb, E(PRb, M)] = D[PRb, E(PUb, M)] \n \n \n \n2.3 RSA Algorithm: \nDiffie and Hellman challenged cryptologists to come up with a cryptographic algorithm that \nmet the requirements for public-key systems. \nOne of the first successful responses to the challenge was developed in 1977 by Ron Rivest, Adi \nShamir, and Len Adleman at MIT and first published in 1978. The Rivest-Shamir-Adleman (RSA) \nscheme has since that time reigned supreme as the most widely accepted and implemented general-\npurpose approach to public-key encryption. \nThe RSA scheme is a block cipher in which the plaintext and ciphertext are integers between 0 and \nn - 1 for some n. A typical size for n is 1024 bits, or 309 decimal digits. That is, n is less than 21024. \nWe examine RSA in this section in some detail, beginning with an explanation of the algorithm. Then \nwe examine some of the computational and cryptanalytical implications of RSA. \n2.3.1 Description of the Algorithm \nRSA makes use of an expression with exponentials. Plaintext is encrypted in blocks, with each block \nhaving a binary value less than some number n. That is, the block size must be less than or equal to \nlog2(n) + 1; in practice, the block size is i bits, where 2i < n \u2264 2i+1. Encryption and decryption are \nof the following form, for some plaintext block M and ciphertext block C. \n \nBoth sender and receiver must know the value of n. The sender knows the value of e, and \nonly the receiver knows the value of d. Thus, this is a public-key encryption algorithm with a \npublic key of PU = {e, n} and a private key of PR = {d, n}. \nFor this algorithm to be satisfactory for public-key encryption, the following requirements \nmust be met. \n1. It is possible to find values of e, d, n such that Med mod n = M for all M < n. \n2. It is relatively easy to calculate Me mod n and Cd mod n for all values of M < n. \n3. It is infeasible to determine d given e and n. \nWe need to find a relationship of the form \nMed mod n = M \nThe preceding relationship holds if e and d are multiplicative inverses modulo \u03c6(n), where \n\u03c6(n) is the Euler totient function. \nFor p,q prime, \u03c6 (pq) = (p - 1)(q - 1). The relationship between e and d can be expressed as", "chunk_id": "fc7e2fac-97fe-476e-927d-9f0f0475fd33", "chroma:document": "Med mod n = M \nThe preceding relationship holds if e and d are multiplicative inverses modulo \u03c6(n), where \n\u03c6(n) is the Euler totient function. \nFor p,q prime, \u03c6 (pq) = (p - 1)(q - 1). The relationship between e and d can be expressed as"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 2ab47e8b-0cc2-49af-a13c-429148ed1949
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 55, "full_page_content": "56 \n \ned mod \u03c6(n) = 1 \n \nThis is equivalent to saying \n \n \nThat is, e and d are multiplicative inverses mod \uf06a (n). Note that, according to the rules of modular \narithmetic, this is true only if d (and therefore e) is relatively prime to \uf06a (n). Equivalently, gcd( \uf06a (n), \nd) = 1.  \nThe ingredients are the following:  \n \nThe private key consists of {d, n} and the public key consists of {e, n}. Suppose that user A has \npublished its public key and that user B wishes to send the message M to A. Then B calculates C = \nMe mod n and transmits C. On receipt of this ciphertext, user A decrypts by calculating M = C d mod \nn. \nTable :2  RSA Algorithm", "chunk_id": "10694ecd-595e-481e-91c8-1e0d4ee33b1c", "chroma:document": "56 \n \ned mod \u03c6(n) = 1 \n \nThis is equivalent to saying \n \n \nThat is, e and d are multiplicative inverses mod \uf06a (n). Note that, according to the rules of modular \narithmetic, this is true only if d (and therefore e) is relatively prime to \uf06a (n). Equivalently, gcd( \uf06a (n), \nd) = 1.  \nThe ingredients are the following:"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: f22bb0da-4733-4297-8017-6efd3c171a28
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 55, "full_page_content": "56 \n \ned mod \u03c6(n) = 1 \n \nThis is equivalent to saying \n \n \nThat is, e and d are multiplicative inverses mod \uf06a (n). Note that, according to the rules of modular \narithmetic, this is true only if d (and therefore e) is relatively prime to \uf06a (n). Equivalently, gcd( \uf06a (n), \nd) = 1.  \nThe ingredients are the following:  \n \nThe private key consists of {d, n} and the public key consists of {e, n}. Suppose that user A has \npublished its public key and that user B wishes to send the message M to A. Then B calculates C = \nMe mod n and transmits C. On receipt of this ciphertext, user A decrypts by calculating M = C d mod \nn. \nTable :2  RSA Algorithm", "chunk_id": "d1b27caf-20a3-4ff8-a9b6-ff1db45641b7", "chroma:document": "The private key consists of {d, n} and the public key consists of {e, n}. Suppose that user A has \npublished its public key and that user B wishes to send the message M to A. Then B calculates C = \nMe mod n and transmits C. On receipt of this ciphertext, user A decrypts by calculating M = C d mod \nn. \nTable :2  RSA Algorithm"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 5ba5f90f-5926-44ea-b770-e98101b9633d
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 56, "full_page_content": "57 \n \n \nFig.1  Example of RSA Algorithm \n \n2.4 Key Management \nOne of the major roles of public-key encryption has been to address the problem of key distribution. \nThere are actually two distinct aspects to the use of public-key cryptography in this regard: \n\u25cf The distribution of public keys \n\u25cf The use of public-key encryption to distribute secret keys \n2.4.1 Distribution of Public Keys \nSeveral techniques have been proposed for the distribution of public keys. Virtually all these \nproposals can be grouped into the following general schemes: \n\u25cf Public announcement \n\u25cf Publicly available directory \n\u25cf Public-key authority \n\u25cf Public-key certificates \n2.4.1.1 Public Announcement of Public Key \nOn the face of it, the point of public-key encryption is that the public key is public. Thus, if there is \nsome broadly accepted public-key algorithm, such as RSA, any participant can send his or her public \nkey to any other participant or broadcast the key to the community at large", "chunk_id": "1b517a04-b55c-4474-a889-947b354735ce", "chroma:document": "57 \n \n \nFig.1  Example of RSA Algorithm \n \n2.4 Key Management \nOne of the major roles of public-key encryption has been to address the problem of key distribution. \nThere are actually two distinct aspects to the use of public-key cryptography in this regard: \n\u25cf The distribution of public keys \n\u25cf The use of public-key encryption to distribute secret keys"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 6bc1da63-8d89-441b-a5eb-b1d2465bdb46
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 56, "full_page_content": "57 \n \n \nFig.1  Example of RSA Algorithm \n \n2.4 Key Management \nOne of the major roles of public-key encryption has been to address the problem of key distribution. \nThere are actually two distinct aspects to the use of public-key cryptography in this regard: \n\u25cf The distribution of public keys \n\u25cf The use of public-key encryption to distribute secret keys \n2.4.1 Distribution of Public Keys \nSeveral techniques have been proposed for the distribution of public keys. Virtually all these \nproposals can be grouped into the following general schemes: \n\u25cf Public announcement \n\u25cf Publicly available directory \n\u25cf Public-key authority \n\u25cf Public-key certificates \n2.4.1.1 Public Announcement of Public Key \nOn the face of it, the point of public-key encryption is that the public key is public. Thus, if there is \nsome broadly accepted public-key algorithm, such as RSA, any participant can send his or her public \nkey to any other participant or broadcast the key to the community at large", "chunk_id": "ebfb0a3b-d764-4281-8c56-ddf2fffb83ac", "chroma:document": "2.4.1 Distribution of Public Keys \nSeveral techniques have been proposed for the distribution of public keys. Virtually all these \nproposals can be grouped into the following general schemes: \n\u25cf Public announcement \n\u25cf Publicly available directory \n\u25cf Public-key authority \n\u25cf Public-key certificates \n2.4.1.1 Public Announcement of Public Key"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 226c6ffb-52bf-4681-9e00-b5e907ae0124
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 56, "full_page_content": "57 \n \n \nFig.1  Example of RSA Algorithm \n \n2.4 Key Management \nOne of the major roles of public-key encryption has been to address the problem of key distribution. \nThere are actually two distinct aspects to the use of public-key cryptography in this regard: \n\u25cf The distribution of public keys \n\u25cf The use of public-key encryption to distribute secret keys \n2.4.1 Distribution of Public Keys \nSeveral techniques have been proposed for the distribution of public keys. Virtually all these \nproposals can be grouped into the following general schemes: \n\u25cf Public announcement \n\u25cf Publicly available directory \n\u25cf Public-key authority \n\u25cf Public-key certificates \n2.4.1.1 Public Announcement of Public Key \nOn the face of it, the point of public-key encryption is that the public key is public. Thus, if there is \nsome broadly accepted public-key algorithm, such as RSA, any participant can send his or her public \nkey to any other participant or broadcast the key to the community at large", "chunk_id": "b938967c-cf30-4afc-a7cf-50279286f0c2", "chroma:document": "On the face of it, the point of public-key encryption is that the public key is public. Thus, if there is \nsome broadly accepted public-key algorithm, such as RSA, any participant can send his or her public \nkey to any other participant or broadcast the key to the community at large"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 3e32ab48-5153-4db9-acff-4cb93b10d36c
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 57, "full_page_content": "58 \n \n \n \n \n \nFig: 2 Uncontrolled Public-Key Distribution \nPublicly Available Directory \nA greater degree of security can be achieved by maintaining a publicly available dynamic directory \nof public keys. Maintenance and distribution of the public directory would have to be the \nresponsibility of some trusted entity or organization (Figure 3). Such a scheme would include the \nfollowing elements: \n \nFig : 3 Public-Key Publication \n \n1. The authority maintains a directory with a {name, public key} entry for each participant. \n2. Each participant registers a public key with the directory authority. Registration would have to be  \nin person or by some form of secure authenticated communication.", "chunk_id": "0fa98fd5-20a9-4fcb-b117-d09e0d51d997", "chroma:document": "58 \n \n \n \n \n \nFig: 2 Uncontrolled Public-Key Distribution \nPublicly Available Directory \nA greater degree of security can be achieved by maintaining a publicly available dynamic directory \nof public keys. Maintenance and distribution of the public directory would have to be the \nresponsibility of some trusted entity or organization (Figure 3). Such a scheme would include the"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: ee62b546-da62-468c-a03b-ac237c8d8a69
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 57, "full_page_content": "58 \n \n \n \n \n \nFig: 2 Uncontrolled Public-Key Distribution \nPublicly Available Directory \nA greater degree of security can be achieved by maintaining a publicly available dynamic directory \nof public keys. Maintenance and distribution of the public directory would have to be the \nresponsibility of some trusted entity or organization (Figure 3). Such a scheme would include the \nfollowing elements: \n \nFig : 3 Public-Key Publication \n \n1. The authority maintains a directory with a {name, public key} entry for each participant. \n2. Each participant registers a public key with the directory authority. Registration would have to be  \nin person or by some form of secure authenticated communication.", "chunk_id": "770ba102-7c31-4924-adfb-9caa9000c557", "chroma:document": "following elements: \n \nFig : 3 Public-Key Publication \n \n1. The authority maintains a directory with a {name, public key} entry for each participant. \n2. Each participant registers a public key with the directory authority. Registration would have to be  \nin person or by some form of secure authenticated communication."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: d7e74e79-ceab-4dc7-9c8b-0367acb8ae60
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 58, "full_page_content": "59 \n \n3. A participant may replace the existing key with a new one at any time, either because of the  \ndesire to replace a public key that has already been used for a large amount of data, or because  \nthe corresponding private key has been compromised in some way. \n4. Participants could also access the directory electronically. For this purpose, secure, authenticated  \ncommunication from the authority to the participant is mandatory. \n2.4.1.2 Public-Key Authority \nStronger security for public-key distribution can be achieved by providing tighter control over the  \ndistribution of public keys from the directory. A typical scenario is illustrated in Figure 4 As before, \nthe scenario assumes that a central authority maintains a dynamic directory of public keys of all \nparticipants. In addition, each participant reliably knows a public key for the authority, with only the \nauthority knowing the corresponding private key.  \n \n1. A sends a timestamped message to the public-key authority containing a request for the current  \npublic key of B.  \n2. The authority responds with a message that is encrypted using the authority's private key, PRauth \nThus, A is able to decrypt the message using the authority's public key. Therefore, A is assured  \nthat the message originated with the authority. The message includes the following:  \n\u25cf B's public key, PUb  which A can use to encrypt messages destined for B \n\u25cf The original request, to enable A to match this response with the corresponding earlier  \nrequest and to verify that the original request was not altered before reception by the  \nauthority", "chunk_id": "452b821a-4d1b-4743-bf94-439872da79b7", "chroma:document": "59 \n \n3. A participant may replace the existing key with a new one at any time, either because of the  \ndesire to replace a public key that has already been used for a large amount of data, or because  \nthe corresponding private key has been compromised in some way. \n4. Participants could also access the directory electronically. For this purpose, secure, authenticated"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: f226fcff-bdab-496b-a7af-0b7c892d2e34
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 58, "full_page_content": "59 \n \n3. A participant may replace the existing key with a new one at any time, either because of the  \ndesire to replace a public key that has already been used for a large amount of data, or because  \nthe corresponding private key has been compromised in some way. \n4. Participants could also access the directory electronically. For this purpose, secure, authenticated  \ncommunication from the authority to the participant is mandatory. \n2.4.1.2 Public-Key Authority \nStronger security for public-key distribution can be achieved by providing tighter control over the  \ndistribution of public keys from the directory. A typical scenario is illustrated in Figure 4 As before, \nthe scenario assumes that a central authority maintains a dynamic directory of public keys of all \nparticipants. In addition, each participant reliably knows a public key for the authority, with only the \nauthority knowing the corresponding private key.  \n \n1. A sends a timestamped message to the public-key authority containing a request for the current  \npublic key of B.  \n2. The authority responds with a message that is encrypted using the authority's private key, PRauth \nThus, A is able to decrypt the message using the authority's public key. Therefore, A is assured  \nthat the message originated with the authority. The message includes the following:  \n\u25cf B's public key, PUb  which A can use to encrypt messages destined for B \n\u25cf The original request, to enable A to match this response with the corresponding earlier  \nrequest and to verify that the original request was not altered before reception by the  \nauthority", "chunk_id": "f79b0322-f5f6-4930-b628-47866827a993", "chroma:document": "communication from the authority to the participant is mandatory. \n2.4.1.2 Public-Key Authority \nStronger security for public-key distribution can be achieved by providing tighter control over the  \ndistribution of public keys from the directory. A typical scenario is illustrated in Figure 4 As before,"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 947a3061-993f-4b2c-88ee-bc27a9026781
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 58, "full_page_content": "59 \n \n3. A participant may replace the existing key with a new one at any time, either because of the  \ndesire to replace a public key that has already been used for a large amount of data, or because  \nthe corresponding private key has been compromised in some way. \n4. Participants could also access the directory electronically. For this purpose, secure, authenticated  \ncommunication from the authority to the participant is mandatory. \n2.4.1.2 Public-Key Authority \nStronger security for public-key distribution can be achieved by providing tighter control over the  \ndistribution of public keys from the directory. A typical scenario is illustrated in Figure 4 As before, \nthe scenario assumes that a central authority maintains a dynamic directory of public keys of all \nparticipants. In addition, each participant reliably knows a public key for the authority, with only the \nauthority knowing the corresponding private key.  \n \n1. A sends a timestamped message to the public-key authority containing a request for the current  \npublic key of B.  \n2. The authority responds with a message that is encrypted using the authority's private key, PRauth \nThus, A is able to decrypt the message using the authority's public key. Therefore, A is assured  \nthat the message originated with the authority. The message includes the following:  \n\u25cf B's public key, PUb  which A can use to encrypt messages destined for B \n\u25cf The original request, to enable A to match this response with the corresponding earlier  \nrequest and to verify that the original request was not altered before reception by the  \nauthority", "chunk_id": "a55f47c7-7081-4635-acc5-f0585be6b80a", "chroma:document": "the scenario assumes that a central authority maintains a dynamic directory of public keys of all \nparticipants. In addition, each participant reliably knows a public key for the authority, with only the \nauthority knowing the corresponding private key.  \n \n1. A sends a timestamped message to the public-key authority containing a request for the current  \npublic key of B."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: d6e83b97-7750-4c41-93f4-ed6b37677102
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 58, "full_page_content": "59 \n \n3. A participant may replace the existing key with a new one at any time, either because of the  \ndesire to replace a public key that has already been used for a large amount of data, or because  \nthe corresponding private key has been compromised in some way. \n4. Participants could also access the directory electronically. For this purpose, secure, authenticated  \ncommunication from the authority to the participant is mandatory. \n2.4.1.2 Public-Key Authority \nStronger security for public-key distribution can be achieved by providing tighter control over the  \ndistribution of public keys from the directory. A typical scenario is illustrated in Figure 4 As before, \nthe scenario assumes that a central authority maintains a dynamic directory of public keys of all \nparticipants. In addition, each participant reliably knows a public key for the authority, with only the \nauthority knowing the corresponding private key.  \n \n1. A sends a timestamped message to the public-key authority containing a request for the current  \npublic key of B.  \n2. The authority responds with a message that is encrypted using the authority's private key, PRauth \nThus, A is able to decrypt the message using the authority's public key. Therefore, A is assured  \nthat the message originated with the authority. The message includes the following:  \n\u25cf B's public key, PUb  which A can use to encrypt messages destined for B \n\u25cf The original request, to enable A to match this response with the corresponding earlier  \nrequest and to verify that the original request was not altered before reception by the  \nauthority", "chunk_id": "5a9dd434-b355-45ec-b9a4-80bd19875682", "chroma:document": "public key of B.  \n2. The authority responds with a message that is encrypted using the authority's private key, PRauth \nThus, A is able to decrypt the message using the authority's public key. Therefore, A is assured  \nthat the message originated with the authority. The message includes the following:  \n\u25cf B's public key, PUb  which A can use to encrypt messages destined for B"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 188a5e4d-897c-4235-a7a7-1d9cd2344708
encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 58, "full_page_content": "59 \n \n3. A participant may replace the existing key with a new one at any time, either because of the  \ndesire to replace a public key that has already been used for a large amount of data, or because  \nthe corresponding private key has been compromised in some way. \n4. Participants could also access the directory electronically. For this purpose, secure, authenticated  \ncommunication from the authority to the participant is mandatory. \n2.4.1.2 Public-Key Authority \nStronger security for public-key distribution can be achieved by providing tighter control over the  \ndistribution of public keys from the directory. A typical scenario is illustrated in Figure 4 As before, \nthe scenario assumes that a central authority maintains a dynamic directory of public keys of all \nparticipants. In addition, each participant reliably knows a public key for the authority, with only the \nauthority knowing the corresponding private key.  \n \n1. A sends a timestamped message to the public-key authority containing a request for the current  \npublic key of B.  \n2. The authority responds with a message that is encrypted using the authority's private key, PRauth \nThus, A is able to decrypt the message using the authority's public key. Therefore, A is assured  \nthat the message originated with the authority. The message includes the following:  \n\u25cf B's public key, PUb  which A can use to encrypt messages destined for B \n\u25cf The original request, to enable A to match this response with the corresponding earlier  \nrequest and to verify that the original request was not altered before reception by the  \nauthority", "chunk_id": "207179cb-7dc6-414d-83a3-80d25e6f08d1", "chroma:document": "\u25cf The original request, to enable A to match this response with the corresponding earlier  \nrequest and to verify that the original request was not altered before reception by the  \nauthority"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "6b1ad080-500b-44e5-8767-8f5fb8baae12", "chroma:document": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "de5384e3-4c31-4001-9d34-47a9b1f72b9f", "chroma:document": "4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "96d0511c-215f-494b-ad1a-2c340a9bd44d", "chroma:document": "generated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "41c15afd-e5ee-4d23-a396-bf1f2b5ba5b6", "chroma:document": "without contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "37a06b94-0892-49a8-8b51-d5e6f04f9e87", "chroma:document": "institution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "058f7389-3e5a-48d1-ab97-c035e4ffadc7", "chroma:document": "We can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 59, "full_page_content": "60 \n \n\u25cf The original timestamp, so A can determine that this is not an old message from the  \nauthority containing a key other than B's current public key \n3. A stores B's public key and also uses it to encrypt a message to B containing an identifier of A  \n(IDA) and a nonce (N1), which is used to identify this transaction uniquely.  \n4. B retrieves A's public key from the authority in the same manner as A retrieved B's public key.  \nAt this point, public keys have been securely delivered to A and B, and they may begin their  \nprotected exchange. However, two additional steps are desirable:  \n6. B sends a message to A encrypted with PUa  and containing A's nonce (N1) as well as a new nonce  \ngenerated by B (N2) Because only B could have decrypted message (3), the presence of N1 in  \nmessage (6) assures A that the correspondent is B.  \n7. A returns N2, encrypted using B's public key, to assure B that its correspondent is A.  \n2.4.1.3 Public-Key Certificates \nThe public key certificate relies on certificates that can be used by participants to exchange keys \nwithout contacting a public-key authority, in a way that is as reliable as if the keys were obtained \ndirectly from a public-key authority. In essence, a certificate consists of a public key, an identifier of \nthe key owner, and the whole block signed by a trusted third party. \n Typically, the third party is a certificate authority, such as a government agency or a financial \ninstitution that is trusted by the user community. A user can present his or her public key to the \nauthority in a secure manner and obtain a certificate. The user can then publish the certificate. Anyone \nneeding this user\u2019s public key can obtain the certificate and verify that it is valid by way of the \nattached trusted signature. \nWe can place the following requirements on this scheme: \n1.Any participant can read a certificate to determine the name and public key of the certificate\u2019s \nowner. \n2.Any participant can verify that the certificate originated from the certificate authority and is not \ncounterfeit. \n3.Only the certificate authority can create and update certificates. \n4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate.", "chunk_id": "cbcfb35c-be30-4ff1-a2de-cbb77e03b9f2", "chroma:document": "4.Any participant can verify the currency of the certificate. \nA certificate scheme is illustrated in Figure 5. Each participant applies to the certificate authority,  \nsupplying a public key and requesting a certificate."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 60, "full_page_content": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this  \ncertificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the \ncertificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new \nprivate/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography \nOnce public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates \nthat can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:", "chunk_id": "c2ec7456-0a43-42df-b975-ceb09caa87a0", "chroma:document": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 60, "full_page_content": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this  \ncertificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the \ncertificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new \nprivate/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography \nOnce public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates \nthat can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:", "chunk_id": "e4ea4729-8ade-4c6e-b2ae-4d63f5e33b87", "chroma:document": "certificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 60, "full_page_content": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this  \ncertificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the \ncertificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new \nprivate/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography \nOnce public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates \nthat can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:", "chunk_id": "20663e06-861d-4ea0-a6fe-48728226d787", "chroma:document": "certificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 60, "full_page_content": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this  \ncertificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the \ncertificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new \nprivate/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography \nOnce public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates \nthat can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:", "chunk_id": "2b099978-4a18-4f1f-a336-77c6eb9b48f2", "chroma:document": "private/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 60, "full_page_content": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this  \ncertificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the \ncertificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new \nprivate/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography \nOnce public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates \nthat can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:", "chunk_id": "e2e3c832-bb26-4b02-afc5-d393ecff5483", "chroma:document": "Once public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 60, "full_page_content": "61 \n \n \nFig: 6 Exchange of Public-Key Certificates \n \nApplication must be in person or by some form of secure authenticated communication. For \nparticipant A, the authority provides a certificate of the form \nCA = E(PRauth, [T||IDA||PUa]) \nwhere PRauth is the private key used by the authority and T is a timestamp. A may then pass this  \ncertificate on to any other participant, who reads and verifies the certificate as follows: \nD(PUauth, CA) = D(PUauth, E(PRauth, [T||IDA||PUa])) = (T||IDA||PUa) \nThe recipient uses the authority's public key, PUauth to decrypt the certificate. Because the certificate \nis readable only using the authority's public key, this verifies that the certificate came from the \ncertificate authority. The elements IDA and PUa provide the recipient with the name and public key \nof the certificate's holder. The timestamp T validates the currency of the certificate. The timestamp \ncounters the following scenario. A's private key is learned by an adversary. A generates a new \nprivate/public key pair and applies to the certificate authority for a new certificate. Meanwhile, the \nadversary replays the old certificate to B. If B then encrypts messages using the compromised old \npublic key, the adversary can read those messages. \n2.4.2 Distribution of Secret Keys Using Public-Key Cryptography \nOnce public keys have been distributed or have become accessible, secure communication that \nthwarts eavesdropping, tampering, or both is possible. However, few users will wish to make \nexclusive use of public-key encryption for communication because of the relatively slow data rates \nthat can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:", "chunk_id": "5a72beff-bfbe-433d-bbe3-06ee58f88500", "chroma:document": "that can be achieved. Accordingly, public-key encryption provides for the distribution of secret keys \nto be used for conventional encryption. \n2.4.2.1 Simple Secret Key Distribution \nIf A wishes to communicate with B, the following procedure is employed:"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 61, "full_page_content": "62 \n \n1. A generates a public/private key pair {PUa , PRa} and transmits a message to B consisting of PUa \nand an identifier of A, IDA.  \n2. B generates a secret key, Ks, and transmits it to A, encrypted with A's public key.  \n3. A computes D(PRa , E(PUa , Ks)) to recover the secret key. Because only A can decrypt the  \nmessage, only A and B will know the identity of Ks.  \n4. A discards PUa and PRa and B discards PUa. \n \nFig: 6 Simple Use of Public-Key Encryption to Establish a Session Key \nA and B can now securely communicate using conventional encryption and the session key Ks. At \nthe completion of the exchange, both A and B discard Ks. Despite its simplicity, this is an attractive \nprotocol. No keys exist before the start of the communication and none exist after the completion of \ncommunication. Thus, the risk of compromise of the keys is minimal. At the same time, the \ncommunication is secure from eavesdropping. \n2.4.2.2 Secret Key Distribution with Confidentiality and Authentication \nIt provides protection against both active and passive attacks. \n \nFig: 7 Public-Key Distribution of Secret Keys \n \nThen the following steps occur:  \n1. A uses B's public key to encrypt a message to B containing an identifier of A (IDA) and a nonce \n(N1), which is used to identify this transaction uniquely.", "chunk_id": "077b6dba-2b26-4640-a9ff-38699fe08ef8", "chroma:document": "62 \n \n1. A generates a public/private key pair {PUa , PRa} and transmits a message to B consisting of PUa \nand an identifier of A, IDA.  \n2. B generates a secret key, Ks, and transmits it to A, encrypted with A's public key.  \n3. A computes D(PRa , E(PUa , Ks)) to recover the secret key. Because only A can decrypt the  \nmessage, only A and B will know the identity of Ks."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 61, "full_page_content": "62 \n \n1. A generates a public/private key pair {PUa , PRa} and transmits a message to B consisting of PUa \nand an identifier of A, IDA.  \n2. B generates a secret key, Ks, and transmits it to A, encrypted with A's public key.  \n3. A computes D(PRa , E(PUa , Ks)) to recover the secret key. Because only A can decrypt the  \nmessage, only A and B will know the identity of Ks.  \n4. A discards PUa and PRa and B discards PUa. \n \nFig: 6 Simple Use of Public-Key Encryption to Establish a Session Key \nA and B can now securely communicate using conventional encryption and the session key Ks. At \nthe completion of the exchange, both A and B discard Ks. Despite its simplicity, this is an attractive \nprotocol. No keys exist before the start of the communication and none exist after the completion of \ncommunication. Thus, the risk of compromise of the keys is minimal. At the same time, the \ncommunication is secure from eavesdropping. \n2.4.2.2 Secret Key Distribution with Confidentiality and Authentication \nIt provides protection against both active and passive attacks. \n \nFig: 7 Public-Key Distribution of Secret Keys \n \nThen the following steps occur:  \n1. A uses B's public key to encrypt a message to B containing an identifier of A (IDA) and a nonce \n(N1), which is used to identify this transaction uniquely.", "chunk_id": "79a7a15a-417b-4789-b425-25b628ff3f92", "chroma:document": "4. A discards PUa and PRa and B discards PUa. \n \nFig: 6 Simple Use of Public-Key Encryption to Establish a Session Key \nA and B can now securely communicate using conventional encryption and the session key Ks. At \nthe completion of the exchange, both A and B discard Ks. Despite its simplicity, this is an attractive"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 61, "full_page_content": "62 \n \n1. A generates a public/private key pair {PUa , PRa} and transmits a message to B consisting of PUa \nand an identifier of A, IDA.  \n2. B generates a secret key, Ks, and transmits it to A, encrypted with A's public key.  \n3. A computes D(PRa , E(PUa , Ks)) to recover the secret key. Because only A can decrypt the  \nmessage, only A and B will know the identity of Ks.  \n4. A discards PUa and PRa and B discards PUa. \n \nFig: 6 Simple Use of Public-Key Encryption to Establish a Session Key \nA and B can now securely communicate using conventional encryption and the session key Ks. At \nthe completion of the exchange, both A and B discard Ks. Despite its simplicity, this is an attractive \nprotocol. No keys exist before the start of the communication and none exist after the completion of \ncommunication. Thus, the risk of compromise of the keys is minimal. At the same time, the \ncommunication is secure from eavesdropping. \n2.4.2.2 Secret Key Distribution with Confidentiality and Authentication \nIt provides protection against both active and passive attacks. \n \nFig: 7 Public-Key Distribution of Secret Keys \n \nThen the following steps occur:  \n1. A uses B's public key to encrypt a message to B containing an identifier of A (IDA) and a nonce \n(N1), which is used to identify this transaction uniquely.", "chunk_id": "a42fd53d-5e8d-4b84-93fe-43784cc90b7a", "chroma:document": "protocol. No keys exist before the start of the communication and none exist after the completion of \ncommunication. Thus, the risk of compromise of the keys is minimal. At the same time, the \ncommunication is secure from eavesdropping. \n2.4.2.2 Secret Key Distribution with Confidentiality and Authentication \nIt provides protection against both active and passive attacks."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 61, "full_page_content": "62 \n \n1. A generates a public/private key pair {PUa , PRa} and transmits a message to B consisting of PUa \nand an identifier of A, IDA.  \n2. B generates a secret key, Ks, and transmits it to A, encrypted with A's public key.  \n3. A computes D(PRa , E(PUa , Ks)) to recover the secret key. Because only A can decrypt the  \nmessage, only A and B will know the identity of Ks.  \n4. A discards PUa and PRa and B discards PUa. \n \nFig: 6 Simple Use of Public-Key Encryption to Establish a Session Key \nA and B can now securely communicate using conventional encryption and the session key Ks. At \nthe completion of the exchange, both A and B discard Ks. Despite its simplicity, this is an attractive \nprotocol. No keys exist before the start of the communication and none exist after the completion of \ncommunication. Thus, the risk of compromise of the keys is minimal. At the same time, the \ncommunication is secure from eavesdropping. \n2.4.2.2 Secret Key Distribution with Confidentiality and Authentication \nIt provides protection against both active and passive attacks. \n \nFig: 7 Public-Key Distribution of Secret Keys \n \nThen the following steps occur:  \n1. A uses B's public key to encrypt a message to B containing an identifier of A (IDA) and a nonce \n(N1), which is used to identify this transaction uniquely.", "chunk_id": "61914c25-e2ae-42eb-a536-a519da8689c9", "chroma:document": "Fig: 7 Public-Key Distribution of Secret Keys \n \nThen the following steps occur:  \n1. A uses B's public key to encrypt a message to B containing an identifier of A (IDA) and a nonce \n(N1), which is used to identify this transaction uniquely."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "0dce8555-4df3-4bba-91f9-b73d3eb610e3", "chroma:document": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "b3beb7e0-5ea2-475f-a890-c27909fbba64", "chroma:document": "4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "ee846651-d4f9-4ef9-86cd-3c59a8e60603", "chroma:document": "This scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach:"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "7da0e85e-5ad8-46eb-82d8-376c223d5d94", "chroma:document": "approach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "d1ef41e6-eddd-433f-aa21-76332844c22b", "chroma:document": "encryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "cc26a155-7165-471c-961f-edf5c5c092f2", "chroma:document": "The purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "c866c533-c6c2-49a3-98fd-afd4c5f2d1fb", "chroma:document": "logarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 62, "full_page_content": "63 \n \n 2. B sends a message to A encrypted with PUa and containing A's nonce (N1) as well as a new nonce \ngenerated by B (N2) Because only B could have decrypted message (1), the presence of N1 in message \n(2) assures A that the correspondent is B. \n 3. A returns N2 encrypted using B's public key, to assure B that its correspondent is A.  \n4. A selects a secret key Ks and sends M = E(PUb , E(PRa , Ks )) to B. Encryption of this message \nwith B's public key ensures that only B can read it; encryption with A's private key ensures that only \nA could have sent it. \n 5. B computes D(PUa , D(PRb , M)) to recover the secret key. \n2.4.3 A Hybrid Scheme \nThis scheme retains the use of a key distribution center (KDC) that shares a secret master key with \neach user and distributes secret session keys encrypted with the master key. A public key scheme is \nused to distribute the master keys. The following rationale is provided for using this three-level \napproach: \n\u25cf Performance: There are many applications, especially transaction-oriented applications, in which \nthe session keys change frequently. Distribution of session keys by public-key encryption could \ndegrade overall system performance because of the relatively high computational load of public-key \nencryption and decryption. With a three-level hierarchy, public-key encryption is used only \noccasionally to update the master key between a user and the KDC. \n\u25cf Backward compatibility: The hybrid scheme is easily overlaid on an existing KDC scheme, with  \nminimal disruption or software changes \n2.5 Diffie-Hellman Key Exchange \nThe purpose of the algorithm is to enable two users to exchange a key securely that can then be used \nfor subsequent encryption of messages. The algorithm itself is limited to the exchange of secret \nvalues. \nThe Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete  \nlogarithms. we define a primitive root of a prime number p as one whose powers modulo p generate \nall the integers from 1 to p 1. That is, if a is a primitive root of the prime number p, then the numbers \na mod p, a2 mod p,..., ap1 mod p \nare distinct and consist of the integers from 1 through p-1 in some permutation. \nFor any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two", "chunk_id": "1b0bbf45-676f-4199-8b72-9fcac666bc35", "chroma:document": "For any integer b and a primitive root a of prime number p, we can find a unique exponent i such that \n \nThe exponent i is referred to as the discrete logarithm of b for the base a, mod p. \n2.5.1 The Algorithm \nFigure 8 .summarizes the Diffie-Hellman key exchange algorithm. For this scheme, there are two"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 63, "full_page_content": "64 \n \npublicly known numbers: a prime number q and an integer that is a primitive root of q. Suppose the  \nusers A and B wish to exchange a key. User A selects a random integer XA < q and computes YA = \n\u03b1XA mod q. Similarly, user B independently selects a random integer XA < q and computes YB = \u03b1 \nXB mod q. Each side keeps the X value private and makes the Y value available publicly to the other \nside. User A computes the key as K = (YB) XA mod q and user B computes the key as K = (YA)XB  \nmod q. These two calculations produce identical results \nFigure 8 The Diffie-Hellman Key Exchange Algorithm \n \nThe security of the Diffie-Hellman key exchange lies in the fact that, while it is relatively easy to  \ncalculate exponentials modulo a prime, it is very difficult to calculate discrete logarithms. For large  \nprimes, the latter task is considered infeasible. \n2.5.2 Key Exchange Protocols \nFig : 9 shows a simple protocol that makes use of the Diffie-Hellman calculation. Suppose that user  \nA wishes to set up a connection with user B and use a secret key to encrypt messages on that", "chunk_id": "51242d1a-c85c-444d-8998-74094b5a8dfe", "chroma:document": "64 \n \npublicly known numbers: a prime number q and an integer that is a primitive root of q. Suppose the  \nusers A and B wish to exchange a key. User A selects a random integer XA < q and computes YA = \n\u03b1XA mod q. Similarly, user B independently selects a random integer XA < q and computes YB = \u03b1"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 63, "full_page_content": "64 \n \npublicly known numbers: a prime number q and an integer that is a primitive root of q. Suppose the  \nusers A and B wish to exchange a key. User A selects a random integer XA < q and computes YA = \n\u03b1XA mod q. Similarly, user B independently selects a random integer XA < q and computes YB = \u03b1 \nXB mod q. Each side keeps the X value private and makes the Y value available publicly to the other \nside. User A computes the key as K = (YB) XA mod q and user B computes the key as K = (YA)XB  \nmod q. These two calculations produce identical results \nFigure 8 The Diffie-Hellman Key Exchange Algorithm \n \nThe security of the Diffie-Hellman key exchange lies in the fact that, while it is relatively easy to  \ncalculate exponentials modulo a prime, it is very difficult to calculate discrete logarithms. For large  \nprimes, the latter task is considered infeasible. \n2.5.2 Key Exchange Protocols \nFig : 9 shows a simple protocol that makes use of the Diffie-Hellman calculation. Suppose that user  \nA wishes to set up a connection with user B and use a secret key to encrypt messages on that", "chunk_id": "2cd82f62-805c-4280-98c0-79ec48ae389b", "chroma:document": "XB mod q. Each side keeps the X value private and makes the Y value available publicly to the other \nside. User A computes the key as K = (YB) XA mod q and user B computes the key as K = (YA)XB  \nmod q. These two calculations produce identical results \nFigure 8 The Diffie-Hellman Key Exchange Algorithm"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 63, "full_page_content": "64 \n \npublicly known numbers: a prime number q and an integer that is a primitive root of q. Suppose the  \nusers A and B wish to exchange a key. User A selects a random integer XA < q and computes YA = \n\u03b1XA mod q. Similarly, user B independently selects a random integer XA < q and computes YB = \u03b1 \nXB mod q. Each side keeps the X value private and makes the Y value available publicly to the other \nside. User A computes the key as K = (YB) XA mod q and user B computes the key as K = (YA)XB  \nmod q. These two calculations produce identical results \nFigure 8 The Diffie-Hellman Key Exchange Algorithm \n \nThe security of the Diffie-Hellman key exchange lies in the fact that, while it is relatively easy to  \ncalculate exponentials modulo a prime, it is very difficult to calculate discrete logarithms. For large  \nprimes, the latter task is considered infeasible. \n2.5.2 Key Exchange Protocols \nFig : 9 shows a simple protocol that makes use of the Diffie-Hellman calculation. Suppose that user  \nA wishes to set up a connection with user B and use a secret key to encrypt messages on that", "chunk_id": "33dde466-f2e5-4ad8-808f-85e7e6a6c457", "chroma:document": "The security of the Diffie-Hellman key exchange lies in the fact that, while it is relatively easy to  \ncalculate exponentials modulo a prime, it is very difficult to calculate discrete logarithms. For large  \nprimes, the latter task is considered infeasible. \n2.5.2 Key Exchange Protocols"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 63, "full_page_content": "64 \n \npublicly known numbers: a prime number q and an integer that is a primitive root of q. Suppose the  \nusers A and B wish to exchange a key. User A selects a random integer XA < q and computes YA = \n\u03b1XA mod q. Similarly, user B independently selects a random integer XA < q and computes YB = \u03b1 \nXB mod q. Each side keeps the X value private and makes the Y value available publicly to the other \nside. User A computes the key as K = (YB) XA mod q and user B computes the key as K = (YA)XB  \nmod q. These two calculations produce identical results \nFigure 8 The Diffie-Hellman Key Exchange Algorithm \n \nThe security of the Diffie-Hellman key exchange lies in the fact that, while it is relatively easy to  \ncalculate exponentials modulo a prime, it is very difficult to calculate discrete logarithms. For large  \nprimes, the latter task is considered infeasible. \n2.5.2 Key Exchange Protocols \nFig : 9 shows a simple protocol that makes use of the Diffie-Hellman calculation. Suppose that user  \nA wishes to set up a connection with user B and use a secret key to encrypt messages on that", "chunk_id": "d060066f-89de-4933-a237-b2d473b860f0", "chroma:document": "Fig : 9 shows a simple protocol that makes use of the Diffie-Hellman calculation. Suppose that user  \nA wishes to set up a connection with user B and use a secret key to encrypt messages on that"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 64, "full_page_content": "65 \n \nconnection. User A can generate a one-time private key XA, calculate YA, and send that to user B. \nUser B responds by generating a private value XB calculating YB, and sending YB to user A. Both \nusers can now calculate the key. The necessary public values q and \u03b1 would need to be known ahead \nof time. Alternatively, user A could pick values for q and \u03b1 and include those in the first message. \n \n \nFig : 9 Diffie-Hellman Key Exchange \n2.6 Message Authentication \nAuthentication Requirements \nAuthentication Functions \nMessage Encryption \nMessage Authentication Code \nHash Function \n2.6.1 Authentication Requirements \nIn the context of communications across a network, the following attacks can be identified: \n1. Disclosure: Release of message contents to any person or process not possessing the  \nappropriate cryptographic key. \n2. Traffic analysis: Discovery of the pattern of traffic between parties. In a connection-oriented  \napplication, the frequency and duration of connections could be determined. In either a  \nconnection-oriented or connectionless environment, the number and length of messages between  \nparties could be determined. \n3. Masquerade: Insertion of messages into the network from a fraudulent source. This includes", "chunk_id": "a33e88d2-664b-4e39-b925-59916f14ece5", "chroma:document": "65 \n \nconnection. User A can generate a one-time private key XA, calculate YA, and send that to user B. \nUser B responds by generating a private value XB calculating YB, and sending YB to user A. Both \nusers can now calculate the key. The necessary public values q and \u03b1 would need to be known ahead"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 64, "full_page_content": "65 \n \nconnection. User A can generate a one-time private key XA, calculate YA, and send that to user B. \nUser B responds by generating a private value XB calculating YB, and sending YB to user A. Both \nusers can now calculate the key. The necessary public values q and \u03b1 would need to be known ahead \nof time. Alternatively, user A could pick values for q and \u03b1 and include those in the first message. \n \n \nFig : 9 Diffie-Hellman Key Exchange \n2.6 Message Authentication \nAuthentication Requirements \nAuthentication Functions \nMessage Encryption \nMessage Authentication Code \nHash Function \n2.6.1 Authentication Requirements \nIn the context of communications across a network, the following attacks can be identified: \n1. Disclosure: Release of message contents to any person or process not possessing the  \nappropriate cryptographic key. \n2. Traffic analysis: Discovery of the pattern of traffic between parties. In a connection-oriented  \napplication, the frequency and duration of connections could be determined. In either a  \nconnection-oriented or connectionless environment, the number and length of messages between  \nparties could be determined. \n3. Masquerade: Insertion of messages into the network from a fraudulent source. This includes", "chunk_id": "400c0c99-84e6-49a9-831b-f39aad235484", "chroma:document": "of time. Alternatively, user A could pick values for q and \u03b1 and include those in the first message. \n \n \nFig : 9 Diffie-Hellman Key Exchange \n2.6 Message Authentication \nAuthentication Requirements \nAuthentication Functions \nMessage Encryption \nMessage Authentication Code \nHash Function \n2.6.1 Authentication Requirements"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 64, "full_page_content": "65 \n \nconnection. User A can generate a one-time private key XA, calculate YA, and send that to user B. \nUser B responds by generating a private value XB calculating YB, and sending YB to user A. Both \nusers can now calculate the key. The necessary public values q and \u03b1 would need to be known ahead \nof time. Alternatively, user A could pick values for q and \u03b1 and include those in the first message. \n \n \nFig : 9 Diffie-Hellman Key Exchange \n2.6 Message Authentication \nAuthentication Requirements \nAuthentication Functions \nMessage Encryption \nMessage Authentication Code \nHash Function \n2.6.1 Authentication Requirements \nIn the context of communications across a network, the following attacks can be identified: \n1. Disclosure: Release of message contents to any person or process not possessing the  \nappropriate cryptographic key. \n2. Traffic analysis: Discovery of the pattern of traffic between parties. In a connection-oriented  \napplication, the frequency and duration of connections could be determined. In either a  \nconnection-oriented or connectionless environment, the number and length of messages between  \nparties could be determined. \n3. Masquerade: Insertion of messages into the network from a fraudulent source. This includes", "chunk_id": "1af66619-2f77-4d18-8cfa-737295caa029", "chroma:document": "In the context of communications across a network, the following attacks can be identified: \n1. Disclosure: Release of message contents to any person or process not possessing the  \nappropriate cryptographic key. \n2. Traffic analysis: Discovery of the pattern of traffic between parties. In a connection-oriented"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 64, "full_page_content": "65 \n \nconnection. User A can generate a one-time private key XA, calculate YA, and send that to user B. \nUser B responds by generating a private value XB calculating YB, and sending YB to user A. Both \nusers can now calculate the key. The necessary public values q and \u03b1 would need to be known ahead \nof time. Alternatively, user A could pick values for q and \u03b1 and include those in the first message. \n \n \nFig : 9 Diffie-Hellman Key Exchange \n2.6 Message Authentication \nAuthentication Requirements \nAuthentication Functions \nMessage Encryption \nMessage Authentication Code \nHash Function \n2.6.1 Authentication Requirements \nIn the context of communications across a network, the following attacks can be identified: \n1. Disclosure: Release of message contents to any person or process not possessing the  \nappropriate cryptographic key. \n2. Traffic analysis: Discovery of the pattern of traffic between parties. In a connection-oriented  \napplication, the frequency and duration of connections could be determined. In either a  \nconnection-oriented or connectionless environment, the number and length of messages between  \nparties could be determined. \n3. Masquerade: Insertion of messages into the network from a fraudulent source. This includes", "chunk_id": "3bbdb5e0-f0d8-4066-80e6-1945ee04de96", "chroma:document": "application, the frequency and duration of connections could be determined. In either a  \nconnection-oriented or connectionless environment, the number and length of messages between  \nparties could be determined. \n3. Masquerade: Insertion of messages into the network from a fraudulent source. This includes"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "9473c890-a999-4d3a-b894-319f03047161", "chroma:document": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "74b106aa-a327-4100-a36c-8927c2adc45e", "chroma:document": "5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "205d3176-84e7-4632-b17d-d573660d6ceb", "chroma:document": "individual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "b88d8020-d49f-4e9c-bf55-49e445b82c08", "chroma:document": "Any message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "5923e112-396b-48fa-adc9-e8812ec5d2d2", "chroma:document": "authentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "fad19263-8a89-453c-8369-3bbbe4489408", "chroma:document": "produces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 65, "full_page_content": "66 \n \nthe creation of messages by an opponent that are purported to come from an authorized entity.  \nAlso included are fraudulent acknowledgments of message receipt or nonreceipt by someone  \nother than the message recipient. \n4. Content modification: Changes to the contents of a message, including insertion, deletion,  \ntransposition, and modification. \n5. Sequence modification: Any modification to a sequence of messages between parties,  \nincluding insertion, deletion, and reordering. \n6. Timing modification: Delay or replay of messages. In a connection-oriented application, an  \nentire session or sequence of messages could be a replay of some previous valid session, or  \nindividual messages in the sequence could be delayed or replayed. In a connectionless  \napplication, an individual message (e.g., datagram) could be delayed or replayed. \n7. Source repudiation: Denial of transmission of message by source. \n8. Destination repudiation: Denial of receipt of message by destination. \n2.6.2 Authentication Functions \nAny message authentication or digital signature mechanism has two levels of functionality. At the \nlower level, there must be some sort of function that produces an authenticator: a value to be used to \nauthenticate a message. This lower-level function is then used as a primitive in a higher-level \nauthentication protocol that enables a receiver to verify the authenticity of a message \nThe types of functions that may be used to produce an authenticator that are grouped into three \nclasses, as follows: \n\u25cf Message encryption: The ciphertext of the entire message serves as its authenticator \n\u25cf Message authentication code (MAC): A function of the message and a secret key that  \nproduces a fixed-length value that serves as the authenticator \n\u25cf Hash function: A function that maps a message of any length into a fixed-length hash \nvalue,  \nwhich serves as the authenticator \n2.6.2.1 Message Encryption \nMessage encryption by itself can provide a measure of authentication. The analysis differs for \nsymmetric and public-key encryption schemes. \n2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party", "chunk_id": "57a41bd1-0c16-464a-9b0d-edbc9e654dfb", "chroma:document": "2.6.2.1.1 Symmetric Encryption \nConsider the straightforward use of symmetric encryption (Figure 11.1a). A message M transmitted \nfrom source A to destination B is encrypted using a secret key K shared by A and B. If no other party"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: d103825f-e027-4bc2-b2ce-15ae88722270
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 66, "full_page_content": "67 \n \nknows the key, then confidentiality is provided: No other party can recover the plaintext of the \nmessage \n \nFigure 9 Basic Uses of Message Encryption \n \nIn addition, we may say that B is assured that the message was generated by A. The message must \nhave come from A because A is the only other party that possesses K and therefore the only other \nparty with the information necessary to construct ciphertext that can be decrypted with K. \nFurthermore, if M is recovered, B knows that none of the bits of M have been altered, because an \nopponent that does not know K would not know how to alter bits in the ciphertext to produce desired \nchanges in the plaintext. Symmetric encryption provides authentication as well as confidentiality.  \n2.6.2.1.2 Public-Key Encryption \nThe straightforward use of public-key encryption Figure 9b provides confidentiality but not \nauthentication. The source (A) uses the public key PUb of the destination (B) to encrypt M. Because \nonly B has the corresponding private key PRb , only B can decrypt the message. This scheme provides \nno authentication because any opponent could also use B's public key to encrypt a message, claiming \nto be A.", "chunk_id": "871be34c-5684-48bd-a65e-7dd77135fe48", "chroma:document": "67 \n \nknows the key, then confidentiality is provided: No other party can recover the plaintext of the \nmessage \n \nFigure 9 Basic Uses of Message Encryption \n \nIn addition, we may say that B is assured that the message was generated by A. The message must \nhave come from A because A is the only other party that possesses K and therefore the only other"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 66, "full_page_content": "67 \n \nknows the key, then confidentiality is provided: No other party can recover the plaintext of the \nmessage \n \nFigure 9 Basic Uses of Message Encryption \n \nIn addition, we may say that B is assured that the message was generated by A. The message must \nhave come from A because A is the only other party that possesses K and therefore the only other \nparty with the information necessary to construct ciphertext that can be decrypted with K. \nFurthermore, if M is recovered, B knows that none of the bits of M have been altered, because an \nopponent that does not know K would not know how to alter bits in the ciphertext to produce desired \nchanges in the plaintext. Symmetric encryption provides authentication as well as confidentiality.  \n2.6.2.1.2 Public-Key Encryption \nThe straightforward use of public-key encryption Figure 9b provides confidentiality but not \nauthentication. The source (A) uses the public key PUb of the destination (B) to encrypt M. Because \nonly B has the corresponding private key PRb , only B can decrypt the message. This scheme provides \nno authentication because any opponent could also use B's public key to encrypt a message, claiming \nto be A.", "chunk_id": "173664e7-8379-45ee-9ebd-8e70ba438d97", "chroma:document": "party with the information necessary to construct ciphertext that can be decrypted with K. \nFurthermore, if M is recovered, B knows that none of the bits of M have been altered, because an \nopponent that does not know K would not know how to alter bits in the ciphertext to produce desired"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 79c3691f-83d9-47c6-8427-7e1cbbb05188
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 66, "full_page_content": "67 \n \nknows the key, then confidentiality is provided: No other party can recover the plaintext of the \nmessage \n \nFigure 9 Basic Uses of Message Encryption \n \nIn addition, we may say that B is assured that the message was generated by A. The message must \nhave come from A because A is the only other party that possesses K and therefore the only other \nparty with the information necessary to construct ciphertext that can be decrypted with K. \nFurthermore, if M is recovered, B knows that none of the bits of M have been altered, because an \nopponent that does not know K would not know how to alter bits in the ciphertext to produce desired \nchanges in the plaintext. Symmetric encryption provides authentication as well as confidentiality.  \n2.6.2.1.2 Public-Key Encryption \nThe straightforward use of public-key encryption Figure 9b provides confidentiality but not \nauthentication. The source (A) uses the public key PUb of the destination (B) to encrypt M. Because \nonly B has the corresponding private key PRb , only B can decrypt the message. This scheme provides \nno authentication because any opponent could also use B's public key to encrypt a message, claiming \nto be A.", "chunk_id": "b980cff0-3552-4680-aa1d-c563d094ecdf", "chroma:document": "changes in the plaintext. Symmetric encryption provides authentication as well as confidentiality.  \n2.6.2.1.2 Public-Key Encryption \nThe straightforward use of public-key encryption Figure 9b provides confidentiality but not \nauthentication. The source (A) uses the public key PUb of the destination (B) to encrypt M. Because"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 0af39a66-77df-4f16-a5a4-3d716f639b58
encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 66, "full_page_content": "67 \n \nknows the key, then confidentiality is provided: No other party can recover the plaintext of the \nmessage \n \nFigure 9 Basic Uses of Message Encryption \n \nIn addition, we may say that B is assured that the message was generated by A. The message must \nhave come from A because A is the only other party that possesses K and therefore the only other \nparty with the information necessary to construct ciphertext that can be decrypted with K. \nFurthermore, if M is recovered, B knows that none of the bits of M have been altered, because an \nopponent that does not know K would not know how to alter bits in the ciphertext to produce desired \nchanges in the plaintext. Symmetric encryption provides authentication as well as confidentiality.  \n2.6.2.1.2 Public-Key Encryption \nThe straightforward use of public-key encryption Figure 9b provides confidentiality but not \nauthentication. The source (A) uses the public key PUb of the destination (B) to encrypt M. Because \nonly B has the corresponding private key PRb , only B can decrypt the message. This scheme provides \nno authentication because any opponent could also use B's public key to encrypt a message, claiming \nto be A.", "chunk_id": "054381bd-5de0-4783-b004-2ec6e58e1bf4", "chroma:document": "only B has the corresponding private key PRb , only B can decrypt the message. This scheme provides \nno authentication because any opponent could also use B's public key to encrypt a message, claiming \nto be A."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 8cc363f2-d1a4-4209-9403-e480f60ebade
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "26ad53e4-89dd-48c7-9098-1f5df30de2f8", "chroma:document": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: d23c6fc9-37f4-4300-b93a-9e1a3b11c421
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "ef2536ac-3c10-4ca5-9ae4-bd7a12f55bfa", "chroma:document": "possesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: b4220637-c755-4df8-a2f1-09f3e1559e6a
encoding: FLOAT32
metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "46c0285b-61c2-4eac-94ee-b17e50da7125", "chroma:document": "technique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 13a26aef-11c3-4da1-bd60-283a9b6c4274
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "8ef66512-68aa-4530-9cbc-b0e8f4dbffd4", "chroma:document": "The message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "fb81c61f-0b08-4f27-b1df-af0922cd21d6", "chroma:document": "sender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "0e6021fa-00c3-4861-ad1a-7bffa8654397", "chroma:document": "received MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: a31406a9-799b-4753-ba1f-ee2411ca17bc
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 67, "full_page_content": "68 \n \nTo provide authentication, A uses its private key to encrypt the message, and B uses A's public key \nto decrypt (Figure 9c). This provides authentication using the same type of reasoning as in the \nsymmetric encryption case: The message must have come from A because A is the only party that \npossesses PRa and therefore the only party with the information necessary to construct ciphertext that \ncan be decrypted with PUa.  \n2.6.2.2 Message Authentication Code \nAn alternative authentication technique involves the use of a secret key to generate a small fixed-size  \nblock of data, known as a cryptographic checksum or MAC that is appended to the message. This  \ntechnique assumes that two communicating parties, say A and B, share a common secret key K. When \nA has a message to send to B, it calculates the MAC as a function of the message and the key:MAC \n= C(K, M), where \nM = input message \nC = MAC function \nK = shared secret key \nMAC = message authentication code \nThe message plus MAC is transmitted to the intended recipient. The recipient performs the same  \ncalculation on the received message, using the same secret key, to generate a new MAC. The received  \nMAC is compared to the calculated MAC (Figure 10a). If we assume that only the receiver and the  \nsender know the identity of the secret key, and if the received MAC matches the calculated MAC, \nthen \n1. The receiver is assured that the message has not been altered. If an attacker alters the message  \nbut does not alter the MAC, then the receiver's calculation of the MAC will differ from the  \nreceived MAC. Because the attacker is assumed not to know the secret key, the attacker cannot  \nalter the MAC to correspond to the alterations in the message. \n2. The receiver is assured that the message is from the alleged sender. Because no one else knows  \nthe secret key, no one else could prepare a message with a proper MAC. \n3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number.", "chunk_id": "afcdc223-280a-4d06-b8ec-3d73df57e28c", "chroma:document": "3. If the message includes a sequence number, then the receiver can be assured of the proper sequence \nbecause an attacker cannot successfully alter the sequence number."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 68, "full_page_content": "69 \n \n \nFig :10 Basic Uses of Message Authentication Code (MAC) \n2.6.2.3 Hash Function \nA variation on the message authentication code is the one-way hash function. As with the message \nauthentication code, a hash function accepts a variable-size message M as input and produces a fixed \n-size output, referred to as a hash code H(M). Unlike a MAC, a hash code does not use a key but is a \nfunction only of the input message. The hash code is also referred to as a message digest or hash \nvalue. The hash code is a function of all the bits of the message and provides an error-detection \ncapability: A change to any bit or bits in the message results in a change to the hash code. \nFig 11 illustrates a variety of ways in which a hash code can be used to provide message \nauthentication, as follows", "chunk_id": "897c6a31-09f9-45d2-80b1-fbd4b9a06256", "chroma:document": "69 \n \n \nFig :10 Basic Uses of Message Authentication Code (MAC) \n2.6.2.3 Hash Function \nA variation on the message authentication code is the one-way hash function. As with the message \nauthentication code, a hash function accepts a variable-size message M as input and produces a fixed"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 68, "full_page_content": "69 \n \n \nFig :10 Basic Uses of Message Authentication Code (MAC) \n2.6.2.3 Hash Function \nA variation on the message authentication code is the one-way hash function. As with the message \nauthentication code, a hash function accepts a variable-size message M as input and produces a fixed \n-size output, referred to as a hash code H(M). Unlike a MAC, a hash code does not use a key but is a \nfunction only of the input message. The hash code is also referred to as a message digest or hash \nvalue. The hash code is a function of all the bits of the message and provides an error-detection \ncapability: A change to any bit or bits in the message results in a change to the hash code. \nFig 11 illustrates a variety of ways in which a hash code can be used to provide message \nauthentication, as follows", "chunk_id": "f7123d85-0e14-4311-9b1a-2f71186e2a32", "chroma:document": "-size output, referred to as a hash code H(M). Unlike a MAC, a hash code does not use a key but is a \nfunction only of the input message. The hash code is also referred to as a message digest or hash \nvalue. The hash code is a function of all the bits of the message and provides an error-detection"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: b86b4e14-d62e-4961-ad71-0082f244175e
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 68, "full_page_content": "69 \n \n \nFig :10 Basic Uses of Message Authentication Code (MAC) \n2.6.2.3 Hash Function \nA variation on the message authentication code is the one-way hash function. As with the message \nauthentication code, a hash function accepts a variable-size message M as input and produces a fixed \n-size output, referred to as a hash code H(M). Unlike a MAC, a hash code does not use a key but is a \nfunction only of the input message. The hash code is also referred to as a message digest or hash \nvalue. The hash code is a function of all the bits of the message and provides an error-detection \ncapability: A change to any bit or bits in the message results in a change to the hash code. \nFig 11 illustrates a variety of ways in which a hash code can be used to provide message \nauthentication, as follows", "chunk_id": "ff2ad38d-51f3-4f1a-9c37-47e24247f946", "chroma:document": "capability: A change to any bit or bits in the message results in a change to the hash code. \nFig 11 illustrates a variety of ways in which a hash code can be used to provide message \nauthentication, as follows"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 7960cf05-495c-47ad-8f26-9b0936ed9259
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 69, "full_page_content": "70 \n \n \nFigure 11. Basic Uses of Hash Function \na. The message plus concatenated hash code is encrypted using symmetric encryption. This is  \nidentical in structure to the internal error control strategy shown in Figure 11.2a. The same line  \nof reasoning applies: Because only A and B share the secret key, the message must have come  \nfrom A and has not been altered. The hash code provides the structure or redundancy required  \nto achieve authentication. Because encryption is applied to the entire message plus hash code,  \nconfidentiality is also provided. \nb. Only the hash code is encrypted, using symmetric encryption. This reduces the processing  \nburden for those applications that do not require confidentiality. \nc. Only the hash code is encrypted, using public-key encryption and using the sender's private key.  \nAs with (b), this provides authentication. It also provides a digital signature, because only the  \nsender could have produced the encrypted hash code. In fact, this is the essence of the digital  \nsignature technique. \nd. If confidentiality as well as a digital signature is desired, then the message plus the private-key \nencrypted hash code can be encrypted using a symmetric secret key. This is a common technique.", "chunk_id": "9aa67b3a-f7c6-4668-a8ac-fb59d2045ac0", "chroma:document": "70 \n \n \nFigure 11. Basic Uses of Hash Function \na. The message plus concatenated hash code is encrypted using symmetric encryption. This is  \nidentical in structure to the internal error control strategy shown in Figure 11.2a. The same line  \nof reasoning applies: Because only A and B share the secret key, the message must have come"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 69, "full_page_content": "70 \n \n \nFigure 11. Basic Uses of Hash Function \na. The message plus concatenated hash code is encrypted using symmetric encryption. This is  \nidentical in structure to the internal error control strategy shown in Figure 11.2a. The same line  \nof reasoning applies: Because only A and B share the secret key, the message must have come  \nfrom A and has not been altered. The hash code provides the structure or redundancy required  \nto achieve authentication. Because encryption is applied to the entire message plus hash code,  \nconfidentiality is also provided. \nb. Only the hash code is encrypted, using symmetric encryption. This reduces the processing  \nburden for those applications that do not require confidentiality. \nc. Only the hash code is encrypted, using public-key encryption and using the sender's private key.  \nAs with (b), this provides authentication. It also provides a digital signature, because only the  \nsender could have produced the encrypted hash code. In fact, this is the essence of the digital  \nsignature technique. \nd. If confidentiality as well as a digital signature is desired, then the message plus the private-key \nencrypted hash code can be encrypted using a symmetric secret key. This is a common technique.", "chunk_id": "91338468-12d2-4014-aea4-2bd6159777a5", "chroma:document": "from A and has not been altered. The hash code provides the structure or redundancy required  \nto achieve authentication. Because encryption is applied to the entire message plus hash code,  \nconfidentiality is also provided. \nb. Only the hash code is encrypted, using symmetric encryption. This reduces the processing"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 60d52ba1-051d-4c17-a79c-499e04b6e4ed
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metadata:
{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 69, "full_page_content": "70 \n \n \nFigure 11. Basic Uses of Hash Function \na. The message plus concatenated hash code is encrypted using symmetric encryption. This is  \nidentical in structure to the internal error control strategy shown in Figure 11.2a. The same line  \nof reasoning applies: Because only A and B share the secret key, the message must have come  \nfrom A and has not been altered. The hash code provides the structure or redundancy required  \nto achieve authentication. Because encryption is applied to the entire message plus hash code,  \nconfidentiality is also provided. \nb. Only the hash code is encrypted, using symmetric encryption. This reduces the processing  \nburden for those applications that do not require confidentiality. \nc. Only the hash code is encrypted, using public-key encryption and using the sender's private key.  \nAs with (b), this provides authentication. It also provides a digital signature, because only the  \nsender could have produced the encrypted hash code. In fact, this is the essence of the digital  \nsignature technique. \nd. If confidentiality as well as a digital signature is desired, then the message plus the private-key \nencrypted hash code can be encrypted using a symmetric secret key. This is a common technique.", "chunk_id": "4f7d7fa7-8159-4916-9645-4149b95212ee", "chroma:document": "burden for those applications that do not require confidentiality. \nc. Only the hash code is encrypted, using public-key encryption and using the sender's private key.  \nAs with (b), this provides authentication. It also provides a digital signature, because only the  \nsender could have produced the encrypted hash code. In fact, this is the essence of the digital"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: a95d800e-f545-4f82-9a8b-9e69cde7e0e1
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 69, "full_page_content": "70 \n \n \nFigure 11. Basic Uses of Hash Function \na. The message plus concatenated hash code is encrypted using symmetric encryption. This is  \nidentical in structure to the internal error control strategy shown in Figure 11.2a. The same line  \nof reasoning applies: Because only A and B share the secret key, the message must have come  \nfrom A and has not been altered. The hash code provides the structure or redundancy required  \nto achieve authentication. Because encryption is applied to the entire message plus hash code,  \nconfidentiality is also provided. \nb. Only the hash code is encrypted, using symmetric encryption. This reduces the processing  \nburden for those applications that do not require confidentiality. \nc. Only the hash code is encrypted, using public-key encryption and using the sender's private key.  \nAs with (b), this provides authentication. It also provides a digital signature, because only the  \nsender could have produced the encrypted hash code. In fact, this is the essence of the digital  \nsignature technique. \nd. If confidentiality as well as a digital signature is desired, then the message plus the private-key \nencrypted hash code can be encrypted using a symmetric secret key. This is a common technique.", "chunk_id": "8c5a3433-57ca-4bae-8b1f-be71143de3ef", "chroma:document": "signature technique. \nd. If confidentiality as well as a digital signature is desired, then the message plus the private-key \nencrypted hash code can be encrypted using a symmetric secret key. This is a common technique."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "67de7661-ac83-41a8-a612-7b452b6797ae", "chroma:document": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "97da4d2f-eada-4464-a4d5-fa24f4fd3202", "chroma:document": "Because B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "bcf44997-5958-4d37-a268-5eb68b428b5e", "chroma:document": "2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "9275397e-c4c3-440b-b773-e2601e181c76", "chroma:document": "The receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "7fd679a6-fd99-49d8-a450-24abb80b0b34", "chroma:document": "To be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "c9837086-3759-49f8-86fe-cc78479e39ad", "chroma:document": "4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 70, "full_page_content": "71 \n \ne. It is possible to use a hash function but no encryption for message authentication. The technique  \nassumes that the two communicating parties share a common secret value S. A compute the  \nhash value over the concatenation of M and S and appends the resulting hash value to M.  \nBecause B possesses S, it can recompute the hash value to verify. Because the secret value itself  \nis not sent, an opponent cannot modify an intercepted message and cannot generate a false  \nmessage. \nf. Confidentiality can be added to the approach of (e) by encrypting the entire message plus the  \nhash code. \n \n2.7 Hash Functions \nA hash value h is generated by a function H of the form \nh = H(M) \nwhere M is a variable-length message and H(M) is the fixed-length hash value. The hash value is  \nappended to the message at the source at a time when the message is assumed or known to be correct.  \nThe receiver authenticates that message by recomputing the hash value. Because the hash function  \nitself is not considered to be secret, some means is required to protect the hash value. \nRequirements for a Hash Function \nThe purpose of a hash function is to produce a \"fingerprint\" of a file, message, or other block of data. \nTo be useful for message authentication, a hash function H must have the following properties \n1. H can be applied to a block of data of any size. \n2. H produces a fixed-length output. \n3. H(x) is relatively easy to compute for any given x, making both hardware and software  \nimplementations practical. \n4. For any given value h, it is computationally infeasible to find x such that H(x) = h. This is  \nsometimes referred to in the literature as the one-way property. \n5. For any given block x, it is computationally infeasible to find y\u2260x such that H(y) = H(x). This  \nis sometimes referred to as weak collision resistance. \n6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a", "chunk_id": "8f90e9f7-f2b0-41c0-be2c-97ab5311c3f2", "chroma:document": "6. It is computationally infeasible to find any pair (x, y) such that H(x) = H(y). This is sometimes  \nreferred to as strong collision resistance. \nThe first three properties are requirements for the practical application of a hash function to message \nauthentication. The fourth property, the one-way property, states that it is easy to generate a code given a"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 71, "full_page_content": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack. \n2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be  \nexpressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash \nvalue is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit. \nb. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values.", "chunk_id": "649ee701-1c94-4967-909e-3ce0c8183d31", "chroma:document": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 130b42a3-2ab5-43c9-91a2-b96a11cf8bb9
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 71, "full_page_content": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack. \n2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be  \nexpressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash \nvalue is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit. \nb. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values.", "chunk_id": "1c81edeb-908c-42c0-8d55-eed722541072", "chroma:document": "2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 71, "full_page_content": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack. \n2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be  \nexpressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash \nvalue is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit. \nb. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values.", "chunk_id": "9e0ff982-5f59-4533-a622-a6306384ff1a", "chroma:document": "expressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 71, "full_page_content": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack. \n2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be  \nexpressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash \nvalue is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit. \nb. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values.", "chunk_id": "951fe66c-1a4e-4ee1-8ee5-9cc650b9e71c", "chroma:document": "value is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: d34c561b-942a-4eea-a9b4-2e8e6356426c
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 71, "full_page_content": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack. \n2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be  \nexpressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash \nvalue is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit. \nb. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values.", "chunk_id": "72b1b6c0-7788-44d1-8300-9b2a76cd4916", "chroma:document": "2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 15772293-2d06-478d-a8d2-83ea97b567c1
encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 71, "full_page_content": "72 \n \nmessage but virtually impossible to generate a message given a code. The fifth property guarantees that an \nalternative message hashing to the same value as a given message cannot be found. This prevents forgery \nwhen an encrypted hash code is used. The sixth property refers to how resistant the hash function is to a \ntype of attack known as the birthday attack. \n2.7.1 Simple Hash Functions \nAll hash functions operate using the following general principles. The input (message, file, etc.) is  \nviewed as a sequence of n-bit blocks. The input is processed one block at a time in an iterative fashion  \nto produce an n-bit hash function. \nOne of the simplest hash functions is the bit-by-bit exclusive-OR (XOR) of every block. This can be  \nexpressed as follows: \n \nThis operation produces a simple parity for each bit position and is known as a longitudinal \nredundancy check. It is reasonably effective for random data as a data integrity check. Each n-bit \nhash value is equally likely. Thus, the probability that a data error will result in an unchanged hash \nvalue is 2n. With more predictably formatted data, the function is less effective. For example, in most \nnormal text files, the high-order bit of each octet is always zero. So if a 128-bit hash value is used, \ninstead of an effectiveness of 2128, the hash function on this type of data has an effectiveness of \n2112. \nA simple way to improve matters is to perform a one-bit circular shift, or rotation, on the hash value  \nafter each block is processed. The procedure can be summarized as follows: \n1. Initially set the n-bit hash value to zero. \n2. Process each successive n-bit block of data as follows: \na. Rotate the current hash value to the left by one bit. \nb. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values.", "chunk_id": "e9084801-54c2-4eef-b697-b0a4f1be619a", "chroma:document": "b. XOR the block into the hash value. \nFig .12 illustrates these two types of hash functions for 16-bit hash values."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 087feedd-c7d9-4c91-8bb3-ad45e0ce1691
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 72, "full_page_content": "73 \n \n \nFig. 12 Two types of hash Functions \nAlthough the second procedure provides a good measure of data integrity, it is virtually useless for \ndata security when an encrypted hash code is used with a plaintext message, as in Figures 11.5b and \nc.  \nGiven a message, it is an easy matter to produce a new message that yields that hash code: Simply \nprepare the desired alternate message and then append an n-bit block that forces the new message \nplus block to yield the desired hash code. \nAlthough a simple XOR or rotated XOR (RXOR) is insufficient if only the hash code is encrypted, \nyou may still feel that such a simple function could be useful when the message as well as the hash \ncode are encrypted (Figure 11.5a). But you must be careful. A technique originally proposed by the \nNational Bureau of Standards used the simple XOR applied to 64-bit blocks of the message and then \nan encryption of the entire message that used the cipher block chaining (CBC) mode. We can define \nthe scheme as follows: Given a message consisting of a sequence of 64-bit blocks X1, X2,..., XN,", "chunk_id": "6987f7c4-b91c-4819-b36b-19c3e5b02b6d", "chroma:document": "73 \n \n \nFig. 12 Two types of hash Functions \nAlthough the second procedure provides a good measure of data integrity, it is virtually useless for \ndata security when an encrypted hash code is used with a plaintext message, as in Figures 11.5b and \nc.  \nGiven a message, it is an easy matter to produce a new message that yields that hash code: Simply"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 72, "full_page_content": "73 \n \n \nFig. 12 Two types of hash Functions \nAlthough the second procedure provides a good measure of data integrity, it is virtually useless for \ndata security when an encrypted hash code is used with a plaintext message, as in Figures 11.5b and \nc.  \nGiven a message, it is an easy matter to produce a new message that yields that hash code: Simply \nprepare the desired alternate message and then append an n-bit block that forces the new message \nplus block to yield the desired hash code. \nAlthough a simple XOR or rotated XOR (RXOR) is insufficient if only the hash code is encrypted, \nyou may still feel that such a simple function could be useful when the message as well as the hash \ncode are encrypted (Figure 11.5a). But you must be careful. A technique originally proposed by the \nNational Bureau of Standards used the simple XOR applied to 64-bit blocks of the message and then \nan encryption of the entire message that used the cipher block chaining (CBC) mode. We can define \nthe scheme as follows: Given a message consisting of a sequence of 64-bit blocks X1, X2,..., XN,", "chunk_id": "5db074ff-4fca-48fe-8e2e-963ee6816cd3", "chroma:document": "prepare the desired alternate message and then append an n-bit block that forces the new message \nplus block to yield the desired hash code. \nAlthough a simple XOR or rotated XOR (RXOR) is insufficient if only the hash code is encrypted, \nyou may still feel that such a simple function could be useful when the message as well as the hash"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 72, "full_page_content": "73 \n \n \nFig. 12 Two types of hash Functions \nAlthough the second procedure provides a good measure of data integrity, it is virtually useless for \ndata security when an encrypted hash code is used with a plaintext message, as in Figures 11.5b and \nc.  \nGiven a message, it is an easy matter to produce a new message that yields that hash code: Simply \nprepare the desired alternate message and then append an n-bit block that forces the new message \nplus block to yield the desired hash code. \nAlthough a simple XOR or rotated XOR (RXOR) is insufficient if only the hash code is encrypted, \nyou may still feel that such a simple function could be useful when the message as well as the hash \ncode are encrypted (Figure 11.5a). But you must be careful. A technique originally proposed by the \nNational Bureau of Standards used the simple XOR applied to 64-bit blocks of the message and then \nan encryption of the entire message that used the cipher block chaining (CBC) mode. We can define \nthe scheme as follows: Given a message consisting of a sequence of 64-bit blocks X1, X2,..., XN,", "chunk_id": "05ae577d-de92-4499-8f3c-288cf5e16b4e", "chroma:document": "code are encrypted (Figure 11.5a). But you must be careful. A technique originally proposed by the \nNational Bureau of Standards used the simple XOR applied to 64-bit blocks of the message and then \nan encryption of the entire message that used the cipher block chaining (CBC) mode. We can define"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: bbc4e1a7-5e48-4b2d-ba3c-50e42a5072de
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 72, "full_page_content": "73 \n \n \nFig. 12 Two types of hash Functions \nAlthough the second procedure provides a good measure of data integrity, it is virtually useless for \ndata security when an encrypted hash code is used with a plaintext message, as in Figures 11.5b and \nc.  \nGiven a message, it is an easy matter to produce a new message that yields that hash code: Simply \nprepare the desired alternate message and then append an n-bit block that forces the new message \nplus block to yield the desired hash code. \nAlthough a simple XOR or rotated XOR (RXOR) is insufficient if only the hash code is encrypted, \nyou may still feel that such a simple function could be useful when the message as well as the hash \ncode are encrypted (Figure 11.5a). But you must be careful. A technique originally proposed by the \nNational Bureau of Standards used the simple XOR applied to 64-bit blocks of the message and then \nan encryption of the entire message that used the cipher block chaining (CBC) mode. We can define \nthe scheme as follows: Given a message consisting of a sequence of 64-bit blocks X1, X2,..., XN,", "chunk_id": "b42a18f6-e278-4c0f-9903-313fe52ac940", "chroma:document": "the scheme as follows: Given a message consisting of a sequence of 64-bit blocks X1, X2,..., XN,"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 0e356af9-b002-4510-b8bb-5cb5c6d64fb4
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 73, "full_page_content": "74 \n \ndefine the hash code C as the block-by-block XOR of all blocks and append the hash code as the final \nblock: \n \nNext, encrypt the entire message plus hash code, using CBC mode to produce the encrypted message Y1, \nY2,..., YN+1. \n \n \nBecause the terms in the preceding equation can be XORed in any order, it follows that the hash code  \nwould not change if the ciphertext blocks were permuted. \n2.7.2 Birthday Attacks \nSuppose that a 64-bit hash code is used. One might think that this is quite secure. For example, if an \nencrypted hash code C is transmitted with the corresponding unencrypted message M, then an \nopponent would need to find an M' such that H(M') = H(M) to substitute another message and fool \nthe receiver. A different sort of attack is possible, based on the birthday paradox. \n1. The source, A, is prepared to \"sign\" a message by appending the appropriate m-bit hash code  \nand encrypting that hash code with A's private key. \n2. The opponent generates 2m/2 variations on the message, all of which convey essentially the  \nsame meaning. The opponent prepares an equal number of messages, all of which are variations  \non the fraudulent message to be substituted for the real one. \n3. The two sets of messages are compared to find a pair of messages that produces the same hash  \ncode. The probability of success, by the birthday paradox, is greater than 0.5. If no match is  \nfound, additional valid and fraudulent messages are generated until a match is made. \n4. The opponent offers the valid variation to A for signature. This signature can then be attached to", "chunk_id": "e9e9e775-af75-4e34-86d7-985aea2b8827", "chroma:document": "74 \n \ndefine the hash code C as the block-by-block XOR of all blocks and append the hash code as the final \nblock: \n \nNext, encrypt the entire message plus hash code, using CBC mode to produce the encrypted message Y1, \nY2,..., YN+1. \n \n \nBecause the terms in the preceding equation can be XORed in any order, it follows that the hash code"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 5e2787a1-2f12-4617-ab1b-b36b08d8a3b0
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 73, "full_page_content": "74 \n \ndefine the hash code C as the block-by-block XOR of all blocks and append the hash code as the final \nblock: \n \nNext, encrypt the entire message plus hash code, using CBC mode to produce the encrypted message Y1, \nY2,..., YN+1. \n \n \nBecause the terms in the preceding equation can be XORed in any order, it follows that the hash code  \nwould not change if the ciphertext blocks were permuted. \n2.7.2 Birthday Attacks \nSuppose that a 64-bit hash code is used. One might think that this is quite secure. For example, if an \nencrypted hash code C is transmitted with the corresponding unencrypted message M, then an \nopponent would need to find an M' such that H(M') = H(M) to substitute another message and fool \nthe receiver. A different sort of attack is possible, based on the birthday paradox. \n1. The source, A, is prepared to \"sign\" a message by appending the appropriate m-bit hash code  \nand encrypting that hash code with A's private key. \n2. The opponent generates 2m/2 variations on the message, all of which convey essentially the  \nsame meaning. The opponent prepares an equal number of messages, all of which are variations  \non the fraudulent message to be substituted for the real one. \n3. The two sets of messages are compared to find a pair of messages that produces the same hash  \ncode. The probability of success, by the birthday paradox, is greater than 0.5. If no match is  \nfound, additional valid and fraudulent messages are generated until a match is made. \n4. The opponent offers the valid variation to A for signature. This signature can then be attached to", "chunk_id": "711d253a-937f-4fa8-b198-287aeb1e23a5", "chroma:document": "would not change if the ciphertext blocks were permuted. \n2.7.2 Birthday Attacks \nSuppose that a 64-bit hash code is used. One might think that this is quite secure. For example, if an \nencrypted hash code C is transmitted with the corresponding unencrypted message M, then an \nopponent would need to find an M' such that H(M') = H(M) to substitute another message and fool"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 73, "full_page_content": "74 \n \ndefine the hash code C as the block-by-block XOR of all blocks and append the hash code as the final \nblock: \n \nNext, encrypt the entire message plus hash code, using CBC mode to produce the encrypted message Y1, \nY2,..., YN+1. \n \n \nBecause the terms in the preceding equation can be XORed in any order, it follows that the hash code  \nwould not change if the ciphertext blocks were permuted. \n2.7.2 Birthday Attacks \nSuppose that a 64-bit hash code is used. One might think that this is quite secure. For example, if an \nencrypted hash code C is transmitted with the corresponding unencrypted message M, then an \nopponent would need to find an M' such that H(M') = H(M) to substitute another message and fool \nthe receiver. A different sort of attack is possible, based on the birthday paradox. \n1. The source, A, is prepared to \"sign\" a message by appending the appropriate m-bit hash code  \nand encrypting that hash code with A's private key. \n2. The opponent generates 2m/2 variations on the message, all of which convey essentially the  \nsame meaning. The opponent prepares an equal number of messages, all of which are variations  \non the fraudulent message to be substituted for the real one. \n3. The two sets of messages are compared to find a pair of messages that produces the same hash  \ncode. The probability of success, by the birthday paradox, is greater than 0.5. If no match is  \nfound, additional valid and fraudulent messages are generated until a match is made. \n4. The opponent offers the valid variation to A for signature. This signature can then be attached to", "chunk_id": "54439510-a7df-453a-9bab-b1d81e090b0b", "chroma:document": "the receiver. A different sort of attack is possible, based on the birthday paradox. \n1. The source, A, is prepared to \"sign\" a message by appending the appropriate m-bit hash code  \nand encrypting that hash code with A's private key. \n2. The opponent generates 2m/2 variations on the message, all of which convey essentially the"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 73, "full_page_content": "74 \n \ndefine the hash code C as the block-by-block XOR of all blocks and append the hash code as the final \nblock: \n \nNext, encrypt the entire message plus hash code, using CBC mode to produce the encrypted message Y1, \nY2,..., YN+1. \n \n \nBecause the terms in the preceding equation can be XORed in any order, it follows that the hash code  \nwould not change if the ciphertext blocks were permuted. \n2.7.2 Birthday Attacks \nSuppose that a 64-bit hash code is used. One might think that this is quite secure. For example, if an \nencrypted hash code C is transmitted with the corresponding unencrypted message M, then an \nopponent would need to find an M' such that H(M') = H(M) to substitute another message and fool \nthe receiver. A different sort of attack is possible, based on the birthday paradox. \n1. The source, A, is prepared to \"sign\" a message by appending the appropriate m-bit hash code  \nand encrypting that hash code with A's private key. \n2. The opponent generates 2m/2 variations on the message, all of which convey essentially the  \nsame meaning. The opponent prepares an equal number of messages, all of which are variations  \non the fraudulent message to be substituted for the real one. \n3. The two sets of messages are compared to find a pair of messages that produces the same hash  \ncode. The probability of success, by the birthday paradox, is greater than 0.5. If no match is  \nfound, additional valid and fraudulent messages are generated until a match is made. \n4. The opponent offers the valid variation to A for signature. This signature can then be attached to", "chunk_id": "bba12ecd-4bf8-48c8-8a4a-898a66eaf2d5", "chroma:document": "same meaning. The opponent prepares an equal number of messages, all of which are variations  \non the fraudulent message to be substituted for the real one. \n3. The two sets of messages are compared to find a pair of messages that produces the same hash  \ncode. The probability of success, by the birthday paradox, is greater than 0.5. If no match is"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 73, "full_page_content": "74 \n \ndefine the hash code C as the block-by-block XOR of all blocks and append the hash code as the final \nblock: \n \nNext, encrypt the entire message plus hash code, using CBC mode to produce the encrypted message Y1, \nY2,..., YN+1. \n \n \nBecause the terms in the preceding equation can be XORed in any order, it follows that the hash code  \nwould not change if the ciphertext blocks were permuted. \n2.7.2 Birthday Attacks \nSuppose that a 64-bit hash code is used. One might think that this is quite secure. For example, if an \nencrypted hash code C is transmitted with the corresponding unencrypted message M, then an \nopponent would need to find an M' such that H(M') = H(M) to substitute another message and fool \nthe receiver. A different sort of attack is possible, based on the birthday paradox. \n1. The source, A, is prepared to \"sign\" a message by appending the appropriate m-bit hash code  \nand encrypting that hash code with A's private key. \n2. The opponent generates 2m/2 variations on the message, all of which convey essentially the  \nsame meaning. The opponent prepares an equal number of messages, all of which are variations  \non the fraudulent message to be substituted for the real one. \n3. The two sets of messages are compared to find a pair of messages that produces the same hash  \ncode. The probability of success, by the birthday paradox, is greater than 0.5. If no match is  \nfound, additional valid and fraudulent messages are generated until a match is made. \n4. The opponent offers the valid variation to A for signature. This signature can then be attached to", "chunk_id": "dec5c764-69a1-4727-ba0a-207cb562d0cb", "chroma:document": "found, additional valid and fraudulent messages are generated until a match is made. \n4. The opponent offers the valid variation to A for signature. This signature can then be attached to"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 74, "full_page_content": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques \nA number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday \nattack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E. \n5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However, \nit does not protect the two parties against each other. Several forms of dispute between the two are \npossible.", "chunk_id": "2079af98-6168-4426-b9c6-4d9fb53b6dbd", "chroma:document": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 74, "full_page_content": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques \nA number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday \nattack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E. \n5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However, \nit does not protect the two parties against each other. Several forms of dispute between the two are \npossible.", "chunk_id": "c2a170f5-2956-4381-afa9-95fc874de3af", "chroma:document": "A number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: e90a5df4-3c73-4448-9da7-de4748669d6d
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 74, "full_page_content": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques \nA number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday \nattack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E. \n5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However, \nit does not protect the two parties against each other. Several forms of dispute between the two are \npossible.", "chunk_id": "da673fc8-8918-4b47-ae2f-0d496dfa6def", "chroma:document": "attack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: c8e536f2-5f7d-4d0a-9881-7882ec68d9e7
encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 74, "full_page_content": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques \nA number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday \nattack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E. \n5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However, \nit does not protect the two parties against each other. Several forms of dispute between the two are \npossible.", "chunk_id": "0604f758-0cbe-4572-9744-8bf6fb1a6067", "chroma:document": "code G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: f3cf88d2-d455-4b8b-9aa9-349c2cab50ae
encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 74, "full_page_content": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques \nA number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday \nattack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E. \n5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However, \nit does not protect the two parties against each other. Several forms of dispute between the two are \npossible.", "chunk_id": "279eeaa9-d7b3-4882-bf51-11074d9b1da7", "chroma:document": "5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However,"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 74, "full_page_content": "75 \n \nthe fraudulent variation for transmission to the intended recipient. Because the two variations  \nhave the same hash code, they will produce the same signature; the opponent is assured of  \nsuccess even though the encryption key is not known. \n \nThus, if a 64-bit hash code is used, the level of effort required is only on the order of 232. \n2.7.3 Block Chaining Techniques \nA number of proposals have been made for hash functions based on using a cipher block chaining \ntechnique, but without the secret key. \nDivide a message M into fixed-size blocks M1, M2,..., MN and use a symmetric encryption system to \ncompute the hash code G as follows: \n \nThere is no secret key in this scheme. As with any hash code, this scheme is subject to the birthday \nattack, and if the encryption algorithm is DES and only a 64-bit hash code is produced, then the \nsystem is vulnerable. the opponent intercepts a message with a signature in the form of an encrypted \nhash code and that the unencrypted hash code is m bits long: \n1. Use the algorithm defined at the beginning of this subsection to calculate the unencrypted hash  \ncode G. \n2. Construct any desired message in the form Q1, Q2,..., QN2. \n3. Compute for Hi = E(Qi, Hi1) for 1 i (N 2). \n4. Generate 2m/2 random blocks; for each block X, compute E(X, HN2). Generate an additional 2m/2 \nrandom blocks; for each block Y, compute D(Y, G), where D is the decryption function  \ncorresponding to E. \n5. Based on the birthday paradox, with high probability there will be an X and Y such that E(X, HN2)  \n= D(Y, G). \n6. Form the message Q1, Q2,..., QN2, X, Y. This message has the hash code G and therefore can be \nused with the intercepted encrypted signature. \n2.8 Digital Signatures \nMessage authentication protects two parties who exchange messages from any third party. However, \nit does not protect the two parties against each other. Several forms of dispute between the two are \npossible.", "chunk_id": "2e2de8bd-35d2-44a0-bafb-c7a4ea3f87f7", "chroma:document": "it does not protect the two parties against each other. Several forms of dispute between the two are \npossible."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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encoding: FLOAT32
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "2cc074e4-1a32-42f1-b313-9d9949e6000a", "chroma:document": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 50b1e817-7d89-49eb-830d-c74410c1c655
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "0495b215-30be-4fb5-b6cf-66059dcf4bc8", "chroma:document": "2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "f9771255-c352-450d-a48a-22b654275226", "chroma:document": "digital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "b2ff01b3-7b45-40a3-949c-04d3bed5776f", "chroma:document": "On the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "99e09f7b-54f9-4693-9c56-5bacd584e296", "chroma:document": "\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "dbfba409-753e-45b3-89c1-0473b924fae2", "chroma:document": "A variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 75, "full_page_content": "76 \n \n2.8.1 Requirements \nFor example, suppose that John sends an authenticated message to Mary. Consider the following \ndisputes that could arise: \n1. Mary may forge a different message and claim that it came from John. Mary would simply have  \nto create a message and append an authentication code using the key that John and Mary share. \n2. John can deny sending the message. Because it is possible for Mary to forge a message, there is  \nno way to prove that John did in fact send the message. \nIn situations where there is not complete trust between sender and receiver, something more than \nauthentication is needed. The most attractive solution to this problem is the digital signature. The \ndigital signature is analogous to the handwritten signature. It must have the following properties: \n\u25cf It must verify the author and the date and time of the signature. \n\u25cf It must to authenticate the contents at the time of the signature. \n\u25cf It must be verifiable by third parties, to resolve disputes. \nThus, the digital signature function includes the authentication function. \nOn the basis of these properties, we can formulate the following requirements for a digital signature: \n\u25cf The signature must be a bit pattern that depends on the message being signed. \n\u25cf The signature must use some information unique to the sender, to prevent both forgery and  \ndenial. \n\u25cf It must be relatively easy to produce the digital signature. \n\u25cf It must be relatively easy to recognize and verify the digital signature. \n\u25cf It must be computationally infeasible to forge a digital signature, either by constructing a new  \nmessage for an existing digital signature or by constructing a fraudulent digital signature for a  \ngiven message. \n\u25cf It must be practical to retain a copy of the digital signature in storage. \nA variety of approaches has been proposed for the digital signature function. These approaches fall \ninto two categories: direct and arbitrated. \n1. Direct Digital Signature \n2. Arbitrated Digital Signature \n2.8.2 Direct Digital Signature \nThe direct digital signature involves only the communicating parties (source, destination). It is \nassumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key", "chunk_id": "54968ba0-7b3d-499d-889b-f38f4c5480d9", "chroma:document": "assumed that the destination knows the public key of the source. A digital signature may be formed \nby encrypting the entire message with the sender's private key or by encrypting a hash code of the \nmessage with the sender's private key"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "00d88541-a08d-4d40-81ce-c2e54c896487", "chroma:document": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: cd6b6d96-1416-4dd5-b155-fd10bb9c2e62
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "aafc7935-282a-4b63-b06a-ea0e26c07fd7", "chroma:document": "to deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "37442e22-6e97-4386-a478-b07c93feb76c", "chroma:document": "least to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "db81c41f-ddd5-493e-ba36-66a4e772dd76", "chroma:document": "2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "b24ba600-7d6b-4945-b26e-b4c709d62622", "chroma:document": "dated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "dd853351-a050-43e3-ace0-f8fe2226641c", "chroma:document": "secret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "0bf06a51-2197-44b9-a8ef-e51c8f18551e", "chroma:document": "the hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 76, "full_page_content": "77 \n \nConfidentiality can be provided by further encrypting the entire message plus signature with either \nthe receiver's public key (public-key encryption) or a shared secret key (symmetric encryption). \nThe validity of the scheme depends on the security of the sender's private key. If a sender later wishes \nto deny sending a particular message, the sender can claim that the private key was lost or stolen and \nthat someone else forged his or her signature. Administrative controls relating to the security of \nprivate keys can be employed to thwart or at least weaken this ploy, but the threat is still there, at \nleast to some degree. One example is to require every signed message to include a timestamp (date \nand time) and to require prompt reporting of compromised keys to a central authority. \nAnother threat is that some private key might actually be stolen from X at time T. The opponent can \nthen send a message signed with X's signature and stamped with a time before or equal to T. \n2.8.3 Arbitrated Digital Signature \nThe problems associated with direct digital signatures can be addressed by using an arbiter. \nEvery signed message from a sender X to a receiver Y goes first to an arbiter A, who subjects the \nmessage and its signature to a number of tests to check its origin and content. The message is then \ndated and sent to Y with an indication that it has been verified to the satisfaction of the arbiter. The \npresence of A solves the problem faced by direct signature schemes: that X might disown the \nmessage. \nIn the first, symmetric encryption is used. It is assumed that the sender X and the arbiter A share a \nsecret key Kxa and that A and Y share secret key Kay. X constructs a message M and computes its \nhash value H(M). Then X transmits the message plus a signature to A. The signature consists of an \nidentifier IDX of X plus the hash value, all encrypted using Kxa. A decrypts the signature and checks \nthe hash value to validate the message. Then A transmits a message to Y, encrypted with Kay. The \nmessage includes IDX, the original message from X, the signature, and a timestamp. Y can decrypt \nthis to recover the message and the signature. The timestamp informs Y that this message is timely \nand not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:", "chunk_id": "099d1a36-d7ce-4ebf-bbde-f2fe9a865bb8", "chroma:document": "and not a replay. Y can store M and the signature. In case of dispute, Y, who claims to have received \nM from X, sends the following message to A:"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: e664f92e-f0fc-4b96-8035-4af75003f3bd
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 77, "full_page_content": "78 \n \n \nTable 3. Arbitrated Digital Signature Techniques \nThe arbiter uses Kay to recover IDX, M, and the signature, and then uses Kxa to decrypt the signature \nand verify the hash code. In this scheme, Y cannot directly check X's signature; the signature is there \nsolely to settle disputes. Y considers the message from X authentic because it comes through A. In \nthis scenario, both sides must have a high degree of trust in A: \n\u25cf X must trust A not to reveal Kxa and not to generate false signatures of the form E(Kxa, [IDX||H \n(M)]). \n\u25cf Y must trust A to send E(Kay, [IDX||M||E(Kxa, [IDX||H(M)])||T]) only if the hash value is correct  \nand the signature was generated by X. \n\u25cf Both sides must trust A to resolve disputes fairly. \nIf the arbiter does live up to this trust, then X is assured that no one can forge his signature and Y is  \nassured that X cannot disavow his signature. \n2.9 Authentication Protocols \nTwo general areas involved in authentication protocol. \n1. Mutual authentication \n2. One-way authentication \n2.9.1 Mutual Authentication \nThis protocol enables communicating parties to satisfy themselves mutually about each other's \nidentity and to exchange session keys.", "chunk_id": "6964bd59-335a-4a6e-8dcf-7a9e9a6975cd", "chroma:document": "78 \n \n \nTable 3. Arbitrated Digital Signature Techniques \nThe arbiter uses Kay to recover IDX, M, and the signature, and then uses Kxa to decrypt the signature \nand verify the hash code. In this scheme, Y cannot directly check X's signature; the signature is there \nsolely to settle disputes. Y considers the message from X authentic because it comes through A. In"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 77, "full_page_content": "78 \n \n \nTable 3. Arbitrated Digital Signature Techniques \nThe arbiter uses Kay to recover IDX, M, and the signature, and then uses Kxa to decrypt the signature \nand verify the hash code. In this scheme, Y cannot directly check X's signature; the signature is there \nsolely to settle disputes. Y considers the message from X authentic because it comes through A. In \nthis scenario, both sides must have a high degree of trust in A: \n\u25cf X must trust A not to reveal Kxa and not to generate false signatures of the form E(Kxa, [IDX||H \n(M)]). \n\u25cf Y must trust A to send E(Kay, [IDX||M||E(Kxa, [IDX||H(M)])||T]) only if the hash value is correct  \nand the signature was generated by X. \n\u25cf Both sides must trust A to resolve disputes fairly. \nIf the arbiter does live up to this trust, then X is assured that no one can forge his signature and Y is  \nassured that X cannot disavow his signature. \n2.9 Authentication Protocols \nTwo general areas involved in authentication protocol. \n1. Mutual authentication \n2. One-way authentication \n2.9.1 Mutual Authentication \nThis protocol enables communicating parties to satisfy themselves mutually about each other's \nidentity and to exchange session keys.", "chunk_id": "2513adbb-e7c4-49a8-b772-f8efa8b4db5f", "chroma:document": "this scenario, both sides must have a high degree of trust in A: \n\u25cf X must trust A not to reveal Kxa and not to generate false signatures of the form E(Kxa, [IDX||H \n(M)]). \n\u25cf Y must trust A to send E(Kay, [IDX||M||E(Kxa, [IDX||H(M)])||T]) only if the hash value is correct  \nand the signature was generated by X. \n\u25cf Both sides must trust A to resolve disputes fairly."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 77, "full_page_content": "78 \n \n \nTable 3. Arbitrated Digital Signature Techniques \nThe arbiter uses Kay to recover IDX, M, and the signature, and then uses Kxa to decrypt the signature \nand verify the hash code. In this scheme, Y cannot directly check X's signature; the signature is there \nsolely to settle disputes. Y considers the message from X authentic because it comes through A. In \nthis scenario, both sides must have a high degree of trust in A: \n\u25cf X must trust A not to reveal Kxa and not to generate false signatures of the form E(Kxa, [IDX||H \n(M)]). \n\u25cf Y must trust A to send E(Kay, [IDX||M||E(Kxa, [IDX||H(M)])||T]) only if the hash value is correct  \nand the signature was generated by X. \n\u25cf Both sides must trust A to resolve disputes fairly. \nIf the arbiter does live up to this trust, then X is assured that no one can forge his signature and Y is  \nassured that X cannot disavow his signature. \n2.9 Authentication Protocols \nTwo general areas involved in authentication protocol. \n1. Mutual authentication \n2. One-way authentication \n2.9.1 Mutual Authentication \nThis protocol enables communicating parties to satisfy themselves mutually about each other's \nidentity and to exchange session keys.", "chunk_id": "f5e88ae9-3461-4d40-b6ca-02e3d2281933", "chroma:document": "If the arbiter does live up to this trust, then X is assured that no one can forge his signature and Y is  \nassured that X cannot disavow his signature. \n2.9 Authentication Protocols \nTwo general areas involved in authentication protocol. \n1. Mutual authentication \n2. One-way authentication \n2.9.1 Mutual Authentication"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 77, "full_page_content": "78 \n \n \nTable 3. Arbitrated Digital Signature Techniques \nThe arbiter uses Kay to recover IDX, M, and the signature, and then uses Kxa to decrypt the signature \nand verify the hash code. In this scheme, Y cannot directly check X's signature; the signature is there \nsolely to settle disputes. Y considers the message from X authentic because it comes through A. In \nthis scenario, both sides must have a high degree of trust in A: \n\u25cf X must trust A not to reveal Kxa and not to generate false signatures of the form E(Kxa, [IDX||H \n(M)]). \n\u25cf Y must trust A to send E(Kay, [IDX||M||E(Kxa, [IDX||H(M)])||T]) only if the hash value is correct  \nand the signature was generated by X. \n\u25cf Both sides must trust A to resolve disputes fairly. \nIf the arbiter does live up to this trust, then X is assured that no one can forge his signature and Y is  \nassured that X cannot disavow his signature. \n2.9 Authentication Protocols \nTwo general areas involved in authentication protocol. \n1. Mutual authentication \n2. One-way authentication \n2.9.1 Mutual Authentication \nThis protocol enables communicating parties to satisfy themselves mutually about each other's \nidentity and to exchange session keys.", "chunk_id": "d962358c-1ee8-4707-97ff-41beb5d0826b", "chroma:document": "This protocol enables communicating parties to satisfy themselves mutually about each other's \nidentity and to exchange session keys."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "c1d3d111-555e-4d35-a5a0-ce99ee78c671", "chroma:document": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "cbd9b955-a851-43ff-bdbb-4d09a46e8982", "chroma:document": "of secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "dc8fad45-2e86-4930-a473-199b5d2bf55d", "chroma:document": "replay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "bb034db5-6362-480a-a21a-7cd1f5d4c82b", "chroma:document": "could have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "0eaf7a06-58cc-47dd-8ccf-c74bfccb9b0f", "chroma:document": "One approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "4e2e2c2f-9212-4570-a8d5-e9b5b5b7a558", "chroma:document": "number for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "892e9ade-3ccb-4e41-ad39-2d1e3a3422a9", "chroma:document": "that, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "b5170f21-cb90-4e2a-ae7d-738fdd8bf4b4", "chroma:document": "nonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key,"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 78, "full_page_content": "79 \n \nCentral to the problem of authenticated key exchange are two issues: confidentiality and timeliness. \nTo prevent masquerade and to prevent compromise of session keys, essential identification and \nsession key information must be communicated in encrypted form. This requires the prior existence \nof secret or public keys that can be used for this purpose. The second issue, timeliness, is important \nbecause of the threat of message replays. Such replays, at worst, could allow an opponent to \ncompromise a session key or successfully impersonate another party. At minimum, a successful \nreplay can disrupt operations by presenting parties with messages that appear genuine but are not. \n\u2022 Simple replay: The opponent simply copies a message and replays it later. \n\u25cf Repetition that can be logged: An opponent can replay a timestamped message within the  \nvalid time window. \n\u25cf Repetition that cannot be detected: This situation could arise because the original message  \ncould have been suppressed and thus did not arrive at its destination; only the replay message  \narrives. \n\u25cf Backward replay without modification: This is a replay back to the message sender. This  \nattack is possible if symmetric encryption is used and the sender cannot easily recognize the  \ndifference between messages sent and messages received on the basis of content. \nOne approach to coping with replay attacks is to attach a sequence number to each message used in \nan authentication exchange. A new message is accepted only if its sequence number is in the proper \norder. The difficulty with this approach is that it requires each party to keep track of the last sequence \nnumber for each claimant it has dealt with. Because of this overhead, sequence numbers are generally \nnot used for authentication and key exchange. Instead, one of the following two general approaches \nis used: \n\u25cf Timestamps: Party A accepts a message as fresh only if the message contains a timestamp  \nthat, in A's judgment, is close enough to A's knowledge of current time. This approach requires  \nthat clocks among the various participants be synchronized. \n\u25cf Challenge/response: Party A, expecting a fresh message from B, first sends B a nonce  \n(challenge) and requires that the subsequent message (response) received from B contain the correct \nnonce value. \nTwo-level hierarchy of symmetric encryption keys can be used to provide confidentiality for \ncommunication in a distributed environment. In general, this strategy involves the use of a trusted \nkey distribution center (KDC). Each party in the network shares a secret key, known as a master key, \nwith the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:", "chunk_id": "8d1014cd-82ce-420b-ba76-fa5a58b0c113", "chroma:document": "with the KDC. The KDC is responsible for generating keys to be used for a short time over a \nconnection between two parties, known as session keys, and for distributing those keys using the \nmaster keys to protect the distribution.  \n Needham and Schroeder protocol can be summarized as follows:"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: 0531d34b-f49f-4c83-9e08-4a5e8c8cf8ca
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 79, "full_page_content": "80 \n \n \n \nSecret keys Ka and Kb are shared between A and the KDC and B and the KDC, respectively. The \npurpose of the protocol is to distribute securely a session key Ks to A and B. A securely acquires a \nnew session key in step 2. The message in step 3 can be decrypted, and hence understood, only by B. \nStep 4 reflects B's knowledge of Ks, and step 5 assures B of A's knowledge of Ks and assures B that \nthis is a fresh message because of the use of the nonce N2. The purpose of steps 4 and 5 is to prevent \na certain type of replay attack. \nDenning proposes to overcome this weakness by a modification to the Needham/Schroeder protocol \nthat includes the addition of a timestamp to steps 2 and 3. Her proposal assumes that the master keys, \nKa and Kb are secure, and it consists of the following steps:", "chunk_id": "7a5231a0-a3d7-4879-a22d-46f84c7225ec", "chroma:document": "80 \n \n \n \nSecret keys Ka and Kb are shared between A and the KDC and B and the KDC, respectively. The \npurpose of the protocol is to distribute securely a session key Ks to A and B. A securely acquires a \nnew session key in step 2. The message in step 3 can be decrypted, and hence understood, only by B."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
id: b74cdfe0-123c-410d-8875-fb1cab16ca96
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 79, "full_page_content": "80 \n \n \n \nSecret keys Ka and Kb are shared between A and the KDC and B and the KDC, respectively. The \npurpose of the protocol is to distribute securely a session key Ks to A and B. A securely acquires a \nnew session key in step 2. The message in step 3 can be decrypted, and hence understood, only by B. \nStep 4 reflects B's knowledge of Ks, and step 5 assures B of A's knowledge of Ks and assures B that \nthis is a fresh message because of the use of the nonce N2. The purpose of steps 4 and 5 is to prevent \na certain type of replay attack. \nDenning proposes to overcome this weakness by a modification to the Needham/Schroeder protocol \nthat includes the addition of a timestamp to steps 2 and 3. Her proposal assumes that the master keys, \nKa and Kb are secure, and it consists of the following steps:", "chunk_id": "beadf1f3-016e-4800-bfc7-a932dbd793e8", "chroma:document": "Step 4 reflects B's knowledge of Ks, and step 5 assures B of A's knowledge of Ks and assures B that \nthis is a fresh message because of the use of the nonce N2. The purpose of steps 4 and 5 is to prevent \na certain type of replay attack. \nDenning proposes to overcome this weakness by a modification to the Needham/Schroeder protocol"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 79, "full_page_content": "80 \n \n \n \nSecret keys Ka and Kb are shared between A and the KDC and B and the KDC, respectively. The \npurpose of the protocol is to distribute securely a session key Ks to A and B. A securely acquires a \nnew session key in step 2. The message in step 3 can be decrypted, and hence understood, only by B. \nStep 4 reflects B's knowledge of Ks, and step 5 assures B of A's knowledge of Ks and assures B that \nthis is a fresh message because of the use of the nonce N2. The purpose of steps 4 and 5 is to prevent \na certain type of replay attack. \nDenning proposes to overcome this weakness by a modification to the Needham/Schroeder protocol \nthat includes the addition of a timestamp to steps 2 and 3. Her proposal assumes that the master keys, \nKa and Kb are secure, and it consists of the following steps:", "chunk_id": "6eccb728-f8e7-49ce-adc6-5b90bcd9f5a6", "chroma:document": "that includes the addition of a timestamp to steps 2 and 3. Her proposal assumes that the master keys, \nKa and Kb are secure, and it consists of the following steps:"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "ea2b673d-3cdd-4249-b79e-58d08698762b", "chroma:document": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "ac323d13-4e4c-416f-b5cd-fc7d95bc1902", "chroma:document": "B) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely."}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "5dd8d573-1c2d-4597-a497-ea88958b5724", "chroma:document": "by B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "3a6cc0ed-dcd9-4f8a-9716-b1a531cf6d22", "chroma:document": "vulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "ddfc074a-e5db-496a-8571-b97e24d31ef5", "chroma:document": "identifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,"}


created_at: 2025-01-28 05:36:03
topic: persistent://default/default/a5c4f461-3901-4175-9ce9-937730884692
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "a4d66583-80d6-4183-b183-e3e710ad989f", "chroma:document": "assuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "1966d21b-da20-4b9b-9df0-2d13bfffdcc0", "chroma:document": "The KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 80, "full_page_content": "81 \n \nT is a timestamp that assures A and B that the session key has only just been generated. Thus, both \nA and B know that the key distribution is a fresh exchange. A and B can verify timeliness by checking \nthat \n \nwhere \u2206t1 is the estimated normal discrepancy between the KDC's clock and the local clock (at A or \nB) and \u2206t2 is the expected network delay time. Each node can set its clock against some standard \nreference source. Because the timestamp T is encrypted using the secure master keys, an opponent, \neven with knowledge of an old session key, cannot succeed because a replay of step 3 will be detected \nby B as untimely. \nOne way to counter suppress-replay attacks is to enforce the requirement that parties regularly check \ntheir clocks against the KDC's clock. The other alternative, which avoids the need for clock \nsynchronization, is to rely on handshaking protocols using nonces. This latter alternative is not \nvulnerable to a suppress-replay attack because the nonces the recipient will choose in the future are \nunpredictable to the sender. \nan improved strategy was presented in \n \nLet us follow this exchange step by step. \n1. A initiates the authentication exchange by generating a nonce, Na, and sending that plus its  \nidentifier to B in plaintext. This nonce will be returned to A in an encrypted message that includes  \nthe session key, assuring A of its timeliness.  \n2. B alerts the KDC that a session key is needed. Its message to the KDC includes its identifier and a  \nnonce, Nb This nonce will be returned to B in an encrypted message that includes the session key,  \nassuring B of its timeliness. B's message to the KDC also includes a block encrypted with the  \nsecret key shared by B and the KDC. This block is used to instruct the KDC to issue credentials to  \nA; the block specifies the intended recipient of the credentials, a suggested expiration time for the  \ncredentials, and the nonce received from A. \nThe KDC passes on to A B's nonce and a block encrypted with the secret key that B shares with  \nthe KDC. The block serves as a \"ticket\" that can be used by A for subsequent authentications, as  \nwill be seen. The KDC also sends to A a block encrypted with the secret key shared by A and the  \nKDC. This block verifies that B has received A's initial message (IDB) and that this is a timely", "chunk_id": "478f3bf8-d455-4eb4-88f0-208e732012a6", "chroma:document": "KDC. This block verifies that B has received A's initial message (IDB) and that this is a timely"}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 81, "full_page_content": "82 \n \nmessage and not a replay (Na) and it provides A with a session key (Ks) and the time limit on its  \nuse (Tb).  \n4. A transmits the ticket to B, together with the B's nonce, the latter encrypted with the session key.  \nThe ticket provides B with the secret key that is used to decrypt E(Ks, Nb) to recover the nonce.  \nThe fact that B's nonce is encrypted with the session key authenticates that the message came  \nfrom A and is not a replay. \nThis protocol provides an effective, secure means for A and B to establish a session with a secure  \nsession key.  Furthermore, the protocol leaves A in possession of a key that can be used for subsequent \nauthentication to B, avoiding the need to contact the authentication server repeatedly. Suppose that \nA and B establish a session using the aforementioned protocol and then conclude that session. \nSubsequently, but within the time limit established by the protocol, A desires a new session with B. \nThe following protocol ensues: \n \nWhen B receives the message in step 1, it verifies that the ticket has not expired. The newly generated  \nnonces N'a and N'b assure each party that there is no replay attack. \n2.9.2 One-Way Authentication \nWith some refinement, the KDC strategy is a candidate for encrypted electronic mail.  \nBecause we wish to avoid requiring that the recipient (B) be on line at the same time as the sender \n(A), steps 4 and 5 must be eliminated. \n For a message with content M, the sequence is as follows: \n \nThis approach guarantees that only the intended recipient of a message will be able to read it. \n It also provides a level of authentication that the sender is A. \nReferences: \n\u2022 William Stallings, \u201c Cryptography and Network Security\u201d, 4th Edition, Pearson, 2009. \n\u2022 Behrouz A. Forouzan, \u201c Cryptography and Network Security\u201d, Tata McGraw-Hill, 2008.", "chunk_id": "abd001e8-8e68-43ab-ace9-6b0d70acaaf6", "chroma:document": "82 \n \nmessage and not a replay (Na) and it provides A with a session key (Ks) and the time limit on its  \nuse (Tb).  \n4. A transmits the ticket to B, together with the B's nonce, the latter encrypted with the session key.  \nThe ticket provides B with the secret key that is used to decrypt E(Ks, Nb) to recover the nonce."}


created_at: 2025-01-28 05:36:03
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{"producer": "Microsoft\u00ae Word 2019", "creator": "Microsoft\u00ae Word 2019", "creationdate": "2022-02-08T09:25:32+05:30", "source": "data/SITA1602.pdf", "file_path": "data/SITA1602.pdf", "total_pages": 165, "format": "PDF 1.7", "title": "", "author": "Jabez J", "subject": "", "keywords": "", "moddate": "2022-02-08T09:25:32+05:30", "trapped": "", "page": 81, "full_page_content": "82 \n \nmessage and not a replay (Na) and it provides A with a session key (Ks) and the time limit on its  \nuse (Tb).  \n4. A transmits the ticket to B, together with the B's nonce, the latter encrypted with the session key.  \nThe ticket provides B with the secret key that is used to decrypt E(Ks, Nb) to recover the nonce.  \nThe fact that B's nonce is encrypted with the session key authenticates that the message came  \nfrom A and is not a replay. \nThis protocol provides an effective, secure means for A and B to establish a session with a secure  \nsession key.  Furthermore, the protocol leaves A in possession of a key that can be used for subsequent \nauthentication to B, avoiding the need to contact the authentication server repeatedly. Suppose that \nA and B establish a session using the aforementioned protocol and then conclude that session. \nSubsequently, but within the time limit established by the protocol, A desires a new session with B. \nThe following protocol ensues: \n \nWhen B receives the message in step 1, it verifies that the ticket has not expired. The newly generated  \nnonces N'a and N'b assure each party that there is no replay attack. \n2.9.2 One-Way Authentication \nWith some refinement, the KDC strategy is a candidate for encrypted electronic mail.  \nBecause we wish to avoid requiring that the recipient (B) be on line at the same time as the sender \n(A), steps 4 and 5 must be eliminated. \n For a message with content M, the sequence is as follows: \n \nThis approach guarantees that only the intended recipient of a message will be able to read it. \n It also provides a level of authentication that the sender is A. \nReferences: \n\u2022 William Stallings, \u201c Cryptography and Network Security\u201d, 4th Edition, Pearson, 2009. \n\u2022 Behrouz A. Forouzan, \u201c Cryptography and Network Security\u201d, Tata McGraw-Hill, 2008.", "chunk_id": "60f13949-403c-4a8d-b937-f27dc22eea8d", "chroma:document": "The fact that B's nonce is encrypted with the session key authenticates that the message came  \nfrom A and is not a replay. \nThis protocol provides an effective, secure means for A and B to establish a session with a secure  \nsession key.  Furthermore, the protocol leaves A in possession of a key that can be used for subsequent"}


