in modern computing era , health is an important aspect for society since 
 it involves every citizen .
the current health care system is designed to reward 
 medical doctors and medical institutions to treat people when they are sick , 
 and not acting proactively thus preventing them from being sick .
recently , in 
 many countries the health care system is subject to reform since the rapidly 
 growing populations of elderly combined with the increasing cost of health care 
 services impose several challenges on health care providers , 
 insurance companies , hospitals , and even on patients .
all these suggest that 
 first of all healthcare needs a major shift toward a more proactive direction 
 focusing on prevention and/or early detection of acute events and afterwards 
 more scalable and more affordable solutions should be offered .
therefore , all 
 the above - mentioned requirements have accentuated the need for pervasive and 
 ubiquitous embedded e - health environments , given that limited financial and 
 human resources will be committed .
the modern backbone communication infrastructures , networks , and 
 technologies like gsm , umts , wcdma , wimax , internet , wireless , and bluetooth 
 protocols provide extraordinary high data rates , thus allowing cost - efficient 
 and time - efficient remote delivering of medical data that have been collected 
 from the portable , embedded devices that reside onto the end - users ( monitored 
 patients ) toward remote medical servers , for further processing .
furthermore , 
 the pervasiveness and ubiquitous character of modern user - centric nomadic 
 environments , in which the user is the central point surrounded by different 
 types of embedded and small computing devices , like , for example , electrocardiograph 
 ( ecg ) and pulse , oxygen saturation , and blood pressure sensors , add extra 
 requirements concerning security aspects such as the protection of sensitive 
 medical data and measurements , data integrity and confidentiality , and 
 protection of patients privacy . in such environments , it is imperative to 
 design and deploy efficient and effective network architectures as well as a 
 generic , if possible , communication interface targeted to connect the external 
 networks with the  smart  individual - person ( equipped with different types of 
  smart  embedded medical devices ( emds ) ) satisfying the basic security 
 requirements for real - time , secure data communication , and protection of 
 sensitive medical data and measurements , data integrity and confidentiality , 
 and protection of the monitored patient 's privacy . the architectures and
the interface 
 must consider the limited resources of the interconnected embedded systems , 
 especially in light of the significant resources required for implementing 
 security , which , in 
 general , are quite resource - hungry leading thus to significant technical problems .
mpeg-21 is a standard that defines mechanisms and tools as means of 
 sharing digital rights , permissions , and restrictions for digital content from 
 content creator to content consumer .
it is an xml - based standard that is 
 designed to communicate machine - readable license information in an ubiquitous , 
 unambiguous , and secure manner between peer entities .
although mpeg-21 is a 
 standard that is used for sharing multimedia digital content , under well - defined 
 terms , we argue that it could be used for protection of medical data and user 's 
 privacy in a pervasive healthcare environment , assuming that the digital 
 content is the medical data generated by the emds . the content creator is any 
  user  under monitoring and the  end - user  is anyone having access to a   remote medical server located in a hospital 
 either being supervisors , trained medical stuff , or doctors . in our work , we propose a generic security framework based on the 
 mpeg-21 standard adopted for wearable emds thus filling an existing gap which 
 made these devices and the data acquired by them vulnerable to any kind of 
 attacks .
although the mpeg-21 standard has been adopted for delivery of 
 multimedia content , we argue that it can be used in our architecture in order 
 to enhance users ' privacy and to enhance security requirements that are applied in such 
 environments .
moreover , since the medical measurements that taken from 
 patients ' emds can include different data types , besides raw data , like , for 
 example , a snapshot of electrocardiograph data in a jpeg file , or a video file 
 of electrocardiograph data , the mpeg-21 standard can help us in content 
 delivery , with security enhancement toward different types of end - users .
our 
 endeavor demonstrates that no general - purpose home server is required for 
 processing medical data before sent toward end - users , that is , doctors , medical 
 staff , thus making the proposed architecture a good candidate for portable 
 devices in pervasive healthcare environments exposing limited resources .
we strongly believe that the outcome of this work contributes toward the 
 establishment of a standard context - aware security environment in which parts 
 of sensitive personal information can be viewed only by valid users even though 
 many users can have access to them .
the main characteristics of our approach , 
 which directly affects medical safety and treatment efficacy , comprise 
 standardization , minimalizm , and sophistication .
ultimately , affects reduction of 
 total health care cost , thus leading to a better utilization of limited 
 healthcare resources .
more specifically , section 2 gives a presentation of the relevant work , 
 while section 3 analyzes the emerging of emds security requirements in combination with 
 mpeg-21 standard .
section 4 describes our proposed architecture and section 5 
 provides the conclusions and the future work projection .
gialelis et al .   propose a pervasive healthcare architecture into 
 which a wearable health monitoring system is integrated into a broad 
 telemedical infrastructure allowing high - risk cardiovascular patients to 
 closely monitor changes in their critical vital signs and get experts feedback 
 to help maintain optimal health status .
consistent with the major challenge to 
 provide good quality and reliable health care services to an increasing number 
 of people utilizing limited financial and human resources , they propose a 
 person - based health care system which consists of wearable commercial 
 of - the - shelf nodes which are already used in the hospital environment ,   and they are capable of sensing and processing 
 blood - oxygen , blood - pressure , ecgs , and other vital signs and can be seamlessly 
 integrated into wireless personal area networks ( wpans ) for ubiquitous real - time 
 patient monitoring .
their architecture lacks safety , security , and privacy 
 considerations , which may lead to serious breaches to architecture 's and emds functionalities 
 or to users ' privacy .
venkatasubramanian and gupta   made a survey 
 on security solutions for pervasive healthcare environments focusing on 
 securing of data collected by emds , securing the communications between emds 
 and investigation of mechanisms for controlling the access to medical data . 

they propose the use of cryptographic primitives , where measurements of 
 physiological values are used for cryptographic keys , eliminating thus the 
 necessity for key distribution , for securing data , and for the establishment of 
 secure communications between two entities .
concerning the access control to 
 medical data , they survey methods that are based on role - based access control 
 ( rbac ) , extending it for usage in pervasive healthcare environments . as far as we know
, the only proposal for usage of mpeg-21 as a mechanism 
 to access control to medical records has been proposed by brox .
the author 
 links patients records into mpeg-21 digital items and attempts to find access 
 control mechanisms based on mpeg-21 standard . in this work
, the author does not 
 provide a clear architecture that implements the usage of mpeg-21 and also he 
 does not use the mpeg-21 intellectual property management and protection ( ipmp ) 
 components for the protection of medical records , but he mentions its use as a 
 future and open research issue .
the primary function of a pervasive healthcare architecture is to 
 collect , to process , and to store medical data from different types of emds , 
 which are located on the patient , locally into general - purpose computing 
 devices  for further 
 handling or to remote - located servers . in order to identify the security 
 mechanisms that should be deployed into the proposed architecture for pervasive 
 healthcare with the utilization of emds
, we must identify and classify ( i ) 
 possible attackers and malicious users of the aforementioned environment ; ( ii ) 
 safety , security , and privacy requirements .
provide a short classification of possible malicious 
 users and adversaries in a pervasive healthcare environment , identifying 
 active adversaries which are malicious users that have explicit 
 interference and physical access to an emd ( i.e. , launching probing attacks , 
 tampering attacks),passive adversaries which are malicious users that have implicit 
 interference with an emd , through eavesdropping the communication link between 
 an emd and another system or through side - channel attacks , insiders which comprise the most probable adversaries in 
 such environments .
such attackers include healthcare personnel , nurses , 
 doctors , it professionals , and even the patients themselves . 

security is a general requirement in modern computing environments , but 
 in pervasive healthcare systems security is an imperative requirement because 
 those systems handle very sensitive data like medical data and electronic personal 
 records ( eprs ) . in order to identify the security aspects and requirements in 
 such environments
, we have to identify the threat model ; some of the most 
 significant threats for pervasive healthcare environments are ( a ) nonauthorized access to patient 's medical 
 data , that is , a nurse and a doctor must have different authorities and 
 access control to medical data ; ( b ) intentional 
 alteration of medical data , thus leading to incorrect diagnosis and 
 patient 's treatment ; ( c ) disclosure of 
 medical data to third parties ( e.g. , to insurance companies or any third 
 parties that may use such records to gain profit ) , aiming to increase their 
 revenue . in their work , halperin et al . , also , describe a generic framework 
 for analysis , design , and evaluation of security and privacy issues in 
 implantable medical devices ( imds ) .
although our architecture does not contain 
 any type of imds , a subset of the security and safety goals that they describe 
 in their work applies to us , also .
they identify two directions , one concerning 
 safety and utilization goals and the other concerning security and privacy 
 goals , and furthermore they are trying to find tradeoffs and tensions between 
 those directions .
safety and utility goals are traditional requirements in 
 pervasive healthcare systems , involving some security aspects .
such goals are ( a ) accessibility to medical data , that 
 is , ensuring that only appropriate entities must have access to emds and their 
 medical data ; ( b ) accuracy of 
 measurements and data , that is , all data and measurements taken from the 
 emd must be accurate ; ( c ) traceability 
 and identification of emds , that is , an emd must have mechanisms that allow 
 it to make its presence clear to authorized entities , whenever it is necessary ; 
 ( d ) maintenance and reconfigurability , 
 that is , authorized personnel may alter emds configuration , locally or 
 remotely ; finally , ( e ) resources efficiency , 
 that is , extend emds battery life , through minimization of power consumption . 
 besides safety and utility goals , due to their nature , the modern pervasive 
 healthcare environments have also to fulfill some security- and privacy - related 
 goals and requirements .
those goals are not different from traditional security requirements 
 of computing systems that basically rely on the attainment of authentication 
 and authorization , data confidentiality , data integrity , availability and 
 protection of users ' privacy , and have to be extended and possibly reviewed in 
 the context of pervasive healthcare environments . authentication . refers to methods and mechanisms which allow 
 to an entity to prove to a remote end its identity , that is , in a transaction 
 between two end - users over a possibly unsafe communication network , there must 
 be mechanisms that assure that each part can be authenticated by a remote end .
authorization , refers to access 
 control mechanisms and to the ability of an entity to access shared resources . 

two basic subcategories of authorization can be distinguished ( a ) personal authorization , that is , 
 specific people or groups of people may access patients ' data and perform 
 specific action over it ; ( b ) role - based 
 authorization , that is , a person may have access to medical data based on a 
 specific role that he has , for example , a doctor , a nurse , a caregiver .
mechanisms ensure 
 that when there is an interchange of data between two peer entities , the 
 received data and the original ones are the same , and that no intermediate 
 alteration has occurred , for example , through interference of an eavesdropper . 
 in a typical pervasive healthcare system
, various messages and data are 
 interchanged between different participating entities , so the integrity of the 
 transmitted messages and data is a basic requirement .
data confidentiality , it assures that 
 stored or transmitted data are well protected from possible disclosure .
it is a security 
 requirement which implies that a malicious user may not be able to passively or 
 actively perform a denial - of - service attack to an emd , for example , battery 
 attack , memory overflow , jam the communication interface , thus preventing 
 it from operating normal and smoothly .
privacy , it can be defined as an entity 's ability to control 
 how , when , and to what extent personal information about the entity will be 
 communicated to third parties .
anderson 
   defines privacy as the secrecy for the benefit of an individual entity , 
 where secrecy refers to generic mechanisms that do not allow unauthorized usage 
 and access of data and resources . extending privacy in the context of pervasive 
 healthcare environments
, we refer to ( i ) emd - existence 
 and emd - type privacy , that is , an emd should not make its presence and its 
 type clear to an unauthorized party , since the user ( patient ) might not want to 
 know nonauthorized users what type of emd they carry with them and what type of 
 functions it serves .
active adversaries which are malicious users that have explicit 
 interference and physical access to an emd ( i.e. , launching probing attacks , 
 tampering attacks ) , passive adversaries which are malicious users that have implicit 
 interference with an emd , through eavesdropping the communication link between 
 an emd and another system or through side - channel attacks , insiders which comprise the most probable adversaries in 
 such environments .
such attackers include healthcare personnel , nurses , 
 doctors , it professionals , and even the patients themselves .
our proposed architecture addresses authentication and authorization 
 issues , since each user has a license that defines what he / she has access to .
moreover , 
 data confidentiality is achieved through cryptographic mechanisms , that is , 
 sensitive data are encrypted and data integrity is achieved transparently by 
 the doctor 's devices that have access to the data .
finally , the utilization of 
 a drm mechanism through the mpeg-21 framework helps in the protection of user 's 
 privacy , that is , different groups of users have access to different types of 
 medical data .
mpeg-21 is a new standard which has been proposed for primary use in the 
 context of multimedia world , allowing the seamless , transparent , and universal 
 delivery of multimedia content to the end - user , thus solving any 
 interoperability issues .
the core notion into the standard is the digital item 
 ( di ) that represents the digital asset ( e.g. , a movie , an audio track , or other 
 data ) , and which contains the digital content and other related metadata ( e.g. , 
 creator 's details , usage rules and terms , licenses , security related 
 information ) ; the di hierarchy is represented in digital item declaration language 
 ( didl ) which is an xml - based document . in the digital item hierarchy , see figure 1 , we identify ( i ) resources which 
 are the individual multimedia data , that is , a picture , audio or video data , or 
 any other data ; ( ii ) components which 
 are collection of resources with their descriptors .
a component 
 by itself is not an item , but 
 the components are the basic building 
 blocks of items , and ( iii ) descriptors which are metadata that accompany a resource , containing information that concerns all or 
 part of the specific resource . 
 also , a container is a structure 
 which comprises of items and containers , forming thus logical packages for interexchanges 
 between entities .
the security problems may arise from the fact that the digital item 's description , that is , its 
 structure , contents , attributes , and metadata , is a clear xml document and it 
 is easily visible to anyone and vulnerable to nonauthorized usage . due to that 
 fact , the mpeg-21 includes a part named intellectual property management and 
 protection ( ipmp ) which provide mechanisms for protection of digital item .
more 
 specifically , mpeg-21 ipmp in conjunction with the mpeg - rel rights expression 
 language ( rel ) provide a framework that enables all users in the digital 
 contents delivery chain to express their rights and interests in digital items 
 and to have the assurance that those rights and interests will be persistently 
 and reliably managed and protected across a wide range of networks and devices 
 .
the core notion in mpeg-21 ipmp is related with the ipmp tools that are 
 used to protect the digital item .
those tools are not predescribed by the 
 standard , but each user , vendor , and so forth , may define and implement his own 
 set of tools which perform basic security functions like encryption / decryption 
 algorithms , authentication and data integrity mechanisms , watermarking , and fingerprinting . 
 with the use of mpeg-21 ipmp components , we may protect the whole di or a part 
 of it through the encapsulation of the original didl elements that we want to 
 protect , with additional information ( ipmp info ) that refer to mechanisms and 
 tools for the protection of the original elements .
mpeg-21 ipmp defines a new 
 set of ipmp didl elements which have the same role and semantics as an element 
 defined in didl .
the ipmpdidl : info element contains information about protection 
 and usage rules of the digital content , which may be categorized to ( i ) 
 information about protection of the whole digital item , which is included in 
 the child element ipmpdidl : ipmpgeneralinfodescriptor and ( ii ) information about 
 protection of a certain part of the digital item 's hierarchy , which is included 
 in the child element ipmpdidl : ipmpinfodescriptor , see figure 2 .
both prementioned child elements have two purposes of existence ( a ) to 
 describe the tools that are used for digital items protection , and ( b ) to 
 provide a set of licenses that accompany the content and define its usage 
 rules . more specifically , the ipmpdidl : ipmpinfodescriptor 
  element contains the following child elements ( see figure 3 ) : ( a ) the ipmpinfo : tool 
  child element which is used to specify a tool ( or tools ) that protect the 
 specified part of the di 's hierarchy .
each tool has a unique i d and may be 
 either referenced , if it is located in a remote ipmp tools server or it may be 
 included in line to the digital item ( in the latter case , the base-64 encoded 
 version of the tool is included ) ; ( b ) the ipmpinfo : rightsdescriptor child 
 element which contains the licenses that govern the usage of contents .
part 5 
 of mpeg-21 standard   defines the mpeg rights expression language ( rel ) 
 which a language that is used to create licenses that express usage rules and 
 rights set by the creators of the digital items , regarding actions over them . 

moreover , the license can be used to convey some other sensitive data , like , 
 for example , decryption keys for the encrypted ( protected ) contents of the 
 digital item .
the mpeg - rel defines the encryptedlicense element which 
 contains the license 's contents in an encrypted form and it is used when the 
 issuer wants to keep the content of the license confidential . when decrypted , 
 the original license 's contents are unveiled .
the child element ipmpdidl : contents contains the 
 protected digital asset itself which has been protected with a set of tools ( e.g. , 
 cryptographic tools , watermarking , hashing , digital signatures ) that have been 
 described in the child element ipmpdidl : info .
in the high - level view of the proposed architecture as depicted in 
 figure 4 , we can identify the user at home , equipped with different portable 
 emds that transmit their measurements into a pda which aggregates them for 
 temporal storage and further processing ( creation of encapsulated mpeg-21 ipmp - protected 
 metadata file ) .
then , the generated file is sent to a data server which is 
 located at the patient 's hospital and it is stored to a database . if it is 
 necessary , the patient 's doctor may extract data from that file remotely 
 through his pda device , acting and informing accordingly the patient . more specifically
, tier 1 encompasses a number of portable emds equipped with the 
 corresponding sensors , easy to handle and maintain , which are integrated into a 
 wireless wearable personal area network ( wwpan ) .
each of them can acquire , 
 sample , and process one or more physiological parameters .
more specifically , a 
 small ( 5 cm  5 cm ) portable electrocardiogram device is utilized for the heart 
 activity monitoring by providing a full 12-lead ecg by collecting signals 
 through ten sensors and electrodes with fixed position .
the ten input channels 
 ( vla , vra , vll , vrl , v1-v6 ) are sampled at 500 hz with a 10-bit resolution 
 analog to digital ( a / d ) converter . a small ( watch size ) portable wrist ( and arm 
 if chosen ) blood pressure device is utilized for monitoring patient 's blood pressure 
 upon request .
oxygen saturation is monitored through a small ( 2 cm  2 cm ) 
 portable device which its sensor fits to one of patient 's figures .
pulse rate 
 is also measured either from the portable wrist or the ecg device .
tier 2 encompasses a personal server application running on a personal digital 
 assistant , a cellular phone , a laptop , or a home pc .
the personal server 
 undertakes a number of tasks such as a transparent interface to the wwpan 
 ( portable devices ) , an interface to the user and an interface to tier 3 ( medical server & thin client ) . 

the network configuration task , among other functions , supports device 
 and sensor registration and initialization , customization , and network 
 communication setup .
after the network is configured , the personal server application 
 is initiated in order to manage the network , that is , channel and time 
 synchronization , data acquisition , data processing , data fusion , and so forth . 

furthermore , upon the availability of a communication channel , the personal server 
 establishes a secure link toward tier 3 and transmits reports or files which 
 are being further processed and integrated in the patient 's health record . in 
 case
the availability of a communication channel is not possible , the personal server 
 stores the data locally until the channel becomes available .
tier 3 comprises the medical server which , actually , encompasses other 
 servers such as emergency server , healthcare server , medical records server , 
 mail server , and the  thin - client  used for remote accessing of medical server 
 applications utilizing a  visualization  applet under secure link .
the medical server runs a large diversity of applications comprising 
 setting up communication channel to personal servers , collecting users ' 
 reports , integrating data into patients ' medical records data bases , processing 
 medical records upon authorized doctors and/or specialized personnel demand , 
 processing patients messages and other critical applications .
as soon as the medical data measurements are collected by the emds , they 
 are sent toward the pda ( tier 2 ) which is responsible for the creation of the 
 mpeg-21-protected container that contains the medical measurements with 
 appropriate usage licenses , as it can be seen in figure 5 . in steps 14 , medical data 
 measurements from different user - located emds ( ecg , blood pressure and oxygen 
 saturation , and pulse rate ) are taken and sent toward the pda , which in turn , 
 aggregates them and creates an initial packaged data file that contains the 
 previous data measurements .
afterwards , the packaged file is amended to further 
 processing in order to be  encoded  according to mpeg-21 terms , with 
 appropriate metadata , protection information , and patient 's instructions 
 ( relevant usage licenses ) ( step 5 ) .
then , the new mpeg-21-based packaged file 
 is sent to the hospital 's servers for further handling , that is , storage in 
 data servers , and informing physicians and doctors about patient 's situation 
 ( step 6 ) . in the following figures ,
we depict an abstract view of an mpeg-21 
 digital item that contains emds measurements , figure 6 , and the schematic 
 encapsulation of them into an ipmp container , see figure 7 .
as we have stated 
 before , the mpeg-21-based encapsulation of data protects it from unauthorized 
 view and possible malicious usage . in section 4 , we have emphasized that in such pervasive healthcare 
 environments the protection of patient 's privacy and medical data 
 confidentiality are key issues .
so when the mpeg-21-based packaged file comes to the hospital , 
 its structure and its contents should not be fully accessible to nonappropriate 
 users .
we identify 
 three groups of people that should have different access rights to the protected 
 contents ( i ) the it supervisors which are responsible for storing the received 
 packaged files to databases , ( b ) the specialized medical personnel like , for 
 example , the nurses , and ( c ) the doctors , who are responsible for the 
 attendance of the patients .
for example , the it stuff may just see the patient 's identification 
 number , ( patid ) , which is unique for each patient , in order to store the 
 packaged file in data server and update patient 's electronic record . on the 
 other hand ,
a nurse or trained medical stuff must be able to see some details 
 about the patient , for example , a part of patients ' personal data like surname , 
 name , and maybe an initial diagnosis , which may have automatically taken part 
 at patient 's home after the occurrences of data measurements , in order to 
 inform the patient 's doctor for further handling of the patient 's situation . 

finally , the patient 's doctor may have full access to contents of mpeg-21-packaged 
 files , that is , patients personal data , detailed medical data measurements 
 taken by emds , time of measurements , and initial automated diagnosis .
so the 
 generated mpeg-21 container contains three different items ; the first item is 
 unprotected and contains a text data file with the patient 's identification 
 number , which can be used for storage of the file to a database for further 
 handling , and some other data , like the time that the file was created at the 
 user 's pda .
the other two items are protected with the mpeg-21 ipmp components 
 and are indented for use by the trained medical staff and the doctors , 
 containing appropriate data .
each of these items contains a license of usage , 
 in an encrypted form , which grants access to contents of file to specific user . 

the license also contains the key which has been used from the patient 's pda 
 for the encryption of the medical data file .
we assume that each patient and 
 each of the doctors and trained medical staff have a prearranged set of 
 public - private keys ; those key pairs are assigned by the main hospital 's server 
 and can be revoked at any time since there is continuous communication between 
 the hospital 's server and the patient 's ( home ) server .
so the license for data 
 usage can be encrypted using the public key of the entity with which it is 
 related , for example , the doctor with whom the patient is related . in order to 
 access the protected items ' contents , the end - user must decrypt the license 
 with his private key , retrieve the decryption key from the license , and decrypt 
 the encrypted contents .
following , in figure 8 , we depict a schematic view of the encapsulated 
 mpeg-21-based data file which is transmitted from patient 's home server toward 
 hospital data servers . finally , in figure 9 , we present an xml - view of the mpeg-21 ipmp - protected 
 container that contains the three prementioned items . the contents of each item 
 are protected ( encrypted ) with the use of a tool that implements a specific 
 symmetric cryptographic algorithm , and it is remote referenced into the digital 
 items ' description .
even if one 
 malicious user has access to the remote location of the tool , he needs some 
 cryptographic sensitive information like , for example , a decryption key for 
 decoding the protected contents ; the key for the decryption is included into 
 the encrypted license that accompanies each item , which furthermore defines the 
 usage rules of the contents .
each item contains some information that identifies 
 the user for whom this item is destined , that is , item 1 has to be processed by 
 the it stuff , item 2 has to be taken care by a nurse , and so forth . after the 
 reception of each item , each relevant user initiates the procedure which will 
 decrypt his / her license  with the use of 
 his private key and then he / she will decrypt the protected contents  with the 
 symmetric key that is embedded into his / her license , thus revealing the 
 original packaged medical information .
we strongly believe that the outcome of this work contributes toward the 
 establishment of a standard security environment in which parts of sensitive 
 personal information can be viewed only by valid users even though many users 
 can have access to them .
the main characteristics of our approach , which 
 directly affect 
 medical safety and treatment efficacy , comprise standardization , minimalizm , and 
 sophistication .
ultimately , affects reduction of total health care cost , thus 
 leading to a better utilization of limited healthcare resources .
moreover , our 
 endeavor demonstrates that no general - purpose home server is required for 
 processing of medical data before sent toward end - users , that is , doctors , 
 medical staff , thus making the proposed architecture a good candidate for 
 portable devices in pervasive healthcare environments exposing limited 
 resources . in our proposal , we use the mpeg-21 standards ' ipmp components in 
 order to enhance users ' privacy and achieve security requirements that are applied in such 
 environments . to our knowledge , there is no other security framework compliant 
 with mpeg-21 that has been applied to protect such content , thus no comparison 
 with other similar frameworks is provided . as a matter of fact
furthermore , with respect to future 
 work , we are planning to exploit some other elements of the mpeg-21 standard 
 which , for example , would allow us to include ( in line ) into the ipmp - protected 
 digital item the protection tools that are used to govern the protected item 
 rather than remote referenced them , and also we could use some other elements 
 of mpeg-21 ipmp that allow digitally authentication of the protection tools , that 
 is , each tool carries a digital signature which validated each time the tool is 
 used , before appliance of them to the protected contents .
a lot of our research 
 work is taken place investigating issues that are related with the security of 
 our architecture under known attacks . moreover , as the mpeg-21 is a quite new 
 open standard that can be used for protection of sensitive data with the use of 
 drm , as a future work , we 
 are investigating the identification of possible leaks and 
 vulnerabilities of the standard , that may lead to attacks and a compromised system . 

we are also investigating issues that are related with the safe destruction of 
 the medical data after their viewing ; in that context , the use of trusted 
 platform architectures   could be a direction that will lead to a solution . at 
 this time , we assume that the hospital 's server is a trusted one , and that the 
 devices on which those data are viewed are also safe and trusted , and that 
 there is no possibility for data storage or alteration .
 nowadays in modern and ubiquitous computing environments , it is imperative more than ever the necessity for deployment of pervasive healthcare architectures into which the patient is the central point surrounded by different types of embedded and small computing devices , which measure sensitive physical indications , interacting with hospitals databases , allowing thus urgent medical response in occurrences of critical situations . 
 such environments must be developed satisfying the basic security requirements for real - time secure data communication , and protection of sensitive medical data and measurements , data integrity and confidentiality , and protection of the monitored patient 's privacy . in this work 
 , we argue that the mpeg-21 intellectual property management and protection ( ipmp ) components can be used in order to achieve protection of transmitted medical information and enhance patient 's privacy , since there is selective and controlled access to medical data that sent toward the hospital 's servers . 
1. Introduction
2. Related Work
3. Security RequirementsThreat Model
4. Proposed Architecture
5. Conclusions