Secure communication
Encryption is a method in which data is rendered hard to read by an unauthorized party. Since encryption methods are created to extremely hard to break, many communication methods either use deliberately weaker encryption than possible, or have backdoors inserted to permit rapid decryption. In some cases government authorities have required backdoors be installed in secret. Many methods of encryption are also subject to "man in the middle" attack whereby a third party who can 'see' the establishment of the secure communication is made privy to the encryption method, this would apply for example to interception of computer use at an ISP. Provided it is correctly programmed, sufficiently powerful, and the keys not intercepted, encryption would usually be considered secure. The article on key size examines the key requirements for certain degrees of encryption security.
Column level encryption
Generally, when data are being collected and stored as records, those records will appear in a tabular format in rows in the database with each rows logging specific attributes. Some data can be more sensitive than others, for example, data of birth, social security number, home address, etc., which can act as a personal identification. In order to ensure that these private information is transferred and stored securely, data goes through encryption, which is the process of encoding plaintext into ciphertext. Non-designated readers or receivers will not be able to read the data without the decryption key. Another example to illustrate this concept is, given a database stores client's phone numbers. The set of phone numbers will appear to most readers as gibberish alphanumerical text with a mix of symbols, totally useless to those who do not have access privilege to view the data in plaintext (original form).