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.
Database encryption
Asymmetric encryption expands on symmetric encryption by incorporating two different types of keys into the encryption method: private and public keys. A public key can be accessed by anyone and is unique to one user whereas a private key is a secret key that is unique to and only known by one user. In most scenarios the public key is the encryption key whereas the private key is the decryption key. As an example, if individual A would like to send a message to individual B using asymmetric encryption, he would encrypt the message using Individual B's public key and then send the encrypted version. Individual B would then be able to decrypt the message using his private key. Individual C would not be able to decrypt Individual A's message, as Individual C's private key is not the same as Individual B's private key. Asymmetric encryption is often described as being more secure in comparison to symmetric database encryption given that private keys do not need to be shared as two separate keys handle encryption and decryption processes.