Something you know – a password, pass phrase or some other known information that can be used to calculate function from a secret message. Something you are – A physical characteristic of your body such as your finger print, the retina print of your eye or your DNA. Encryption is a means of taking some plain readable text into a cipher text utilizing some form of algorithmic mapping. The intended receiver of such a cipher text must have the means to reverse the process by knowing the same algorithm, but an attacker cannot know the process.
Encryption systems must use mathematically complex algorithms so as to provide a good enough deterrent from attackers to be able to use some brute force method of calculating the algorithm in use. Two common methods of encryption are Symmetric Encryption Systems and Public Key Encryption Systems: Symmetric encryption simply uses an identical key for encryption of the plain text and decryption of the cipher text.