In
cryptography, a
Caesar cipher, also known as
Caesar's cipher, the
shift cipher,
Caesar's code or
Caesar shift, is one of the simplest and most widely known
encryption techniques. It is a type of
substitution cipher in which each letter in the
plaintext is replaced by a letter some fixed number of positions down the
alphabet. For example, with a left shift of 3,
D would be replaced by
A,
E would become
B, and so on. The method is named after
Julius Caesar, who used it in his private correspondence.