Caesar Cipher

Caesar shifting adjusts the alphabet by an offset.

Example

The transformation can be represented by aligning two alphabets; the cipher alphabet is the plain alphabet rotated left or right by some number of positions. For instance, here is a Caesar cipher using a left rotation of three places (the shift parameter, here 3, is used as the key):

Plain:      ABCDEFGHIJKLMNOPQRSTUVWXYZ


Cipher:  DEFGHIJKLMNOPQRSTUVWXYZABC

When encrypting, a person looks up each letter of the message in the "plain" line and writes down the corresponding letter in the "cipher" line. Deciphering is done in reverse.

Plaintext:    the quick brown fox jumps over the lazy dog


Ciphertext: WKH TXLFN EURZQ IRA MXPSV RYHU WKH ODCB GRJ 

Sources

http://en.wikipedia.org/wiki/Caesar_cipher

http://en.wikipedia.org/wiki/Caesar_cipher