Caesar's method is an encryption scheme involving shifting an alphabet (so 
, 
, 
, 
, etc., 
,
,
). It is one of the most basic encryption methods, and
is a specialized form of a transposition cipher.
Because the alphabet is rotated, the shift is consistent. A mapping of 
,
, etc. is termed ROT 1 because the letters are shifted
by one. Note that 
would map to 
due to the circular aspect of the rotation.
Encrypting with ROT 
and ROT 
yields the same ciphertext if and only if 
(mod 26).
ROT 13 is a popular encryption method on the Internet since it obfuscates text sufficiently to prevent accidental reading of the text. It is commonly used to list answers of puzzles, for example.
Caesar's method is a very weak encryption scheme, since there are 26 possibilities (of which one, ROT 26, is trivial). These can be easily checked by hand.
