ROT13, also known as rotate by 13 or ROT-13 is a simple letter substitution cipher that replaces a letter with the 13th letter after it, in the alphabet.
You can think of ROT13 as a special case of the Caesar cipher. Since there are 26 letters in the basic Latin alphabet, ROT13 is its own inverse; that is, to undo ROT13, the same algorithm is applied, so the same process can be used for encoding and decoding.
ROT13 is mostly used in online forums as a means of hiding spoilers, punch lines, puzzle solutions, and offensive materials from the casual glance.
Use the above ROT13 decoder and encoder to encrypt/decrypt simple messages.