You can use this to write secret messages! =O  Enter your message, then enter a key value (how many letters it is away from the original alphabet- if you type 'abc' with a key value of 1, the message is 'bcd'), then click Encode Message.

If you want to send a message to someone, be sure to include the message, key value, and a link to this page so they can decode it. :)  Shuuuzam.