Secret Cipher Tool

Type a message, hit Encode, and send it off in secret code. Hit Decode to read one you received.

Enter your message:

Result:

How it works

This tool uses ROT13, a classic letter-substitution cipher that swaps each letter with the one 13 places away in the alphabet. Numbers, spaces and punctuation stay the same. Because the alphabet has 26 letters, running the cipher twice gets you right back to your original message, so Encode and Decode do the same trick.

Everything happens in your browser. Your messages are never sent anywhere.