A monoalphabetic substitution cipher known as the Caesar cipher (or Caesar code) replaces each letter with a letter that is somewhat further along the alphabet (therefore shifted but always the same for given cipher message). The offset, which can be either right (from A to B) or left (from B to C), determines the shift distance (B to A).
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| Cipher Encrypter Tool |
Caesar cipher decryption tool
You may use the next tool to encrypt a document using the Caesar cipher's straightforward offset technique. The end result is identical to a rot13 encryption if you use 13 as the key. When "guess" is used as the key, the algorithm searches for the correct key and guesses its way through the text to decode it. I have prepared a brief post (with a source) on how to decipher a text that has been encrypted using the Caesar cipher in an unknowable environment.