Need Letters First!
Rot13 encoding is the most basic substitution cipher in existance; all of the text in a message is shifted 13 positions in the alphabet (A->N, etc.). The same mechanism can be used to code and encode text, since shifting the letters in a piece of text 13 spaces twice will bring you back to where you started. While infomation encrypted using rot13 is considered trivial to crack (since it has only one possible key), encrypting a piece of text using this system is usually sufficient to obscure a message from a casual observer including most web-scraping robots. The next level up from rot13 in terms of complexity would be a caesar cipher (see our Caesar Cipher Decoder for details and history), which expands the possible keyspace to 26 values (different alphabet shifts).