Cryptology

Originally Posted by elrabin

I do not think this is a direct-substituion cipher. Reason: There are many 3-letter words and they do not seem to fit in together. "q" appears as the second letter in 3 of those words. I cannot think of any 3 (distinct) three-letter words that share the same middle letter. Additionally, q appears only once in the rest of the cipher.

This leads me to believe that this code was generated using some other method. I think this falls under the Vigenere Cipher (Polyalphabetic cipher), where a keyword is used to shift the letters.

That is what I originally believed it to be as well, but the original post does say that it is a single letter-letter substitution. If it hadn't said that, I would've thought that the coder had just used one of the online enigma machine-like applets to write the sequence.