Alice

Welcome to Bletchley. It works like this: I'll say something to Bob, and he'll say something back. Our communication will be encrypted in some manner, or at least obfuscated. Your job is to get the plaintext, and find the puzzle key.

Bob

Sometimes the plaintext from one puzzle will give you a hint (or the cryptogaphic key) for the next. When we give you such keys, we'll always do so in a straightforward manner. The puzzle key for each puzzle is always in what I say, and there shouldn't be any tricks involved in figuring out what it is.

Alice

Good Luck!

Bob

You'll need it. By the way, the key is 'dirtbags'.