I just finished reading the Cryptography section of the 70-536 book. While I do understand, conceptually, how all this stuff works, I have to say that I may be in trouble on the test if I really need to memorize the difference between, say, RIPEMD160 and HMACSHA1. I can’t think of any reasonable mnemonic device that will help me remember that RIPEMD160 is a non-keyed hashing algorithm, and HMACSHA1 is a keyed hashing algorithm.