[Deque]

about theory: I think the best way to learn theory is to also learn history: start at simple transposition and monoalphabetic substitution ciphers, then go all the way to modern encryption. writing encryption/decryption software is not hard when you know both theory and programming. cracking is difficult as you need to know a lot about cryptanalysis and a lot of math.

I fully agree with you here.

md5 is not that strong, but distributed is a good idea anyway

What do you mean with not that strong? Bruteforcing 128 bit hashes can take years. That are about 3.4 * 10^38 possible hashes to check. Too many to store them all in rainbowtables and too many to bruteforce them fast enough unless the password is insecure (i.e. not long enough).

[unknownAttacker]

md5 is not considered secure anymore as the known rainbowtables for it are huge now (remember, rainbowtable is not the same as lookup table) and there are at least 2 known collision attacks