All you need is a hashing algorithm (something like md5, but not md5, of course). If you can memorize a hashing algorithm, then you can use the hash to verify

All you need is a hashing algorithm (something like md5, but not md5, of course). If you can memorize a hashing algorithm, then you can use the hash to verify larger pieces of software that you can't memorize. So large, complex crypto doesn't ever need to be memorized - all you need is an easy to memorize hashing algorithm.