If you're totally unfamiliar wish hashing, think of it like a fingerprint for data. Any data can be processed through the algorithm and will generate a hash, which to the best of our knowledge, is unique. It's also one way -- while you know the same data will always produce the same hash, you can't derive what that data is from a hash, just like you can't figure out what someone looks like based on their fingerprint. But if you know Adam's fingerprint, and have a print that matches, you know Adam must have created it. The math is tedious but if you sat down with a pencil and paper and went through it methodically it's not THAT hard.