What is the down side of truncating a hash? For example, an SHA-256 hash is 256 bits. Is it any less secure if one was to drop the last 128 bits to make a 128 bit hash or take the MD5 hash of the SHA-256 hash to get a 128 bit hash? It does not seem that such an action would make it any easier to brute force reverse the hash, but then again, I am clearly not a security expert. Jay
