It attaches great importance to having a 1:1 mapping from keys to hashes. If that is critical, then presumably the intent must not be to shorten the hash, becau

It attaches great importance to having a 1:1 mapping from keys to hashes. If that is critical, then presumably the intent must not be to shorten the hash, because once you've shortened the hash, the 1:1 mapping is lost. Having a hash function that gives a 1:1 mapping for short keys could be considered a positive feature, all else being equal, but in reality, all else would not be equal, because this property doesn't naturally go along with the things that make a good hash function generally. It would certainly come at a cost, and it serves little purpose. It makes no sense to me, and I think the author must have been making it up as he went.