On Wed, Oct 11, 2017 at 1:11 PM, Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > Indeed the correct functions to use would be siphash_1u32 or > siphash_1u64, depending. Depending on the popularity of that, we might > even consider making a siphash_1ulong helper, I suppose. Yeah, siphash is probably the sanest thing to use. How bad would it be to use HalfSipHash on 32-bit architectures? On a 32-bit machine, the full siphash is pretty expensive - big constants, and lots of 64-bit shifts. And 32-bit machines also tend to mean "slow machines" these days. I suspect there's little point in worrying a ton about the 64-bit key, considering that I think the *input* is generally more guessable than the output or the key. Linus