Re: [PATCH v2 3/4] secure_seq: use siphash24 instead of md5_transform

From: Jason A. Donenfeld
Date: Wed Dec 14 2016 - 16:01:39 EST

On Wed, Dec 14, 2016 at 9:12 PM, Tom Herbert <tom@xxxxxxxxxxxxxxx> wrote:
> If you pad the data structure to 64 bits then we can call the version
> of siphash that only deals in 64 bit words. Writing a zero in the
> padding will be cheaper than dealing with odd lengths in siphash24.
On Wed, Dec 14, 2016 at 9:27 PM, Hannes Frederic Sowa
<hannes@xxxxxxxxxxxxxxxxxxx> wrote:
> What I don't really understand is that the addition of this complexity
> actually reduces the performance, as you have to take the "if (left)"
> branch during hashing and causes you to make a load_unaligned_zeropad.

Oh, duh, you guys are right. Fixed in my repo [1]. I'll submit the
next version in a day or so to let some other comments come in.

Thanks again for your reviews.