On Sat, Mar 30, 2019 at 6:53 AM Eric Biggers [off-list ref] wrote:

poly1305-simd is among the failing algorithms because it loses carry bits when
handling long "all 0xff bytes" inputs.  poly1305-avx2-x86_64.S is definitely
broken, and poly1305-sse2-x86_64.S *might* be too.  I am working on a patch...

Yea.... yikes. I'm kind of souring on this plan of having to deal with
that code in Zinc, versus the extensively studied, fuzzed, and
scrutinized code from Andy. Subtle carry bugs like that are kind of a
testament to my overall plan of preferring formally verified or
heavily used implementations to bespoke ones. This stuff is hard to
get right.

Jason