[Babel-users] [babel] rather than ripemd160...

[Markus Stenberg]

Here's some raw numbers (clickbait):

- my Macbook (sanity check)
- Turris Omnia (2016 highend)
- Buffalo WZR-600DHP (2012 midend)

https://github.com/fingon/go-hashperf

TL;DR (probably the interesting part):

2012 midend home router does 40 bytes:
- 37.5k pps of SHA256
- bit over 40k pps of Blake2B
- 91k pps of Blake2S

Setup overhead disappears both in SHA256 and Blake2 at ~500 byte mark (500 and 1200 bytes roughly equal MB/s); with 200 byte packets setup still wastes ~1/4 of performance (both SHA256 and Blake2) and even more with 40 byte packets.

With these numbers, I withdraw my support of including anything else than SHA256 as MTI. I think specifying Blake2B or 2S as well makes sense (mostly for crypto robustness reasons for having alternative that is specified) but making it MAY-SHOULD seems sensible to me.

The code is there, go ahead to test on your own routers if you care. I didn't bother testing arm64 in the end, as those are even faster than arm (the ridiculous blake2s number of 460k pps for Blake2s on Turris Omnia convinced me that it is not really worth it to test on faster hardware).

-Markus