[Babel-users] hmac merge

[Juliusz Chroboczek]

>> Yeah, we should just include an implementation of SHA-256 in the code.

> There's also the option...

Given that the main selling point of HMAC vs. DTLS is that it has no
dependencies, it wouldn't be particularly wise to make the reference
implementation depend on a Linux-specific library.

Of course, we'll make it easy for distributors to replace our bundled
implementation of SHA-256 with whatever it is they find convenient.  (I
expect Dave to replace it with his hand-written implementation that
interleaves MMX with AVX2 while simultaneously performing modular
multiplication in the U pipe to hash 27.7 bytes per cycle per core.)

(If you know what the U pipe is, you're old.)

-- Juliusz