[noise] MixKey during initialization

[Jason A. Donenfeld]

On Mon, Aug 31, 2015 at 6:07 PM, Trevor Perrin <trevp at trevp.net> wrote:
>
> No, this isn't special-cased currently.  But note that without a
> pre-shared key, this calculates a constant for k, so you're welcome to
> store the constant and skip the calculation.

Okay, that's what I thought -- it's just a way of differentiating
between protocols.

Since this isn't really secret data, and it's just for differentiation
in my case, I think rather than storing a constant that's the result
of a known MixKey(name) operation, I'm just going to store 32 bytes of
something known.

A related question -- with the HandshakeIS, my "initial" hash value is
just going to be HASH(remote_static), right? I believe this is due to
the pre-message, which is only an "s", which is then written in the
clear and MixHash'd on.