[noise] Signatures and handshake payloads (was Re: Noise @ Highload++ in Moscow)

[David Wong]

> For future-proofing I think we should encourage extensible encodings
> in handshake payloads (protobufs, JSON, etc).

At the moment I don't have versioning in place, so I don't think it is
going to be an issue. As for more complicated things, the verifier
takes the whole payload and can do whatever it wants with it. That
includes parsing a protobuf structure if the peer wants to do that.
I'm really not keen on parsing anything. I like how Wireguard keep
things simple. But I think there are definitely good arguments in
favor of something like protobuf and it is indeed a discussions we
should have. I'll probably come back to that once I've looked more at
NoiseSocket though.
Another good question to ask is what is Noise trying to solve? Will
things like SNI or X.509 ever be relevant for Noise?

David