[noise] NLS implementation in Go

[Trevor Perrin]

On Thu, May 24, 2018 at 8:18 PM, Gerardo Di Giacomo <gedigi at live.com> wrote:
>
> I'm not sure if anybody else is looking at this and has an opinion, but from my initial investigation, having a single protobuf seems to be an simpler approach.

I think I see your point, let me try to spell out a protobuf naming
you might be happier with.

(It's worth emphasizing that none of this affects bytes on the wire,
it's just spec notation).


Right now, we have an all-inclusive proto that defines all possible
fields any NLS handshake payload could use:

message NoiseLingoHandshakePayload {
    repeated string evidence_request_type = 1;
    repeated string evidence_blob_type = 2;
    repeated bytes evidence_blob = 3;
    bytes psk_id = 4;
    NoiseLingoTransportOptions transport_options = 5;
}


Profiles like NoiseLink, NoiseZeroLink, etc, take a subset of those
fields for their handshake payloads, and the protos are named like:

NoiseZeroLink:
 -> NoiseZeroLinkHandshakePayloadRequest1
 <- NoiseZeroLinkHandshakePayloadResponse1

NoiseLink:
 ->
 <- NoiseLinkHandshakePayloadResponse1
 -> NoiseLinkHandshakePayloadRequest2

The first and second payloads in NoiseLink/NoiseZeroLink serve the
same role and have the same contents.  So I think you're asking
whether we should just have a single proto for them, like:

NoiseZeroLink:
 -> NoiseLinkPayload1
 <- NoiseLinkPayload2

NoiseLink:
 ->
 <- NoiseLinkPayload1
 -> NoiseLinkPayload2

These names no longer indicate the exact profile (since NoiseLink
protos are used with NoiseZeroLink), nor do they indicate the
round-trip number.  But on the other hand, they're simpler and
shorter.

Extending this to other NLS profiles, we'd get something like:

NoiseTinyLink:
 -> NoiseTinyLinkPayload1
 <- NoiseTinyLinkPayload2
 -> NoiseTinyLinkPayload3

NoiseAnonBox
 -> NoiseAnonBoxPayload1

NoiseAuthBox
 -> NoiseAuthBoxPayload1


I think the simpler and shorter names are better, so this would be
worth changing.  What do other people think?  Are there other
proposals?

Trevor