Using WG for transport security in a p2p network

[Jason A. Donenfeld]

Hey Ximin,

Nice to see that you're thinking through these issues in a concrete setting.

For a while I had some notions about allowing WireGuard to pop up
initiaton messages from unauthenticated peers to userspace for userspace to
then validate in one way or another asynchornously, followed by userspace
adding that peer's key to the list of peers (or not), and initiating the
handshake back the other way reusing the initial UDP port. This wouldn't add
that much complexity and I think it'd be fairly reliable. However, I've held
off on implementing it because I'm skepical that people would actually use it
in a way that makes sense. For example, in your case, you already have some
other aspect of the protocol which seeks to exchange this information; in
that case, doing the exchange there makes most sense, since you can morph and
change that for your particular requirements. In other words, I like the idea
you presented in your follow up email. Does that seem like a okay solution for
you? Or do you think you do have a compelling reason for adding the above
semantics?

Jason