Please read https://noiseprotocol.org/noise.html#handshake-patterns.

radicle-node, as of 2025-05-13, implements an XK handshake.

We should think about the consequences of moving to XX, or a deferred pattern.

In particular, we would have to think about what happens when the responder sends a key that is different from what the initiator would expect, based on earlier handshaking. This reminds of "known hosts" in SSH.

By switching to a handshake pattern that does not require the key of the responder to initiate, we would unlock some nicer UX.