In order to decrypt the DM, the client must have control of the private key. But yes, they donât have to sign anythingâjust prove that they have the private key to decrypt the DM.
I guess the question is whether your service wants to run its own relay. If youâre running your own relay, the client *should* automatically respond to a NIP42 auth request transparently without the user having to do anything.
If youâre not running your own relay, then NIP42 connection-level auth wonât help you.