[tor-dev] Using hidden service key with TLS client authentication

Hi tor-dev mailing list, Is there a way to capsulate a Tor hidden service Ed25519 private key inside a TLS EE certificate and use it in TLS? I wanted to use this specifically for XMPP's server-to-server TLS connections, which uses mTLS to prove if the client connecting is who they say they are. Currently with XMPP Tor server-to-server connections, we have to use dialback (telling the server to connect back to the client to authenticate its identity, https://xmpp.org/extensions/xep-0220.html) to prove it, which is a legacy and insecure form of server-to-server authentication If this is possible, then it would get rid of a reason to keep dialback around and less roundtrip for the server authentication. Kind regards, techmetx11