Add support for channel binding

[xdg]

See RFC-5802 Sec 6.

[Neustradamus]

@xdg: Thanks!

[Neustradamus]

It is official for TLS 1.3 Binding!

• RFC 9266: Channel Bindings for TLS 1.3: https://tools.ietf.org/html/rfc9266

Details:

• tls-unique for TLS =< 1.2
• tls-exporter for TLS = 1.3

[ehuelsmann]

@xdg Thank you for creating this module! It allowed me to implement a wrapper module to plug into Authen::SASL and have a working prototype within hours! I've published a more complete version on CPAN under the name Authen::SASL::SCRAM. With this new dist, I was able to add SCRAM-SHA-512 to a Perl program called sendxmpp without changing a single line of code to the original!

I'm now researching the possibilities to add support channel binding to the Authen::SASL::SCRAM dist, both for completeness as well as because the server that the sendxmpp application is talking to, supports it. I've shortly looked at whether it's possible for me to support channel binding without bothering you, but that's unfortunately not the case due to the impact on the messages being exchanged being tracked by Authen::SCRAM.

So: could you please consider implementing channel binding, so I can add support for it to the Authen::SASL::SCRAM dist?

If you provide me with directions on how you want it added to your module, I'm willing to do the legwork and provide you with a PR as well.