Hello,
I wanted to propose adding support for SCRAM channel binding (SCRAM-SHA-256-PLUS) to Postgrex. I'm happy to contribute a PR for the same.
Currently, Postgrex only uses SCRAM-SHA-256 without channel binding, even if the server supports it. I think it should support the more secure mechanism wherever the server advertises support for it.
We can further provide a client-side option called channel_binding, which can be prefer/require/disable, to configure behavior similar to libpq.
Happy to discuss any design proposals, or get to work on a PR if this would be welcome.
Thanks!