Use hexadecimal encoding and decoding for certificate fingerprints

[hslatman]

The spec says: "SHA256 certificate fingerprints are encoded into a hexadecimal string, and must be decoded as hexadecimal string before it can be used as input".

Base64 was used before, resulting in hash length errors.

[wcoenraads]

Thank you for the contributions! I've set aside a bit of time tomorrow to review them and probably merge them. I also have some time set aside to do any more necessary updates to ensure conformance to v1.0 of the S2 Connect specification. After that I'll prepare a new release for crates.io.

Out of interest, are you looking to use this crate somewhere? We're always interested to learn where S2 and the associated tools are used 😄

[hslatman]

Thank you for the contributions! I've set aside a bit of time tomorrow to review them and probably merge them. I also have some time set aside to do any more necessary updates to ensure conformance to v1.0 of the S2 Connect specification. After that I'll prepare a new release for crates.io.

Awesome! 😄

Out of interest, are you looking to use this crate somewhere? We're always interested to learn where S2 and the associated tools are used 😄

I started hacking on a Go implementation of S2 and Connect out of personal interest and wanted to work on some interesting new stuff. Also always interested in protocols that depend on PKI / certs in some way 😄

Had my own demo CEM and RM talking to each other, but needed to verify things cooperated with the rest of the ecosystem. Did some hacking in Python first, but moved on to s2-rust to be able to test S2 Connect. I have some more ideas in mind for the future, but still brewing on that. Will make the repo public soon too.