JOSE support

[whyoleg]

Introduce standalone JOSE support module with JWT/JWK/etc.
Support for JWK encoding/decoding can also be used afterwards in providers other than WebCrypto.

Full list of RFCs:

• JWS: https://datatracker.ietf.org/doc/html/rfc7515
• JWE: https://datatracker.ietf.org/doc/html/rfc7516
• JWK: https://datatracker.ietf.org/doc/html/rfc7517
• JWA: https://datatracker.ietf.org/doc/html/rfc7518
• JWT: https://datatracker.ietf.org/doc/html/rfc7519
• JOSE examples: https://datatracker.ietf.org/doc/html/rfc7520

[malhobayyeb]

Up

[waltkb]

Hi, is there anything we (walt.id) could maybe help implement here?

[whyoleg]

Hey, @waltkb, thank you for the interest! That would be really nice!
I've created a branch jose (from main), and we could start creating PR's there as a start.
What I wanted from the initial version is to implement JWT and JWK support. I have no time to investigate the API which would fit Kotlin, so overall, it is up to you to start, and I will review PRs as we go.
To begin, let us add jose module under cryptography-serialization folder. You can also take a look on setup of asn1 module as a base for it — all targets + kotlinx-serialization-json. No other dependencies, at least for now.
The main idea would be to be simple enough and use kotlinx-serialization-json to handle serialisation (obviously).
Also, we will need Base64 - I would propose to just use the one which is already available in kotlin-stdlib. It is experimental, but I believe it should be fine.
If you have any other questions, feel free to ask here or anywhere else linked on GitHub!

When we have all the base blocks from the serialisation part, then we can start thinking about how to integrate it with signing part of core module to have the best experience.

Thank you once more, I'm looking forward to it!

[aschulz90]

I am currently in the progress of implementing a JWT library for Kotlin Multiplatform supporting all platforms this library also supports and have signing and verification done very easily so far.
Next step is JWKS support, but is is currently blocked by missing support for decoding public keys using JWK format.

The current progress is avaiable here: https://github.com/Appstractive/jwt-kt
The JWK handling is implemented here.

Maybe the repository will be useful to you by using it as a playground to test the JWK implementation.
There is a test in the jwt-jwks module, that should pass, once JWK decoding works for all platforms (pending interface changes).