X25519 and ECDH-ES+XC20PKW

[oed]

Hi, I wanted to use the ECDH-ES+XC20PKW with the x25519 curve but noticed that I get an error when trying to do that:

JWKKeySupport: the key does not support ECDH-ES+XC20PKW key management (encryption) algorithm

I assume this is because this library doesn't register the ECDH-ES+XC20PKW alg for x25519. I tried added the following line to my code and I could successfully create a JWE.

const registry = require('jose/lib/registry')
registry.JWK.OKP.deriveKey['ECDH-ES+XC20PKW'] = key => (key.use === 'enc' || key.use === undefined) && key.keyObject.asymmetricKeyType.startsWith('x')

Is it ok to do this, might I be missing something?

[panva]

What’s your nodejs version?

[oed]

$ node -v                                                                                                                                                                                                                                 15:58
v14.4.0

[panva]

It's just that x25519 and x448 ECDH wasn't added to Node.js until recently and I completely forgot to update this to reflect that.

I've released v1.1.0 that resolves that for both x25519 and x448

[panva]

Thanks for bringing this up, please consider supporting the library if it provides value to you or your company and this support was of help to you. Supporting the library means, amongst other things, that such support and the library will be available in the future.

[oed]

Thanks for clarifying 🙏 That was my guess of what was going on, just wanted to make sure I was thinking about it in the right way!