Enhance Digital Signature API

[anchupin]

1. Add API to retrieve PublicKey from PrivateKey. (ECDSA)

Right now it's impossible to import PublicKey from PrivateKey and nobody keep PublicKey if you already have Private, internally you already do this, but this API is not exposed.

Swift Example:

2. Add None CryptographyAlgorithmId in case if data for digital signature has already hashed, so
   For java it will be like NoneWithECDSA.
   For Apple you can use kSecKeyAlgorithmECDSASignatureDigestX962.
   For OpenSSL it's NULL parameter in EVP_PKEY_sign_init
   For Web, this is the problem, web doesn't allow to send already hashed bytes, noble can, but not sure if you want to use it

private object None : CryptographyAlgorithmId<Digest>("NONE")
OR
public fun signatureGenerator(
      digest: CryptographyAlgorithmId<Digest>?,
      format: SignatureFormat,
): SignatureGenerator

[whyoleg]

Hey! Thanks for raising the issue!

1. will be available in the next release - the branch with changes is already there, I just need to perform some additional testing in combination with upcoming JWK keys support in all providers
2. Hm, I think that it might be possible to do something here. What will be the use case for this, by the way? And yes, WebCrypto doesn't support this, but that's fine, as the policy is that at least two providers/platforms should support the feature. In this case, Android and iOS will be supported, so that's fine. I don't plan to add additional JS dependencies or providers at this moment.

[anchupin]

Thank you for your reply.
2. Yeah, I think Web exclusive is OK for now, in overall it's pretty important feature, especially within crypto, when you should often use ripemd, blake, keccak for hashing and it doesn't take much time(I think it will be less than 50-100 LoC).