feat: add secp256k1 diddoc and verification method

[sairanjit]

Summary

• Added keyDidSecp256k1
• Added Verification method Type EcdsaSecp256k1VerificationKey2019
• Added a test-vector from https://github.com/w3c-ccg/did-method-key/blob/main/test-vectors/secp256k1.json

[sairanjit]

There are two formats of verification methods for key-type secp256k1 from test vectors

• https://github.com/w3c-ccg/did-method-key/blob/main/test-vectors/secp256k1.json
• https://github.com/transmute-industries/did-key.js/blob/main/packages/did-key-test-vectors/src/secp256k1/did-key-secp256k1-case-0.json

Which verification method should be used ?

{
  "id": "did:key:zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme#zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme",
  "type": "EcdsaSecp256k1VerificationKey2019",
  "controller": "did:key:zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme",
  "publicKeyBase58": "23o6Sau8NxxzXcgSc3PLcNxrzrZpbLeBn1izfv3jbKhuv"
}

or

{
  "id": "did:key:zQ3shjRPgHQQbTtXyofk1ygghRJ75RZpXmWBMY1BKnhyz7zKp#zQ3shjRPgHQQbTtXyofk1ygghRJ75RZpXmWBMY1BKnhyz7zKp",
  "type": "JsonWebKey2020",
  "controller": "did:key:zQ3shjRPgHQQbTtXyofk1ygghRJ75RZpXmWBMY1BKnhyz7zKp",
  "publicKeyJwk": {
    "kty": "EC",
    "crv": "secp256k1",
    "x": "RwiZITTa2Dcmq-V1j-5tgPUshOLO31FbsnhVS-7lskc",
    "y": "3o1-UCc3ABh757P58gDISSc4hOj9qyfSGl3SGGA7xdc"
  }
}

[TimoGlastra]

Let's use JsonWebKey by default. This seems to be one of the two defaults in DataIntegrity. I think they're moving away from key specific types

[sairanjit]

• Updated to JsonWebKey as default
• Should we later add a way to use different didDoc If someone specifically wants to use them ?

[TimoGlastra]

Yeah that might be useful -- currently they can call the getSecpVerificationMethod and construct a did doc on their own.

[TimoGlastra]

@sairanjit would be great to get this in for 0.5.0, so if you can update it somewhere today to use JsonWebKey that would be great, thanks 🙏

[sairanjit]

@sairanjit would be great to get this in for 0.5.0, so if you can update it somewhere today to use JsonWebKey that would be great, thanks 🙏

Sure will do it today itself