Missing the method to compute the Subject Key Identifier in Native C509 Certificate

[xipki]

We need to specify the method to compute the key identifier over the public key. The method specified in RFC 5280 (https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.2) cannot be used here, due to the possible different encoded subjectPublicKey.

For the EC public keys (Weierstraß, EdDSA, X25519/X448), the subjectPublicKeyare of the same in X509 and C509. But at least for RSA, it is different.

[xipki]

@gselander Could you add the discussion result here?

[emanjon]

I intended to make a PR but accidently pushed to main.
8e6decb

[emanjon]

Changed to

"In natively signed certificates, KeyIdentifier SHOULD be composed of the leftmost 160-bits of the SHA-256 hash of the CBOR encoded subjectPublicKey. Other methods of generating unique numbers can be used."

@xipki can we close this?