As suggested in https://pkg.go.dev/golang.org/x/crypto/curve25519#ScalarBaseMult,
use X25519 instead of ScalarBaseMult. When using Basepoint, it may employ
some precomputed values, enhancing performance.
Co-authored-by: Wade Simmons <wade@wades.im>
Co-authored-by: Wade Simmons <wadey@slack-corp.com>
`func (nc *NebulaCertificate) VerifyPrivateKey(key []byte) error` would
previously return an error even if passed the correct private key for a
CA certificate `nc`.
That function has been updated to support CA certificates, and
nebula-cert now calls it before signing a new certificate. Previously,
it would perform all constraint checks against the CA certificate
provided, take a SHA256 fingerprint of the provided certificate, insert
it into the new node certificate, and then finally sign it with the
mismatching private key provided.