case *ecdsa.PublicKey:
		oid, ok := oidFromNamedCurve(pub.Curve)
		if !ok {
			return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
		}
		if !pub.Curve.IsOnCurve(pub.X, pub.Y) {
			return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: invalid elliptic curve public key")
		}
		publicKeyBytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)