// For a more flexible key format which is not EC specific, use
// [MarshalPKCS8PrivateKey].
func MarshalECPrivateKey(key *ecdsa.PrivateKey) ([]byte, error) {
	oid, ok := oidFromNamedCurve(key.Curve)
	if !ok {
		return nil, errors.New("x509: unknown elliptic curve")
	}

	return marshalECPrivateKeyWithOID(key, oid)
}

		privKey.Algo = pkix.AlgorithmIdentifier{
			Algorithm:  oidPublicKeyRSA,
			Parameters: asn1.NullRawValue,
		}
		privKey.PrivateKey = MarshalPKCS1PrivateKey(k)

	case *ecdsa.PrivateKey:
		oid, ok := oidFromNamedCurve(k.Curve)
		if !ok {
			return nil, errors.New("x509: unknown curve while marshaling to PKCS#8")
		}
		oidBytes, err := asn1.Marshal(oid)
		if err != nil {

		// This is a NULL parameters value which is required by
		// RFC 3279, Section 2.3.1.
		publicKeyAlgorithm.Parameters = asn1.NullRawValue
	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) {