kb, _ := pem.Decode(keyBytes)
	if kb == nil {
		return nil, fmt.Errorf("invalid PEM-encoded key")
	}

	switch kb.Type {
	case blockTypeECPrivateKey:
		key, err := x509.ParseECPrivateKey(kb.Bytes)
		if err != nil {
			return nil, fmt.Errorf("failed to parse the ECDSA private key: %v", err)
		}
		return key, nil
	case blockTypeRSAPrivateKey:
		key, err := x509.ParsePKCS1PrivateKey(kb.Bytes)

		case *rsa.PrivateKey, *ecdsa.PrivateKey, ed25519.PrivateKey:
			return key, nil
		default:
			return nil, errors.New("tls: found unknown private key type in PKCS#8 wrapping")
		}
	}
	if key, err := x509.ParseECPrivateKey(der); err == nil {
		return key, nil
	}

	return nil, errors.New("tls: failed to parse private key")