verify function

bool verify(dynamic sig, dynamic data, dynamic publicKey)

Implementation

bool verify(sig, data, publicKey) {
  if (!(sig is Uint8List) && !(sig is String)) {
    throw "'sig' must be a string or Uint8List";
  }

  if (!(data is Uint8List) && !(data is String)) {
    throw "'data' must be a string or Uint8List";
  }

  if (!(publicKey is Uint8List) && !(publicKey is String)) {
    throw "'publicKey' must be a string or Uint8List";
  }

  if (sig is String) {
    if (isHex(sig)) {
      sig = hexToUint8List(sig);
    } else {
      throw "'signature' must be an hexadecimal string";
    }
  }

  if (data is String) {
    if (isHex(data)) {
      data = hexToUint8List(data);
    } else {
      data = Uint8List.fromList(utf8.encode(data));
    }
  }

  if (publicKey is String) {
    if (isHex(publicKey)) {
      publicKey = hexToUint8List(publicKey);
    } else {
      throw "'publicKey' must be an hexadecimal string";
    }
  }

  final Uint8List curveBuf = publicKey.sublist(0, 1);
  final Uint8List pubBuf = publicKey.sublist(2, publicKey.length);

  switch (curveBuf[0]) {
    case 0:
      final ed25519.VerifyKey verifyKey = ed25519.VerifyKey(pubBuf);
      return verifyKey.verify(signature: ed25519.Signature(sig), message: data);
    case 1:
      final Digest sha256 = Digest('SHA-256');
      final Uint8List msgHash = sha256.process(data);

      final elliptic.EllipticCurve ec = elliptic.getP256();
      final elliptic.PublicKey publicKey =
          elliptic.PublicKey.fromHex(ec, uint8ListToHex(pubBuf));
      final ecdsa.Signature signature = ecdsa.Signature.fromASN1(sig);
      return ecdsa.verify(publicKey, msgHash, signature);
    case 2:
      final Digest sha256 = Digest('SHA-256');
      final Uint8List msgHash = sha256.process(data);

      final elliptic.Curve ec = elliptic.getSecp256k1();
      final elliptic.PublicKey publicKey =
          elliptic.PublicKey.fromHex(ec, uint8ListToHex(pubBuf));
      final ecdsa.Signature signature = ecdsa.Signature.fromASN1(sig);
      return ecdsa.verify(publicKey, msgHash, signature);

    default:
      throw 'Curve not supported';
  }
}