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";
    }
  }

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

  switch (curveBuf[0]) {
    case 0:
      Digest sha512 = new Digest("SHA-512");
      Uint8List msgHash = sha512.process(data);
      final verifyKey = ed25519.VerifyKey(pubBuf);
      return verifyKey.verify(
          signature: ed25519.Signature(sig), message: msgHash);
    case 1:
      Digest sha256 = new Digest("SHA-256");
      Uint8List msgHash = sha256.process(data);

      final ECDomainParameters curve = ECCurve_prime256v1();

      BigInt r = decodeBigInt(sig.sublist(0, 32));
      BigInt s = decodeBigInt(sig.sublist(32, 64));
      final signer = ECDSASigner(null, HMac(sha256, 64));
      signer.init(
          false,
          new PublicKeyParameter(
              new ECPublicKey(curve.curve.decodePoint(pubBuf), curve)));
      return signer.verifySignature(msgHash, new ECSignature(r, s));

    case 2:
      Digest sha256 = new Digest("SHA-256");
      Uint8List msgHash = sha256.process(data);

      final ECDomainParameters curve = ECCurve_secp256k1();

      BigInt r = decodeBigInt(sig.sublist(0, 32));
      BigInt s = decodeBigInt(sig.sublist(32, 64));
      final signer = ECDSASigner(null, HMac(sha256, 64));
      signer.init(
          false,
          new PublicKeyParameter(
              new ECPublicKey(curve.curve.decodePoint(pubBuf), curve)));
      return signer.verifySignature(msgHash, new ECSignature(r, s));

    default:
      throw "Curve not supported";
  }
}