boolean verifySign()

in src/main/java/org/openvasp/client/service/impl/SignServiceImpl.java [66:107]
36 lines of code
6 McCabe index (conditional complexity)

    boolean verifySign(String payload, String sign, String pubKey) {
        pubKey = Numeric.cleanHexPrefix(pubKey);
        pubKey = pubKey.length() > 128 ? pubKey.substring(pubKey.length() - 128) : pubKey; // for compatibility with C# client
        String expectedSignerAddress = Keys.getAddress(pubKey);
        String MESSAGE_PREFIX = "\u0019Ethereum Signed Message:\n";
        String prefix = MESSAGE_PREFIX + payload.length();
        byte[] msgHash = Hash.sha3((prefix + payload).getBytes());

        byte[] signatureBytes = Numeric.hexStringToByteArray(sign);
        byte v = signatureBytes[64];
        if (v < 27) {
            v += 27;
        }

        Sign.SignatureData sd =
                new Sign.SignatureData(
                        v,
                        (byte[]) Arrays.copyOfRange(signatureBytes, 0, 32),
                        (byte[]) Arrays.copyOfRange(signatureBytes, 32, 64));

        String addressRecovered = null;
        boolean match = false;

        // Iterate for each possible key to recover
        for (int i = 0; i < 4; i++) {
            BigInteger publicKey =
                    Sign.recoverFromSignature(
                            (byte) i,
                            new ECDSASignature(
                                    new BigInteger(1, sd.getR()), new BigInteger(1, sd.getS())),
                            msgHash);

            if (publicKey != null) {
                addressRecovered = Keys.getAddress(publicKey);
                if (addressRecovered.equals(expectedSignerAddress)) {
                    match = true;
                    break;
                }
            }
        }
        return match;
    }