Example usage for org.bouncycastle.crypto.engines RSABlindedEngine init

Introduction

In this page you can find the example usage for org.bouncycastle.crypto.engines RSABlindedEngine init.

Prototype

public void init(boolean forEncryption, CipherParameters param) 

Source Link

Document

initialise the RSA engine.

Usage

From source file:bluecrystal.service.service.SignVerifyService.java

License:Open Source License

public boolean verify(int hashId, byte[] contentHash, byte[] sigBytes, X509Certificate cert) throws Exception {
    RSAPublicKey pubK = (RSAPublicKey) cert.getPublicKey();
    CipherParameters param = new RSAKeyParameters(false, pubK.getModulus(), pubK.getPublicExponent());
    RSABlindedEngine cipher2 = new RSABlindedEngine();
    cipher2.init(false, param);
    AsymmetricBlockCipher cipher = new PKCS1Encoding(cipher2);
    byte[] sig = cipher.processBlock(sigBytes, 0, sigBytes.length);
    AlgorithmIdentifier algId = createAlgorithm(hashId);
    byte[] expected = derEncode(contentHash, algId);

    LOG.debug("Sig:(" + sigBytes.length + ")" + Utils.conv(sigBytes));
    LOG.debug("Has:(" + contentHash.length + ")" + Utils.conv(contentHash));
    LOG.debug("Sig:(" + sig.length + ")" + Utils.conv(sig));
    LOG.debug("Exp:(" + expected.length + ")" + Utils.conv(expected));

    if (sig.length == expected.length) {
        for (int i = 0; i < sig.length; i++) {
            if (sig[i] != expected[i]) {
                return false;
            }//from   ww  w .  j  a  va  2s. co  m
        }
    } else if (sig.length == expected.length - 2) // NULL left out
    {
        int sigOffset = sig.length - contentHash.length - 2;
        int expectedOffset = expected.length - contentHash.length - 2;

        expected[1] -= 2; // adjust lengths
        expected[3] -= 2;

        for (int i = 0; i < contentHash.length; i++) {
            if (sig[sigOffset + i] != expected[expectedOffset + i]) // check hash
            {
                return false;
            }
        }

        for (int i = 0; i < sigOffset; i++) {
            if (sig[i] != expected[i]) // check header less NULL
            {
                return false;
            }
        }
    } else {
        return false;
    }

    return true;

}

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