Example usage for org.bouncycastle.crypto.ec ECPair getY

Introduction

In this page you can find the example usage for org.bouncycastle.crypto.ec ECPair getY.

Prototype

public ECPoint getY() 

Source Link

Usage

From source file:org.cryptoworkshop.ximix.node.crypto.test.BasicShamirSharingTest.java

License:Apache License

private void doTest(ECDomainParameters domainParams, AsymmetricCipherKeyPair[] kps, int threshold,
        boolean shouldPass, int... missing) {
    int numberOfPeers = kps.length;

    // create the splitter for the peers/threshold over the order of the curve.
    ShamirSecretSplitter secretSplitter = new ShamirSecretSplitter(numberOfPeers, threshold,
            domainParams.getN(), new SecureRandom());

    // Having created a private key the server creates shares of that
    // private key. It would keep one share for itself and sends the others
    // shares to the other servers.
    BigInteger[][] privateKeyShares = new BigInteger[numberOfPeers][];
    BigInteger[] finalPrivateKeyShares = new BigInteger[numberOfPeers];
    for (int i = 0; i < numberOfPeers; i++) {
        privateKeyShares[i] = secretSplitter.split(((ECPrivateKeyParameters) kps[i].getPrivate()).getD())
                .getShares();/*from  ww w  .  j a  v a 2  s .  c  o m*/
    }

    // Simulates distributing shares and combining them
    for (int i = 0; i < numberOfPeers; i++) {
        finalPrivateKeyShares[i] = privateKeyShares[0][i];
        for (int j = 1; j < numberOfPeers; j++) {
            finalPrivateKeyShares[i] = finalPrivateKeyShares[i].add(privateKeyShares[j][i]);
        }
    }

    ECPoint pubPoint = ((ECPublicKeyParameters) kps[0].getPublic()).getQ();

    for (int i = 1; i < numberOfPeers; i++) {
        pubPoint = pubPoint.add(((ECPublicKeyParameters) kps[i].getPublic()).getQ());
    }

    ECPublicKeyParameters jointPub = new ECPublicKeyParameters(pubPoint, domainParams);

    // Create a random plaintext
    ECPoint plaintext = generatePoint(domainParams, new SecureRandom());

    // Encrypt it using the joint public key
    ECEncryptor enc = new ECElGamalEncryptor();

    enc.init(new ParametersWithRandom(jointPub, new SecureRandom()));

    ECPair cipherText = enc.encrypt(plaintext);

    // do partial decrypts
    ECPoint[] partialDecs = new ECPoint[numberOfPeers];

    for (int i = 0; i < numberOfPeers; i++) {
        partialDecs[i] = cipherText.getX().multiply(finalPrivateKeyShares[i]);
    }

    // simulate missing peers
    for (int i = 0; i != missing.length; i++) {
        partialDecs[missing[i]] = null;
    }

    // decryption step
    LagrangeWeightCalculator lagrangeWeightCalculator = new LagrangeWeightCalculator(numberOfPeers,
            domainParams.getN());

    BigInteger[] weights = lagrangeWeightCalculator.computeWeights(partialDecs);

    // weighting
    ECPoint weightedDecryption = partialDecs[0].multiply(weights[0]);
    for (int i = 1; i < weights.length; i++) {
        if (partialDecs[i] != null) {
            weightedDecryption = weightedDecryption.add(partialDecs[i].multiply(weights[i]));
        }
    }

    // Do final decryption to recover plaintext ECPoint
    ECPoint decrypted = cipherText.getY().add(weightedDecryption.negate());

    Assert.assertEquals(shouldPass, plaintext.equals(decrypted));
}

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From source file:org.cryptoworkshop.ximix.node.crypto.test.NewDKGTest.java

License:Apache License

private void doTest(ECDomainParameters domainParams, AsymmetricCipherKeyPair[] kps, int threshold,
        boolean shouldPass, int... missing) {
    int numberOfPeers = kps.length;

    // create the splitter for the peers/threshold over the order of the curve.
    ECPoint hVal = domainParams.getG().multiply(getRandomInteger(domainParams.getN(), new SecureRandom()));
    ECNewDKGSecretSplitter secretSplitter = new ECNewDKGSecretSplitter(numberOfPeers, threshold, hVal,
            domainParams, new SecureRandom());

    // Having created a private key the server creates shares of that
    // private key. It would keep one share for itself and sends the others
    // shares to the other servers.
    ECCommittedSplitSecret[] privateKeyShares = new ECCommittedSplitSecret[numberOfPeers];
    BigInteger[] finalPrivateKeyShares = new BigInteger[numberOfPeers];
    for (int i = 0; i < numberOfPeers; i++) {
        privateKeyShares[i] = secretSplitter.split(((ECPrivateKeyParameters) kps[i].getPrivate()).getD());
    }/*from w w w. ja va  2s.com*/

    // Simulates distributing shares and combining them
    for (int i = 0; i < numberOfPeers; i++) {
        finalPrivateKeyShares[i] = privateKeyShares[0].getShares()[i];
        for (int j = 1; j < numberOfPeers; j++) {
            finalPrivateKeyShares[i] = finalPrivateKeyShares[i].add(privateKeyShares[j].getShares()[i]);
        }
    }

    //
    // check the commitment values.
    //
    for (int i = 0; i != numberOfPeers; i++) {
        ECCommittedSecretShare[] shares = privateKeyShares[i].getCommittedShares();
        for (int j = 0; j != numberOfPeers; j++) {
            Assert.assertTrue(shares[j].isRevealed(j, domainParams, hVal));
        }
    }

    ECPoint pubPoint = ((ECPublicKeyParameters) kps[0].getPublic()).getQ();

    for (int i = 1; i < numberOfPeers; i++) {
        pubPoint = pubPoint.add(((ECPublicKeyParameters) kps[i].getPublic()).getQ());
    }

    ECPublicKeyParameters jointPub = new ECPublicKeyParameters(pubPoint, domainParams);

    //
    // check the public key commitment values.
    //
    for (int i = 0; i != numberOfPeers; i++) {
        BigInteger[] aCoefficients = privateKeyShares[i].getCoefficients();
        ECPoint[] qCommitments = new ECPoint[aCoefficients.length];

        for (int k = 0; k != qCommitments.length; k++) {
            qCommitments[k] = domainParams.getG().multiply(aCoefficients[k]);
        }

        for (int j = 0; j != numberOfPeers; j++) {
            ECPoint val = qCommitments[0];
            for (int k = 1; k != qCommitments.length; k++) {
                val = val.add(qCommitments[k].multiply(BigInteger.valueOf(j + 1).pow(k)));
            }

            Assert.assertEquals(domainParams.getG().multiply(privateKeyShares[i].getShares()[j]), val);
        }
    }

    // Create a random plaintext
    ECPoint plaintext = generatePoint(domainParams, new SecureRandom());

    // Encrypt it using the joint public key
    ECEncryptor enc = new ECElGamalEncryptor();

    enc.init(new ParametersWithRandom(jointPub, new SecureRandom()));

    ECPair cipherText = enc.encrypt(plaintext);

    // do partial decrypts
    ECPoint[] partialDecs = new ECPoint[numberOfPeers];

    for (int i = 0; i < numberOfPeers; i++) {
        partialDecs[i] = cipherText.getX().multiply(finalPrivateKeyShares[i]);
    }

    // simulate missing peers
    for (int i = 0; i != missing.length; i++) {
        partialDecs[missing[i]] = null;
    }

    // decryption step
    LagrangeWeightCalculator lagrangeWeightCalculator = new LagrangeWeightCalculator(numberOfPeers,
            domainParams.getN());

    BigInteger[] weights = lagrangeWeightCalculator.computeWeights(partialDecs);

    // weighting
    ECPoint weightedDecryption = partialDecs[0].multiply(weights[0]);
    for (int i = 1; i < weights.length; i++) {
        if (partialDecs[i] != null) {
            weightedDecryption = weightedDecryption.add(partialDecs[i].multiply(weights[i]));
        }
    }

    // Do final decryption to recover plaintext ECPoint
    ECPoint decrypted = cipherText.getY().add(weightedDecryption.negate());

    Assert.assertEquals(shouldPass, plaintext.equals(decrypted));
}

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