Example usage for org.bouncycastle.crypto.ec ECFixedTransform ECFixedTransform

Introduction

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

Prototype

public ECFixedTransform(BigInteger k) 

Source Link

Usage

From source file:org.cryptoworkshop.ximix.client.verify.ECShuffledTranscriptVerifier.java

License:Apache License

/**
 * Verify that the transcripts are valid, throwing an exception if an issue is found.
 *
 * @throws TranscriptVerificationException on verification failure.
 *//* w  w w  .  ja v  a2  s  .com*/
public void verify() throws TranscriptVerificationException {
    // if we've been past streams we have to read the lot in one go.
    int batchSize = (initialTranscript instanceof InputStream) ? -1 : 2000; // TODO: make batch size configurable
    boolean moreWitnesses = true;

    while (moreWitnesses) {
        moreWitnesses = loadWitnesses(witnessTranscript, batchSize);

        if (witnesses.isEmpty()) {
            break;
        }

        if (initialTranscript instanceof InputStream) {
            loadCommitments((InputStream) initialTranscript, (InputStream) finalTranscript);
        } else {
            try {
                InputStream initTranscript = new BufferedInputStream(
                        new FileInputStream((File) initialTranscript));
                InputStream finTranscript = new BufferedInputStream(
                        new FileInputStream((File) finalTranscript));

                loadCommitments(initTranscript, finTranscript);

                initTranscript.close();
                finTranscript.close();
            } catch (IOException e) {
                throw new TranscriptVerificationException("Exception validating transcripts: " + e.getMessage(),
                        e);
            }
        }

        if (initialMap.size() != witnesses.size()) {
            throw new TranscriptVerificationException("Initial transcript incomplete "
                    + (witnesses.size() - initialMap.size()) + " messages missing.");
        }

        if (!finalIndexesOfInterest.isEmpty()) {
            throw new TranscriptVerificationException(
                    "Final transcript incomplete " + finalIndexesOfInterest.size() + " messages missing.");
        }

        try {
            for (Integer msgIndex : witnesses.keySet()) {
                PostedMessage initMsg = initialMap.get(msgIndex);
                MessageCommitment comMsg = witnesses.get(msgIndex);

                BigInteger kValue = new BigInteger(1, comMsg.getDetail());
                ECPairFactorTransform transform = new ECFixedTransform(kValue);

                transform.init(pubKey);

                PairSequence ecSeq = PairSequence.getInstance(ecCurve, initMsg.getMessage());
                ECPair[] ecInit = ecSeq.getECPairs();
                ECPair[] ecRes = new ECPair[ecSeq.size()];

                for (int i = 0; i != ecRes.length; i++) {
                    ecRes[i] = transform.transform(ecInit[i]);
                }

                PostedMessage finalMsg = finalMap.get(comMsg.getNewIndex());
                Commitment commitment = new Commitment(comMsg.getSecret(), finalMsg.getCommitment());

                if (commitChecker.isRevealed(commitment, comMsg.getNewIndex())) {
                    ECPair[] ecFin = PairSequence
                            .getInstance(pubKey.getParameters().getCurve(), finalMsg.getMessage()).getECPairs();

                    if (!Arrays.equals(ecFin, ecRes)) {
                        throw new TranscriptVerificationException(
                                "Transformed cipher text does not match for relationship " + initMsg.getIndex()
                                        + " -> " + comMsg.getNewIndex());
                    }
                } else {
                    throw new TranscriptVerificationException("Commitment check failed for relationship "
                            + initMsg.getIndex() + " -> " + comMsg.getNewIndex());
                }
            }
        } catch (TranscriptVerificationException e) {
            throw e;
        } catch (Exception e) {
            throw new TranscriptVerificationException("Exception validating transcripts: " + e.getMessage(), e);
        }

        witnesses.clear();
        initialMap.clear();
        finalMap.clear();
        finalIndexesOfInterest.clear();
    }
}

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From source file:org.cryptoworkshop.ximix.node.mixnet.transform.MultiColumnRowTransform.java

License:Apache License

public void init(Object o) {
    this.parameters = (ECPublicKeyParameters) o;

    BigInteger kValue = generateK(parameters.getParameters().getN(), new SecureRandom()); // TODO: make configurable?

    transform = new ECFixedTransform(kValue);

    transform.init(parameters);/*from  w w  w .  j a  va  2 s.  c o m*/
}

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