org.cryptoworkshop.ximix.common.asn1.message.MessageCommitment.java Source code

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Here is the source code for org.cryptoworkshop.ximix.common.asn1.message.MessageCommitment.java

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/**
 * Copyright 2013 Crypto Workshop Pty Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.cryptoworkshop.ximix.common.asn1.message;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;

/**
 * Carrier message for a message commitment secrets and transformation details.
 */
public class MessageCommitment extends ASN1Object {
    private final byte[] detail;
    private final int newIndex;
    private final byte[] secret;

    private MessageCommitment(ASN1Sequence seq) {
        this.newIndex = ASN1Integer.getInstance(seq.getObjectAt(0)).getValue().intValue();
        this.secret = ASN1OctetString.getInstance(seq.getObjectAt(1)).getOctets();

        if (seq.size() > 2) {
            this.detail = ASN1OctetString.getInstance(seq.getObjectAt(2)).getOctets();
        } else {
            this.detail = null;
        }
    }

    /**
     * Constructor for a secret only commitment message.
     *
     * @param newIndex the index of the shuffled message the secret relates to.
     * @param secret the secret related to the commitment.
     */
    public MessageCommitment(int newIndex, byte[] secret) {
        this.detail = null;
        this.newIndex = newIndex;
        this.secret = secret;
    }

    /**
     * Constructor for a commitment message containing both the commitment message and the detail associated with transformation
     * of the message the commitment is based on.
     *
     * @param newIndex the index of the shuffled message the secret and detail relate to.
     * @param secret the secret related to the commitment.
     * @param detail data related to the committed message - usually the random value mixed in.
     */
    public MessageCommitment(int newIndex, byte[] secret, byte[] detail) {
        this.detail = detail.clone();
        this.newIndex = newIndex;
        this.secret = secret;
    }

    public static final MessageCommitment getInstance(Object o) {
        if (o instanceof MessageCommitment) {
            return (MessageCommitment) o;
        } else if (o != null) {
            return new MessageCommitment(ASN1Sequence.getInstance(o));
        }

        return null;
    }

    @Override
    public ASN1Primitive toASN1Primitive() {
        ASN1EncodableVector v = new ASN1EncodableVector();

        v.add(new ASN1Integer(newIndex));
        v.add(new DEROctetString(secret));

        if (detail != null) {
            v.add(new DEROctetString(detail));
        }

        return new DERSequence(v);
    }

    public byte[] getSecret() {
        return secret;
    }

    public byte[] getDetail() {
        if (detail != null) {
            return detail.clone();
        }

        return null;
    }

    public int getNewIndex() {
        return newIndex;
    }
}