de.tsenger.animamea.crypto.AmDESCrypto.java Source code

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Here is the source code for de.tsenger.animamea.crypto.AmDESCrypto.java

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/**
 *  Copyright 2011, Tobias Senger
 *  
 *  This file is part of animamea.
 *
 *  Animamea is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Animamea is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License   
 *  along with animamea.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.tsenger.animamea.crypto;

import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.Mac;
import org.bouncycastle.crypto.engines.DESEngine;
import org.bouncycastle.crypto.engines.DESedeEngine;
import org.bouncycastle.crypto.macs.ISO9797Alg3Mac;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.paddings.ISO7816d4Padding;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;

/**
 * @author Tobias Senger (tobias@t-senger.de)
 * 
 */
public class AmDESCrypto extends AmCryptoProvider {

    public static int blockSize = 8;
    private byte[] keyBytes;
    private KeyParameter keyP = null;
    private byte[] IV = null;
    private byte[] sscBytes = null;

    private void initCiphers(byte[] key, byte[] iv) {
        // get the keyBytes
        keyBytes = new byte[key.length];
        System.arraycopy(key, 0, keyBytes, 0, key.length);

        // get the IV
        IV = new byte[blockSize];
        System.arraycopy(iv, 0, IV, 0, iv.length);

        keyP = new KeyParameter(keyBytes);

        encryptCipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new DESedeEngine()),
                new ISO7816d4Padding());
        decryptCipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new DESedeEngine()),
                new ISO7816d4Padding());

        // create the IV parameter
        ParametersWithIV parameterIV = new ParametersWithIV(keyP, IV);

        encryptCipher.init(true, parameterIV);
        decryptCipher.init(false, parameterIV);
    }

    /*
     * (non-Javadoc)
     * 
     * @see de.tsenger.animamea.crypto.AmCryptoProvider#init(byte[], long)
     */
    @Override
    public void init(byte[] keyBytes, byte[] ssc) {
        sscBytes = ssc.clone();
        initCiphers(keyBytes, new byte[blockSize]);
    }

    /*
     * (non-Javadoc)
     * 
     * @see de.tsenger.animamea.crypto.AmCryptoProvider#getMAC(byte[])
     */
    @Override
    public byte[] getMAC(byte[] data) {

        byte[] n = new byte[8 + data.length];
        System.arraycopy(sscBytes, 0, n, 0, 8);
        System.arraycopy(data, 0, n, 8, data.length);

        BlockCipher cipher = new DESEngine();
        Mac mac = new ISO9797Alg3Mac(cipher, 64, new ISO7816d4Padding());

        ParametersWithIV parameterIV = new ParametersWithIV(keyP, IV);

        mac.init(parameterIV);
        mac.update(n, 0, n.length);

        byte[] out = new byte[8];

        mac.doFinal(out, 0);

        return out;
    }

    /**
     * Dekodiert einen Block mit DES
     * 
     * @param key
     *            Byte-Array enthlt den 3DES-Schlssel
     * @param z
     *            verschlsselter Block
     * @return entschlsselter block
     */
    @Override
    public byte[] decryptBlock(byte[] key, byte[] z) {
        byte[] s = new byte[16];
        KeyParameter encKey = new KeyParameter(key);
        BlockCipher cipher = new DESedeEngine();
        cipher.init(false, encKey);
        cipher.processBlock(z, 0, s, 0);
        return s;
    }

    /*
     * (non-Javadoc)
     * 
     * @see de.tsenger.animamea.crypto.AmCryptoProvider#getMAC(byte[], byte[])
     */
    @Override
    public byte[] getMAC(byte[] key, byte[] data) {
        BlockCipher cipher = new DESEngine();
        Mac mac = new ISO9797Alg3Mac(cipher, 64, new ISO7816d4Padding());

        KeyParameter keyP = new KeyParameter(key);
        mac.init(keyP);
        mac.update(data, 0, data.length);

        byte[] out = new byte[8];

        mac.doFinal(out, 0);

        return out;
    }

    /*
     * (non-Javadoc)
     * 
     * @see de.tsenger.animamea.crypto.AmCryptoProvider#getBlockSize()
     */
    @Override
    public int getBlockSize() {
        return blockSize;
    }

}