package org.bouncycastle.crypto.engines;

import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.params.KeyParameter;

a class that provides a basic DESede (or Triple DES) engine.
/** * a class that provides a basic DESede (or Triple DES) engine. */
public class DESedeEngine extends DESEngine { protected static final int BLOCK_SIZE = 8; private int[] workingKey1 = null; private int[] workingKey2 = null; private int[] workingKey3 = null; private boolean forEncryption;
standard constructor.
/** * standard constructor. */
public DESedeEngine() { }
initialise a DESede cipher.
Params:
  • encrypting – whether or not we are for encryption.
  • params – the parameters required to set up the cipher.
Throws:
/** * initialise a DESede cipher. * * @param encrypting whether or not we are for encryption. * @param params the parameters required to set up the cipher. * @exception IllegalArgumentException if the params argument is * inappropriate. */
public void init( boolean encrypting, CipherParameters params) { if (!(params instanceof KeyParameter)) { throw new IllegalArgumentException("invalid parameter passed to DESede init - " + params.getClass().getName()); } byte[] keyMaster = ((KeyParameter)params).getKey(); if (keyMaster.length > 24) { throw new IllegalArgumentException("key size greater than 24 bytes"); } this.forEncryption = encrypting; byte[] key1 = new byte[8]; System.arraycopy(keyMaster, 0, key1, 0, key1.length); workingKey1 = generateWorkingKey(encrypting, key1); byte[] key2 = new byte[8]; System.arraycopy(keyMaster, 8, key2, 0, key2.length); workingKey2 = generateWorkingKey(!encrypting, key2); if (keyMaster.length == 24) { byte[] key3 = new byte[8]; System.arraycopy(keyMaster, 16, key3, 0, key3.length); workingKey3 = generateWorkingKey(encrypting, key3); } else // 16 byte key { workingKey3 = workingKey1; } } public String getAlgorithmName() { return "DESede"; } public int getBlockSize() { return BLOCK_SIZE; } public int processBlock( byte[] in, int inOff, byte[] out, int outOff) { if (workingKey1 == null) { throw new IllegalStateException("DESede engine not initialised"); } if ((inOff + BLOCK_SIZE) > in.length) { throw new DataLengthException("input buffer too short"); } if ((outOff + BLOCK_SIZE) > out.length) { throw new DataLengthException("output buffer too short"); } byte[] temp = new byte[BLOCK_SIZE]; if (forEncryption) { desFunc(workingKey1, in, inOff, temp, 0); desFunc(workingKey2, temp, 0, temp, 0); desFunc(workingKey3, temp, 0, out, outOff); } else { desFunc(workingKey3, in, inOff, temp, 0); desFunc(workingKey2, temp, 0, temp, 0); desFunc(workingKey1, temp, 0, out, outOff); } return BLOCK_SIZE; } public void reset() { } }