des3.java

The Javatm Telnet Application/Applet 很好用的

/*
 * This file is part of "The Java Telnet Application".
 *
 * (c) Matthias L. Jugel, Marcus Mei遪er 1996-2002. All Rights Reserved.
 *
 * Please visit http://javatelnet.org/ for updates and contact.
 *
 * --LICENSE NOTICE--
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * --LICENSE NOTICE--
 *
 * Additional NOTICE: This file uses DES (see DES.java for copyright
 * information!)
 */
package de.mud.ssh;


public final class DES3 extends Cipher {
  static {
    System.err.println("3DES Cipher.");
  }

  DES des1 = new DES();
  DES des2 = new DES();
  DES des3 = new DES();

  public synchronized void encrypt(byte[] src, int srcOff, byte[] dest, int destOff, int len) {
    des1.encrypt(src, srcOff, dest, destOff, len);
    des2.decrypt(dest, destOff, dest, destOff, len);
    des3.encrypt(dest, destOff, dest, destOff, len);
  }

  public synchronized void decrypt(byte[] src, int srcOff, byte[] dest, int destOff, int len) {
    des3.decrypt(src, srcOff, dest, destOff, len);
    des2.encrypt(dest, destOff, dest, destOff, len);
    des1.decrypt(dest, destOff, dest, destOff, len);
  }

  public void setKey(byte[] key) {
    byte[] subKey = new byte[8];
    des1.setKey(key);
    System.arraycopy(key, 8, subKey, 0, 8);
    des2.setKey(subKey);
    System.arraycopy(key, 16, subKey, 0, 8);
    des3.setKey(subKey);
  }

  /* !!! DEBUG
  public static void main(String[] argv) {
    byte[] key = {
      (byte)0x12, (byte)0x34, (byte)0x56, (byte)0x78,
      (byte)0x87, (byte)0x65, (byte)0x43, (byte)0x21,
      (byte)0x44, (byte)0x55, (byte)0x66, (byte)0x77,
      (byte)0x87, (byte)0x65, (byte)0x43, (byte)0x21,
      (byte)0x87, (byte)0x65, (byte)0x43, (byte)0x21,
      (byte)0x12, (byte)0x34, (byte)0x56, (byte)0x78,
    };

    byte[] txt = {
      (byte)0x00, (byte)0x11, (byte)0x22, (byte)0x33,
      (byte)0x44, (byte)0x55, (byte)0x66, (byte)0x77,
      (byte)0x00, (byte)0x11, (byte)0x22, (byte)0x33,
      (byte)0x44, (byte)0x55, (byte)0x66, (byte)0x77,
      (byte)0x00, (byte)0x11, (byte)0x22, (byte)0x33,
      (byte)0x44, (byte)0x55, (byte)0x66, (byte)0x77
    };

    byte[] enc;
    byte[] dec;

    System.out.println("key: " + printHex(key));
    System.out.println("txt: " + printHex(txt));

    DES3 cipher = new DES3();
    cipher.setKey(key);

    enc = cipher.encrypt(txt);
    System.out.println("enc: " + printHex(enc));

    cipher = new DES3();
    cipher.setKey(key);

    dec = cipher.decrypt(enc);

    System.out.println("dec: " + printHex(dec));
  }

  static String printHex(byte[] buf) {
    byte[] out = new byte[buf.length + 1];
    out[0] = 0;
    System.arraycopy(buf, 0, out, 1, buf.length);
    BigInteger big = new BigInteger(out);
    return big.toString(16);
  }
  static String printHex(int i) {
    BigInteger b = BigInteger.valueOf((long)i + 0x100000000L);
    BigInteger c = BigInteger.valueOf(0x100000000L);
    if(b.compareTo(c) != -1)
      b = b.subtract(c);
    return b.toString(16);
  }

    */

}