| /* DESedeKeySpec.java -- Keys for triple-DES. |
| Copyright (C) 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath 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, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package javax.crypto.spec; |
| |
| import java.security.InvalidKeyException; |
| import java.security.spec.KeySpec; |
| |
| /** |
| * This class is a transparent wrapper for DES-EDE (Triple-DES) keys, |
| * which are arrays of 24 bytes. |
| * |
| * @author Casey Marshall (csm@gnu.org) |
| * @since 1.4 |
| */ |
| public class DESedeKeySpec implements KeySpec |
| { |
| |
| // Constants. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * The length of a triple-DES key, in bytes. |
| */ |
| public static final int DES_EDE_KEY_LEN = 24; |
| |
| /** |
| * The key bytes. |
| */ |
| private byte[] key; |
| |
| // Constructors. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Create a new DES-EDE key spec, copying the first 24 bytes from the |
| * byte array. |
| * |
| * @param key The key bytes. |
| * @throws java.security.InvalidKeyException If there are less than 24 |
| * bytes in the array. |
| */ |
| public DESedeKeySpec(byte[] key) throws InvalidKeyException |
| { |
| this(key, 0); |
| } |
| |
| /** |
| * Create a new DES-EDE key spec, starting at <code>offset</code> in |
| * the byte array. The first 24 bytes starting at <code>offset</code> |
| * are copied. |
| * |
| * @param key The key bytes. |
| * @param offset The offset into the byte array at which to begin. |
| * @throws java.security.InvalidKeyException If there are less than 24 |
| * bytes starting at <code>offset</code>. |
| */ |
| public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException |
| { |
| if (key.length - offset < DES_EDE_KEY_LEN) |
| { |
| throw new InvalidKeyException("DES-EDE keys must be 24 bytes long"); |
| } |
| this.key = new byte[DES_EDE_KEY_LEN]; |
| System.arraycopy(key, offset, this.key, 0, DES_EDE_KEY_LEN); |
| } |
| |
| // Class methods. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Returns whether or not the given key is <i>parity adjusted</i>; |
| * i.e. every byte in the key has an odd number of "1" bits. |
| * |
| * @param key The key bytes, considered between <code>[offset, |
| * offset+23]</code> |
| * @param offset The offset into the byte array at which to begin. |
| * @return True if all bytes have an odd number of "1" bits. |
| * @throws java.security.InvalidKeyException If there are not enough |
| * bytes in the array. |
| */ |
| public static boolean isParityAdjusted(byte[] key, int offset) |
| throws InvalidKeyException |
| { |
| if (key.length - offset < DES_EDE_KEY_LEN) |
| { |
| throw new InvalidKeyException("DES-EDE keys must be 24 bytes long"); |
| } |
| boolean parity = false; |
| boolean oddbits = false; |
| for (int i = 0; i < DES_EDE_KEY_LEN; i++) |
| { |
| oddbits = false; |
| for (int j = 0; j < 8; j++) |
| { |
| oddbits ^= (key[i+offset] & 1 << j) != 0; |
| } |
| parity &= oddbits; |
| } |
| return parity; |
| } |
| |
| // Instance methods. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Return the key as a byte array. This method does not copy the byte |
| * array. |
| * |
| * @return The key bytes. |
| */ |
| public byte[] getKey() |
| { |
| return key; |
| } |
| } |