1package ch.ethz.ssh2.crypto.cipher;
2
3/*
4 This file was shamelessly taken (and modified) from the Bouncy Castle Crypto package.
5 Their licence file states the following:
6
7 Copyright (c) 2000 - 2004 The Legion Of The Bouncy Castle
8 (http://www.bouncycastle.org)
9
10 Permission is hereby granted, free of charge, to any person obtaining a copy
11 of this software and associated documentation files (the "Software"), to deal
12 in the Software without restriction, including without limitation the rights
13 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 copies of the Software, and to permit persons to whom the Software is
15 furnished to do so, subject to the following conditions:
16
17 The above copyright notice and this permission notice shall be included in
18 all copies or substantial portions of the Software.
19
20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
23 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 THE SOFTWARE.
27 */
28
29/**
30 * DESede.
31 *
32 * @author See comments in the source file
33 * @version 2.50, 03/15/10
34 *
35 */
36public class DESede extends DES
37{
38	private int[] key1 = null;
39	private int[] key2 = null;
40	private int[] key3 = null;
41
42	private boolean encrypt;
43
44	/**
45	 * standard constructor.
46	 */
47	public DESede()
48	{
49	}
50
51	/**
52	 * initialise a DES cipher.
53	 *
54	 * @param encrypting
55	 *            whether or not we are for encryption.
56	 * @param key
57	 *            the parameters required to set up the cipher.
58	 * @exception IllegalArgumentException
59	 *                if the params argument is inappropriate.
60	 */
61	@Override
62	public void init(boolean encrypting, byte[] key)
63	{
64		key1 = generateWorkingKey(encrypting, key, 0);
65		key2 = generateWorkingKey(!encrypting, key, 8);
66		key3 = generateWorkingKey(encrypting, key, 16);
67
68		encrypt = encrypting;
69	}
70
71	@Override
72	public String getAlgorithmName()
73	{
74		return "DESede";
75	}
76
77	@Override
78	public int getBlockSize()
79	{
80		return 8;
81	}
82
83	@Override
84	public void transformBlock(byte[] in, int inOff, byte[] out, int outOff)
85	{
86		if (key1 == null)
87		{
88			throw new IllegalStateException("DESede engine not initialised!");
89		}
90
91		if (encrypt)
92		{
93			desFunc(key1, in, inOff, out, outOff);
94			desFunc(key2, out, outOff, out, outOff);
95			desFunc(key3, out, outOff, out, outOff);
96		}
97		else
98		{
99			desFunc(key3, in, inOff, out, outOff);
100			desFunc(key2, out, outOff, out, outOff);
101			desFunc(key1, out, outOff, out, outOff);
102		}
103	}
104
105	@Override
106	public void reset()
107	{
108	}
109}
110