1/*
2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
3 * Please refer to the LICENSE.txt for licensing details.
4 */
5package ch.ethz.ssh2.crypto.digest;
6
7/**
8 * MD5. Based on the example code in RFC 1321. Optimized (...a little).
9 *
10 * @author Christian Plattner
11 * @version 2.50, 03/15/10
12 */
13
14/*
15 * The following disclaimer has been copied from RFC 1321:
16 *
17 * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All rights
18 * reserved.
19 *
20 * License to copy and use this software is granted provided that it is
21 * identified as the "RSA Data Security, Inc. MD5 Message-Digest Algorithm" in
22 * all material mentioning or referencing this software or this function.
23 *
24 * License is also granted to make and use derivative works provided that such
25 * works are identified as "derived from the RSA Data Security, Inc. MD5
26 * Message-Digest Algorithm" in all material mentioning or referencing the
27 * derived work.
28 *
29 * RSA Data Security, Inc. makes no representations concerning either the
30 * merchantability of this software or the suitability of this software for any
31 * particular purpose. It is provided "as is" without express or implied
32 * warranty of any kind.
33 *
34 * These notices must be retained in any copies of any part of this
35 * documentation and/or software.
36 *
37 */
38
39public final class MD5 implements Digest
40{
41	private int state0, state1, state2, state3;
42	private long count;
43	private final byte[] block = new byte[64];
44	private final int x[] = new int[16];
45
46	private static final byte[] padding = new byte[] { (byte) 128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
47			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
48			0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
49
50	public MD5()
51	{
52		reset();
53	}
54
55	private static int FF(int a, int b, int c, int d, int x, int s, int ac)
56	{
57		a += ((b & c) | ((~b) & d)) + x + ac;
58		return ((a << s) | (a >>> (32 - s))) + b;
59	}
60
61	private static int GG(int a, int b, int c, int d, int x, int s, int ac)
62	{
63		a += ((b & d) | (c & (~d))) + x + ac;
64		return ((a << s) | (a >>> (32 - s))) + b;
65	}
66
67	private static int HH(int a, int b, int c, int d, int x, int s, int ac)
68	{
69		a += (b ^ c ^ d) + x + ac;
70		return ((a << s) | (a >>> (32 - s))) + b;
71	}
72
73	private static int II(int a, int b, int c, int d, int x, int s, int ac)
74	{
75		a += (c ^ (b | (~d))) + x + ac;
76		return ((a << s) | (a >>> (32 - s))) + b;
77	}
78
79	private static void encode(byte[] dst, int dstoff, int word)
80	{
81		dst[dstoff] = (byte) (word);
82		dst[dstoff + 1] = (byte) (word >> 8);
83		dst[dstoff + 2] = (byte) (word >> 16);
84		dst[dstoff + 3] = (byte) (word >> 24);
85	}
86
87	private void transform(byte[] src, int pos)
88	{
89		int a = state0;
90		int b = state1;
91		int c = state2;
92		int d = state3;
93
94		for (int i = 0; i < 16; i++, pos += 4)
95		{
96			x[i] = (src[pos] & 0xff) | ((src[pos + 1] & 0xff) << 8) | ((src[pos + 2] & 0xff) << 16)
97					| ((src[pos + 3] & 0xff) << 24);
98		}
99
100		/* Round 1 */
101
102		a = FF(a, b, c, d, x[0], 7, 0xd76aa478); /* 1 */
103		d = FF(d, a, b, c, x[1], 12, 0xe8c7b756); /* 2 */
104		c = FF(c, d, a, b, x[2], 17, 0x242070db); /* 3 */
105		b = FF(b, c, d, a, x[3], 22, 0xc1bdceee); /* 4 */
106		a = FF(a, b, c, d, x[4], 7, 0xf57c0faf); /* 5 */
107		d = FF(d, a, b, c, x[5], 12, 0x4787c62a); /* 6 */
108		c = FF(c, d, a, b, x[6], 17, 0xa8304613); /* 7 */
109		b = FF(b, c, d, a, x[7], 22, 0xfd469501); /* 8 */
110		a = FF(a, b, c, d, x[8], 7, 0x698098d8); /* 9 */
111		d = FF(d, a, b, c, x[9], 12, 0x8b44f7af); /* 10 */
112		c = FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
113		b = FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
114		a = FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
115		d = FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
116		c = FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
117		b = FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
118
119		/* Round 2 */
120		a = GG(a, b, c, d, x[1], 5, 0xf61e2562); /* 17 */
121		d = GG(d, a, b, c, x[6], 9, 0xc040b340); /* 18 */
122		c = GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
123		b = GG(b, c, d, a, x[0], 20, 0xe9b6c7aa); /* 20 */
124		a = GG(a, b, c, d, x[5], 5, 0xd62f105d); /* 21 */
125		d = GG(d, a, b, c, x[10], 9, 0x2441453); /* 22 */
126		c = GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
127		b = GG(b, c, d, a, x[4], 20, 0xe7d3fbc8); /* 24 */
128		a = GG(a, b, c, d, x[9], 5, 0x21e1cde6); /* 25 */
129		d = GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
130		c = GG(c, d, a, b, x[3], 14, 0xf4d50d87); /* 27 */
131		b = GG(b, c, d, a, x[8], 20, 0x455a14ed); /* 28 */
132		a = GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
133		d = GG(d, a, b, c, x[2], 9, 0xfcefa3f8); /* 30 */
134		c = GG(c, d, a, b, x[7], 14, 0x676f02d9); /* 31 */
135		b = GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
136
137		/* Round 3 */
138		a = HH(a, b, c, d, x[5], 4, 0xfffa3942); /* 33 */
139		d = HH(d, a, b, c, x[8], 11, 0x8771f681); /* 34 */
140		c = HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
141		b = HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
142		a = HH(a, b, c, d, x[1], 4, 0xa4beea44); /* 37 */
143		d = HH(d, a, b, c, x[4], 11, 0x4bdecfa9); /* 38 */
144		c = HH(c, d, a, b, x[7], 16, 0xf6bb4b60); /* 39 */
145		b = HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
146		a = HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
147		d = HH(d, a, b, c, x[0], 11, 0xeaa127fa); /* 42 */
148		c = HH(c, d, a, b, x[3], 16, 0xd4ef3085); /* 43 */
149		b = HH(b, c, d, a, x[6], 23, 0x4881d05); /* 44 */
150		a = HH(a, b, c, d, x[9], 4, 0xd9d4d039); /* 45 */
151		d = HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
152		c = HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
153		b = HH(b, c, d, a, x[2], 23, 0xc4ac5665); /* 48 */
154
155		/* Round 4 */
156		a = II(a, b, c, d, x[0], 6, 0xf4292244); /* 49 */
157		d = II(d, a, b, c, x[7], 10, 0x432aff97); /* 50 */
158		c = II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
159		b = II(b, c, d, a, x[5], 21, 0xfc93a039); /* 52 */
160		a = II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
161		d = II(d, a, b, c, x[3], 10, 0x8f0ccc92); /* 54 */
162		c = II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
163		b = II(b, c, d, a, x[1], 21, 0x85845dd1); /* 56 */
164		a = II(a, b, c, d, x[8], 6, 0x6fa87e4f); /* 57 */
165		d = II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
166		c = II(c, d, a, b, x[6], 15, 0xa3014314); /* 59 */
167		b = II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
168		a = II(a, b, c, d, x[4], 6, 0xf7537e82); /* 61 */
169		d = II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
170		c = II(c, d, a, b, x[2], 15, 0x2ad7d2bb); /* 63 */
171		b = II(b, c, d, a, x[9], 21, 0xeb86d391); /* 64 */
172
173		state0 += a;
174		state1 += b;
175		state2 += c;
176		state3 += d;
177	}
178
179	public final void reset()
180	{
181		count = 0;
182
183		state0 = 0x67452301;
184		state1 = 0xefcdab89;
185		state2 = 0x98badcfe;
186		state3 = 0x10325476;
187
188		/* Clear traces in memory... */
189
190		for (int i = 0; i < 16; i++)
191			x[i] = 0;
192	}
193
194	public final void update(byte b)
195	{
196		final int space = 64 - ((int) (count & 0x3f));
197
198		count++;
199
200		block[64 - space] = b;
201
202		if (space == 1)
203			transform(block, 0);
204	}
205
206	public final void update(byte[] buff, int pos, int len)
207	{
208		int space = 64 - ((int) (count & 0x3f));
209
210		count += len;
211
212		while (len > 0)
213		{
214			if (len < space)
215			{
216				System.arraycopy(buff, pos, block, 64 - space, len);
217				break;
218			}
219
220			if (space == 64)
221			{
222				transform(buff, pos);
223			}
224			else
225			{
226				System.arraycopy(buff, pos, block, 64 - space, space);
227				transform(block, 0);
228			}
229
230			pos += space;
231			len -= space;
232			space = 64;
233		}
234	}
235
236	public final void update(byte[] b)
237	{
238		update(b, 0, b.length);
239	}
240
241	public final void digest(byte[] dst, int pos)
242	{
243		byte[] bits = new byte[8];
244
245		encode(bits, 0, (int) (count << 3));
246		encode(bits, 4, (int) (count >> 29));
247
248		int idx = (int) count & 0x3f;
249		int padLen = (idx < 56) ? (56 - idx) : (120 - idx);
250
251		update(padding, 0, padLen);
252		update(bits, 0, 8);
253
254		encode(dst, pos, state0);
255		encode(dst, pos + 4, state1);
256		encode(dst, pos + 8, state2);
257		encode(dst, pos + 12, state3);
258
259		reset();
260	}
261
262	public final void digest(byte[] dst)
263	{
264		digest(dst, 0);
265	}
266
267	public final int getDigestLength()
268	{
269		return 16;
270	}
271}
272