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/Modules/md5.c

http://unladen-swallow.googlecode.com/
C | 394 lines | 270 code | 27 blank | 97 comment | 17 complexity | cde8744da846bbcd348a5126acb9f7b0 MD5 | raw file
  1/*
  2  Copyright (C) 1999, 2000, 2002 Aladdin Enterprises.  All rights reserved.
  3
  4  This software is provided 'as-is', without any express or implied
  5  warranty.  In no event will the authors be held liable for any damages
  6  arising from the use of this software.
  7
  8  Permission is granted to anyone to use this software for any purpose,
  9  including commercial applications, and to alter it and redistribute it
 10  freely, subject to the following restrictions:
 11
 12  1. The origin of this software must not be misrepresented; you must not
 13     claim that you wrote the original software. If you use this software
 14     in a product, an acknowledgment in the product documentation would be
 15     appreciated but is not required.
 16  2. Altered source versions must be plainly marked as such, and must not be
 17     misrepresented as being the original software.
 18  3. This notice may not be removed or altered from any source distribution.
 19
 20  L. Peter Deutsch
 21  ghost@aladdin.com
 22
 23 */
 24/* $Id: md5.c,v 1.6 2002/04/13 19:20:28 lpd Exp $ */
 25/*
 26  Independent implementation of MD5 (RFC 1321).
 27
 28  This code implements the MD5 Algorithm defined in RFC 1321, whose
 29  text is available at
 30	http://www.ietf.org/rfc/rfc1321.txt
 31  The code is derived from the text of the RFC, including the test suite
 32  (section A.5) but excluding the rest of Appendix A.  It does not include
 33  any code or documentation that is identified in the RFC as being
 34  copyrighted.
 35
 36  The original and principal author of md5.c is L. Peter Deutsch
 37  <ghost@aladdin.com>.  Other authors are noted in the change history
 38  that follows (in reverse chronological order):
 39
 40  2002-04-13 lpd Clarified derivation from RFC 1321; now handles byte order
 41	either statically or dynamically; added missing #include <string.h>
 42	in library.
 43  2002-03-11 lpd Corrected argument list for main(), and added int return
 44	type, in test program and T value program.
 45  2002-02-21 lpd Added missing #include <stdio.h> in test program.
 46  2000-07-03 lpd Patched to eliminate warnings about "constant is
 47	unsigned in ANSI C, signed in traditional"; made test program
 48	self-checking.
 49  1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
 50  1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5).
 51  1999-05-03 lpd Original version.
 52 */
 53
 54#include "md5.h"
 55#include <string.h>
 56#include <limits.h>
 57
 58#undef BYTE_ORDER	/* 1 = big-endian, -1 = little-endian, 0 = unknown */
 59#ifdef ARCH_IS_BIG_ENDIAN
 60#  define BYTE_ORDER (ARCH_IS_BIG_ENDIAN ? 1 : -1)
 61#else
 62#  define BYTE_ORDER 0
 63#endif
 64
 65#define T_MASK ((md5_word_t)~0)
 66#define T1 /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
 67#define T2 /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
 68#define T3    0x242070db
 69#define T4 /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
 70#define T5 /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
 71#define T6    0x4787c62a
 72#define T7 /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
 73#define T8 /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
 74#define T9    0x698098d8
 75#define T10 /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
 76#define T11 /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
 77#define T12 /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
 78#define T13    0x6b901122
 79#define T14 /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
 80#define T15 /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
 81#define T16    0x49b40821
 82#define T17 /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
 83#define T18 /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
 84#define T19    0x265e5a51
 85#define T20 /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
 86#define T21 /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
 87#define T22    0x02441453
 88#define T23 /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
 89#define T24 /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
 90#define T25    0x21e1cde6
 91#define T26 /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
 92#define T27 /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
 93#define T28    0x455a14ed
 94#define T29 /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
 95#define T30 /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
 96#define T31    0x676f02d9
 97#define T32 /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
 98#define T33 /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
 99#define T34 /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
100#define T35    0x6d9d6122
101#define T36 /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
102#define T37 /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
103#define T38    0x4bdecfa9
104#define T39 /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
105#define T40 /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
106#define T41    0x289b7ec6
107#define T42 /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
108#define T43 /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
109#define T44    0x04881d05
110#define T45 /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
111#define T46 /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
112#define T47    0x1fa27cf8
113#define T48 /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
114#define T49 /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
115#define T50    0x432aff97
116#define T51 /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
117#define T52 /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
118#define T53    0x655b59c3
119#define T54 /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
120#define T55 /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
121#define T56 /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
122#define T57    0x6fa87e4f
123#define T58 /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
124#define T59 /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
125#define T60    0x4e0811a1
126#define T61 /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
127#define T62 /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
128#define T63    0x2ad7d2bb
129#define T64 /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)
130
131
132static void
133md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
134{
135    md5_word_t
136	a = pms->abcd[0], b = pms->abcd[1],
137	c = pms->abcd[2], d = pms->abcd[3];
138    md5_word_t t;
139#if BYTE_ORDER > 0
140    /* Define storage only for big-endian CPUs. */
141    md5_word_t X[16];
142#else
143    /* Define storage for little-endian or both types of CPUs. */
144    md5_word_t xbuf[16];
145    const md5_word_t *X;
146#endif
147
148    {
149#if BYTE_ORDER == 0
150	/*
151	 * Determine dynamically whether this is a big-endian or
152	 * little-endian machine, since we can use a more efficient
153	 * algorithm on the latter.
154	 */
155	static const int w = 1;
156
157	if (*((const md5_byte_t *)&w)) /* dynamic little-endian */
158#endif
159#if BYTE_ORDER <= 0		/* little-endian */
160	{
161	    /*
162	     * On little-endian machines, we can process properly aligned
163	     * data without copying it.
164	     */
165	    if (!((data - (const md5_byte_t *)0) & 3)) {
166		/* data are properly aligned */
167		X = (const md5_word_t *)data;
168	    } else {
169		/* not aligned */
170		memcpy(xbuf, data, 64);
171		X = xbuf;
172	    }
173	}
174#endif
175#if BYTE_ORDER == 0
176	else			/* dynamic big-endian */
177#endif
178#if BYTE_ORDER >= 0		/* big-endian */
179	{
180	    /*
181	     * On big-endian machines, we must arrange the bytes in the
182	     * right order.
183	     */
184	    const md5_byte_t *xp = data;
185	    int i;
186
187#  if BYTE_ORDER == 0
188	    X = xbuf;		/* (dynamic only) */
189#  else
190#    define xbuf X		/* (static only) */
191#  endif
192	    for (i = 0; i < 16; ++i, xp += 4)
193		xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
194	}
195#endif
196    }
197
198#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
199
200    /* Round 1. */
201    /* Let [abcd k s i] denote the operation
202       a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
203#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
204#define SET(a, b, c, d, k, s, Ti)\
205  t = a + F(b,c,d) + X[k] + Ti;\
206  a = ROTATE_LEFT(t, s) + b
207    /* Do the following 16 operations. */
208    SET(a, b, c, d,  0,  7,  T1);
209    SET(d, a, b, c,  1, 12,  T2);
210    SET(c, d, a, b,  2, 17,  T3);
211    SET(b, c, d, a,  3, 22,  T4);
212    SET(a, b, c, d,  4,  7,  T5);
213    SET(d, a, b, c,  5, 12,  T6);
214    SET(c, d, a, b,  6, 17,  T7);
215    SET(b, c, d, a,  7, 22,  T8);
216    SET(a, b, c, d,  8,  7,  T9);
217    SET(d, a, b, c,  9, 12, T10);
218    SET(c, d, a, b, 10, 17, T11);
219    SET(b, c, d, a, 11, 22, T12);
220    SET(a, b, c, d, 12,  7, T13);
221    SET(d, a, b, c, 13, 12, T14);
222    SET(c, d, a, b, 14, 17, T15);
223    SET(b, c, d, a, 15, 22, T16);
224#undef SET
225
226     /* Round 2. */
227     /* Let [abcd k s i] denote the operation
228          a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
229#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
230#define SET(a, b, c, d, k, s, Ti)\
231  t = a + G(b,c,d) + X[k] + Ti;\
232  a = ROTATE_LEFT(t, s) + b
233     /* Do the following 16 operations. */
234    SET(a, b, c, d,  1,  5, T17);
235    SET(d, a, b, c,  6,  9, T18);
236    SET(c, d, a, b, 11, 14, T19);
237    SET(b, c, d, a,  0, 20, T20);
238    SET(a, b, c, d,  5,  5, T21);
239    SET(d, a, b, c, 10,  9, T22);
240    SET(c, d, a, b, 15, 14, T23);
241    SET(b, c, d, a,  4, 20, T24);
242    SET(a, b, c, d,  9,  5, T25);
243    SET(d, a, b, c, 14,  9, T26);
244    SET(c, d, a, b,  3, 14, T27);
245    SET(b, c, d, a,  8, 20, T28);
246    SET(a, b, c, d, 13,  5, T29);
247    SET(d, a, b, c,  2,  9, T30);
248    SET(c, d, a, b,  7, 14, T31);
249    SET(b, c, d, a, 12, 20, T32);
250#undef SET
251
252     /* Round 3. */
253     /* Let [abcd k s t] denote the operation
254          a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
255#define H(x, y, z) ((x) ^ (y) ^ (z))
256#define SET(a, b, c, d, k, s, Ti)\
257  t = a + H(b,c,d) + X[k] + Ti;\
258  a = ROTATE_LEFT(t, s) + b
259     /* Do the following 16 operations. */
260    SET(a, b, c, d,  5,  4, T33);
261    SET(d, a, b, c,  8, 11, T34);
262    SET(c, d, a, b, 11, 16, T35);
263    SET(b, c, d, a, 14, 23, T36);
264    SET(a, b, c, d,  1,  4, T37);
265    SET(d, a, b, c,  4, 11, T38);
266    SET(c, d, a, b,  7, 16, T39);
267    SET(b, c, d, a, 10, 23, T40);
268    SET(a, b, c, d, 13,  4, T41);
269    SET(d, a, b, c,  0, 11, T42);
270    SET(c, d, a, b,  3, 16, T43);
271    SET(b, c, d, a,  6, 23, T44);
272    SET(a, b, c, d,  9,  4, T45);
273    SET(d, a, b, c, 12, 11, T46);
274    SET(c, d, a, b, 15, 16, T47);
275    SET(b, c, d, a,  2, 23, T48);
276#undef SET
277
278     /* Round 4. */
279     /* Let [abcd k s t] denote the operation
280          a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
281#define I(x, y, z) ((y) ^ ((x) | ~(z)))
282#define SET(a, b, c, d, k, s, Ti)\
283  t = a + I(b,c,d) + X[k] + Ti;\
284  a = ROTATE_LEFT(t, s) + b
285     /* Do the following 16 operations. */
286    SET(a, b, c, d,  0,  6, T49);
287    SET(d, a, b, c,  7, 10, T50);
288    SET(c, d, a, b, 14, 15, T51);
289    SET(b, c, d, a,  5, 21, T52);
290    SET(a, b, c, d, 12,  6, T53);
291    SET(d, a, b, c,  3, 10, T54);
292    SET(c, d, a, b, 10, 15, T55);
293    SET(b, c, d, a,  1, 21, T56);
294    SET(a, b, c, d,  8,  6, T57);
295    SET(d, a, b, c, 15, 10, T58);
296    SET(c, d, a, b,  6, 15, T59);
297    SET(b, c, d, a, 13, 21, T60);
298    SET(a, b, c, d,  4,  6, T61);
299    SET(d, a, b, c, 11, 10, T62);
300    SET(c, d, a, b,  2, 15, T63);
301    SET(b, c, d, a,  9, 21, T64);
302#undef SET
303
304     /* Then perform the following additions. (That is increment each
305        of the four registers by the value it had before this block
306        was started.) */
307    pms->abcd[0] += a;
308    pms->abcd[1] += b;
309    pms->abcd[2] += c;
310    pms->abcd[3] += d;
311}
312
313void
314md5_init(md5_state_t *pms)
315{
316    pms->count[0] = pms->count[1] = 0;
317    pms->abcd[0] = 0x67452301;
318    pms->abcd[1] = /*0xefcdab89*/ T_MASK ^ 0x10325476;
319    pms->abcd[2] = /*0x98badcfe*/ T_MASK ^ 0x67452301;
320    pms->abcd[3] = 0x10325476;
321}
322
323void
324md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
325{
326    const md5_byte_t *p = data;
327    int left = nbytes;
328    int offset = (pms->count[0] >> 3) & 63;
329    md5_word_t nbits = (md5_word_t)(nbytes << 3);
330
331    if (nbytes <= 0)
332	return;
333
334    /* this special case is handled recursively */
335    if (nbytes > INT_MAX - offset) {
336        int overlap;
337
338        /* handle the append in two steps to prevent overflow */
339        overlap = 64 - offset;
340
341        md5_append(pms, data, overlap);
342        md5_append(pms, data + overlap, nbytes - overlap); 
343        return;
344    }
345
346    /* Update the message length. */
347    pms->count[1] += nbytes >> 29;
348    pms->count[0] += nbits;
349    if (pms->count[0] < nbits)
350	pms->count[1]++;
351
352    /* Process an initial partial block. */
353    if (offset) {
354	int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);
355
356	memcpy(pms->buf + offset, p, copy);
357	if (offset + copy < 64)
358	    return;
359	p += copy;
360	left -= copy;
361	md5_process(pms, pms->buf);
362    }
363
364    /* Process full blocks. */
365    for (; left >= 64; p += 64, left -= 64)
366	md5_process(pms, p);
367
368    /* Process a final partial block. */
369    if (left)
370	memcpy(pms->buf, p, left);
371}
372
373void
374md5_finish(md5_state_t *pms, md5_byte_t digest[16])
375{
376    static const md5_byte_t pad[64] = {
377	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
378	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
379	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
380	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
381    };
382    md5_byte_t data[8];
383    int i;
384
385    /* Save the length before padding. */
386    for (i = 0; i < 8; ++i)
387	data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
388    /* Pad to 56 bytes mod 64. */
389    md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
390    /* Append the length. */
391    md5_append(pms, data, 8);
392    for (i = 0; i < 16; ++i)
393	digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
394}