/[winpt]/trunk/Gnupg/md5.c
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Contents of /trunk/Gnupg/md5.c

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Revision 2 - (show annotations)
Mon Jan 31 11:02:21 2005 UTC (20 years, 1 month ago) by twoaday
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WinPT initial checkin.


1 /* md5.c - MD5 Message-Digest Algorithm
2 * Copyright (C) 1995, 1996, 1998, 1999,
3 * 2000, 2001 Free Software Foundation, Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2, or (at your option) any
8 * later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software Foundation,
17 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * According to the definition of MD5 in RFC 1321 from April 1992.
20 * NOTE: This is *not* the same file as the one from glibc.
21 */
22 /* Written by Ulrich Drepper <[email protected]>, 1995. */
23 /* Heavily modified for GnuPG by <[email protected]> */
24
25 /* Test values:
26 * "" D4 1D 8C D9 8F 00 B2 04 E9 80 09 98 EC F8 42 7E
27 * "a" 0C C1 75 B9 C0 F1 B6 A8 31 C3 99 E2 69 77 26 61
28 * "abc 90 01 50 98 3C D2 4F B0 D6 96 3F 7D 28 E1 7F 72
29 * "message digest" F9 6B 69 7D 7C B7 93 8D 52 5A 2F 31 AA F1 61 D0
30 */
31
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <assert.h>
36
37 #include "md.h"
38
39
40 void
41 md5_init( MD5_CONTEXT *ctx )
42 {
43 ctx->A = 0x67452301;
44 ctx->B = 0xefcdab89;
45 ctx->C = 0x98badcfe;
46 ctx->D = 0x10325476;
47
48 ctx->nblocks = 0;
49 ctx->count = 0;
50 }
51
52
53
54
55 /* These are the four functions used in the four steps of the MD5 algorithm
56 and defined in the RFC 1321. The first function is a little bit optimized
57 (as found in Colin Plumbs public domain implementation). */
58 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
59 #define FF(b, c, d) (d ^ (b & (c ^ d)))
60 #define FG(b, c, d) FF (d, b, c)
61 #define FH(b, c, d) (b ^ c ^ d)
62 #define FI(b, c, d) (c ^ (b | ~d))
63
64 static void
65 burn_stack (int bytes)
66 {
67 char buf[128];
68
69 memset(buf, 0, sizeof buf);
70 bytes -= sizeof buf;
71 if (bytes > 0)
72 burn_stack (bytes);
73 }
74
75
76
77 /****************
78 * transform n*64 bytes
79 */
80 static void
81 /*transform( MD5_CONTEXT *ctx, const void *buffer, size_t len )*/
82 transform( MD5_CONTEXT *ctx, unsigned char *data )
83 {
84 unsigned long correct_words[16];
85 unsigned long A = ctx->A;
86 unsigned long B = ctx->B;
87 unsigned long C = ctx->C;
88 unsigned long D = ctx->D;
89 unsigned long *cwp = correct_words;
90
91 #ifdef BIG_ENDIAN_HOST
92 { int i;
93 unsigned char *p2, *p1;
94 for(i=0, p1=data, p2=(unsigned char*)correct_words; i < 16; i++, p2 += 4 ) {
95 p2[3] = *p1++;
96 p2[2] = *p1++;
97 p2[1] = *p1++;
98 p2[0] = *p1++;
99 }
100 }
101 #else
102 memcpy( correct_words, data, 64 );
103 #endif
104
105
106 #define OP(a, b, c, d, s, T) \
107 do \
108 { \
109 a += FF (b, c, d) + (*cwp++) + T; \
110 a = rol(a, s); \
111 a += b; \
112 } \
113 while (0)
114
115 /* Before we start, one word about the strange constants.
116 They are defined in RFC 1321 as
117
118 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
119 */
120
121 /* Round 1. */
122 OP (A, B, C, D, 7, 0xd76aa478);
123 OP (D, A, B, C, 12, 0xe8c7b756);
124 OP (C, D, A, B, 17, 0x242070db);
125 OP (B, C, D, A, 22, 0xc1bdceee);
126 OP (A, B, C, D, 7, 0xf57c0faf);
127 OP (D, A, B, C, 12, 0x4787c62a);
128 OP (C, D, A, B, 17, 0xa8304613);
129 OP (B, C, D, A, 22, 0xfd469501);
130 OP (A, B, C, D, 7, 0x698098d8);
131 OP (D, A, B, C, 12, 0x8b44f7af);
132 OP (C, D, A, B, 17, 0xffff5bb1);
133 OP (B, C, D, A, 22, 0x895cd7be);
134 OP (A, B, C, D, 7, 0x6b901122);
135 OP (D, A, B, C, 12, 0xfd987193);
136 OP (C, D, A, B, 17, 0xa679438e);
137 OP (B, C, D, A, 22, 0x49b40821);
138
139 #undef OP
140 #define OP(f, a, b, c, d, k, s, T) \
141 do \
142 { \
143 a += f (b, c, d) + correct_words[k] + T; \
144 a = rol(a, s); \
145 a += b; \
146 } \
147 while (0)
148
149 /* Round 2. */
150 OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
151 OP (FG, D, A, B, C, 6, 9, 0xc040b340);
152 OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
153 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
154 OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
155 OP (FG, D, A, B, C, 10, 9, 0x02441453);
156 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
157 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
158 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
159 OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
160 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
161 OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
162 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
163 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
164 OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
165 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
166
167 /* Round 3. */
168 OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
169 OP (FH, D, A, B, C, 8, 11, 0x8771f681);
170 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
171 OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
172 OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
173 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
174 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
175 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
176 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
177 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
178 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
179 OP (FH, B, C, D, A, 6, 23, 0x04881d05);
180 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
181 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
182 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
183 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
184
185 /* Round 4. */
186 OP (FI, A, B, C, D, 0, 6, 0xf4292244);
187 OP (FI, D, A, B, C, 7, 10, 0x432aff97);
188 OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
189 OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
190 OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
191 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
192 OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
193 OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
194 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
195 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
196 OP (FI, C, D, A, B, 6, 15, 0xa3014314);
197 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
198 OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
199 OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
200 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
201 OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
202
203 /* Put checksum in context given as argument. */
204 ctx->A += A;
205 ctx->B += B;
206 ctx->C += C;
207 ctx->D += D;
208 }
209
210
211
212 /* The routine updates the message-digest context to
213 * account for the presence of each of the characters inBuf[0..inLen-1]
214 * in the message whose digest is being computed.
215 */
216 void
217 md5_write( MD5_CONTEXT *hd, unsigned char *inbuf, size_t inlen)
218 {
219 if( hd->count == 64 ) { /* flush the buffer */
220 transform( hd, hd->buf );
221 burn_stack (80+6*sizeof(void*));
222 hd->count = 0;
223 hd->nblocks++;
224 }
225 if( !inbuf )
226 return;
227 if( hd->count ) {
228 for( ; inlen && hd->count < 64; inlen-- )
229 hd->buf[hd->count++] = *inbuf++;
230 md5_write( hd, NULL, 0 );
231 if( !inlen )
232 return;
233 }
234
235 while( inlen >= 64 ) {
236 transform( hd, inbuf );
237 hd->count = 0;
238 hd->nblocks++;
239 inlen -= 64;
240 inbuf += 64;
241 }
242 burn_stack (80+6*sizeof(void*));
243 for( ; inlen && hd->count < 64; inlen-- )
244 hd->buf[hd->count++] = *inbuf++;
245 }
246
247
248
249 /* The routine final terminates the message-digest computation and
250 * ends with the desired message digest in mdContext->digest[0...15].
251 * The handle is prepared for a new MD5 cycle.
252 * Returns 16 bytes representing the digest.
253 */
254
255 void
256 md5_final( MD5_CONTEXT *hd )
257 {
258 unsigned long t, msb, lsb;
259 unsigned char *p;
260
261 md5_write(hd, NULL, 0); /* flush */;
262
263 t = hd->nblocks;
264 /* multiply by 64 to make a unsigned char count */
265 lsb = t << 6;
266 msb = t >> 26;
267 /* add the count */
268 t = lsb;
269 if( (lsb += hd->count) < t )
270 msb++;
271 /* multiply by 8 to make a bit count */
272 t = lsb;
273 lsb <<= 3;
274 msb <<= 3;
275 msb |= t >> 29;
276
277 if( hd->count < 56 ) { /* enough room */
278 hd->buf[hd->count++] = 0x80; /* pad */
279 while( hd->count < 56 )
280 hd->buf[hd->count++] = 0; /* pad */
281 }
282 else { /* need one extra block */
283 hd->buf[hd->count++] = 0x80; /* pad character */
284 while( hd->count < 64 )
285 hd->buf[hd->count++] = 0;
286 md5_write(hd, NULL, 0); /* flush */;
287 memset(hd->buf, 0, 56 ); /* fill next block with zeroes */
288 }
289 /* append the 64 bit count */
290 hd->buf[56] = lsb ;
291 hd->buf[57] = lsb >> 8;
292 hd->buf[58] = lsb >> 16;
293 hd->buf[59] = lsb >> 24;
294 hd->buf[60] = msb ;
295 hd->buf[61] = msb >> 8;
296 hd->buf[62] = msb >> 16;
297 hd->buf[63] = msb >> 24;
298 transform( hd, hd->buf );
299 burn_stack (80+6*sizeof(void*));
300
301 p = hd->buf;
302 #ifdef BIG_ENDIAN_HOST
303 #define X(a) do { *p++ = hd-> a ; *p++ = hd-> a >> 8; \
304 *p++ = hd-> a >> 16; *p++ = hd-> a >> 24; } while(0)
305 #else /* little endian */
306 #define X(a) do { *(unsigned long*)p = hd-> a ; p += 4; } while(0)
307 #endif
308 X(A);
309 X(B);
310 X(C);
311 X(D);
312 #undef X
313
314 }
315
316 unsigned char *
317 md5_read( MD5_CONTEXT *hd )
318 {
319 return hd->buf;
320 }

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