OpenWrt – Blame information for rev 1

Subversion Repositories:
Rev:
Rev Author Line No. Line
1 office 1 /* crypto/bn/bn_exp.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58 /* ====================================================================
59 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
60 *
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
63 * are met:
64 *
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
67 *
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
71 * distribution.
72 *
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77 *
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
82 *
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
86 *
87 * 6. Redistributions of any form whatsoever must retain the following
88 * acknowledgment:
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91 *
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
105 *
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
109 *
110 */
111  
112  
113 #include <stdio.h>
114 #include "bn_lcl.h"
115  
116 #define TABLE_SIZE 32
117  
118 /* slow but works */
119 int BN_mod_mul(BIGNUM *ret, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx)
120 {
121 BIGNUM *t;
122 int r=0;
123  
124 bn_check_top(a);
125 bn_check_top(b);
126 bn_check_top(m);
127  
128 BN_CTX_start(ctx);
129 if ((t = BN_CTX_get(ctx)) == NULL) goto err;
130 if (a == b)
131 { if (!BN_sqr(t,a,ctx)) goto err; }
132 else
133 { if (!BN_mul(t,a,b,ctx)) goto err; }
134 if (!BN_mod(ret,t,m,ctx)) goto err;
135 r=1;
136 err:
137 BN_CTX_end(ctx);
138 return(r);
139 }
140  
141 int BN_mod_exp(BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
142 BN_CTX *ctx)
143 {
144 int ret;
145  
146 bn_check_top(a);
147 bn_check_top(p);
148 bn_check_top(m);
149  
150 #ifdef MONT_MUL_MOD
151 /* I have finally been able to take out this pre-condition of
152 * the top bit being set. It was caused by an error in BN_div
153 * with negatives. There was also another problem when for a^b%m
154 * a >= m. eay 07-May-97 */
155 /* if ((m->d[m->top-1]&BN_TBIT) && BN_is_odd(m)) */
156  
157 if (BN_is_odd(m))
158 {
159 if (a->top == 1)
160 {
161 BN_ULONG A = a->d[0];
162 ret=BN_mod_exp_mont_word(r,A,p,m,ctx,NULL);
163 }
164 else
165 ret=BN_mod_exp_mont(r,a,p,m,ctx,NULL);
166 }
167 else
168 #endif
169 #ifdef RECP_MUL_MOD
170 { ret=BN_mod_exp_recp(r,a,p,m,ctx); }
171 #else
172 { ret=BN_mod_exp_simple(r,a,p,m,ctx); }
173 #endif
174  
175 return(ret);
176 }
177  
178  
179 #ifdef RECP_MUL_MOD
180 int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
181 const BIGNUM *m, BN_CTX *ctx)
182 {
183 int i,j,bits,ret=0,wstart,wend,window,wvalue;
184 int start=1,ts=0;
185 BIGNUM *aa;
186 BIGNUM val[TABLE_SIZE];
187 BN_RECP_CTX recp;
188  
189 bits=BN_num_bits(p);
190  
191 if (bits == 0)
192 {
193 BN_one(r);
194 return(1);
195 }
196  
197 BN_CTX_start(ctx);
198 if ((aa = BN_CTX_get(ctx)) == NULL) goto err;
199  
200 BN_RECP_CTX_init(&recp);
201 if (BN_RECP_CTX_set(&recp,m,ctx) <= 0) goto err;
202  
203 BN_init(&(val[0]));
204 ts=1;
205  
206 if (!BN_mod(&(val[0]),a,m,ctx)) goto err; /* 1 */
207  
208 window = BN_window_bits_for_exponent_size(bits);
209 if (window > 1)
210 {
211 if (!BN_mod_mul_reciprocal(aa,&(val[0]),&(val[0]),&recp,ctx))
212 goto err; /* 2 */
213 j=1<<(window-1);
214 for (i=1; i<j; i++)
215 {
216 BN_init(&val[i]);
217 if (!BN_mod_mul_reciprocal(&(val[i]),&(val[i-1]),aa,&recp,ctx))
218 goto err;
219 }
220 ts=i;
221 }
222  
223 start=1; /* This is used to avoid multiplication etc
224 * when there is only the value '1' in the
225 * buffer. */
226 wvalue=0; /* The 'value' of the window */
227 wstart=bits-1; /* The top bit of the window */
228 wend=0; /* The bottom bit of the window */
229  
230 if (!BN_one(r)) goto err;
231  
232 for (;;)
233 {
234 if (BN_is_bit_set(p,wstart) == 0)
235 {
236 if (!start)
237 if (!BN_mod_mul_reciprocal(r,r,r,&recp,ctx))
238 goto err;
239 if (wstart == 0) break;
240 wstart--;
241 continue;
242 }
243 /* We now have wstart on a 'set' bit, we now need to work out
244 * how bit a window to do. To do this we need to scan
245 * forward until the last set bit before the end of the
246 * window */
247 j=wstart;
248 wvalue=1;
249 wend=0;
250 for (i=1; i<window; i++)
251 {
252 if (wstart-i < 0) break;
253 if (BN_is_bit_set(p,wstart-i))
254 {
255 wvalue<<=(i-wend);
256 wvalue|=1;
257 wend=i;
258 }
259 }
260  
261 /* wend is the size of the current window */
262 j=wend+1;
263 /* add the 'bytes above' */
264 if (!start)
265 for (i=0; i<j; i++)
266 {
267 if (!BN_mod_mul_reciprocal(r,r,r,&recp,ctx))
268 goto err;
269 }
270  
271 /* wvalue will be an odd number < 2^window */
272 if (!BN_mod_mul_reciprocal(r,r,&(val[wvalue>>1]),&recp,ctx))
273 goto err;
274  
275 /* move the 'window' down further */
276 wstart-=wend+1;
277 wvalue=0;
278 start=0;
279 if (wstart < 0) break;
280 }
281 ret=1;
282 err:
283 BN_CTX_end(ctx);
284 for (i=0; i<ts; i++)
285 BN_clear_free(&(val[i]));
286 BN_RECP_CTX_free(&recp);
287 return(ret);
288 }
289 #else
290  
291 /* The old fallback, simple version :-) */
292 int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
293 const BIGNUM *m, BN_CTX *ctx)
294 {
295 int i,j,bits,ret=0,wstart,wend,window,wvalue,ts=0;
296 int start=1;
297 BIGNUM *d;
298 BIGNUM val[TABLE_SIZE];
299  
300 bits=BN_num_bits(p);
301  
302 if (bits == 0)
303 {
304 BN_one(r);
305 return(1);
306 }
307  
308 BN_CTX_start(ctx);
309 if ((d = BN_CTX_get(ctx)) == NULL) goto err;
310  
311 BN_init(&(val[0]));
312 ts=1;
313 if (!BN_mod(&(val[0]),a,m,ctx)) goto err; /* 1 */
314  
315 window = BN_window_bits_for_exponent_size(bits);
316 if (window > 1)
317 {
318 if (!BN_mod_mul(d,&(val[0]),&(val[0]),m,ctx))
319 goto err; /* 2 */
320 j=1<<(window-1);
321 for (i=1; i<j; i++)
322 {
323 BN_init(&(val[i]));
324 if (!BN_mod_mul(&(val[i]),&(val[i-1]),d,m,ctx))
325 goto err;
326 }
327 ts=i;
328 }
329  
330 start=1; /* This is used to avoid multiplication etc
331 * when there is only the value '1' in the
332 * buffer. */
333 wvalue=0; /* The 'value' of the window */
334 wstart=bits-1; /* The top bit of the window */
335 wend=0; /* The bottom bit of the window */
336  
337 if (!BN_one(r)) goto err;
338  
339 for (;;)
340 {
341 if (BN_is_bit_set(p,wstart) == 0)
342 {
343 if (!start)
344 if (!BN_mod_mul(r,r,r,m,ctx))
345 goto err;
346 if (wstart == 0) break;
347 wstart--;
348 continue;
349 }
350 /* We now have wstart on a 'set' bit, we now need to work out
351 * how bit a window to do. To do this we need to scan
352 * forward until the last set bit before the end of the
353 * window */
354 j=wstart;
355 wvalue=1;
356 wend=0;
357 for (i=1; i<window; i++)
358 {
359 if (wstart-i < 0) break;
360 if (BN_is_bit_set(p,wstart-i))
361 {
362 wvalue<<=(i-wend);
363 wvalue|=1;
364 wend=i;
365 }
366 }
367  
368 /* wend is the size of the current window */
369 j=wend+1;
370 /* add the 'bytes above' */
371 if (!start)
372 for (i=0; i<j; i++)
373 {
374 if (!BN_mod_mul(r,r,r,m,ctx))
375 goto err;
376 }
377  
378 /* wvalue will be an odd number < 2^window */
379 if (!BN_mod_mul(r,r,&(val[wvalue>>1]),m,ctx))
380 goto err;
381  
382 /* move the 'window' down further */
383 wstart-=wend+1;
384 wvalue=0;
385 start=0;
386 if (wstart < 0) break;
387 }
388 ret=1;
389 err:
390 BN_CTX_end(ctx);
391 for (i=0; i<ts; i++)
392 BN_clear_free(&(val[i]));
393 return(ret);
394 }
395 #endif