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d02b48c6 | 1 | /* crypto/bn/bn_mont.c */ |
58964a49 | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
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 | */ | |
675f605d BM |
58 | /* ==================================================================== |
59 | * Copyright (c) 1998-2006 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 | */ | |
d02b48c6 | 111 | |
1b3b0a54 | 112 | /* |
b99b1107 BM |
113 | * Details about Montgomery multiplication algorithms can be found at |
114 | * http://security.ece.orst.edu/publications.html, e.g. | |
115 | * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and | |
116 | * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf | |
1b3b0a54 RE |
117 | */ |
118 | ||
73e45b2d | 119 | |
a27de7b7 | 120 | |
d02b48c6 RE |
121 | #include "cryptlib.h" |
122 | #include "bn_lcl.h" | |
123 | ||
6535eb17 UM |
124 | #define MONT_WORD /* use the faster word-based algorithm */ |
125 | ||
9b4eab50 AP |
126 | #ifdef MONT_WORD |
127 | static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); | |
128 | #endif | |
129 | ||
020fc820 | 130 | int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, |
84c15db5 | 131 | BN_MONT_CTX *mont, BN_CTX *ctx) |
d02b48c6 | 132 | { |
757e392d | 133 | BIGNUM *tmp; |
0b8fa44e | 134 | int ret=0; |
9b4eab50 | 135 | #if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD) |
e7382805 AP |
136 | int num = mont->N.top; |
137 | ||
138 | if (num>1 && a->top==num && b->top==num) | |
139 | { | |
9b4eab50 | 140 | if (bn_wexpand(r,num) == NULL) return(0); |
ca04d7a2 AP |
141 | if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,mont->n0,num)) |
142 | { | |
143 | r->neg = a->neg^b->neg; | |
144 | r->top = num; | |
9b4eab50 AP |
145 | bn_correct_top(r); |
146 | return(1); | |
ca04d7a2 | 147 | } |
e7382805 AP |
148 | } |
149 | #endif | |
dfeab068 | 150 | |
9b141126 UM |
151 | BN_CTX_start(ctx); |
152 | tmp = BN_CTX_get(ctx); | |
e1a8ac49 | 153 | if (tmp == NULL) goto err; |
d02b48c6 | 154 | |
dfeab068 | 155 | bn_check_top(tmp); |
d02b48c6 RE |
156 | if (a == b) |
157 | { | |
158 | if (!BN_sqr(tmp,a,ctx)) goto err; | |
159 | } | |
160 | else | |
161 | { | |
dfeab068 | 162 | if (!BN_mul(tmp,a,b,ctx)) goto err; |
d02b48c6 RE |
163 | } |
164 | /* reduce from aRR to aR */ | |
9b4eab50 AP |
165 | #ifdef MONT_WORD |
166 | if (!BN_from_montgomery_word(r,tmp,mont)) goto err; | |
167 | #else | |
d02b48c6 | 168 | if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err; |
9b4eab50 | 169 | #endif |
d870740c | 170 | bn_check_top(r); |
0b8fa44e | 171 | ret=1; |
d02b48c6 | 172 | err: |
0b8fa44e UM |
173 | BN_CTX_end(ctx); |
174 | return(ret); | |
d02b48c6 RE |
175 | } |
176 | ||
6535eb17 | 177 | #ifdef MONT_WORD |
9b4eab50 AP |
178 | static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) |
179 | { | |
180 | BIGNUM *n; | |
25348918 AP |
181 | BN_ULONG *ap,*np,*rp,n0,v,carry; |
182 | int nl,max,i; | |
d02b48c6 | 183 | |
6535eb17 | 184 | n= &(mont->N); |
6535eb17 | 185 | nl=n->top; |
25348918 | 186 | if (nl == 0) { ret->top=0; return(1); } |
d02b48c6 | 187 | |
25348918 | 188 | max=(2*nl); /* carry is stored separately */ |
9b4eab50 | 189 | if (bn_wexpand(r,max) == NULL) return(0); |
d02b48c6 | 190 | |
9b4eab50 | 191 | r->neg^=n->neg; |
6535eb17 UM |
192 | np=n->d; |
193 | rp=r->d; | |
d02b48c6 | 194 | |
6535eb17 | 195 | /* clear the top words of T */ |
58964a49 | 196 | #if 1 |
6535eb17 | 197 | for (i=r->top; i<max; i++) /* memset? XXX */ |
78f288d5 | 198 | rp[i]=0; |
58964a49 | 199 | #else |
78f288d5 | 200 | memset(&(rp[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); |
58964a49 | 201 | #endif |
d02b48c6 | 202 | |
6535eb17 | 203 | r->top=max; |
4d524040 | 204 | n0=mont->n0[0]; |
d02b48c6 | 205 | |
25348918 | 206 | for (carry=0, i=0; i<nl; i++, rp++) |
6535eb17 UM |
207 | { |
208 | v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2); | |
78f288d5 AP |
209 | v = (v+carry+rp[nl])&BN_MASK2; |
210 | carry |= (v != rp[nl]); | |
211 | carry &= (v <= rp[nl]); | |
212 | rp[nl]=v; | |
9b4eab50 | 213 | } |
6b6443de | 214 | |
25348918 AP |
215 | if (bn_wexpand(ret,nl) == NULL) return(0); |
216 | ret->top=nl; | |
9b4eab50 | 217 | ret->neg=r->neg; |
6b6443de AP |
218 | |
219 | rp=ret->d; | |
25348918 | 220 | ap=&(r->d[nl]); |
6b6443de | 221 | |
25348918 AP |
222 | #define BRANCH_FREE 1 |
223 | #if BRANCH_FREE | |
673c55a2 | 224 | { |
25348918 AP |
225 | BN_ULONG *nrp; |
226 | size_t m; | |
c693b5a5 | 227 | |
25348918 AP |
228 | v=bn_sub_words(rp,ap,np,nl)-carry; |
229 | /* if subtraction result is real, then | |
673c55a2 AP |
230 | * trick unconditional memcpy below to perform in-place |
231 | * "refresh" instead of actual copy. */ | |
25348918 AP |
232 | m=(0-(size_t)v); |
233 | nrp=(BN_ULONG *)(((PTR_SIZE_INT)rp&~m)|((PTR_SIZE_INT)ap&m)); | |
6b6443de | 234 | |
25348918 | 235 | for (i=0,nl-=4; i<nl; i+=4) |
6b6443de AP |
236 | { |
237 | BN_ULONG t1,t2,t3,t4; | |
238 | ||
239 | t1=nrp[i+0]; | |
240 | t2=nrp[i+1]; | |
241 | t3=nrp[i+2]; ap[i+0]=0; | |
242 | t4=nrp[i+3]; ap[i+1]=0; | |
243 | rp[i+0]=t1; ap[i+2]=0; | |
244 | rp[i+1]=t2; ap[i+3]=0; | |
245 | rp[i+2]=t3; | |
246 | rp[i+3]=t4; | |
247 | } | |
25348918 | 248 | for (nl+=4; i<nl; i++) |
6b6443de | 249 | rp[i]=nrp[i], ap[i]=0; |
25348918 | 250 | } |
6b6443de | 251 | #else |
25348918 AP |
252 | if (bn_sub_words (rp,ap,np,nl)-carry) |
253 | memcpy(rp,ap,nl*sizeof(BN_ULONG)); | |
6b6443de | 254 | #endif |
25348918 AP |
255 | bn_correct_top(r); |
256 | bn_correct_top(ret); | |
9b4eab50 AP |
257 | bn_check_top(ret); |
258 | ||
259 | return(1); | |
260 | } | |
261 | #endif /* MONT_WORD */ | |
262 | ||
263 | int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, | |
264 | BN_CTX *ctx) | |
265 | { | |
266 | int retn=0; | |
267 | #ifdef MONT_WORD | |
268 | BIGNUM *t; | |
269 | ||
270 | BN_CTX_start(ctx); | |
271 | if ((t = BN_CTX_get(ctx)) && BN_copy(t,a)) | |
272 | retn = BN_from_montgomery_word(ret,t,mont); | |
273 | BN_CTX_end(ctx); | |
274 | #else /* !MONT_WORD */ | |
6535eb17 | 275 | BIGNUM *t1,*t2; |
58964a49 | 276 | |
6535eb17 UM |
277 | BN_CTX_start(ctx); |
278 | t1 = BN_CTX_get(ctx); | |
279 | t2 = BN_CTX_get(ctx); | |
280 | if (t1 == NULL || t2 == NULL) goto err; | |
281 | ||
282 | if (!BN_copy(t1,a)) goto err; | |
283 | BN_mask_bits(t1,mont->ri); | |
284 | ||
285 | if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err; | |
286 | BN_mask_bits(t2,mont->ri); | |
287 | ||
288 | if (!BN_mul(t1,t2,&mont->N,ctx)) goto err; | |
289 | if (!BN_add(t2,a,t1)) goto err; | |
9cdf87f1 | 290 | if (!BN_rshift(ret,t2,mont->ri)) goto err; |
6535eb17 UM |
291 | |
292 | if (BN_ucmp(ret, &(mont->N)) >= 0) | |
58964a49 | 293 | { |
8dea52fa | 294 | if (!BN_usub(ret,ret,&(mont->N))) goto err; |
dfeab068 | 295 | } |
6535eb17 | 296 | retn=1; |
d870740c | 297 | bn_check_top(ret); |
e93f9a32 | 298 | err: |
9b141126 | 299 | BN_CTX_end(ctx); |
9b4eab50 | 300 | #endif /* MONT_WORD */ |
e93f9a32 | 301 | return(retn); |
dfeab068 | 302 | } |
d02b48c6 | 303 | |
6b691a5c | 304 | BN_MONT_CTX *BN_MONT_CTX_new(void) |
d02b48c6 RE |
305 | { |
306 | BN_MONT_CTX *ret; | |
307 | ||
26a3a48d | 308 | if ((ret=(BN_MONT_CTX *)OPENSSL_malloc(sizeof(BN_MONT_CTX))) == NULL) |
d02b48c6 | 309 | return(NULL); |
dfeab068 RE |
310 | |
311 | BN_MONT_CTX_init(ret); | |
312 | ret->flags=BN_FLG_MALLOCED; | |
d02b48c6 RE |
313 | return(ret); |
314 | } | |
315 | ||
6b691a5c | 316 | void BN_MONT_CTX_init(BN_MONT_CTX *ctx) |
dfeab068 | 317 | { |
dfeab068 RE |
318 | ctx->ri=0; |
319 | BN_init(&(ctx->RR)); | |
320 | BN_init(&(ctx->N)); | |
321 | BN_init(&(ctx->Ni)); | |
d05a4745 | 322 | ctx->n0[0] = ctx->n0[1] = 0; |
dfeab068 RE |
323 | ctx->flags=0; |
324 | } | |
325 | ||
6b691a5c | 326 | void BN_MONT_CTX_free(BN_MONT_CTX *mont) |
d02b48c6 | 327 | { |
e03ddfae BL |
328 | if(mont == NULL) |
329 | return; | |
330 | ||
dfeab068 RE |
331 | BN_free(&(mont->RR)); |
332 | BN_free(&(mont->N)); | |
333 | BN_free(&(mont->Ni)); | |
334 | if (mont->flags & BN_FLG_MALLOCED) | |
26a3a48d | 335 | OPENSSL_free(mont); |
d02b48c6 RE |
336 | } |
337 | ||
84c15db5 | 338 | int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) |
d02b48c6 | 339 | { |
c86f2054 GT |
340 | int ret = 0; |
341 | BIGNUM *Ri,*R; | |
dfeab068 | 342 | |
c86f2054 GT |
343 | BN_CTX_start(ctx); |
344 | if((Ri = BN_CTX_get(ctx)) == NULL) goto err; | |
dfeab068 | 345 | R= &(mont->RR); /* grab RR as a temp */ |
a0e7c8ee | 346 | if (!BN_copy(&(mont->N),mod)) goto err; /* Set N */ |
8dea52fa | 347 | mont->N.neg = 0; |
dfeab068 | 348 | |
6535eb17 | 349 | #ifdef MONT_WORD |
dfeab068 RE |
350 | { |
351 | BIGNUM tmod; | |
352 | BN_ULONG buf[2]; | |
353 | ||
7c9882eb | 354 | BN_init(&tmod); |
4d524040 AP |
355 | tmod.d=buf; |
356 | tmod.dmax=2; | |
357 | tmod.neg=0; | |
358 | ||
dfeab068 | 359 | mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2; |
4d524040 AP |
360 | |
361 | #if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) | |
fabe640f BM |
362 | /* Only certain BN_BITS2<=32 platforms actually make use of |
363 | * n0[1], and we could use the #else case (with a shorter R | |
364 | * value) for the others. However, currently only the assembler | |
365 | * files do know which is which. */ | |
366 | ||
4d524040 AP |
367 | BN_zero(R); |
368 | if (!(BN_set_bit(R,2*BN_BITS2))) goto err; | |
369 | ||
370 | tmod.top=0; | |
c2012f9b AP |
371 | if ((buf[0] = mod->d[0])) tmod.top=1; |
372 | if ((buf[1] = mod->top>1 ? mod->d[1] : 0)) tmod.top=2; | |
4d524040 AP |
373 | |
374 | if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL) | |
375 | goto err; | |
376 | if (!BN_lshift(Ri,Ri,2*BN_BITS2)) goto err; /* R*Ri */ | |
377 | if (!BN_is_zero(Ri)) | |
378 | { | |
379 | if (!BN_sub_word(Ri,1)) goto err; | |
380 | } | |
381 | else /* if N mod word size == 1 */ | |
382 | { | |
383 | if (bn_expand(Ri,(int)sizeof(BN_ULONG)*2) == NULL) | |
384 | goto err; | |
385 | /* Ri-- (mod double word size) */ | |
386 | Ri->neg=0; | |
387 | Ri->d[0]=BN_MASK2; | |
388 | Ri->d[1]=BN_MASK2; | |
389 | Ri->top=2; | |
390 | } | |
391 | if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; | |
392 | /* Ni = (R*Ri-1)/N, | |
393 | * keep only couple of least significant words: */ | |
394 | mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; | |
395 | mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0; | |
396 | #else | |
b6358c89 | 397 | BN_zero(R); |
9cdf87f1 | 398 | if (!(BN_set_bit(R,BN_BITS2))) goto err; /* R */ |
dfeab068 | 399 | |
e93f9a32 | 400 | buf[0]=mod->d[0]; /* tmod = N mod word size */ |
dfeab068 | 401 | buf[1]=0; |
17a2994d | 402 | tmod.top = buf[0] != 0 ? 1 : 0; |
e93f9a32 | 403 | /* Ri = R^-1 mod N*/ |
c86f2054 | 404 | if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL) |
dfeab068 | 405 | goto err; |
c86f2054 GT |
406 | if (!BN_lshift(Ri,Ri,BN_BITS2)) goto err; /* R*Ri */ |
407 | if (!BN_is_zero(Ri)) | |
8dea52fa | 408 | { |
c86f2054 | 409 | if (!BN_sub_word(Ri,1)) goto err; |
8dea52fa | 410 | } |
e93f9a32 | 411 | else /* if N mod word size == 1 */ |
8dea52fa | 412 | { |
c86f2054 | 413 | if (!BN_set_word(Ri,BN_MASK2)) goto err; /* Ri-- (mod word size) */ |
8dea52fa | 414 | } |
c86f2054 | 415 | if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; |
8dea52fa BM |
416 | /* Ni = (R*Ri-1)/N, |
417 | * keep only least significant word: */ | |
4d524040 AP |
418 | mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; |
419 | mont->n0[1] = 0; | |
420 | #endif | |
dfeab068 | 421 | } |
6535eb17 | 422 | #else /* !MONT_WORD */ |
e93f9a32 | 423 | { /* bignum version */ |
8dea52fa | 424 | mont->ri=BN_num_bits(&mont->N); |
b6358c89 | 425 | BN_zero(R); |
8dea52fa BM |
426 | if (!BN_set_bit(R,mont->ri)) goto err; /* R = 2^ri */ |
427 | /* Ri = R^-1 mod N*/ | |
c86f2054 | 428 | if ((BN_mod_inverse(Ri,R,&mont->N,ctx)) == NULL) |
dfeab068 | 429 | goto err; |
c86f2054 GT |
430 | if (!BN_lshift(Ri,Ri,mont->ri)) goto err; /* R*Ri */ |
431 | if (!BN_sub_word(Ri,1)) goto err; | |
e93f9a32 | 432 | /* Ni = (R*Ri-1) / N */ |
c86f2054 | 433 | if (!BN_div(&(mont->Ni),NULL,Ri,&mont->N,ctx)) goto err; |
dfeab068 | 434 | } |
d02b48c6 RE |
435 | #endif |
436 | ||
437 | /* setup RR for conversions */ | |
b6358c89 | 438 | BN_zero(&(mont->RR)); |
8dea52fa BM |
439 | if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err; |
440 | if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err; | |
d02b48c6 | 441 | |
c86f2054 | 442 | ret = 1; |
d02b48c6 | 443 | err: |
c86f2054 GT |
444 | BN_CTX_end(ctx); |
445 | return ret; | |
d02b48c6 RE |
446 | } |
447 | ||
6b691a5c | 448 | BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) |
dfeab068 RE |
449 | { |
450 | if (to == from) return(to); | |
451 | ||
156e8557 BM |
452 | if (!BN_copy(&(to->RR),&(from->RR))) return NULL; |
453 | if (!BN_copy(&(to->N),&(from->N))) return NULL; | |
454 | if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL; | |
dfeab068 | 455 | to->ri=from->ri; |
4d524040 AP |
456 | to->n0[0]=from->n0[0]; |
457 | to->n0[1]=from->n0[1]; | |
dfeab068 RE |
458 | return(to); |
459 | } | |
460 | ||
6ec8e63a DSH |
461 | BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock, |
462 | const BIGNUM *mod, BN_CTX *ctx) | |
463 | { | |
4584ecce | 464 | BN_MONT_CTX *ret; |
675f605d BM |
465 | |
466 | CRYPTO_r_lock(lock); | |
12e9f627 GT |
467 | ret = *pmont; |
468 | CRYPTO_r_unlock(lock); | |
469 | if (ret) | |
470 | return ret; | |
471 | ||
472 | /* We don't want to serialise globally while doing our lazy-init math in | |
473 | * BN_MONT_CTX_set. That punishes threads that are doing independent | |
474 | * things. Instead, punish the case where more than one thread tries to | |
475 | * lazy-init the same 'pmont', by having each do the lazy-init math work | |
476 | * independently and only use the one from the thread that wins the race | |
477 | * (the losers throw away the work they've done). */ | |
478 | ret = BN_MONT_CTX_new(); | |
479 | if (!ret) | |
480 | return NULL; | |
481 | if (!BN_MONT_CTX_set(ret, mod, ctx)) | |
6ec8e63a | 482 | { |
12e9f627 GT |
483 | BN_MONT_CTX_free(ret); |
484 | return NULL; | |
485 | } | |
675f605d | 486 | |
12e9f627 GT |
487 | /* The locked compare-and-set, after the local work is done. */ |
488 | CRYPTO_w_lock(lock); | |
489 | if (*pmont) | |
490 | { | |
491 | BN_MONT_CTX_free(ret); | |
492 | ret = *pmont; | |
6ec8e63a | 493 | } |
675f605d | 494 | else |
12e9f627 GT |
495 | *pmont = ret; |
496 | CRYPTO_w_unlock(lock); | |
4584ecce | 497 | return ret; |
6ec8e63a | 498 | } |