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Commit | Line | Data |
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0f113f3e | 1 | /* |
edea42c6 | 2 | * Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved. |
aa8f3d76 | 3 | * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved |
f8fe20e0 | 4 | * |
aa6bb135 RS |
5 | * Licensed under the OpenSSL license (the "License"). You may not use |
6 | * this file except in compliance with the License. You can obtain a copy | |
7 | * in the file LICENSE in the source distribution or at | |
8 | * https://www.openssl.org/source/license.html | |
f8fe20e0 | 9 | */ |
aa6bb135 | 10 | |
60428dbf | 11 | #include <openssl/err.h> |
02cbedc3 | 12 | #include <openssl/symhacks.h> |
60428dbf | 13 | |
f8fe20e0 | 14 | #include "ec_lcl.h" |
0657bf9c | 15 | |
0657bf9c | 16 | const EC_METHOD *EC_GFp_simple_method(void) |
0f113f3e MC |
17 | { |
18 | static const EC_METHOD ret = { | |
19 | EC_FLAGS_DEFAULT_OCT, | |
20 | NID_X9_62_prime_field, | |
21 | ec_GFp_simple_group_init, | |
22 | ec_GFp_simple_group_finish, | |
23 | ec_GFp_simple_group_clear_finish, | |
24 | ec_GFp_simple_group_copy, | |
25 | ec_GFp_simple_group_set_curve, | |
26 | ec_GFp_simple_group_get_curve, | |
27 | ec_GFp_simple_group_get_degree, | |
9ff9bccc | 28 | ec_group_simple_order_bits, |
0f113f3e MC |
29 | ec_GFp_simple_group_check_discriminant, |
30 | ec_GFp_simple_point_init, | |
31 | ec_GFp_simple_point_finish, | |
32 | ec_GFp_simple_point_clear_finish, | |
33 | ec_GFp_simple_point_copy, | |
34 | ec_GFp_simple_point_set_to_infinity, | |
35 | ec_GFp_simple_set_Jprojective_coordinates_GFp, | |
36 | ec_GFp_simple_get_Jprojective_coordinates_GFp, | |
37 | ec_GFp_simple_point_set_affine_coordinates, | |
38 | ec_GFp_simple_point_get_affine_coordinates, | |
39 | 0, 0, 0, | |
40 | ec_GFp_simple_add, | |
41 | ec_GFp_simple_dbl, | |
42 | ec_GFp_simple_invert, | |
43 | ec_GFp_simple_is_at_infinity, | |
44 | ec_GFp_simple_is_on_curve, | |
45 | ec_GFp_simple_cmp, | |
46 | ec_GFp_simple_make_affine, | |
47 | ec_GFp_simple_points_make_affine, | |
48 | 0 /* mul */ , | |
49 | 0 /* precompute_mult */ , | |
50 | 0 /* have_precompute_mult */ , | |
51 | ec_GFp_simple_field_mul, | |
52 | ec_GFp_simple_field_sqr, | |
53 | 0 /* field_div */ , | |
54 | 0 /* field_encode */ , | |
55 | 0 /* field_decode */ , | |
9ff9bccc DSH |
56 | 0, /* field_set_to_one */ |
57 | ec_key_simple_priv2oct, | |
58 | ec_key_simple_oct2priv, | |
59 | 0, /* set private */ | |
60 | ec_key_simple_generate_key, | |
61 | ec_key_simple_check_key, | |
62 | ec_key_simple_generate_public_key, | |
63 | 0, /* keycopy */ | |
64 | 0, /* keyfinish */ | |
65 | ecdh_simple_compute_key | |
0f113f3e MC |
66 | }; |
67 | ||
68 | return &ret; | |
69 | } | |
60428dbf | 70 | |
3a83462d MC |
71 | /* |
72 | * Most method functions in this file are designed to work with | |
922fa76e BM |
73 | * non-trivial representations of field elements if necessary |
74 | * (see ecp_mont.c): while standard modular addition and subtraction | |
75 | * are used, the field_mul and field_sqr methods will be used for | |
76 | * multiplication, and field_encode and field_decode (if defined) | |
77 | * will be used for converting between representations. | |
3a83462d | 78 | * |
922fa76e BM |
79 | * Functions ec_GFp_simple_points_make_affine() and |
80 | * ec_GFp_simple_point_get_affine_coordinates() specifically assume | |
81 | * that if a non-trivial representation is used, it is a Montgomery | |
82 | * representation (i.e. 'encoding' means multiplying by some factor R). | |
83 | */ | |
84 | ||
60428dbf | 85 | int ec_GFp_simple_group_init(EC_GROUP *group) |
0f113f3e MC |
86 | { |
87 | group->field = BN_new(); | |
88 | group->a = BN_new(); | |
89 | group->b = BN_new(); | |
90945fa3 | 90 | if (group->field == NULL || group->a == NULL || group->b == NULL) { |
a3853772 RS |
91 | BN_free(group->field); |
92 | BN_free(group->a); | |
93 | BN_free(group->b); | |
0f113f3e MC |
94 | return 0; |
95 | } | |
96 | group->a_is_minus3 = 0; | |
97 | return 1; | |
98 | } | |
60428dbf | 99 | |
bb62a8b0 | 100 | void ec_GFp_simple_group_finish(EC_GROUP *group) |
0f113f3e MC |
101 | { |
102 | BN_free(group->field); | |
103 | BN_free(group->a); | |
104 | BN_free(group->b); | |
105 | } | |
bb62a8b0 BM |
106 | |
107 | void ec_GFp_simple_group_clear_finish(EC_GROUP *group) | |
0f113f3e MC |
108 | { |
109 | BN_clear_free(group->field); | |
110 | BN_clear_free(group->a); | |
111 | BN_clear_free(group->b); | |
112 | } | |
bb62a8b0 BM |
113 | |
114 | int ec_GFp_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src) | |
0f113f3e MC |
115 | { |
116 | if (!BN_copy(dest->field, src->field)) | |
117 | return 0; | |
118 | if (!BN_copy(dest->a, src->a)) | |
119 | return 0; | |
120 | if (!BN_copy(dest->b, src->b)) | |
121 | return 0; | |
bb62a8b0 | 122 | |
0f113f3e | 123 | dest->a_is_minus3 = src->a_is_minus3; |
bb62a8b0 | 124 | |
0f113f3e MC |
125 | return 1; |
126 | } | |
bb62a8b0 | 127 | |
35b73a1f | 128 | int ec_GFp_simple_group_set_curve(EC_GROUP *group, |
0f113f3e MC |
129 | const BIGNUM *p, const BIGNUM *a, |
130 | const BIGNUM *b, BN_CTX *ctx) | |
131 | { | |
132 | int ret = 0; | |
133 | BN_CTX *new_ctx = NULL; | |
134 | BIGNUM *tmp_a; | |
135 | ||
136 | /* p must be a prime > 3 */ | |
137 | if (BN_num_bits(p) <= 2 || !BN_is_odd(p)) { | |
138 | ECerr(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE, EC_R_INVALID_FIELD); | |
139 | return 0; | |
140 | } | |
141 | ||
142 | if (ctx == NULL) { | |
143 | ctx = new_ctx = BN_CTX_new(); | |
144 | if (ctx == NULL) | |
145 | return 0; | |
146 | } | |
147 | ||
148 | BN_CTX_start(ctx); | |
149 | tmp_a = BN_CTX_get(ctx); | |
150 | if (tmp_a == NULL) | |
151 | goto err; | |
152 | ||
153 | /* group->field */ | |
154 | if (!BN_copy(group->field, p)) | |
155 | goto err; | |
156 | BN_set_negative(group->field, 0); | |
157 | ||
158 | /* group->a */ | |
159 | if (!BN_nnmod(tmp_a, a, p, ctx)) | |
160 | goto err; | |
161 | if (group->meth->field_encode) { | |
162 | if (!group->meth->field_encode(group, group->a, tmp_a, ctx)) | |
163 | goto err; | |
164 | } else if (!BN_copy(group->a, tmp_a)) | |
165 | goto err; | |
166 | ||
167 | /* group->b */ | |
168 | if (!BN_nnmod(group->b, b, p, ctx)) | |
169 | goto err; | |
170 | if (group->meth->field_encode) | |
171 | if (!group->meth->field_encode(group, group->b, group->b, ctx)) | |
172 | goto err; | |
173 | ||
174 | /* group->a_is_minus3 */ | |
175 | if (!BN_add_word(tmp_a, 3)) | |
176 | goto err; | |
177 | group->a_is_minus3 = (0 == BN_cmp(tmp_a, group->field)); | |
178 | ||
179 | ret = 1; | |
60428dbf BM |
180 | |
181 | err: | |
0f113f3e | 182 | BN_CTX_end(ctx); |
23a1d5e9 | 183 | BN_CTX_free(new_ctx); |
0f113f3e MC |
184 | return ret; |
185 | } | |
186 | ||
187 | int ec_GFp_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, | |
188 | BIGNUM *b, BN_CTX *ctx) | |
189 | { | |
190 | int ret = 0; | |
191 | BN_CTX *new_ctx = NULL; | |
192 | ||
193 | if (p != NULL) { | |
194 | if (!BN_copy(p, group->field)) | |
195 | return 0; | |
196 | } | |
197 | ||
198 | if (a != NULL || b != NULL) { | |
199 | if (group->meth->field_decode) { | |
200 | if (ctx == NULL) { | |
201 | ctx = new_ctx = BN_CTX_new(); | |
202 | if (ctx == NULL) | |
203 | return 0; | |
204 | } | |
205 | if (a != NULL) { | |
206 | if (!group->meth->field_decode(group, a, group->a, ctx)) | |
207 | goto err; | |
208 | } | |
209 | if (b != NULL) { | |
210 | if (!group->meth->field_decode(group, b, group->b, ctx)) | |
211 | goto err; | |
212 | } | |
213 | } else { | |
214 | if (a != NULL) { | |
215 | if (!BN_copy(a, group->a)) | |
216 | goto err; | |
217 | } | |
218 | if (b != NULL) { | |
219 | if (!BN_copy(b, group->b)) | |
220 | goto err; | |
221 | } | |
222 | } | |
223 | } | |
224 | ||
225 | ret = 1; | |
60428dbf | 226 | |
0f113f3e | 227 | err: |
23a1d5e9 | 228 | BN_CTX_free(new_ctx); |
0f113f3e MC |
229 | return ret; |
230 | } | |
60428dbf | 231 | |
7793f30e | 232 | int ec_GFp_simple_group_get_degree(const EC_GROUP *group) |
0f113f3e MC |
233 | { |
234 | return BN_num_bits(group->field); | |
235 | } | |
7793f30e | 236 | |
17d6bb81 | 237 | int ec_GFp_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx) |
0f113f3e MC |
238 | { |
239 | int ret = 0; | |
240 | BIGNUM *a, *b, *order, *tmp_1, *tmp_2; | |
241 | const BIGNUM *p = group->field; | |
242 | BN_CTX *new_ctx = NULL; | |
243 | ||
244 | if (ctx == NULL) { | |
245 | ctx = new_ctx = BN_CTX_new(); | |
246 | if (ctx == NULL) { | |
247 | ECerr(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT, | |
248 | ERR_R_MALLOC_FAILURE); | |
249 | goto err; | |
250 | } | |
251 | } | |
252 | BN_CTX_start(ctx); | |
253 | a = BN_CTX_get(ctx); | |
254 | b = BN_CTX_get(ctx); | |
255 | tmp_1 = BN_CTX_get(ctx); | |
256 | tmp_2 = BN_CTX_get(ctx); | |
257 | order = BN_CTX_get(ctx); | |
258 | if (order == NULL) | |
259 | goto err; | |
260 | ||
261 | if (group->meth->field_decode) { | |
262 | if (!group->meth->field_decode(group, a, group->a, ctx)) | |
263 | goto err; | |
264 | if (!group->meth->field_decode(group, b, group->b, ctx)) | |
265 | goto err; | |
266 | } else { | |
267 | if (!BN_copy(a, group->a)) | |
268 | goto err; | |
269 | if (!BN_copy(b, group->b)) | |
270 | goto err; | |
271 | } | |
272 | ||
50e735f9 MC |
273 | /*- |
274 | * check the discriminant: | |
275 | * y^2 = x^3 + a*x + b is an elliptic curve <=> 4*a^3 + 27*b^2 != 0 (mod p) | |
276 | * 0 =< a, b < p | |
277 | */ | |
0f113f3e MC |
278 | if (BN_is_zero(a)) { |
279 | if (BN_is_zero(b)) | |
280 | goto err; | |
281 | } else if (!BN_is_zero(b)) { | |
282 | if (!BN_mod_sqr(tmp_1, a, p, ctx)) | |
283 | goto err; | |
284 | if (!BN_mod_mul(tmp_2, tmp_1, a, p, ctx)) | |
285 | goto err; | |
286 | if (!BN_lshift(tmp_1, tmp_2, 2)) | |
287 | goto err; | |
288 | /* tmp_1 = 4*a^3 */ | |
289 | ||
290 | if (!BN_mod_sqr(tmp_2, b, p, ctx)) | |
291 | goto err; | |
292 | if (!BN_mul_word(tmp_2, 27)) | |
293 | goto err; | |
294 | /* tmp_2 = 27*b^2 */ | |
295 | ||
296 | if (!BN_mod_add(a, tmp_1, tmp_2, p, ctx)) | |
297 | goto err; | |
298 | if (BN_is_zero(a)) | |
299 | goto err; | |
300 | } | |
301 | ret = 1; | |
af28dd6c | 302 | |
0f113f3e MC |
303 | err: |
304 | if (ctx != NULL) | |
305 | BN_CTX_end(ctx); | |
23a1d5e9 | 306 | BN_CTX_free(new_ctx); |
0f113f3e MC |
307 | return ret; |
308 | } | |
af28dd6c | 309 | |
60428dbf | 310 | int ec_GFp_simple_point_init(EC_POINT *point) |
0f113f3e MC |
311 | { |
312 | point->X = BN_new(); | |
313 | point->Y = BN_new(); | |
314 | point->Z = BN_new(); | |
315 | point->Z_is_one = 0; | |
316 | ||
90945fa3 | 317 | if (point->X == NULL || point->Y == NULL || point->Z == NULL) { |
23a1d5e9 RS |
318 | BN_free(point->X); |
319 | BN_free(point->Y); | |
320 | BN_free(point->Z); | |
0f113f3e MC |
321 | return 0; |
322 | } | |
323 | return 1; | |
324 | } | |
60428dbf BM |
325 | |
326 | void ec_GFp_simple_point_finish(EC_POINT *point) | |
0f113f3e MC |
327 | { |
328 | BN_free(point->X); | |
329 | BN_free(point->Y); | |
330 | BN_free(point->Z); | |
331 | } | |
60428dbf BM |
332 | |
333 | void ec_GFp_simple_point_clear_finish(EC_POINT *point) | |
0f113f3e MC |
334 | { |
335 | BN_clear_free(point->X); | |
336 | BN_clear_free(point->Y); | |
337 | BN_clear_free(point->Z); | |
338 | point->Z_is_one = 0; | |
339 | } | |
60428dbf BM |
340 | |
341 | int ec_GFp_simple_point_copy(EC_POINT *dest, const EC_POINT *src) | |
0f113f3e MC |
342 | { |
343 | if (!BN_copy(dest->X, src->X)) | |
344 | return 0; | |
345 | if (!BN_copy(dest->Y, src->Y)) | |
346 | return 0; | |
347 | if (!BN_copy(dest->Z, src->Z)) | |
348 | return 0; | |
349 | dest->Z_is_one = src->Z_is_one; | |
b14e6015 | 350 | dest->curve_name = src->curve_name; |
0f113f3e MC |
351 | |
352 | return 1; | |
353 | } | |
354 | ||
355 | int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *group, | |
356 | EC_POINT *point) | |
357 | { | |
358 | point->Z_is_one = 0; | |
359 | BN_zero(point->Z); | |
360 | return 1; | |
361 | } | |
362 | ||
363 | int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group, | |
364 | EC_POINT *point, | |
365 | const BIGNUM *x, | |
366 | const BIGNUM *y, | |
367 | const BIGNUM *z, | |
368 | BN_CTX *ctx) | |
369 | { | |
370 | BN_CTX *new_ctx = NULL; | |
371 | int ret = 0; | |
372 | ||
373 | if (ctx == NULL) { | |
374 | ctx = new_ctx = BN_CTX_new(); | |
375 | if (ctx == NULL) | |
376 | return 0; | |
377 | } | |
378 | ||
379 | if (x != NULL) { | |
380 | if (!BN_nnmod(point->X, x, group->field, ctx)) | |
381 | goto err; | |
382 | if (group->meth->field_encode) { | |
383 | if (!group->meth->field_encode(group, point->X, point->X, ctx)) | |
384 | goto err; | |
385 | } | |
386 | } | |
387 | ||
388 | if (y != NULL) { | |
389 | if (!BN_nnmod(point->Y, y, group->field, ctx)) | |
390 | goto err; | |
391 | if (group->meth->field_encode) { | |
392 | if (!group->meth->field_encode(group, point->Y, point->Y, ctx)) | |
393 | goto err; | |
394 | } | |
395 | } | |
396 | ||
397 | if (z != NULL) { | |
398 | int Z_is_one; | |
399 | ||
400 | if (!BN_nnmod(point->Z, z, group->field, ctx)) | |
401 | goto err; | |
402 | Z_is_one = BN_is_one(point->Z); | |
403 | if (group->meth->field_encode) { | |
404 | if (Z_is_one && (group->meth->field_set_to_one != 0)) { | |
405 | if (!group->meth->field_set_to_one(group, point->Z, ctx)) | |
406 | goto err; | |
407 | } else { | |
408 | if (!group-> | |
409 | meth->field_encode(group, point->Z, point->Z, ctx)) | |
410 | goto err; | |
411 | } | |
412 | } | |
413 | point->Z_is_one = Z_is_one; | |
414 | } | |
415 | ||
416 | ret = 1; | |
417 | ||
bb62a8b0 | 418 | err: |
23a1d5e9 | 419 | BN_CTX_free(new_ctx); |
0f113f3e MC |
420 | return ret; |
421 | } | |
422 | ||
423 | int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *group, | |
424 | const EC_POINT *point, | |
425 | BIGNUM *x, BIGNUM *y, | |
426 | BIGNUM *z, BN_CTX *ctx) | |
427 | { | |
428 | BN_CTX *new_ctx = NULL; | |
429 | int ret = 0; | |
430 | ||
431 | if (group->meth->field_decode != 0) { | |
432 | if (ctx == NULL) { | |
433 | ctx = new_ctx = BN_CTX_new(); | |
434 | if (ctx == NULL) | |
435 | return 0; | |
436 | } | |
437 | ||
438 | if (x != NULL) { | |
439 | if (!group->meth->field_decode(group, x, point->X, ctx)) | |
440 | goto err; | |
441 | } | |
442 | if (y != NULL) { | |
443 | if (!group->meth->field_decode(group, y, point->Y, ctx)) | |
444 | goto err; | |
445 | } | |
446 | if (z != NULL) { | |
447 | if (!group->meth->field_decode(group, z, point->Z, ctx)) | |
448 | goto err; | |
449 | } | |
450 | } else { | |
451 | if (x != NULL) { | |
452 | if (!BN_copy(x, point->X)) | |
453 | goto err; | |
454 | } | |
455 | if (y != NULL) { | |
456 | if (!BN_copy(y, point->Y)) | |
457 | goto err; | |
458 | } | |
459 | if (z != NULL) { | |
460 | if (!BN_copy(z, point->Z)) | |
461 | goto err; | |
462 | } | |
463 | } | |
464 | ||
465 | ret = 1; | |
bb62a8b0 | 466 | |
226cc7de | 467 | err: |
23a1d5e9 | 468 | BN_CTX_free(new_ctx); |
0f113f3e MC |
469 | return ret; |
470 | } | |
471 | ||
472 | int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *group, | |
473 | EC_POINT *point, | |
474 | const BIGNUM *x, | |
475 | const BIGNUM *y, BN_CTX *ctx) | |
476 | { | |
477 | if (x == NULL || y == NULL) { | |
478 | /* | |
479 | * unlike for projective coordinates, we do not tolerate this | |
480 | */ | |
481 | ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES, | |
482 | ERR_R_PASSED_NULL_PARAMETER); | |
483 | return 0; | |
484 | } | |
485 | ||
486 | return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y, | |
487 | BN_value_one(), ctx); | |
488 | } | |
489 | ||
490 | int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group, | |
491 | const EC_POINT *point, | |
492 | BIGNUM *x, BIGNUM *y, | |
493 | BN_CTX *ctx) | |
494 | { | |
495 | BN_CTX *new_ctx = NULL; | |
496 | BIGNUM *Z, *Z_1, *Z_2, *Z_3; | |
497 | const BIGNUM *Z_; | |
498 | int ret = 0; | |
499 | ||
500 | if (EC_POINT_is_at_infinity(group, point)) { | |
501 | ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, | |
502 | EC_R_POINT_AT_INFINITY); | |
503 | return 0; | |
504 | } | |
505 | ||
506 | if (ctx == NULL) { | |
507 | ctx = new_ctx = BN_CTX_new(); | |
508 | if (ctx == NULL) | |
509 | return 0; | |
510 | } | |
511 | ||
512 | BN_CTX_start(ctx); | |
513 | Z = BN_CTX_get(ctx); | |
514 | Z_1 = BN_CTX_get(ctx); | |
515 | Z_2 = BN_CTX_get(ctx); | |
516 | Z_3 = BN_CTX_get(ctx); | |
517 | if (Z_3 == NULL) | |
518 | goto err; | |
519 | ||
520 | /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */ | |
521 | ||
522 | if (group->meth->field_decode) { | |
523 | if (!group->meth->field_decode(group, Z, point->Z, ctx)) | |
524 | goto err; | |
525 | Z_ = Z; | |
526 | } else { | |
527 | Z_ = point->Z; | |
528 | } | |
529 | ||
530 | if (BN_is_one(Z_)) { | |
531 | if (group->meth->field_decode) { | |
532 | if (x != NULL) { | |
533 | if (!group->meth->field_decode(group, x, point->X, ctx)) | |
534 | goto err; | |
535 | } | |
536 | if (y != NULL) { | |
537 | if (!group->meth->field_decode(group, y, point->Y, ctx)) | |
538 | goto err; | |
539 | } | |
540 | } else { | |
541 | if (x != NULL) { | |
542 | if (!BN_copy(x, point->X)) | |
543 | goto err; | |
544 | } | |
545 | if (y != NULL) { | |
546 | if (!BN_copy(y, point->Y)) | |
547 | goto err; | |
548 | } | |
549 | } | |
550 | } else { | |
551 | if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) { | |
552 | ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, | |
553 | ERR_R_BN_LIB); | |
554 | goto err; | |
555 | } | |
556 | ||
557 | if (group->meth->field_encode == 0) { | |
558 | /* field_sqr works on standard representation */ | |
559 | if (!group->meth->field_sqr(group, Z_2, Z_1, ctx)) | |
560 | goto err; | |
561 | } else { | |
562 | if (!BN_mod_sqr(Z_2, Z_1, group->field, ctx)) | |
563 | goto err; | |
564 | } | |
565 | ||
566 | if (x != NULL) { | |
567 | /* | |
568 | * in the Montgomery case, field_mul will cancel out Montgomery | |
569 | * factor in X: | |
570 | */ | |
571 | if (!group->meth->field_mul(group, x, point->X, Z_2, ctx)) | |
572 | goto err; | |
573 | } | |
574 | ||
575 | if (y != NULL) { | |
576 | if (group->meth->field_encode == 0) { | |
577 | /* | |
578 | * field_mul works on standard representation | |
579 | */ | |
580 | if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx)) | |
581 | goto err; | |
582 | } else { | |
583 | if (!BN_mod_mul(Z_3, Z_2, Z_1, group->field, ctx)) | |
584 | goto err; | |
585 | } | |
586 | ||
587 | /* | |
588 | * in the Montgomery case, field_mul will cancel out Montgomery | |
589 | * factor in Y: | |
590 | */ | |
591 | if (!group->meth->field_mul(group, y, point->Y, Z_3, ctx)) | |
592 | goto err; | |
593 | } | |
594 | } | |
595 | ||
596 | ret = 1; | |
226cc7de BM |
597 | |
598 | err: | |
0f113f3e | 599 | BN_CTX_end(ctx); |
23a1d5e9 | 600 | BN_CTX_free(new_ctx); |
0f113f3e MC |
601 | return ret; |
602 | } | |
603 | ||
604 | int ec_GFp_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, | |
605 | const EC_POINT *b, BN_CTX *ctx) | |
606 | { | |
607 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
608 | const BIGNUM *, BN_CTX *); | |
609 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
610 | const BIGNUM *p; | |
611 | BN_CTX *new_ctx = NULL; | |
612 | BIGNUM *n0, *n1, *n2, *n3, *n4, *n5, *n6; | |
613 | int ret = 0; | |
614 | ||
615 | if (a == b) | |
616 | return EC_POINT_dbl(group, r, a, ctx); | |
617 | if (EC_POINT_is_at_infinity(group, a)) | |
618 | return EC_POINT_copy(r, b); | |
619 | if (EC_POINT_is_at_infinity(group, b)) | |
620 | return EC_POINT_copy(r, a); | |
621 | ||
622 | field_mul = group->meth->field_mul; | |
623 | field_sqr = group->meth->field_sqr; | |
624 | p = group->field; | |
625 | ||
626 | if (ctx == NULL) { | |
627 | ctx = new_ctx = BN_CTX_new(); | |
628 | if (ctx == NULL) | |
629 | return 0; | |
630 | } | |
631 | ||
632 | BN_CTX_start(ctx); | |
633 | n0 = BN_CTX_get(ctx); | |
634 | n1 = BN_CTX_get(ctx); | |
635 | n2 = BN_CTX_get(ctx); | |
636 | n3 = BN_CTX_get(ctx); | |
637 | n4 = BN_CTX_get(ctx); | |
638 | n5 = BN_CTX_get(ctx); | |
639 | n6 = BN_CTX_get(ctx); | |
640 | if (n6 == NULL) | |
641 | goto end; | |
642 | ||
643 | /* | |
644 | * Note that in this function we must not read components of 'a' or 'b' | |
645 | * once we have written the corresponding components of 'r'. ('r' might | |
646 | * be one of 'a' or 'b'.) | |
647 | */ | |
648 | ||
649 | /* n1, n2 */ | |
650 | if (b->Z_is_one) { | |
651 | if (!BN_copy(n1, a->X)) | |
652 | goto end; | |
653 | if (!BN_copy(n2, a->Y)) | |
654 | goto end; | |
655 | /* n1 = X_a */ | |
656 | /* n2 = Y_a */ | |
657 | } else { | |
658 | if (!field_sqr(group, n0, b->Z, ctx)) | |
659 | goto end; | |
660 | if (!field_mul(group, n1, a->X, n0, ctx)) | |
661 | goto end; | |
662 | /* n1 = X_a * Z_b^2 */ | |
663 | ||
664 | if (!field_mul(group, n0, n0, b->Z, ctx)) | |
665 | goto end; | |
666 | if (!field_mul(group, n2, a->Y, n0, ctx)) | |
667 | goto end; | |
668 | /* n2 = Y_a * Z_b^3 */ | |
669 | } | |
670 | ||
671 | /* n3, n4 */ | |
672 | if (a->Z_is_one) { | |
673 | if (!BN_copy(n3, b->X)) | |
674 | goto end; | |
675 | if (!BN_copy(n4, b->Y)) | |
676 | goto end; | |
677 | /* n3 = X_b */ | |
678 | /* n4 = Y_b */ | |
679 | } else { | |
680 | if (!field_sqr(group, n0, a->Z, ctx)) | |
681 | goto end; | |
682 | if (!field_mul(group, n3, b->X, n0, ctx)) | |
683 | goto end; | |
684 | /* n3 = X_b * Z_a^2 */ | |
685 | ||
686 | if (!field_mul(group, n0, n0, a->Z, ctx)) | |
687 | goto end; | |
688 | if (!field_mul(group, n4, b->Y, n0, ctx)) | |
689 | goto end; | |
690 | /* n4 = Y_b * Z_a^3 */ | |
691 | } | |
692 | ||
693 | /* n5, n6 */ | |
694 | if (!BN_mod_sub_quick(n5, n1, n3, p)) | |
695 | goto end; | |
696 | if (!BN_mod_sub_quick(n6, n2, n4, p)) | |
697 | goto end; | |
698 | /* n5 = n1 - n3 */ | |
699 | /* n6 = n2 - n4 */ | |
700 | ||
701 | if (BN_is_zero(n5)) { | |
702 | if (BN_is_zero(n6)) { | |
703 | /* a is the same point as b */ | |
704 | BN_CTX_end(ctx); | |
705 | ret = EC_POINT_dbl(group, r, a, ctx); | |
706 | ctx = NULL; | |
707 | goto end; | |
708 | } else { | |
709 | /* a is the inverse of b */ | |
710 | BN_zero(r->Z); | |
711 | r->Z_is_one = 0; | |
712 | ret = 1; | |
713 | goto end; | |
714 | } | |
715 | } | |
716 | ||
717 | /* 'n7', 'n8' */ | |
718 | if (!BN_mod_add_quick(n1, n1, n3, p)) | |
719 | goto end; | |
720 | if (!BN_mod_add_quick(n2, n2, n4, p)) | |
721 | goto end; | |
722 | /* 'n7' = n1 + n3 */ | |
723 | /* 'n8' = n2 + n4 */ | |
724 | ||
725 | /* Z_r */ | |
726 | if (a->Z_is_one && b->Z_is_one) { | |
727 | if (!BN_copy(r->Z, n5)) | |
728 | goto end; | |
729 | } else { | |
730 | if (a->Z_is_one) { | |
731 | if (!BN_copy(n0, b->Z)) | |
732 | goto end; | |
733 | } else if (b->Z_is_one) { | |
734 | if (!BN_copy(n0, a->Z)) | |
735 | goto end; | |
736 | } else { | |
737 | if (!field_mul(group, n0, a->Z, b->Z, ctx)) | |
738 | goto end; | |
739 | } | |
740 | if (!field_mul(group, r->Z, n0, n5, ctx)) | |
741 | goto end; | |
742 | } | |
743 | r->Z_is_one = 0; | |
744 | /* Z_r = Z_a * Z_b * n5 */ | |
745 | ||
746 | /* X_r */ | |
747 | if (!field_sqr(group, n0, n6, ctx)) | |
748 | goto end; | |
749 | if (!field_sqr(group, n4, n5, ctx)) | |
750 | goto end; | |
751 | if (!field_mul(group, n3, n1, n4, ctx)) | |
752 | goto end; | |
753 | if (!BN_mod_sub_quick(r->X, n0, n3, p)) | |
754 | goto end; | |
755 | /* X_r = n6^2 - n5^2 * 'n7' */ | |
756 | ||
757 | /* 'n9' */ | |
758 | if (!BN_mod_lshift1_quick(n0, r->X, p)) | |
759 | goto end; | |
760 | if (!BN_mod_sub_quick(n0, n3, n0, p)) | |
761 | goto end; | |
762 | /* n9 = n5^2 * 'n7' - 2 * X_r */ | |
763 | ||
764 | /* Y_r */ | |
765 | if (!field_mul(group, n0, n0, n6, ctx)) | |
766 | goto end; | |
767 | if (!field_mul(group, n5, n4, n5, ctx)) | |
768 | goto end; /* now n5 is n5^3 */ | |
769 | if (!field_mul(group, n1, n2, n5, ctx)) | |
770 | goto end; | |
771 | if (!BN_mod_sub_quick(n0, n0, n1, p)) | |
772 | goto end; | |
773 | if (BN_is_odd(n0)) | |
774 | if (!BN_add(n0, n0, p)) | |
775 | goto end; | |
776 | /* now 0 <= n0 < 2*p, and n0 is even */ | |
777 | if (!BN_rshift1(r->Y, n0)) | |
778 | goto end; | |
779 | /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */ | |
780 | ||
781 | ret = 1; | |
60428dbf BM |
782 | |
783 | end: | |
0f113f3e MC |
784 | if (ctx) /* otherwise we already called BN_CTX_end */ |
785 | BN_CTX_end(ctx); | |
23a1d5e9 | 786 | BN_CTX_free(new_ctx); |
0f113f3e MC |
787 | return ret; |
788 | } | |
789 | ||
790 | int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, | |
791 | BN_CTX *ctx) | |
792 | { | |
793 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
794 | const BIGNUM *, BN_CTX *); | |
795 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
796 | const BIGNUM *p; | |
797 | BN_CTX *new_ctx = NULL; | |
798 | BIGNUM *n0, *n1, *n2, *n3; | |
799 | int ret = 0; | |
800 | ||
801 | if (EC_POINT_is_at_infinity(group, a)) { | |
802 | BN_zero(r->Z); | |
803 | r->Z_is_one = 0; | |
804 | return 1; | |
805 | } | |
806 | ||
807 | field_mul = group->meth->field_mul; | |
808 | field_sqr = group->meth->field_sqr; | |
809 | p = group->field; | |
810 | ||
811 | if (ctx == NULL) { | |
812 | ctx = new_ctx = BN_CTX_new(); | |
813 | if (ctx == NULL) | |
814 | return 0; | |
815 | } | |
816 | ||
817 | BN_CTX_start(ctx); | |
818 | n0 = BN_CTX_get(ctx); | |
819 | n1 = BN_CTX_get(ctx); | |
820 | n2 = BN_CTX_get(ctx); | |
821 | n3 = BN_CTX_get(ctx); | |
822 | if (n3 == NULL) | |
823 | goto err; | |
824 | ||
825 | /* | |
826 | * Note that in this function we must not read components of 'a' once we | |
827 | * have written the corresponding components of 'r'. ('r' might the same | |
828 | * as 'a'.) | |
829 | */ | |
830 | ||
831 | /* n1 */ | |
832 | if (a->Z_is_one) { | |
833 | if (!field_sqr(group, n0, a->X, ctx)) | |
834 | goto err; | |
835 | if (!BN_mod_lshift1_quick(n1, n0, p)) | |
836 | goto err; | |
837 | if (!BN_mod_add_quick(n0, n0, n1, p)) | |
838 | goto err; | |
839 | if (!BN_mod_add_quick(n1, n0, group->a, p)) | |
840 | goto err; | |
841 | /* n1 = 3 * X_a^2 + a_curve */ | |
842 | } else if (group->a_is_minus3) { | |
843 | if (!field_sqr(group, n1, a->Z, ctx)) | |
844 | goto err; | |
845 | if (!BN_mod_add_quick(n0, a->X, n1, p)) | |
846 | goto err; | |
847 | if (!BN_mod_sub_quick(n2, a->X, n1, p)) | |
848 | goto err; | |
849 | if (!field_mul(group, n1, n0, n2, ctx)) | |
850 | goto err; | |
851 | if (!BN_mod_lshift1_quick(n0, n1, p)) | |
852 | goto err; | |
853 | if (!BN_mod_add_quick(n1, n0, n1, p)) | |
854 | goto err; | |
35a1cc90 MC |
855 | /*- |
856 | * n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2) | |
857 | * = 3 * X_a^2 - 3 * Z_a^4 | |
858 | */ | |
0f113f3e MC |
859 | } else { |
860 | if (!field_sqr(group, n0, a->X, ctx)) | |
861 | goto err; | |
862 | if (!BN_mod_lshift1_quick(n1, n0, p)) | |
863 | goto err; | |
864 | if (!BN_mod_add_quick(n0, n0, n1, p)) | |
865 | goto err; | |
866 | if (!field_sqr(group, n1, a->Z, ctx)) | |
867 | goto err; | |
868 | if (!field_sqr(group, n1, n1, ctx)) | |
869 | goto err; | |
870 | if (!field_mul(group, n1, n1, group->a, ctx)) | |
871 | goto err; | |
872 | if (!BN_mod_add_quick(n1, n1, n0, p)) | |
873 | goto err; | |
874 | /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */ | |
875 | } | |
876 | ||
877 | /* Z_r */ | |
878 | if (a->Z_is_one) { | |
879 | if (!BN_copy(n0, a->Y)) | |
880 | goto err; | |
881 | } else { | |
882 | if (!field_mul(group, n0, a->Y, a->Z, ctx)) | |
883 | goto err; | |
884 | } | |
885 | if (!BN_mod_lshift1_quick(r->Z, n0, p)) | |
886 | goto err; | |
887 | r->Z_is_one = 0; | |
888 | /* Z_r = 2 * Y_a * Z_a */ | |
889 | ||
890 | /* n2 */ | |
891 | if (!field_sqr(group, n3, a->Y, ctx)) | |
892 | goto err; | |
893 | if (!field_mul(group, n2, a->X, n3, ctx)) | |
894 | goto err; | |
895 | if (!BN_mod_lshift_quick(n2, n2, 2, p)) | |
896 | goto err; | |
897 | /* n2 = 4 * X_a * Y_a^2 */ | |
898 | ||
899 | /* X_r */ | |
900 | if (!BN_mod_lshift1_quick(n0, n2, p)) | |
901 | goto err; | |
902 | if (!field_sqr(group, r->X, n1, ctx)) | |
903 | goto err; | |
904 | if (!BN_mod_sub_quick(r->X, r->X, n0, p)) | |
905 | goto err; | |
906 | /* X_r = n1^2 - 2 * n2 */ | |
907 | ||
908 | /* n3 */ | |
909 | if (!field_sqr(group, n0, n3, ctx)) | |
910 | goto err; | |
911 | if (!BN_mod_lshift_quick(n3, n0, 3, p)) | |
912 | goto err; | |
913 | /* n3 = 8 * Y_a^4 */ | |
914 | ||
915 | /* Y_r */ | |
916 | if (!BN_mod_sub_quick(n0, n2, r->X, p)) | |
917 | goto err; | |
918 | if (!field_mul(group, n0, n1, n0, ctx)) | |
919 | goto err; | |
920 | if (!BN_mod_sub_quick(r->Y, n0, n3, p)) | |
921 | goto err; | |
922 | /* Y_r = n1 * (n2 - X_r) - n3 */ | |
923 | ||
924 | ret = 1; | |
60428dbf BM |
925 | |
926 | err: | |
0f113f3e | 927 | BN_CTX_end(ctx); |
23a1d5e9 | 928 | BN_CTX_free(new_ctx); |
0f113f3e MC |
929 | return ret; |
930 | } | |
60428dbf | 931 | |
bb62a8b0 | 932 | int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx) |
0f113f3e MC |
933 | { |
934 | if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(point->Y)) | |
935 | /* point is its own inverse */ | |
936 | return 1; | |
1d5bd6cf | 937 | |
0f113f3e MC |
938 | return BN_usub(point->Y, group->field, point->Y); |
939 | } | |
1d5bd6cf | 940 | |
60428dbf | 941 | int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point) |
0f113f3e MC |
942 | { |
943 | return BN_is_zero(point->Z); | |
944 | } | |
945 | ||
946 | int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, | |
947 | BN_CTX *ctx) | |
948 | { | |
949 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
950 | const BIGNUM *, BN_CTX *); | |
951 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
952 | const BIGNUM *p; | |
953 | BN_CTX *new_ctx = NULL; | |
954 | BIGNUM *rh, *tmp, *Z4, *Z6; | |
955 | int ret = -1; | |
956 | ||
957 | if (EC_POINT_is_at_infinity(group, point)) | |
958 | return 1; | |
959 | ||
960 | field_mul = group->meth->field_mul; | |
961 | field_sqr = group->meth->field_sqr; | |
962 | p = group->field; | |
963 | ||
964 | if (ctx == NULL) { | |
965 | ctx = new_ctx = BN_CTX_new(); | |
966 | if (ctx == NULL) | |
967 | return -1; | |
968 | } | |
969 | ||
970 | BN_CTX_start(ctx); | |
971 | rh = BN_CTX_get(ctx); | |
972 | tmp = BN_CTX_get(ctx); | |
973 | Z4 = BN_CTX_get(ctx); | |
974 | Z6 = BN_CTX_get(ctx); | |
975 | if (Z6 == NULL) | |
976 | goto err; | |
977 | ||
35a1cc90 MC |
978 | /*- |
979 | * We have a curve defined by a Weierstrass equation | |
980 | * y^2 = x^3 + a*x + b. | |
981 | * The point to consider is given in Jacobian projective coordinates | |
982 | * where (X, Y, Z) represents (x, y) = (X/Z^2, Y/Z^3). | |
983 | * Substituting this and multiplying by Z^6 transforms the above equation into | |
984 | * Y^2 = X^3 + a*X*Z^4 + b*Z^6. | |
985 | * To test this, we add up the right-hand side in 'rh'. | |
986 | */ | |
0f113f3e MC |
987 | |
988 | /* rh := X^2 */ | |
989 | if (!field_sqr(group, rh, point->X, ctx)) | |
990 | goto err; | |
991 | ||
992 | if (!point->Z_is_one) { | |
993 | if (!field_sqr(group, tmp, point->Z, ctx)) | |
994 | goto err; | |
995 | if (!field_sqr(group, Z4, tmp, ctx)) | |
996 | goto err; | |
997 | if (!field_mul(group, Z6, Z4, tmp, ctx)) | |
998 | goto err; | |
999 | ||
1000 | /* rh := (rh + a*Z^4)*X */ | |
1001 | if (group->a_is_minus3) { | |
1002 | if (!BN_mod_lshift1_quick(tmp, Z4, p)) | |
1003 | goto err; | |
1004 | if (!BN_mod_add_quick(tmp, tmp, Z4, p)) | |
1005 | goto err; | |
1006 | if (!BN_mod_sub_quick(rh, rh, tmp, p)) | |
1007 | goto err; | |
1008 | if (!field_mul(group, rh, rh, point->X, ctx)) | |
1009 | goto err; | |
1010 | } else { | |
1011 | if (!field_mul(group, tmp, Z4, group->a, ctx)) | |
1012 | goto err; | |
1013 | if (!BN_mod_add_quick(rh, rh, tmp, p)) | |
1014 | goto err; | |
1015 | if (!field_mul(group, rh, rh, point->X, ctx)) | |
1016 | goto err; | |
1017 | } | |
1018 | ||
1019 | /* rh := rh + b*Z^6 */ | |
1020 | if (!field_mul(group, tmp, group->b, Z6, ctx)) | |
1021 | goto err; | |
1022 | if (!BN_mod_add_quick(rh, rh, tmp, p)) | |
1023 | goto err; | |
1024 | } else { | |
1025 | /* point->Z_is_one */ | |
1026 | ||
1027 | /* rh := (rh + a)*X */ | |
1028 | if (!BN_mod_add_quick(rh, rh, group->a, p)) | |
1029 | goto err; | |
1030 | if (!field_mul(group, rh, rh, point->X, ctx)) | |
1031 | goto err; | |
1032 | /* rh := rh + b */ | |
1033 | if (!BN_mod_add_quick(rh, rh, group->b, p)) | |
1034 | goto err; | |
1035 | } | |
1036 | ||
1037 | /* 'lh' := Y^2 */ | |
1038 | if (!field_sqr(group, tmp, point->Y, ctx)) | |
1039 | goto err; | |
1040 | ||
1041 | ret = (0 == BN_ucmp(tmp, rh)); | |
e869d4bd BM |
1042 | |
1043 | err: | |
0f113f3e | 1044 | BN_CTX_end(ctx); |
23a1d5e9 | 1045 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1046 | return ret; |
1047 | } | |
1048 | ||
1049 | int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a, | |
1050 | const EC_POINT *b, BN_CTX *ctx) | |
1051 | { | |
35a1cc90 MC |
1052 | /*- |
1053 | * return values: | |
1054 | * -1 error | |
1055 | * 0 equal (in affine coordinates) | |
1056 | * 1 not equal | |
1057 | */ | |
0f113f3e MC |
1058 | |
1059 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
1060 | const BIGNUM *, BN_CTX *); | |
1061 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
1062 | BN_CTX *new_ctx = NULL; | |
1063 | BIGNUM *tmp1, *tmp2, *Za23, *Zb23; | |
1064 | const BIGNUM *tmp1_, *tmp2_; | |
1065 | int ret = -1; | |
1066 | ||
1067 | if (EC_POINT_is_at_infinity(group, a)) { | |
1068 | return EC_POINT_is_at_infinity(group, b) ? 0 : 1; | |
1069 | } | |
1070 | ||
1071 | if (EC_POINT_is_at_infinity(group, b)) | |
1072 | return 1; | |
1073 | ||
1074 | if (a->Z_is_one && b->Z_is_one) { | |
1075 | return ((BN_cmp(a->X, b->X) == 0) && BN_cmp(a->Y, b->Y) == 0) ? 0 : 1; | |
1076 | } | |
1077 | ||
1078 | field_mul = group->meth->field_mul; | |
1079 | field_sqr = group->meth->field_sqr; | |
1080 | ||
1081 | if (ctx == NULL) { | |
1082 | ctx = new_ctx = BN_CTX_new(); | |
1083 | if (ctx == NULL) | |
1084 | return -1; | |
1085 | } | |
1086 | ||
1087 | BN_CTX_start(ctx); | |
1088 | tmp1 = BN_CTX_get(ctx); | |
1089 | tmp2 = BN_CTX_get(ctx); | |
1090 | Za23 = BN_CTX_get(ctx); | |
1091 | Zb23 = BN_CTX_get(ctx); | |
1092 | if (Zb23 == NULL) | |
1093 | goto end; | |
1094 | ||
35a1cc90 MC |
1095 | /*- |
1096 | * We have to decide whether | |
1097 | * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3), | |
1098 | * or equivalently, whether | |
1099 | * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3). | |
1100 | */ | |
0f113f3e MC |
1101 | |
1102 | if (!b->Z_is_one) { | |
1103 | if (!field_sqr(group, Zb23, b->Z, ctx)) | |
1104 | goto end; | |
1105 | if (!field_mul(group, tmp1, a->X, Zb23, ctx)) | |
1106 | goto end; | |
1107 | tmp1_ = tmp1; | |
1108 | } else | |
1109 | tmp1_ = a->X; | |
1110 | if (!a->Z_is_one) { | |
1111 | if (!field_sqr(group, Za23, a->Z, ctx)) | |
1112 | goto end; | |
1113 | if (!field_mul(group, tmp2, b->X, Za23, ctx)) | |
1114 | goto end; | |
1115 | tmp2_ = tmp2; | |
1116 | } else | |
1117 | tmp2_ = b->X; | |
1118 | ||
1119 | /* compare X_a*Z_b^2 with X_b*Z_a^2 */ | |
1120 | if (BN_cmp(tmp1_, tmp2_) != 0) { | |
1121 | ret = 1; /* points differ */ | |
1122 | goto end; | |
1123 | } | |
1124 | ||
1125 | if (!b->Z_is_one) { | |
1126 | if (!field_mul(group, Zb23, Zb23, b->Z, ctx)) | |
1127 | goto end; | |
1128 | if (!field_mul(group, tmp1, a->Y, Zb23, ctx)) | |
1129 | goto end; | |
1130 | /* tmp1_ = tmp1 */ | |
1131 | } else | |
1132 | tmp1_ = a->Y; | |
1133 | if (!a->Z_is_one) { | |
1134 | if (!field_mul(group, Za23, Za23, a->Z, ctx)) | |
1135 | goto end; | |
1136 | if (!field_mul(group, tmp2, b->Y, Za23, ctx)) | |
1137 | goto end; | |
1138 | /* tmp2_ = tmp2 */ | |
1139 | } else | |
1140 | tmp2_ = b->Y; | |
1141 | ||
1142 | /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */ | |
1143 | if (BN_cmp(tmp1_, tmp2_) != 0) { | |
1144 | ret = 1; /* points differ */ | |
1145 | goto end; | |
1146 | } | |
1147 | ||
1148 | /* points are equal */ | |
1149 | ret = 0; | |
bb62a8b0 BM |
1150 | |
1151 | end: | |
0f113f3e | 1152 | BN_CTX_end(ctx); |
23a1d5e9 | 1153 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1154 | return ret; |
1155 | } | |
1156 | ||
1157 | int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point, | |
1158 | BN_CTX *ctx) | |
1159 | { | |
1160 | BN_CTX *new_ctx = NULL; | |
1161 | BIGNUM *x, *y; | |
1162 | int ret = 0; | |
1163 | ||
1164 | if (point->Z_is_one || EC_POINT_is_at_infinity(group, point)) | |
1165 | return 1; | |
1166 | ||
1167 | if (ctx == NULL) { | |
1168 | ctx = new_ctx = BN_CTX_new(); | |
1169 | if (ctx == NULL) | |
1170 | return 0; | |
1171 | } | |
1172 | ||
1173 | BN_CTX_start(ctx); | |
1174 | x = BN_CTX_get(ctx); | |
1175 | y = BN_CTX_get(ctx); | |
1176 | if (y == NULL) | |
1177 | goto err; | |
1178 | ||
1179 | if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) | |
1180 | goto err; | |
1181 | if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) | |
1182 | goto err; | |
1183 | if (!point->Z_is_one) { | |
1184 | ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_INTERNAL_ERROR); | |
1185 | goto err; | |
1186 | } | |
1187 | ||
1188 | ret = 1; | |
e869d4bd | 1189 | |
226cc7de | 1190 | err: |
0f113f3e | 1191 | BN_CTX_end(ctx); |
23a1d5e9 | 1192 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1193 | return ret; |
1194 | } | |
1195 | ||
1196 | int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, | |
1197 | EC_POINT *points[], BN_CTX *ctx) | |
1198 | { | |
1199 | BN_CTX *new_ctx = NULL; | |
1200 | BIGNUM *tmp, *tmp_Z; | |
1201 | BIGNUM **prod_Z = NULL; | |
1202 | size_t i; | |
1203 | int ret = 0; | |
1204 | ||
1205 | if (num == 0) | |
1206 | return 1; | |
1207 | ||
1208 | if (ctx == NULL) { | |
1209 | ctx = new_ctx = BN_CTX_new(); | |
1210 | if (ctx == NULL) | |
1211 | return 0; | |
1212 | } | |
1213 | ||
1214 | BN_CTX_start(ctx); | |
1215 | tmp = BN_CTX_get(ctx); | |
1216 | tmp_Z = BN_CTX_get(ctx); | |
edea42c6 | 1217 | if (tmp_Z == NULL) |
0f113f3e MC |
1218 | goto err; |
1219 | ||
cbe29648 | 1220 | prod_Z = OPENSSL_malloc(num * sizeof(prod_Z[0])); |
0f113f3e MC |
1221 | if (prod_Z == NULL) |
1222 | goto err; | |
1223 | for (i = 0; i < num; i++) { | |
1224 | prod_Z[i] = BN_new(); | |
1225 | if (prod_Z[i] == NULL) | |
1226 | goto err; | |
1227 | } | |
1228 | ||
1229 | /* | |
1230 | * Set each prod_Z[i] to the product of points[0]->Z .. points[i]->Z, | |
1231 | * skipping any zero-valued inputs (pretend that they're 1). | |
1232 | */ | |
1233 | ||
1234 | if (!BN_is_zero(points[0]->Z)) { | |
1235 | if (!BN_copy(prod_Z[0], points[0]->Z)) | |
1236 | goto err; | |
1237 | } else { | |
1238 | if (group->meth->field_set_to_one != 0) { | |
1239 | if (!group->meth->field_set_to_one(group, prod_Z[0], ctx)) | |
1240 | goto err; | |
1241 | } else { | |
1242 | if (!BN_one(prod_Z[0])) | |
1243 | goto err; | |
1244 | } | |
1245 | } | |
1246 | ||
1247 | for (i = 1; i < num; i++) { | |
1248 | if (!BN_is_zero(points[i]->Z)) { | |
1249 | if (!group-> | |
1250 | meth->field_mul(group, prod_Z[i], prod_Z[i - 1], points[i]->Z, | |
1251 | ctx)) | |
1252 | goto err; | |
1253 | } else { | |
1254 | if (!BN_copy(prod_Z[i], prod_Z[i - 1])) | |
1255 | goto err; | |
1256 | } | |
1257 | } | |
1258 | ||
1259 | /* | |
1260 | * Now use a single explicit inversion to replace every non-zero | |
1261 | * points[i]->Z by its inverse. | |
1262 | */ | |
1263 | ||
1264 | if (!BN_mod_inverse(tmp, prod_Z[num - 1], group->field, ctx)) { | |
1265 | ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB); | |
1266 | goto err; | |
1267 | } | |
1268 | if (group->meth->field_encode != 0) { | |
1269 | /* | |
1270 | * In the Montgomery case, we just turned R*H (representing H) into | |
1271 | * 1/(R*H), but we need R*(1/H) (representing 1/H); i.e. we need to | |
1272 | * multiply by the Montgomery factor twice. | |
1273 | */ | |
1274 | if (!group->meth->field_encode(group, tmp, tmp, ctx)) | |
1275 | goto err; | |
1276 | if (!group->meth->field_encode(group, tmp, tmp, ctx)) | |
1277 | goto err; | |
1278 | } | |
1279 | ||
1280 | for (i = num - 1; i > 0; --i) { | |
1281 | /* | |
1282 | * Loop invariant: tmp is the product of the inverses of points[0]->Z | |
1283 | * .. points[i]->Z (zero-valued inputs skipped). | |
1284 | */ | |
1285 | if (!BN_is_zero(points[i]->Z)) { | |
1286 | /* | |
1287 | * Set tmp_Z to the inverse of points[i]->Z (as product of Z | |
1288 | * inverses 0 .. i, Z values 0 .. i - 1). | |
1289 | */ | |
1290 | if (!group-> | |
1291 | meth->field_mul(group, tmp_Z, prod_Z[i - 1], tmp, ctx)) | |
1292 | goto err; | |
1293 | /* | |
1294 | * Update tmp to satisfy the loop invariant for i - 1. | |
1295 | */ | |
1296 | if (!group->meth->field_mul(group, tmp, tmp, points[i]->Z, ctx)) | |
1297 | goto err; | |
1298 | /* Replace points[i]->Z by its inverse. */ | |
1299 | if (!BN_copy(points[i]->Z, tmp_Z)) | |
1300 | goto err; | |
1301 | } | |
1302 | } | |
1303 | ||
1304 | if (!BN_is_zero(points[0]->Z)) { | |
1305 | /* Replace points[0]->Z by its inverse. */ | |
1306 | if (!BN_copy(points[0]->Z, tmp)) | |
1307 | goto err; | |
1308 | } | |
1309 | ||
1310 | /* Finally, fix up the X and Y coordinates for all points. */ | |
1311 | ||
1312 | for (i = 0; i < num; i++) { | |
1313 | EC_POINT *p = points[i]; | |
1314 | ||
1315 | if (!BN_is_zero(p->Z)) { | |
1316 | /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */ | |
1317 | ||
1318 | if (!group->meth->field_sqr(group, tmp, p->Z, ctx)) | |
1319 | goto err; | |
1320 | if (!group->meth->field_mul(group, p->X, p->X, tmp, ctx)) | |
1321 | goto err; | |
1322 | ||
1323 | if (!group->meth->field_mul(group, tmp, tmp, p->Z, ctx)) | |
1324 | goto err; | |
1325 | if (!group->meth->field_mul(group, p->Y, p->Y, tmp, ctx)) | |
1326 | goto err; | |
1327 | ||
1328 | if (group->meth->field_set_to_one != 0) { | |
1329 | if (!group->meth->field_set_to_one(group, p->Z, ctx)) | |
1330 | goto err; | |
1331 | } else { | |
1332 | if (!BN_one(p->Z)) | |
1333 | goto err; | |
1334 | } | |
1335 | p->Z_is_one = 1; | |
1336 | } | |
1337 | } | |
1338 | ||
1339 | ret = 1; | |
0fe73d6c | 1340 | |
48fe4d62 | 1341 | err: |
0f113f3e | 1342 | BN_CTX_end(ctx); |
23a1d5e9 | 1343 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1344 | if (prod_Z != NULL) { |
1345 | for (i = 0; i < num; i++) { | |
1346 | if (prod_Z[i] == NULL) | |
1347 | break; | |
1348 | BN_clear_free(prod_Z[i]); | |
1349 | } | |
1350 | OPENSSL_free(prod_Z); | |
1351 | } | |
1352 | return ret; | |
1353 | } | |
1354 | ||
1355 | int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, | |
1356 | const BIGNUM *b, BN_CTX *ctx) | |
1357 | { | |
1358 | return BN_mod_mul(r, a, b, group->field, ctx); | |
1359 | } | |
1360 | ||
1361 | int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, | |
1362 | BN_CTX *ctx) | |
1363 | { | |
1364 | return BN_mod_sqr(r, a, group->field, ctx); | |
1365 | } |