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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; | |
350 | ||
351 | return 1; | |
352 | } | |
353 | ||
354 | int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *group, | |
355 | EC_POINT *point) | |
356 | { | |
357 | point->Z_is_one = 0; | |
358 | BN_zero(point->Z); | |
359 | return 1; | |
360 | } | |
361 | ||
362 | int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group, | |
363 | EC_POINT *point, | |
364 | const BIGNUM *x, | |
365 | const BIGNUM *y, | |
366 | const BIGNUM *z, | |
367 | BN_CTX *ctx) | |
368 | { | |
369 | BN_CTX *new_ctx = NULL; | |
370 | int ret = 0; | |
371 | ||
372 | if (ctx == NULL) { | |
373 | ctx = new_ctx = BN_CTX_new(); | |
374 | if (ctx == NULL) | |
375 | return 0; | |
376 | } | |
377 | ||
378 | if (x != NULL) { | |
379 | if (!BN_nnmod(point->X, x, group->field, ctx)) | |
380 | goto err; | |
381 | if (group->meth->field_encode) { | |
382 | if (!group->meth->field_encode(group, point->X, point->X, ctx)) | |
383 | goto err; | |
384 | } | |
385 | } | |
386 | ||
387 | if (y != NULL) { | |
388 | if (!BN_nnmod(point->Y, y, group->field, ctx)) | |
389 | goto err; | |
390 | if (group->meth->field_encode) { | |
391 | if (!group->meth->field_encode(group, point->Y, point->Y, ctx)) | |
392 | goto err; | |
393 | } | |
394 | } | |
395 | ||
396 | if (z != NULL) { | |
397 | int Z_is_one; | |
398 | ||
399 | if (!BN_nnmod(point->Z, z, group->field, ctx)) | |
400 | goto err; | |
401 | Z_is_one = BN_is_one(point->Z); | |
402 | if (group->meth->field_encode) { | |
403 | if (Z_is_one && (group->meth->field_set_to_one != 0)) { | |
404 | if (!group->meth->field_set_to_one(group, point->Z, ctx)) | |
405 | goto err; | |
406 | } else { | |
407 | if (!group-> | |
408 | meth->field_encode(group, point->Z, point->Z, ctx)) | |
409 | goto err; | |
410 | } | |
411 | } | |
412 | point->Z_is_one = Z_is_one; | |
413 | } | |
414 | ||
415 | ret = 1; | |
416 | ||
bb62a8b0 | 417 | err: |
23a1d5e9 | 418 | BN_CTX_free(new_ctx); |
0f113f3e MC |
419 | return ret; |
420 | } | |
421 | ||
422 | int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *group, | |
423 | const EC_POINT *point, | |
424 | BIGNUM *x, BIGNUM *y, | |
425 | BIGNUM *z, BN_CTX *ctx) | |
426 | { | |
427 | BN_CTX *new_ctx = NULL; | |
428 | int ret = 0; | |
429 | ||
430 | if (group->meth->field_decode != 0) { | |
431 | if (ctx == NULL) { | |
432 | ctx = new_ctx = BN_CTX_new(); | |
433 | if (ctx == NULL) | |
434 | return 0; | |
435 | } | |
436 | ||
437 | if (x != NULL) { | |
438 | if (!group->meth->field_decode(group, x, point->X, ctx)) | |
439 | goto err; | |
440 | } | |
441 | if (y != NULL) { | |
442 | if (!group->meth->field_decode(group, y, point->Y, ctx)) | |
443 | goto err; | |
444 | } | |
445 | if (z != NULL) { | |
446 | if (!group->meth->field_decode(group, z, point->Z, ctx)) | |
447 | goto err; | |
448 | } | |
449 | } else { | |
450 | if (x != NULL) { | |
451 | if (!BN_copy(x, point->X)) | |
452 | goto err; | |
453 | } | |
454 | if (y != NULL) { | |
455 | if (!BN_copy(y, point->Y)) | |
456 | goto err; | |
457 | } | |
458 | if (z != NULL) { | |
459 | if (!BN_copy(z, point->Z)) | |
460 | goto err; | |
461 | } | |
462 | } | |
463 | ||
464 | ret = 1; | |
bb62a8b0 | 465 | |
226cc7de | 466 | err: |
23a1d5e9 | 467 | BN_CTX_free(new_ctx); |
0f113f3e MC |
468 | return ret; |
469 | } | |
470 | ||
471 | int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *group, | |
472 | EC_POINT *point, | |
473 | const BIGNUM *x, | |
474 | const BIGNUM *y, BN_CTX *ctx) | |
475 | { | |
476 | if (x == NULL || y == NULL) { | |
477 | /* | |
478 | * unlike for projective coordinates, we do not tolerate this | |
479 | */ | |
480 | ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES, | |
481 | ERR_R_PASSED_NULL_PARAMETER); | |
482 | return 0; | |
483 | } | |
484 | ||
485 | return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y, | |
486 | BN_value_one(), ctx); | |
487 | } | |
488 | ||
489 | int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group, | |
490 | const EC_POINT *point, | |
491 | BIGNUM *x, BIGNUM *y, | |
492 | BN_CTX *ctx) | |
493 | { | |
494 | BN_CTX *new_ctx = NULL; | |
495 | BIGNUM *Z, *Z_1, *Z_2, *Z_3; | |
496 | const BIGNUM *Z_; | |
497 | int ret = 0; | |
498 | ||
499 | if (EC_POINT_is_at_infinity(group, point)) { | |
500 | ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, | |
501 | EC_R_POINT_AT_INFINITY); | |
502 | return 0; | |
503 | } | |
504 | ||
505 | if (ctx == NULL) { | |
506 | ctx = new_ctx = BN_CTX_new(); | |
507 | if (ctx == NULL) | |
508 | return 0; | |
509 | } | |
510 | ||
511 | BN_CTX_start(ctx); | |
512 | Z = BN_CTX_get(ctx); | |
513 | Z_1 = BN_CTX_get(ctx); | |
514 | Z_2 = BN_CTX_get(ctx); | |
515 | Z_3 = BN_CTX_get(ctx); | |
516 | if (Z_3 == NULL) | |
517 | goto err; | |
518 | ||
519 | /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */ | |
520 | ||
521 | if (group->meth->field_decode) { | |
522 | if (!group->meth->field_decode(group, Z, point->Z, ctx)) | |
523 | goto err; | |
524 | Z_ = Z; | |
525 | } else { | |
526 | Z_ = point->Z; | |
527 | } | |
528 | ||
529 | if (BN_is_one(Z_)) { | |
530 | if (group->meth->field_decode) { | |
531 | if (x != NULL) { | |
532 | if (!group->meth->field_decode(group, x, point->X, ctx)) | |
533 | goto err; | |
534 | } | |
535 | if (y != NULL) { | |
536 | if (!group->meth->field_decode(group, y, point->Y, ctx)) | |
537 | goto err; | |
538 | } | |
539 | } else { | |
540 | if (x != NULL) { | |
541 | if (!BN_copy(x, point->X)) | |
542 | goto err; | |
543 | } | |
544 | if (y != NULL) { | |
545 | if (!BN_copy(y, point->Y)) | |
546 | goto err; | |
547 | } | |
548 | } | |
549 | } else { | |
550 | if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) { | |
551 | ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, | |
552 | ERR_R_BN_LIB); | |
553 | goto err; | |
554 | } | |
555 | ||
556 | if (group->meth->field_encode == 0) { | |
557 | /* field_sqr works on standard representation */ | |
558 | if (!group->meth->field_sqr(group, Z_2, Z_1, ctx)) | |
559 | goto err; | |
560 | } else { | |
561 | if (!BN_mod_sqr(Z_2, Z_1, group->field, ctx)) | |
562 | goto err; | |
563 | } | |
564 | ||
565 | if (x != NULL) { | |
566 | /* | |
567 | * in the Montgomery case, field_mul will cancel out Montgomery | |
568 | * factor in X: | |
569 | */ | |
570 | if (!group->meth->field_mul(group, x, point->X, Z_2, ctx)) | |
571 | goto err; | |
572 | } | |
573 | ||
574 | if (y != NULL) { | |
575 | if (group->meth->field_encode == 0) { | |
576 | /* | |
577 | * field_mul works on standard representation | |
578 | */ | |
579 | if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx)) | |
580 | goto err; | |
581 | } else { | |
582 | if (!BN_mod_mul(Z_3, Z_2, Z_1, group->field, ctx)) | |
583 | goto err; | |
584 | } | |
585 | ||
586 | /* | |
587 | * in the Montgomery case, field_mul will cancel out Montgomery | |
588 | * factor in Y: | |
589 | */ | |
590 | if (!group->meth->field_mul(group, y, point->Y, Z_3, ctx)) | |
591 | goto err; | |
592 | } | |
593 | } | |
594 | ||
595 | ret = 1; | |
226cc7de BM |
596 | |
597 | err: | |
0f113f3e | 598 | BN_CTX_end(ctx); |
23a1d5e9 | 599 | BN_CTX_free(new_ctx); |
0f113f3e MC |
600 | return ret; |
601 | } | |
602 | ||
603 | int ec_GFp_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, | |
604 | const EC_POINT *b, BN_CTX *ctx) | |
605 | { | |
606 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
607 | const BIGNUM *, BN_CTX *); | |
608 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
609 | const BIGNUM *p; | |
610 | BN_CTX *new_ctx = NULL; | |
611 | BIGNUM *n0, *n1, *n2, *n3, *n4, *n5, *n6; | |
612 | int ret = 0; | |
613 | ||
614 | if (a == b) | |
615 | return EC_POINT_dbl(group, r, a, ctx); | |
616 | if (EC_POINT_is_at_infinity(group, a)) | |
617 | return EC_POINT_copy(r, b); | |
618 | if (EC_POINT_is_at_infinity(group, b)) | |
619 | return EC_POINT_copy(r, a); | |
620 | ||
621 | field_mul = group->meth->field_mul; | |
622 | field_sqr = group->meth->field_sqr; | |
623 | p = group->field; | |
624 | ||
625 | if (ctx == NULL) { | |
626 | ctx = new_ctx = BN_CTX_new(); | |
627 | if (ctx == NULL) | |
628 | return 0; | |
629 | } | |
630 | ||
631 | BN_CTX_start(ctx); | |
632 | n0 = BN_CTX_get(ctx); | |
633 | n1 = BN_CTX_get(ctx); | |
634 | n2 = BN_CTX_get(ctx); | |
635 | n3 = BN_CTX_get(ctx); | |
636 | n4 = BN_CTX_get(ctx); | |
637 | n5 = BN_CTX_get(ctx); | |
638 | n6 = BN_CTX_get(ctx); | |
639 | if (n6 == NULL) | |
640 | goto end; | |
641 | ||
642 | /* | |
643 | * Note that in this function we must not read components of 'a' or 'b' | |
644 | * once we have written the corresponding components of 'r'. ('r' might | |
645 | * be one of 'a' or 'b'.) | |
646 | */ | |
647 | ||
648 | /* n1, n2 */ | |
649 | if (b->Z_is_one) { | |
650 | if (!BN_copy(n1, a->X)) | |
651 | goto end; | |
652 | if (!BN_copy(n2, a->Y)) | |
653 | goto end; | |
654 | /* n1 = X_a */ | |
655 | /* n2 = Y_a */ | |
656 | } else { | |
657 | if (!field_sqr(group, n0, b->Z, ctx)) | |
658 | goto end; | |
659 | if (!field_mul(group, n1, a->X, n0, ctx)) | |
660 | goto end; | |
661 | /* n1 = X_a * Z_b^2 */ | |
662 | ||
663 | if (!field_mul(group, n0, n0, b->Z, ctx)) | |
664 | goto end; | |
665 | if (!field_mul(group, n2, a->Y, n0, ctx)) | |
666 | goto end; | |
667 | /* n2 = Y_a * Z_b^3 */ | |
668 | } | |
669 | ||
670 | /* n3, n4 */ | |
671 | if (a->Z_is_one) { | |
672 | if (!BN_copy(n3, b->X)) | |
673 | goto end; | |
674 | if (!BN_copy(n4, b->Y)) | |
675 | goto end; | |
676 | /* n3 = X_b */ | |
677 | /* n4 = Y_b */ | |
678 | } else { | |
679 | if (!field_sqr(group, n0, a->Z, ctx)) | |
680 | goto end; | |
681 | if (!field_mul(group, n3, b->X, n0, ctx)) | |
682 | goto end; | |
683 | /* n3 = X_b * Z_a^2 */ | |
684 | ||
685 | if (!field_mul(group, n0, n0, a->Z, ctx)) | |
686 | goto end; | |
687 | if (!field_mul(group, n4, b->Y, n0, ctx)) | |
688 | goto end; | |
689 | /* n4 = Y_b * Z_a^3 */ | |
690 | } | |
691 | ||
692 | /* n5, n6 */ | |
693 | if (!BN_mod_sub_quick(n5, n1, n3, p)) | |
694 | goto end; | |
695 | if (!BN_mod_sub_quick(n6, n2, n4, p)) | |
696 | goto end; | |
697 | /* n5 = n1 - n3 */ | |
698 | /* n6 = n2 - n4 */ | |
699 | ||
700 | if (BN_is_zero(n5)) { | |
701 | if (BN_is_zero(n6)) { | |
702 | /* a is the same point as b */ | |
703 | BN_CTX_end(ctx); | |
704 | ret = EC_POINT_dbl(group, r, a, ctx); | |
705 | ctx = NULL; | |
706 | goto end; | |
707 | } else { | |
708 | /* a is the inverse of b */ | |
709 | BN_zero(r->Z); | |
710 | r->Z_is_one = 0; | |
711 | ret = 1; | |
712 | goto end; | |
713 | } | |
714 | } | |
715 | ||
716 | /* 'n7', 'n8' */ | |
717 | if (!BN_mod_add_quick(n1, n1, n3, p)) | |
718 | goto end; | |
719 | if (!BN_mod_add_quick(n2, n2, n4, p)) | |
720 | goto end; | |
721 | /* 'n7' = n1 + n3 */ | |
722 | /* 'n8' = n2 + n4 */ | |
723 | ||
724 | /* Z_r */ | |
725 | if (a->Z_is_one && b->Z_is_one) { | |
726 | if (!BN_copy(r->Z, n5)) | |
727 | goto end; | |
728 | } else { | |
729 | if (a->Z_is_one) { | |
730 | if (!BN_copy(n0, b->Z)) | |
731 | goto end; | |
732 | } else if (b->Z_is_one) { | |
733 | if (!BN_copy(n0, a->Z)) | |
734 | goto end; | |
735 | } else { | |
736 | if (!field_mul(group, n0, a->Z, b->Z, ctx)) | |
737 | goto end; | |
738 | } | |
739 | if (!field_mul(group, r->Z, n0, n5, ctx)) | |
740 | goto end; | |
741 | } | |
742 | r->Z_is_one = 0; | |
743 | /* Z_r = Z_a * Z_b * n5 */ | |
744 | ||
745 | /* X_r */ | |
746 | if (!field_sqr(group, n0, n6, ctx)) | |
747 | goto end; | |
748 | if (!field_sqr(group, n4, n5, ctx)) | |
749 | goto end; | |
750 | if (!field_mul(group, n3, n1, n4, ctx)) | |
751 | goto end; | |
752 | if (!BN_mod_sub_quick(r->X, n0, n3, p)) | |
753 | goto end; | |
754 | /* X_r = n6^2 - n5^2 * 'n7' */ | |
755 | ||
756 | /* 'n9' */ | |
757 | if (!BN_mod_lshift1_quick(n0, r->X, p)) | |
758 | goto end; | |
759 | if (!BN_mod_sub_quick(n0, n3, n0, p)) | |
760 | goto end; | |
761 | /* n9 = n5^2 * 'n7' - 2 * X_r */ | |
762 | ||
763 | /* Y_r */ | |
764 | if (!field_mul(group, n0, n0, n6, ctx)) | |
765 | goto end; | |
766 | if (!field_mul(group, n5, n4, n5, ctx)) | |
767 | goto end; /* now n5 is n5^3 */ | |
768 | if (!field_mul(group, n1, n2, n5, ctx)) | |
769 | goto end; | |
770 | if (!BN_mod_sub_quick(n0, n0, n1, p)) | |
771 | goto end; | |
772 | if (BN_is_odd(n0)) | |
773 | if (!BN_add(n0, n0, p)) | |
774 | goto end; | |
775 | /* now 0 <= n0 < 2*p, and n0 is even */ | |
776 | if (!BN_rshift1(r->Y, n0)) | |
777 | goto end; | |
778 | /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */ | |
779 | ||
780 | ret = 1; | |
60428dbf BM |
781 | |
782 | end: | |
0f113f3e MC |
783 | if (ctx) /* otherwise we already called BN_CTX_end */ |
784 | BN_CTX_end(ctx); | |
23a1d5e9 | 785 | BN_CTX_free(new_ctx); |
0f113f3e MC |
786 | return ret; |
787 | } | |
788 | ||
789 | int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, | |
790 | BN_CTX *ctx) | |
791 | { | |
792 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
793 | const BIGNUM *, BN_CTX *); | |
794 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
795 | const BIGNUM *p; | |
796 | BN_CTX *new_ctx = NULL; | |
797 | BIGNUM *n0, *n1, *n2, *n3; | |
798 | int ret = 0; | |
799 | ||
800 | if (EC_POINT_is_at_infinity(group, a)) { | |
801 | BN_zero(r->Z); | |
802 | r->Z_is_one = 0; | |
803 | return 1; | |
804 | } | |
805 | ||
806 | field_mul = group->meth->field_mul; | |
807 | field_sqr = group->meth->field_sqr; | |
808 | p = group->field; | |
809 | ||
810 | if (ctx == NULL) { | |
811 | ctx = new_ctx = BN_CTX_new(); | |
812 | if (ctx == NULL) | |
813 | return 0; | |
814 | } | |
815 | ||
816 | BN_CTX_start(ctx); | |
817 | n0 = BN_CTX_get(ctx); | |
818 | n1 = BN_CTX_get(ctx); | |
819 | n2 = BN_CTX_get(ctx); | |
820 | n3 = BN_CTX_get(ctx); | |
821 | if (n3 == NULL) | |
822 | goto err; | |
823 | ||
824 | /* | |
825 | * Note that in this function we must not read components of 'a' once we | |
826 | * have written the corresponding components of 'r'. ('r' might the same | |
827 | * as 'a'.) | |
828 | */ | |
829 | ||
830 | /* n1 */ | |
831 | if (a->Z_is_one) { | |
832 | if (!field_sqr(group, n0, a->X, ctx)) | |
833 | goto err; | |
834 | if (!BN_mod_lshift1_quick(n1, n0, p)) | |
835 | goto err; | |
836 | if (!BN_mod_add_quick(n0, n0, n1, p)) | |
837 | goto err; | |
838 | if (!BN_mod_add_quick(n1, n0, group->a, p)) | |
839 | goto err; | |
840 | /* n1 = 3 * X_a^2 + a_curve */ | |
841 | } else if (group->a_is_minus3) { | |
842 | if (!field_sqr(group, n1, a->Z, ctx)) | |
843 | goto err; | |
844 | if (!BN_mod_add_quick(n0, a->X, n1, p)) | |
845 | goto err; | |
846 | if (!BN_mod_sub_quick(n2, a->X, n1, p)) | |
847 | goto err; | |
848 | if (!field_mul(group, n1, n0, n2, ctx)) | |
849 | goto err; | |
850 | if (!BN_mod_lshift1_quick(n0, n1, p)) | |
851 | goto err; | |
852 | if (!BN_mod_add_quick(n1, n0, n1, p)) | |
853 | goto err; | |
35a1cc90 MC |
854 | /*- |
855 | * n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2) | |
856 | * = 3 * X_a^2 - 3 * Z_a^4 | |
857 | */ | |
0f113f3e MC |
858 | } else { |
859 | if (!field_sqr(group, n0, a->X, ctx)) | |
860 | goto err; | |
861 | if (!BN_mod_lshift1_quick(n1, n0, p)) | |
862 | goto err; | |
863 | if (!BN_mod_add_quick(n0, n0, n1, p)) | |
864 | goto err; | |
865 | if (!field_sqr(group, n1, a->Z, ctx)) | |
866 | goto err; | |
867 | if (!field_sqr(group, n1, n1, ctx)) | |
868 | goto err; | |
869 | if (!field_mul(group, n1, n1, group->a, ctx)) | |
870 | goto err; | |
871 | if (!BN_mod_add_quick(n1, n1, n0, p)) | |
872 | goto err; | |
873 | /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */ | |
874 | } | |
875 | ||
876 | /* Z_r */ | |
877 | if (a->Z_is_one) { | |
878 | if (!BN_copy(n0, a->Y)) | |
879 | goto err; | |
880 | } else { | |
881 | if (!field_mul(group, n0, a->Y, a->Z, ctx)) | |
882 | goto err; | |
883 | } | |
884 | if (!BN_mod_lshift1_quick(r->Z, n0, p)) | |
885 | goto err; | |
886 | r->Z_is_one = 0; | |
887 | /* Z_r = 2 * Y_a * Z_a */ | |
888 | ||
889 | /* n2 */ | |
890 | if (!field_sqr(group, n3, a->Y, ctx)) | |
891 | goto err; | |
892 | if (!field_mul(group, n2, a->X, n3, ctx)) | |
893 | goto err; | |
894 | if (!BN_mod_lshift_quick(n2, n2, 2, p)) | |
895 | goto err; | |
896 | /* n2 = 4 * X_a * Y_a^2 */ | |
897 | ||
898 | /* X_r */ | |
899 | if (!BN_mod_lshift1_quick(n0, n2, p)) | |
900 | goto err; | |
901 | if (!field_sqr(group, r->X, n1, ctx)) | |
902 | goto err; | |
903 | if (!BN_mod_sub_quick(r->X, r->X, n0, p)) | |
904 | goto err; | |
905 | /* X_r = n1^2 - 2 * n2 */ | |
906 | ||
907 | /* n3 */ | |
908 | if (!field_sqr(group, n0, n3, ctx)) | |
909 | goto err; | |
910 | if (!BN_mod_lshift_quick(n3, n0, 3, p)) | |
911 | goto err; | |
912 | /* n3 = 8 * Y_a^4 */ | |
913 | ||
914 | /* Y_r */ | |
915 | if (!BN_mod_sub_quick(n0, n2, r->X, p)) | |
916 | goto err; | |
917 | if (!field_mul(group, n0, n1, n0, ctx)) | |
918 | goto err; | |
919 | if (!BN_mod_sub_quick(r->Y, n0, n3, p)) | |
920 | goto err; | |
921 | /* Y_r = n1 * (n2 - X_r) - n3 */ | |
922 | ||
923 | ret = 1; | |
60428dbf BM |
924 | |
925 | err: | |
0f113f3e | 926 | BN_CTX_end(ctx); |
23a1d5e9 | 927 | BN_CTX_free(new_ctx); |
0f113f3e MC |
928 | return ret; |
929 | } | |
60428dbf | 930 | |
bb62a8b0 | 931 | int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx) |
0f113f3e MC |
932 | { |
933 | if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(point->Y)) | |
934 | /* point is its own inverse */ | |
935 | return 1; | |
1d5bd6cf | 936 | |
0f113f3e MC |
937 | return BN_usub(point->Y, group->field, point->Y); |
938 | } | |
1d5bd6cf | 939 | |
60428dbf | 940 | int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point) |
0f113f3e MC |
941 | { |
942 | return BN_is_zero(point->Z); | |
943 | } | |
944 | ||
945 | int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, | |
946 | BN_CTX *ctx) | |
947 | { | |
948 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
949 | const BIGNUM *, BN_CTX *); | |
950 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
951 | const BIGNUM *p; | |
952 | BN_CTX *new_ctx = NULL; | |
953 | BIGNUM *rh, *tmp, *Z4, *Z6; | |
954 | int ret = -1; | |
955 | ||
956 | if (EC_POINT_is_at_infinity(group, point)) | |
957 | return 1; | |
958 | ||
959 | field_mul = group->meth->field_mul; | |
960 | field_sqr = group->meth->field_sqr; | |
961 | p = group->field; | |
962 | ||
963 | if (ctx == NULL) { | |
964 | ctx = new_ctx = BN_CTX_new(); | |
965 | if (ctx == NULL) | |
966 | return -1; | |
967 | } | |
968 | ||
969 | BN_CTX_start(ctx); | |
970 | rh = BN_CTX_get(ctx); | |
971 | tmp = BN_CTX_get(ctx); | |
972 | Z4 = BN_CTX_get(ctx); | |
973 | Z6 = BN_CTX_get(ctx); | |
974 | if (Z6 == NULL) | |
975 | goto err; | |
976 | ||
35a1cc90 MC |
977 | /*- |
978 | * We have a curve defined by a Weierstrass equation | |
979 | * y^2 = x^3 + a*x + b. | |
980 | * The point to consider is given in Jacobian projective coordinates | |
981 | * where (X, Y, Z) represents (x, y) = (X/Z^2, Y/Z^3). | |
982 | * Substituting this and multiplying by Z^6 transforms the above equation into | |
983 | * Y^2 = X^3 + a*X*Z^4 + b*Z^6. | |
984 | * To test this, we add up the right-hand side in 'rh'. | |
985 | */ | |
0f113f3e MC |
986 | |
987 | /* rh := X^2 */ | |
988 | if (!field_sqr(group, rh, point->X, ctx)) | |
989 | goto err; | |
990 | ||
991 | if (!point->Z_is_one) { | |
992 | if (!field_sqr(group, tmp, point->Z, ctx)) | |
993 | goto err; | |
994 | if (!field_sqr(group, Z4, tmp, ctx)) | |
995 | goto err; | |
996 | if (!field_mul(group, Z6, Z4, tmp, ctx)) | |
997 | goto err; | |
998 | ||
999 | /* rh := (rh + a*Z^4)*X */ | |
1000 | if (group->a_is_minus3) { | |
1001 | if (!BN_mod_lshift1_quick(tmp, Z4, p)) | |
1002 | goto err; | |
1003 | if (!BN_mod_add_quick(tmp, tmp, Z4, p)) | |
1004 | goto err; | |
1005 | if (!BN_mod_sub_quick(rh, rh, tmp, p)) | |
1006 | goto err; | |
1007 | if (!field_mul(group, rh, rh, point->X, ctx)) | |
1008 | goto err; | |
1009 | } else { | |
1010 | if (!field_mul(group, tmp, Z4, group->a, ctx)) | |
1011 | goto err; | |
1012 | if (!BN_mod_add_quick(rh, rh, tmp, p)) | |
1013 | goto err; | |
1014 | if (!field_mul(group, rh, rh, point->X, ctx)) | |
1015 | goto err; | |
1016 | } | |
1017 | ||
1018 | /* rh := rh + b*Z^6 */ | |
1019 | if (!field_mul(group, tmp, group->b, Z6, ctx)) | |
1020 | goto err; | |
1021 | if (!BN_mod_add_quick(rh, rh, tmp, p)) | |
1022 | goto err; | |
1023 | } else { | |
1024 | /* point->Z_is_one */ | |
1025 | ||
1026 | /* rh := (rh + a)*X */ | |
1027 | if (!BN_mod_add_quick(rh, rh, group->a, p)) | |
1028 | goto err; | |
1029 | if (!field_mul(group, rh, rh, point->X, ctx)) | |
1030 | goto err; | |
1031 | /* rh := rh + b */ | |
1032 | if (!BN_mod_add_quick(rh, rh, group->b, p)) | |
1033 | goto err; | |
1034 | } | |
1035 | ||
1036 | /* 'lh' := Y^2 */ | |
1037 | if (!field_sqr(group, tmp, point->Y, ctx)) | |
1038 | goto err; | |
1039 | ||
1040 | ret = (0 == BN_ucmp(tmp, rh)); | |
e869d4bd BM |
1041 | |
1042 | err: | |
0f113f3e | 1043 | BN_CTX_end(ctx); |
23a1d5e9 | 1044 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1045 | return ret; |
1046 | } | |
1047 | ||
1048 | int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a, | |
1049 | const EC_POINT *b, BN_CTX *ctx) | |
1050 | { | |
35a1cc90 MC |
1051 | /*- |
1052 | * return values: | |
1053 | * -1 error | |
1054 | * 0 equal (in affine coordinates) | |
1055 | * 1 not equal | |
1056 | */ | |
0f113f3e MC |
1057 | |
1058 | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | |
1059 | const BIGNUM *, BN_CTX *); | |
1060 | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | |
1061 | BN_CTX *new_ctx = NULL; | |
1062 | BIGNUM *tmp1, *tmp2, *Za23, *Zb23; | |
1063 | const BIGNUM *tmp1_, *tmp2_; | |
1064 | int ret = -1; | |
1065 | ||
1066 | if (EC_POINT_is_at_infinity(group, a)) { | |
1067 | return EC_POINT_is_at_infinity(group, b) ? 0 : 1; | |
1068 | } | |
1069 | ||
1070 | if (EC_POINT_is_at_infinity(group, b)) | |
1071 | return 1; | |
1072 | ||
1073 | if (a->Z_is_one && b->Z_is_one) { | |
1074 | return ((BN_cmp(a->X, b->X) == 0) && BN_cmp(a->Y, b->Y) == 0) ? 0 : 1; | |
1075 | } | |
1076 | ||
1077 | field_mul = group->meth->field_mul; | |
1078 | field_sqr = group->meth->field_sqr; | |
1079 | ||
1080 | if (ctx == NULL) { | |
1081 | ctx = new_ctx = BN_CTX_new(); | |
1082 | if (ctx == NULL) | |
1083 | return -1; | |
1084 | } | |
1085 | ||
1086 | BN_CTX_start(ctx); | |
1087 | tmp1 = BN_CTX_get(ctx); | |
1088 | tmp2 = BN_CTX_get(ctx); | |
1089 | Za23 = BN_CTX_get(ctx); | |
1090 | Zb23 = BN_CTX_get(ctx); | |
1091 | if (Zb23 == NULL) | |
1092 | goto end; | |
1093 | ||
35a1cc90 MC |
1094 | /*- |
1095 | * We have to decide whether | |
1096 | * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3), | |
1097 | * or equivalently, whether | |
1098 | * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3). | |
1099 | */ | |
0f113f3e MC |
1100 | |
1101 | if (!b->Z_is_one) { | |
1102 | if (!field_sqr(group, Zb23, b->Z, ctx)) | |
1103 | goto end; | |
1104 | if (!field_mul(group, tmp1, a->X, Zb23, ctx)) | |
1105 | goto end; | |
1106 | tmp1_ = tmp1; | |
1107 | } else | |
1108 | tmp1_ = a->X; | |
1109 | if (!a->Z_is_one) { | |
1110 | if (!field_sqr(group, Za23, a->Z, ctx)) | |
1111 | goto end; | |
1112 | if (!field_mul(group, tmp2, b->X, Za23, ctx)) | |
1113 | goto end; | |
1114 | tmp2_ = tmp2; | |
1115 | } else | |
1116 | tmp2_ = b->X; | |
1117 | ||
1118 | /* compare X_a*Z_b^2 with X_b*Z_a^2 */ | |
1119 | if (BN_cmp(tmp1_, tmp2_) != 0) { | |
1120 | ret = 1; /* points differ */ | |
1121 | goto end; | |
1122 | } | |
1123 | ||
1124 | if (!b->Z_is_one) { | |
1125 | if (!field_mul(group, Zb23, Zb23, b->Z, ctx)) | |
1126 | goto end; | |
1127 | if (!field_mul(group, tmp1, a->Y, Zb23, ctx)) | |
1128 | goto end; | |
1129 | /* tmp1_ = tmp1 */ | |
1130 | } else | |
1131 | tmp1_ = a->Y; | |
1132 | if (!a->Z_is_one) { | |
1133 | if (!field_mul(group, Za23, Za23, a->Z, ctx)) | |
1134 | goto end; | |
1135 | if (!field_mul(group, tmp2, b->Y, Za23, ctx)) | |
1136 | goto end; | |
1137 | /* tmp2_ = tmp2 */ | |
1138 | } else | |
1139 | tmp2_ = b->Y; | |
1140 | ||
1141 | /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */ | |
1142 | if (BN_cmp(tmp1_, tmp2_) != 0) { | |
1143 | ret = 1; /* points differ */ | |
1144 | goto end; | |
1145 | } | |
1146 | ||
1147 | /* points are equal */ | |
1148 | ret = 0; | |
bb62a8b0 BM |
1149 | |
1150 | end: | |
0f113f3e | 1151 | BN_CTX_end(ctx); |
23a1d5e9 | 1152 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1153 | return ret; |
1154 | } | |
1155 | ||
1156 | int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point, | |
1157 | BN_CTX *ctx) | |
1158 | { | |
1159 | BN_CTX *new_ctx = NULL; | |
1160 | BIGNUM *x, *y; | |
1161 | int ret = 0; | |
1162 | ||
1163 | if (point->Z_is_one || EC_POINT_is_at_infinity(group, point)) | |
1164 | return 1; | |
1165 | ||
1166 | if (ctx == NULL) { | |
1167 | ctx = new_ctx = BN_CTX_new(); | |
1168 | if (ctx == NULL) | |
1169 | return 0; | |
1170 | } | |
1171 | ||
1172 | BN_CTX_start(ctx); | |
1173 | x = BN_CTX_get(ctx); | |
1174 | y = BN_CTX_get(ctx); | |
1175 | if (y == NULL) | |
1176 | goto err; | |
1177 | ||
1178 | if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) | |
1179 | goto err; | |
1180 | if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) | |
1181 | goto err; | |
1182 | if (!point->Z_is_one) { | |
1183 | ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_INTERNAL_ERROR); | |
1184 | goto err; | |
1185 | } | |
1186 | ||
1187 | ret = 1; | |
e869d4bd | 1188 | |
226cc7de | 1189 | err: |
0f113f3e | 1190 | BN_CTX_end(ctx); |
23a1d5e9 | 1191 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1192 | return ret; |
1193 | } | |
1194 | ||
1195 | int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, | |
1196 | EC_POINT *points[], BN_CTX *ctx) | |
1197 | { | |
1198 | BN_CTX *new_ctx = NULL; | |
1199 | BIGNUM *tmp, *tmp_Z; | |
1200 | BIGNUM **prod_Z = NULL; | |
1201 | size_t i; | |
1202 | int ret = 0; | |
1203 | ||
1204 | if (num == 0) | |
1205 | return 1; | |
1206 | ||
1207 | if (ctx == NULL) { | |
1208 | ctx = new_ctx = BN_CTX_new(); | |
1209 | if (ctx == NULL) | |
1210 | return 0; | |
1211 | } | |
1212 | ||
1213 | BN_CTX_start(ctx); | |
1214 | tmp = BN_CTX_get(ctx); | |
1215 | tmp_Z = BN_CTX_get(ctx); | |
edea42c6 | 1216 | if (tmp_Z == NULL) |
0f113f3e MC |
1217 | goto err; |
1218 | ||
cbe29648 | 1219 | prod_Z = OPENSSL_malloc(num * sizeof(prod_Z[0])); |
0f113f3e MC |
1220 | if (prod_Z == NULL) |
1221 | goto err; | |
1222 | for (i = 0; i < num; i++) { | |
1223 | prod_Z[i] = BN_new(); | |
1224 | if (prod_Z[i] == NULL) | |
1225 | goto err; | |
1226 | } | |
1227 | ||
1228 | /* | |
1229 | * Set each prod_Z[i] to the product of points[0]->Z .. points[i]->Z, | |
1230 | * skipping any zero-valued inputs (pretend that they're 1). | |
1231 | */ | |
1232 | ||
1233 | if (!BN_is_zero(points[0]->Z)) { | |
1234 | if (!BN_copy(prod_Z[0], points[0]->Z)) | |
1235 | goto err; | |
1236 | } else { | |
1237 | if (group->meth->field_set_to_one != 0) { | |
1238 | if (!group->meth->field_set_to_one(group, prod_Z[0], ctx)) | |
1239 | goto err; | |
1240 | } else { | |
1241 | if (!BN_one(prod_Z[0])) | |
1242 | goto err; | |
1243 | } | |
1244 | } | |
1245 | ||
1246 | for (i = 1; i < num; i++) { | |
1247 | if (!BN_is_zero(points[i]->Z)) { | |
1248 | if (!group-> | |
1249 | meth->field_mul(group, prod_Z[i], prod_Z[i - 1], points[i]->Z, | |
1250 | ctx)) | |
1251 | goto err; | |
1252 | } else { | |
1253 | if (!BN_copy(prod_Z[i], prod_Z[i - 1])) | |
1254 | goto err; | |
1255 | } | |
1256 | } | |
1257 | ||
1258 | /* | |
1259 | * Now use a single explicit inversion to replace every non-zero | |
1260 | * points[i]->Z by its inverse. | |
1261 | */ | |
1262 | ||
1263 | if (!BN_mod_inverse(tmp, prod_Z[num - 1], group->field, ctx)) { | |
1264 | ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB); | |
1265 | goto err; | |
1266 | } | |
1267 | if (group->meth->field_encode != 0) { | |
1268 | /* | |
1269 | * In the Montgomery case, we just turned R*H (representing H) into | |
1270 | * 1/(R*H), but we need R*(1/H) (representing 1/H); i.e. we need to | |
1271 | * multiply by the Montgomery factor twice. | |
1272 | */ | |
1273 | if (!group->meth->field_encode(group, tmp, tmp, ctx)) | |
1274 | goto err; | |
1275 | if (!group->meth->field_encode(group, tmp, tmp, ctx)) | |
1276 | goto err; | |
1277 | } | |
1278 | ||
1279 | for (i = num - 1; i > 0; --i) { | |
1280 | /* | |
1281 | * Loop invariant: tmp is the product of the inverses of points[0]->Z | |
1282 | * .. points[i]->Z (zero-valued inputs skipped). | |
1283 | */ | |
1284 | if (!BN_is_zero(points[i]->Z)) { | |
1285 | /* | |
1286 | * Set tmp_Z to the inverse of points[i]->Z (as product of Z | |
1287 | * inverses 0 .. i, Z values 0 .. i - 1). | |
1288 | */ | |
1289 | if (!group-> | |
1290 | meth->field_mul(group, tmp_Z, prod_Z[i - 1], tmp, ctx)) | |
1291 | goto err; | |
1292 | /* | |
1293 | * Update tmp to satisfy the loop invariant for i - 1. | |
1294 | */ | |
1295 | if (!group->meth->field_mul(group, tmp, tmp, points[i]->Z, ctx)) | |
1296 | goto err; | |
1297 | /* Replace points[i]->Z by its inverse. */ | |
1298 | if (!BN_copy(points[i]->Z, tmp_Z)) | |
1299 | goto err; | |
1300 | } | |
1301 | } | |
1302 | ||
1303 | if (!BN_is_zero(points[0]->Z)) { | |
1304 | /* Replace points[0]->Z by its inverse. */ | |
1305 | if (!BN_copy(points[0]->Z, tmp)) | |
1306 | goto err; | |
1307 | } | |
1308 | ||
1309 | /* Finally, fix up the X and Y coordinates for all points. */ | |
1310 | ||
1311 | for (i = 0; i < num; i++) { | |
1312 | EC_POINT *p = points[i]; | |
1313 | ||
1314 | if (!BN_is_zero(p->Z)) { | |
1315 | /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */ | |
1316 | ||
1317 | if (!group->meth->field_sqr(group, tmp, p->Z, ctx)) | |
1318 | goto err; | |
1319 | if (!group->meth->field_mul(group, p->X, p->X, tmp, ctx)) | |
1320 | goto err; | |
1321 | ||
1322 | if (!group->meth->field_mul(group, tmp, tmp, p->Z, ctx)) | |
1323 | goto err; | |
1324 | if (!group->meth->field_mul(group, p->Y, p->Y, tmp, ctx)) | |
1325 | goto err; | |
1326 | ||
1327 | if (group->meth->field_set_to_one != 0) { | |
1328 | if (!group->meth->field_set_to_one(group, p->Z, ctx)) | |
1329 | goto err; | |
1330 | } else { | |
1331 | if (!BN_one(p->Z)) | |
1332 | goto err; | |
1333 | } | |
1334 | p->Z_is_one = 1; | |
1335 | } | |
1336 | } | |
1337 | ||
1338 | ret = 1; | |
0fe73d6c | 1339 | |
48fe4d62 | 1340 | err: |
0f113f3e | 1341 | BN_CTX_end(ctx); |
23a1d5e9 | 1342 | BN_CTX_free(new_ctx); |
0f113f3e MC |
1343 | if (prod_Z != NULL) { |
1344 | for (i = 0; i < num; i++) { | |
1345 | if (prod_Z[i] == NULL) | |
1346 | break; | |
1347 | BN_clear_free(prod_Z[i]); | |
1348 | } | |
1349 | OPENSSL_free(prod_Z); | |
1350 | } | |
1351 | return ret; | |
1352 | } | |
1353 | ||
1354 | int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, | |
1355 | const BIGNUM *b, BN_CTX *ctx) | |
1356 | { | |
1357 | return BN_mod_mul(r, a, b, group->field, ctx); | |
1358 | } | |
1359 | ||
1360 | int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, | |
1361 | BN_CTX *ctx) | |
1362 | { | |
1363 | return BN_mod_sqr(r, a, group->field, ctx); | |
1364 | } |