2 * Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
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
11 #include <openssl/err.h>
12 #include <openssl/symhacks.h>
16 const EC_METHOD *EC_GFp_simple_method(void)
18 static const EC_METHOD ret = {
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,
28 ec_group_simple_order_bits,
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,
43 ec_GFp_simple_is_at_infinity,
44 ec_GFp_simple_is_on_curve,
46 ec_GFp_simple_make_affine,
47 ec_GFp_simple_points_make_affine,
49 0 /* precompute_mult */ ,
50 0 /* have_precompute_mult */ ,
51 ec_GFp_simple_field_mul,
52 ec_GFp_simple_field_sqr,
54 0 /* field_encode */ ,
55 0 /* field_decode */ ,
56 0, /* field_set_to_one */
57 ec_key_simple_priv2oct,
58 ec_key_simple_oct2priv,
60 ec_key_simple_generate_key,
61 ec_key_simple_check_key,
62 ec_key_simple_generate_public_key,
65 ecdh_simple_compute_key
72 * Most method functions in this file are designed to work with
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.
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).
85 int ec_GFp_simple_group_init(EC_GROUP *group)
87 group->field = BN_new();
90 if (group->field == NULL || group->a == NULL || group->b == NULL) {
91 BN_free(group->field);
96 group->a_is_minus3 = 0;
100 void ec_GFp_simple_group_finish(EC_GROUP *group)
102 BN_free(group->field);
107 void ec_GFp_simple_group_clear_finish(EC_GROUP *group)
109 BN_clear_free(group->field);
110 BN_clear_free(group->a);
111 BN_clear_free(group->b);
114 int ec_GFp_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src)
116 if (!BN_copy(dest->field, src->field))
118 if (!BN_copy(dest->a, src->a))
120 if (!BN_copy(dest->b, src->b))
123 dest->a_is_minus3 = src->a_is_minus3;
128 int ec_GFp_simple_group_set_curve(EC_GROUP *group,
129 const BIGNUM *p, const BIGNUM *a,
130 const BIGNUM *b, BN_CTX *ctx)
133 BN_CTX *new_ctx = NULL;
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);
143 ctx = new_ctx = BN_CTX_new();
149 tmp_a = BN_CTX_get(ctx);
154 if (!BN_copy(group->field, p))
156 BN_set_negative(group->field, 0);
159 if (!BN_nnmod(tmp_a, a, p, ctx))
161 if (group->meth->field_encode) {
162 if (!group->meth->field_encode(group, group->a, tmp_a, ctx))
164 } else if (!BN_copy(group->a, tmp_a))
168 if (!BN_nnmod(group->b, b, p, ctx))
170 if (group->meth->field_encode)
171 if (!group->meth->field_encode(group, group->b, group->b, ctx))
174 /* group->a_is_minus3 */
175 if (!BN_add_word(tmp_a, 3))
177 group->a_is_minus3 = (0 == BN_cmp(tmp_a, group->field));
183 BN_CTX_free(new_ctx);
187 int ec_GFp_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
188 BIGNUM *b, BN_CTX *ctx)
191 BN_CTX *new_ctx = NULL;
194 if (!BN_copy(p, group->field))
198 if (a != NULL || b != NULL) {
199 if (group->meth->field_decode) {
201 ctx = new_ctx = BN_CTX_new();
206 if (!group->meth->field_decode(group, a, group->a, ctx))
210 if (!group->meth->field_decode(group, b, group->b, ctx))
215 if (!BN_copy(a, group->a))
219 if (!BN_copy(b, group->b))
228 BN_CTX_free(new_ctx);
232 int ec_GFp_simple_group_get_degree(const EC_GROUP *group)
234 return BN_num_bits(group->field);
237 int ec_GFp_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
240 BIGNUM *a, *b, *order, *tmp_1, *tmp_2;
241 const BIGNUM *p = group->field;
242 BN_CTX *new_ctx = NULL;
245 ctx = new_ctx = BN_CTX_new();
247 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT,
248 ERR_R_MALLOC_FAILURE);
255 tmp_1 = BN_CTX_get(ctx);
256 tmp_2 = BN_CTX_get(ctx);
257 order = BN_CTX_get(ctx);
261 if (group->meth->field_decode) {
262 if (!group->meth->field_decode(group, a, group->a, ctx))
264 if (!group->meth->field_decode(group, b, group->b, ctx))
267 if (!BN_copy(a, group->a))
269 if (!BN_copy(b, group->b))
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)
281 } else if (!BN_is_zero(b)) {
282 if (!BN_mod_sqr(tmp_1, a, p, ctx))
284 if (!BN_mod_mul(tmp_2, tmp_1, a, p, ctx))
286 if (!BN_lshift(tmp_1, tmp_2, 2))
290 if (!BN_mod_sqr(tmp_2, b, p, ctx))
292 if (!BN_mul_word(tmp_2, 27))
296 if (!BN_mod_add(a, tmp_1, tmp_2, p, ctx))
306 BN_CTX_free(new_ctx);
310 int ec_GFp_simple_point_init(EC_POINT *point)
317 if (point->X == NULL || point->Y == NULL || point->Z == NULL) {
326 void ec_GFp_simple_point_finish(EC_POINT *point)
333 void ec_GFp_simple_point_clear_finish(EC_POINT *point)
335 BN_clear_free(point->X);
336 BN_clear_free(point->Y);
337 BN_clear_free(point->Z);
341 int ec_GFp_simple_point_copy(EC_POINT *dest, const EC_POINT *src)
343 if (!BN_copy(dest->X, src->X))
345 if (!BN_copy(dest->Y, src->Y))
347 if (!BN_copy(dest->Z, src->Z))
349 dest->Z_is_one = src->Z_is_one;
350 dest->curve_name = src->curve_name;
355 int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *group,
363 int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group,
370 BN_CTX *new_ctx = NULL;
374 ctx = new_ctx = BN_CTX_new();
380 if (!BN_nnmod(point->X, x, group->field, ctx))
382 if (group->meth->field_encode) {
383 if (!group->meth->field_encode(group, point->X, point->X, ctx))
389 if (!BN_nnmod(point->Y, y, group->field, ctx))
391 if (group->meth->field_encode) {
392 if (!group->meth->field_encode(group, point->Y, point->Y, ctx))
400 if (!BN_nnmod(point->Z, z, group->field, ctx))
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))
409 meth->field_encode(group, point->Z, point->Z, ctx))
413 point->Z_is_one = Z_is_one;
419 BN_CTX_free(new_ctx);
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)
428 BN_CTX *new_ctx = NULL;
431 if (group->meth->field_decode != 0) {
433 ctx = new_ctx = BN_CTX_new();
439 if (!group->meth->field_decode(group, x, point->X, ctx))
443 if (!group->meth->field_decode(group, y, point->Y, ctx))
447 if (!group->meth->field_decode(group, z, point->Z, ctx))
452 if (!BN_copy(x, point->X))
456 if (!BN_copy(y, point->Y))
460 if (!BN_copy(z, point->Z))
468 BN_CTX_free(new_ctx);
472 int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *group,
475 const BIGNUM *y, BN_CTX *ctx)
477 if (x == NULL || y == NULL) {
479 * unlike for projective coordinates, we do not tolerate this
481 ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES,
482 ERR_R_PASSED_NULL_PARAMETER);
486 return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y,
487 BN_value_one(), ctx);
490 int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group,
491 const EC_POINT *point,
492 BIGNUM *x, BIGNUM *y,
495 BN_CTX *new_ctx = NULL;
496 BIGNUM *Z, *Z_1, *Z_2, *Z_3;
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);
507 ctx = new_ctx = BN_CTX_new();
514 Z_1 = BN_CTX_get(ctx);
515 Z_2 = BN_CTX_get(ctx);
516 Z_3 = BN_CTX_get(ctx);
520 /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */
522 if (group->meth->field_decode) {
523 if (!group->meth->field_decode(group, Z, point->Z, ctx))
531 if (group->meth->field_decode) {
533 if (!group->meth->field_decode(group, x, point->X, ctx))
537 if (!group->meth->field_decode(group, y, point->Y, ctx))
542 if (!BN_copy(x, point->X))
546 if (!BN_copy(y, point->Y))
551 if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) {
552 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES,
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))
562 if (!BN_mod_sqr(Z_2, Z_1, group->field, ctx))
568 * in the Montgomery case, field_mul will cancel out Montgomery
571 if (!group->meth->field_mul(group, x, point->X, Z_2, ctx))
576 if (group->meth->field_encode == 0) {
578 * field_mul works on standard representation
580 if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx))
583 if (!BN_mod_mul(Z_3, Z_2, Z_1, group->field, ctx))
588 * in the Montgomery case, field_mul will cancel out Montgomery
591 if (!group->meth->field_mul(group, y, point->Y, Z_3, ctx))
600 BN_CTX_free(new_ctx);
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)
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 *);
611 BN_CTX *new_ctx = NULL;
612 BIGNUM *n0, *n1, *n2, *n3, *n4, *n5, *n6;
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);
622 field_mul = group->meth->field_mul;
623 field_sqr = group->meth->field_sqr;
627 ctx = new_ctx = BN_CTX_new();
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);
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'.)
651 if (!BN_copy(n1, a->X))
653 if (!BN_copy(n2, a->Y))
658 if (!field_sqr(group, n0, b->Z, ctx))
660 if (!field_mul(group, n1, a->X, n0, ctx))
662 /* n1 = X_a * Z_b^2 */
664 if (!field_mul(group, n0, n0, b->Z, ctx))
666 if (!field_mul(group, n2, a->Y, n0, ctx))
668 /* n2 = Y_a * Z_b^3 */
673 if (!BN_copy(n3, b->X))
675 if (!BN_copy(n4, b->Y))
680 if (!field_sqr(group, n0, a->Z, ctx))
682 if (!field_mul(group, n3, b->X, n0, ctx))
684 /* n3 = X_b * Z_a^2 */
686 if (!field_mul(group, n0, n0, a->Z, ctx))
688 if (!field_mul(group, n4, b->Y, n0, ctx))
690 /* n4 = Y_b * Z_a^3 */
694 if (!BN_mod_sub_quick(n5, n1, n3, p))
696 if (!BN_mod_sub_quick(n6, n2, n4, p))
701 if (BN_is_zero(n5)) {
702 if (BN_is_zero(n6)) {
703 /* a is the same point as b */
705 ret = EC_POINT_dbl(group, r, a, ctx);
709 /* a is the inverse of b */
718 if (!BN_mod_add_quick(n1, n1, n3, p))
720 if (!BN_mod_add_quick(n2, n2, n4, p))
726 if (a->Z_is_one && b->Z_is_one) {
727 if (!BN_copy(r->Z, n5))
731 if (!BN_copy(n0, b->Z))
733 } else if (b->Z_is_one) {
734 if (!BN_copy(n0, a->Z))
737 if (!field_mul(group, n0, a->Z, b->Z, ctx))
740 if (!field_mul(group, r->Z, n0, n5, ctx))
744 /* Z_r = Z_a * Z_b * n5 */
747 if (!field_sqr(group, n0, n6, ctx))
749 if (!field_sqr(group, n4, n5, ctx))
751 if (!field_mul(group, n3, n1, n4, ctx))
753 if (!BN_mod_sub_quick(r->X, n0, n3, p))
755 /* X_r = n6^2 - n5^2 * 'n7' */
758 if (!BN_mod_lshift1_quick(n0, r->X, p))
760 if (!BN_mod_sub_quick(n0, n3, n0, p))
762 /* n9 = n5^2 * 'n7' - 2 * X_r */
765 if (!field_mul(group, n0, n0, n6, ctx))
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))
771 if (!BN_mod_sub_quick(n0, n0, n1, p))
774 if (!BN_add(n0, n0, p))
776 /* now 0 <= n0 < 2*p, and n0 is even */
777 if (!BN_rshift1(r->Y, n0))
779 /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */
784 if (ctx) /* otherwise we already called BN_CTX_end */
786 BN_CTX_free(new_ctx);
790 int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
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 *);
797 BN_CTX *new_ctx = NULL;
798 BIGNUM *n0, *n1, *n2, *n3;
801 if (EC_POINT_is_at_infinity(group, a)) {
807 field_mul = group->meth->field_mul;
808 field_sqr = group->meth->field_sqr;
812 ctx = new_ctx = BN_CTX_new();
818 n0 = BN_CTX_get(ctx);
819 n1 = BN_CTX_get(ctx);
820 n2 = BN_CTX_get(ctx);
821 n3 = BN_CTX_get(ctx);
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
833 if (!field_sqr(group, n0, a->X, ctx))
835 if (!BN_mod_lshift1_quick(n1, n0, p))
837 if (!BN_mod_add_quick(n0, n0, n1, p))
839 if (!BN_mod_add_quick(n1, n0, group->a, p))
841 /* n1 = 3 * X_a^2 + a_curve */
842 } else if (group->a_is_minus3) {
843 if (!field_sqr(group, n1, a->Z, ctx))
845 if (!BN_mod_add_quick(n0, a->X, n1, p))
847 if (!BN_mod_sub_quick(n2, a->X, n1, p))
849 if (!field_mul(group, n1, n0, n2, ctx))
851 if (!BN_mod_lshift1_quick(n0, n1, p))
853 if (!BN_mod_add_quick(n1, n0, n1, p))
856 * n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2)
857 * = 3 * X_a^2 - 3 * Z_a^4
860 if (!field_sqr(group, n0, a->X, ctx))
862 if (!BN_mod_lshift1_quick(n1, n0, p))
864 if (!BN_mod_add_quick(n0, n0, n1, p))
866 if (!field_sqr(group, n1, a->Z, ctx))
868 if (!field_sqr(group, n1, n1, ctx))
870 if (!field_mul(group, n1, n1, group->a, ctx))
872 if (!BN_mod_add_quick(n1, n1, n0, p))
874 /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */
879 if (!BN_copy(n0, a->Y))
882 if (!field_mul(group, n0, a->Y, a->Z, ctx))
885 if (!BN_mod_lshift1_quick(r->Z, n0, p))
888 /* Z_r = 2 * Y_a * Z_a */
891 if (!field_sqr(group, n3, a->Y, ctx))
893 if (!field_mul(group, n2, a->X, n3, ctx))
895 if (!BN_mod_lshift_quick(n2, n2, 2, p))
897 /* n2 = 4 * X_a * Y_a^2 */
900 if (!BN_mod_lshift1_quick(n0, n2, p))
902 if (!field_sqr(group, r->X, n1, ctx))
904 if (!BN_mod_sub_quick(r->X, r->X, n0, p))
906 /* X_r = n1^2 - 2 * n2 */
909 if (!field_sqr(group, n0, n3, ctx))
911 if (!BN_mod_lshift_quick(n3, n0, 3, p))
916 if (!BN_mod_sub_quick(n0, n2, r->X, p))
918 if (!field_mul(group, n0, n1, n0, ctx))
920 if (!BN_mod_sub_quick(r->Y, n0, n3, p))
922 /* Y_r = n1 * (n2 - X_r) - n3 */
928 BN_CTX_free(new_ctx);
932 int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
934 if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(point->Y))
935 /* point is its own inverse */
938 return BN_usub(point->Y, group->field, point->Y);
941 int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
943 return BN_is_zero(point->Z);
946 int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point,
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 *);
953 BN_CTX *new_ctx = NULL;
954 BIGNUM *rh, *tmp, *Z4, *Z6;
957 if (EC_POINT_is_at_infinity(group, point))
960 field_mul = group->meth->field_mul;
961 field_sqr = group->meth->field_sqr;
965 ctx = new_ctx = BN_CTX_new();
971 rh = BN_CTX_get(ctx);
972 tmp = BN_CTX_get(ctx);
973 Z4 = BN_CTX_get(ctx);
974 Z6 = BN_CTX_get(ctx);
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'.
989 if (!field_sqr(group, rh, point->X, ctx))
992 if (!point->Z_is_one) {
993 if (!field_sqr(group, tmp, point->Z, ctx))
995 if (!field_sqr(group, Z4, tmp, ctx))
997 if (!field_mul(group, Z6, Z4, tmp, ctx))
1000 /* rh := (rh + a*Z^4)*X */
1001 if (group->a_is_minus3) {
1002 if (!BN_mod_lshift1_quick(tmp, Z4, p))
1004 if (!BN_mod_add_quick(tmp, tmp, Z4, p))
1006 if (!BN_mod_sub_quick(rh, rh, tmp, p))
1008 if (!field_mul(group, rh, rh, point->X, ctx))
1011 if (!field_mul(group, tmp, Z4, group->a, ctx))
1013 if (!BN_mod_add_quick(rh, rh, tmp, p))
1015 if (!field_mul(group, rh, rh, point->X, ctx))
1019 /* rh := rh + b*Z^6 */
1020 if (!field_mul(group, tmp, group->b, Z6, ctx))
1022 if (!BN_mod_add_quick(rh, rh, tmp, p))
1025 /* point->Z_is_one */
1027 /* rh := (rh + a)*X */
1028 if (!BN_mod_add_quick(rh, rh, group->a, p))
1030 if (!field_mul(group, rh, rh, point->X, ctx))
1033 if (!BN_mod_add_quick(rh, rh, group->b, p))
1038 if (!field_sqr(group, tmp, point->Y, ctx))
1041 ret = (0 == BN_ucmp(tmp, rh));
1045 BN_CTX_free(new_ctx);
1049 int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a,
1050 const EC_POINT *b, BN_CTX *ctx)
1055 * 0 equal (in affine coordinates)
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_;
1067 if (EC_POINT_is_at_infinity(group, a)) {
1068 return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
1071 if (EC_POINT_is_at_infinity(group, b))
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;
1078 field_mul = group->meth->field_mul;
1079 field_sqr = group->meth->field_sqr;
1082 ctx = new_ctx = BN_CTX_new();
1088 tmp1 = BN_CTX_get(ctx);
1089 tmp2 = BN_CTX_get(ctx);
1090 Za23 = BN_CTX_get(ctx);
1091 Zb23 = BN_CTX_get(ctx);
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).
1103 if (!field_sqr(group, Zb23, b->Z, ctx))
1105 if (!field_mul(group, tmp1, a->X, Zb23, ctx))
1111 if (!field_sqr(group, Za23, a->Z, ctx))
1113 if (!field_mul(group, tmp2, b->X, Za23, ctx))
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 */
1126 if (!field_mul(group, Zb23, Zb23, b->Z, ctx))
1128 if (!field_mul(group, tmp1, a->Y, Zb23, ctx))
1134 if (!field_mul(group, Za23, Za23, a->Z, ctx))
1136 if (!field_mul(group, tmp2, b->Y, Za23, ctx))
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 */
1148 /* points are equal */
1153 BN_CTX_free(new_ctx);
1157 int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point,
1160 BN_CTX *new_ctx = NULL;
1164 if (point->Z_is_one || EC_POINT_is_at_infinity(group, point))
1168 ctx = new_ctx = BN_CTX_new();
1174 x = BN_CTX_get(ctx);
1175 y = BN_CTX_get(ctx);
1179 if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
1181 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
1183 if (!point->Z_is_one) {
1184 ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_INTERNAL_ERROR);
1192 BN_CTX_free(new_ctx);
1196 int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num,
1197 EC_POINT *points[], BN_CTX *ctx)
1199 BN_CTX *new_ctx = NULL;
1200 BIGNUM *tmp, *tmp_Z;
1201 BIGNUM **prod_Z = NULL;
1209 ctx = new_ctx = BN_CTX_new();
1215 tmp = BN_CTX_get(ctx);
1216 tmp_Z = BN_CTX_get(ctx);
1220 prod_Z = OPENSSL_malloc(num * sizeof(prod_Z[0]));
1223 for (i = 0; i < num; i++) {
1224 prod_Z[i] = BN_new();
1225 if (prod_Z[i] == NULL)
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).
1234 if (!BN_is_zero(points[0]->Z)) {
1235 if (!BN_copy(prod_Z[0], points[0]->Z))
1238 if (group->meth->field_set_to_one != 0) {
1239 if (!group->meth->field_set_to_one(group, prod_Z[0], ctx))
1242 if (!BN_one(prod_Z[0]))
1247 for (i = 1; i < num; i++) {
1248 if (!BN_is_zero(points[i]->Z)) {
1250 meth->field_mul(group, prod_Z[i], prod_Z[i - 1], points[i]->Z,
1254 if (!BN_copy(prod_Z[i], prod_Z[i - 1]))
1260 * Now use a single explicit inversion to replace every non-zero
1261 * points[i]->Z by its inverse.
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);
1268 if (group->meth->field_encode != 0) {
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.
1274 if (!group->meth->field_encode(group, tmp, tmp, ctx))
1276 if (!group->meth->field_encode(group, tmp, tmp, ctx))
1280 for (i = num - 1; i > 0; --i) {
1282 * Loop invariant: tmp is the product of the inverses of points[0]->Z
1283 * .. points[i]->Z (zero-valued inputs skipped).
1285 if (!BN_is_zero(points[i]->Z)) {
1287 * Set tmp_Z to the inverse of points[i]->Z (as product of Z
1288 * inverses 0 .. i, Z values 0 .. i - 1).
1291 meth->field_mul(group, tmp_Z, prod_Z[i - 1], tmp, ctx))
1294 * Update tmp to satisfy the loop invariant for i - 1.
1296 if (!group->meth->field_mul(group, tmp, tmp, points[i]->Z, ctx))
1298 /* Replace points[i]->Z by its inverse. */
1299 if (!BN_copy(points[i]->Z, tmp_Z))
1304 if (!BN_is_zero(points[0]->Z)) {
1305 /* Replace points[0]->Z by its inverse. */
1306 if (!BN_copy(points[0]->Z, tmp))
1310 /* Finally, fix up the X and Y coordinates for all points. */
1312 for (i = 0; i < num; i++) {
1313 EC_POINT *p = points[i];
1315 if (!BN_is_zero(p->Z)) {
1316 /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */
1318 if (!group->meth->field_sqr(group, tmp, p->Z, ctx))
1320 if (!group->meth->field_mul(group, p->X, p->X, tmp, ctx))
1323 if (!group->meth->field_mul(group, tmp, tmp, p->Z, ctx))
1325 if (!group->meth->field_mul(group, p->Y, p->Y, tmp, ctx))
1328 if (group->meth->field_set_to_one != 0) {
1329 if (!group->meth->field_set_to_one(group, p->Z, ctx))
1343 BN_CTX_free(new_ctx);
1344 if (prod_Z != NULL) {
1345 for (i = 0; i < num; i++) {
1346 if (prod_Z[i] == NULL)
1348 BN_clear_free(prod_Z[i]);
1350 OPENSSL_free(prod_Z);
1355 int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
1356 const BIGNUM *b, BN_CTX *ctx)
1358 return BN_mod_mul(r, a, b, group->field, ctx);
1361 int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
1364 return BN_mod_sqr(r, a, group->field, ctx);