2 * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 /* ====================================================================
11 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
12 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
13 * and contributed to the OpenSSL project.
16 #include <openssl/err.h>
20 const EC_METHOD *EC_GFp_mont_method(void)
22 static const EC_METHOD ret = {
24 NID_X9_62_prime_field,
25 ec_GFp_mont_group_init,
26 ec_GFp_mont_group_finish,
27 ec_GFp_mont_group_clear_finish,
28 ec_GFp_mont_group_copy,
29 ec_GFp_mont_group_set_curve,
30 ec_GFp_simple_group_get_curve,
31 ec_GFp_simple_group_get_degree,
32 ec_group_simple_order_bits,
33 ec_GFp_simple_group_check_discriminant,
34 ec_GFp_simple_point_init,
35 ec_GFp_simple_point_finish,
36 ec_GFp_simple_point_clear_finish,
37 ec_GFp_simple_point_copy,
38 ec_GFp_simple_point_set_to_infinity,
39 ec_GFp_simple_set_Jprojective_coordinates_GFp,
40 ec_GFp_simple_get_Jprojective_coordinates_GFp,
41 ec_GFp_simple_point_set_affine_coordinates,
42 ec_GFp_simple_point_get_affine_coordinates,
47 ec_GFp_simple_is_at_infinity,
48 ec_GFp_simple_is_on_curve,
50 ec_GFp_simple_make_affine,
51 ec_GFp_simple_points_make_affine,
53 0 /* precompute_mult */ ,
54 0 /* have_precompute_mult */ ,
55 ec_GFp_mont_field_mul,
56 ec_GFp_mont_field_sqr,
58 ec_GFp_mont_field_inv,
59 ec_GFp_mont_field_encode,
60 ec_GFp_mont_field_decode,
61 ec_GFp_mont_field_set_to_one,
62 ec_key_simple_priv2oct,
63 ec_key_simple_oct2priv,
65 ec_key_simple_generate_key,
66 ec_key_simple_check_key,
67 ec_key_simple_generate_public_key,
70 ecdh_simple_compute_key,
71 ec_GFp_simple_blind_coordinates
77 int ec_GFp_mont_group_init(EC_GROUP *group)
81 ok = ec_GFp_simple_group_init(group);
82 group->field_data1 = NULL;
83 group->field_data2 = NULL;
87 void ec_GFp_mont_group_finish(EC_GROUP *group)
89 BN_MONT_CTX_free(group->field_data1);
90 group->field_data1 = NULL;
91 BN_free(group->field_data2);
92 group->field_data2 = NULL;
93 ec_GFp_simple_group_finish(group);
96 void ec_GFp_mont_group_clear_finish(EC_GROUP *group)
98 BN_MONT_CTX_free(group->field_data1);
99 group->field_data1 = NULL;
100 BN_clear_free(group->field_data2);
101 group->field_data2 = NULL;
102 ec_GFp_simple_group_clear_finish(group);
105 int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src)
107 BN_MONT_CTX_free(dest->field_data1);
108 dest->field_data1 = NULL;
109 BN_clear_free(dest->field_data2);
110 dest->field_data2 = NULL;
112 if (!ec_GFp_simple_group_copy(dest, src))
115 if (src->field_data1 != NULL) {
116 dest->field_data1 = BN_MONT_CTX_new();
117 if (dest->field_data1 == NULL)
119 if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
122 if (src->field_data2 != NULL) {
123 dest->field_data2 = BN_dup(src->field_data2);
124 if (dest->field_data2 == NULL)
131 BN_MONT_CTX_free(dest->field_data1);
132 dest->field_data1 = NULL;
136 int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p,
137 const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
139 BN_CTX *new_ctx = NULL;
140 BN_MONT_CTX *mont = NULL;
144 BN_MONT_CTX_free(group->field_data1);
145 group->field_data1 = NULL;
146 BN_free(group->field_data2);
147 group->field_data2 = NULL;
150 ctx = new_ctx = BN_CTX_new();
155 mont = BN_MONT_CTX_new();
158 if (!BN_MONT_CTX_set(mont, p, ctx)) {
159 ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB);
165 if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
168 group->field_data1 = mont;
170 group->field_data2 = one;
173 ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
176 BN_MONT_CTX_free(group->field_data1);
177 group->field_data1 = NULL;
178 BN_free(group->field_data2);
179 group->field_data2 = NULL;
184 BN_CTX_free(new_ctx);
185 BN_MONT_CTX_free(mont);
189 int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
190 const BIGNUM *b, BN_CTX *ctx)
192 if (group->field_data1 == NULL) {
193 ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED);
197 return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
200 int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
203 if (group->field_data1 == NULL) {
204 ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED);
208 return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
212 * Computes the multiplicative inverse of a in GF(p), storing the result in r.
213 * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
214 * We have a Mont structure, so SCA hardening is FLT inversion.
216 int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
220 BN_CTX *new_ctx = NULL;
223 if (group->field_data1 == NULL)
226 if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
230 if ((e = BN_CTX_get(ctx)) == NULL)
233 /* Inverse in constant time with Fermats Little Theorem */
234 if (!BN_set_word(e, 2))
236 if (!BN_sub(e, group->field, e))
239 * Exponent e is public.
240 * No need for scatter-gather or BN_FLG_CONSTTIME.
242 if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
245 /* throw an error on zero */
247 ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
255 BN_CTX_free(new_ctx);
259 int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
260 const BIGNUM *a, BN_CTX *ctx)
262 if (group->field_data1 == NULL) {
263 ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED);
267 return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx);
270 int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r,
271 const BIGNUM *a, BN_CTX *ctx)
273 if (group->field_data1 == NULL) {
274 ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED);
278 return BN_from_montgomery(r, a, group->field_data1, ctx);
281 int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r,
284 if (group->field_data2 == NULL) {
285 ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED);
289 if (!BN_copy(r, group->field_data2))