2 * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
5 * Licensed under the Apache License 2.0 (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>
15 const EC_METHOD *EC_GFp_mont_method(void)
17 static const EC_METHOD ret = {
19 NID_X9_62_prime_field,
20 ec_GFp_mont_group_init,
21 ec_GFp_mont_group_finish,
22 ec_GFp_mont_group_clear_finish,
23 ec_GFp_mont_group_copy,
24 ec_GFp_mont_group_set_curve,
25 ec_GFp_simple_group_get_curve,
26 ec_GFp_simple_group_get_degree,
27 ec_group_simple_order_bits,
28 ec_GFp_simple_group_check_discriminant,
29 ec_GFp_simple_point_init,
30 ec_GFp_simple_point_finish,
31 ec_GFp_simple_point_clear_finish,
32 ec_GFp_simple_point_copy,
33 ec_GFp_simple_point_set_to_infinity,
34 ec_GFp_simple_set_Jprojective_coordinates_GFp,
35 ec_GFp_simple_get_Jprojective_coordinates_GFp,
36 ec_GFp_simple_point_set_affine_coordinates,
37 ec_GFp_simple_point_get_affine_coordinates,
42 ec_GFp_simple_is_at_infinity,
43 ec_GFp_simple_is_on_curve,
45 ec_GFp_simple_make_affine,
46 ec_GFp_simple_points_make_affine,
48 0 /* precompute_mult */ ,
49 0 /* have_precompute_mult */ ,
50 ec_GFp_mont_field_mul,
51 ec_GFp_mont_field_sqr,
53 ec_GFp_mont_field_inv,
54 ec_GFp_mont_field_encode,
55 ec_GFp_mont_field_decode,
56 ec_GFp_mont_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,
66 ecdsa_simple_sign_setup,
67 ecdsa_simple_sign_sig,
68 ecdsa_simple_verify_sig,
69 0, /* field_inverse_mod_ord */
70 ec_GFp_simple_blind_coordinates,
71 ec_GFp_simple_ladder_pre,
72 ec_GFp_simple_ladder_step,
73 ec_GFp_simple_ladder_post
79 int ec_GFp_mont_group_init(EC_GROUP *group)
83 ok = ec_GFp_simple_group_init(group);
84 group->field_data1 = NULL;
85 group->field_data2 = NULL;
89 void ec_GFp_mont_group_finish(EC_GROUP *group)
91 BN_MONT_CTX_free(group->field_data1);
92 group->field_data1 = NULL;
93 BN_free(group->field_data2);
94 group->field_data2 = NULL;
95 ec_GFp_simple_group_finish(group);
98 void ec_GFp_mont_group_clear_finish(EC_GROUP *group)
100 BN_MONT_CTX_free(group->field_data1);
101 group->field_data1 = NULL;
102 BN_clear_free(group->field_data2);
103 group->field_data2 = NULL;
104 ec_GFp_simple_group_clear_finish(group);
107 int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src)
109 BN_MONT_CTX_free(dest->field_data1);
110 dest->field_data1 = NULL;
111 BN_clear_free(dest->field_data2);
112 dest->field_data2 = NULL;
114 if (!ec_GFp_simple_group_copy(dest, src))
117 if (src->field_data1 != NULL) {
118 dest->field_data1 = BN_MONT_CTX_new();
119 if (dest->field_data1 == NULL)
121 if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
124 if (src->field_data2 != NULL) {
125 dest->field_data2 = BN_dup(src->field_data2);
126 if (dest->field_data2 == NULL)
133 BN_MONT_CTX_free(dest->field_data1);
134 dest->field_data1 = NULL;
138 int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p,
139 const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
141 BN_CTX *new_ctx = NULL;
142 BN_MONT_CTX *mont = NULL;
146 BN_MONT_CTX_free(group->field_data1);
147 group->field_data1 = NULL;
148 BN_free(group->field_data2);
149 group->field_data2 = NULL;
152 ctx = new_ctx = BN_CTX_new_ex(group->libctx);
157 mont = BN_MONT_CTX_new();
160 if (!BN_MONT_CTX_set(mont, p, ctx)) {
161 ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB);
167 if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
170 group->field_data1 = mont;
172 group->field_data2 = one;
175 ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
178 BN_MONT_CTX_free(group->field_data1);
179 group->field_data1 = NULL;
180 BN_free(group->field_data2);
181 group->field_data2 = NULL;
186 BN_CTX_free(new_ctx);
187 BN_MONT_CTX_free(mont);
191 int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
192 const BIGNUM *b, BN_CTX *ctx)
194 if (group->field_data1 == NULL) {
195 ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED);
199 return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
202 int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
205 if (group->field_data1 == NULL) {
206 ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED);
210 return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
214 * Computes the multiplicative inverse of a in GF(p), storing the result in r.
215 * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
216 * We have a Mont structure, so SCA hardening is FLT inversion.
218 int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
222 BN_CTX *new_ctx = NULL;
225 if (group->field_data1 == NULL)
229 && (ctx = new_ctx = BN_CTX_secure_new_ex(group->libctx)) == NULL)
233 if ((e = BN_CTX_get(ctx)) == NULL)
236 /* Inverse in constant time with Fermats Little Theorem */
237 if (!BN_set_word(e, 2))
239 if (!BN_sub(e, group->field, e))
242 * Exponent e is public.
243 * No need for scatter-gather or BN_FLG_CONSTTIME.
245 if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
248 /* throw an error on zero */
250 ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
258 BN_CTX_free(new_ctx);
262 int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
263 const BIGNUM *a, BN_CTX *ctx)
265 if (group->field_data1 == NULL) {
266 ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED);
270 return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx);
273 int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r,
274 const BIGNUM *a, BN_CTX *ctx)
276 if (group->field_data1 == NULL) {
277 ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED);
281 return BN_from_montgomery(r, a, group->field_data1, ctx);
284 int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r,
287 if (group->field_data2 == NULL) {
288 ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED);
292 if (!BN_copy(r, group->field_data2))