1 /* $OpenBSD: ecp_mont.c,v 1.20 2021/09/08 17:29:21 tb Exp $ */
2 /*
3 * Originally written by Bodo Moeller for the OpenSSL project.
4 */
5 /* ====================================================================
6 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@openssl.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58 /* ====================================================================
59 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
60 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
61 * and contributed to the OpenSSL project.
62 */
63
64 #include <openssl/err.h>
65
66 #include "ec_lcl.h"
67
68
69 const EC_METHOD *
EC_GFp_mont_method(void)70 EC_GFp_mont_method(void)
71 {
72 static const EC_METHOD ret = {
73 .flags = EC_FLAGS_DEFAULT_OCT,
74 .field_type = NID_X9_62_prime_field,
75 .group_init = ec_GFp_mont_group_init,
76 .group_finish = ec_GFp_mont_group_finish,
77 .group_clear_finish = ec_GFp_mont_group_clear_finish,
78 .group_copy = ec_GFp_mont_group_copy,
79 .group_set_curve = ec_GFp_mont_group_set_curve,
80 .group_get_curve = ec_GFp_simple_group_get_curve,
81 .group_get_degree = ec_GFp_simple_group_get_degree,
82 .group_order_bits = ec_group_simple_order_bits,
83 .group_check_discriminant =
84 ec_GFp_simple_group_check_discriminant,
85 .point_init = ec_GFp_simple_point_init,
86 .point_finish = ec_GFp_simple_point_finish,
87 .point_clear_finish = ec_GFp_simple_point_clear_finish,
88 .point_copy = ec_GFp_simple_point_copy,
89 .point_set_to_infinity = ec_GFp_simple_point_set_to_infinity,
90 .point_set_Jprojective_coordinates =
91 ec_GFp_simple_set_Jprojective_coordinates,
92 .point_get_Jprojective_coordinates =
93 ec_GFp_simple_get_Jprojective_coordinates,
94 .point_set_affine_coordinates =
95 ec_GFp_simple_point_set_affine_coordinates,
96 .point_get_affine_coordinates =
97 ec_GFp_simple_point_get_affine_coordinates,
98 .add = ec_GFp_simple_add,
99 .dbl = ec_GFp_simple_dbl,
100 .invert = ec_GFp_simple_invert,
101 .is_at_infinity = ec_GFp_simple_is_at_infinity,
102 .is_on_curve = ec_GFp_simple_is_on_curve,
103 .point_cmp = ec_GFp_simple_cmp,
104 .make_affine = ec_GFp_simple_make_affine,
105 .points_make_affine = ec_GFp_simple_points_make_affine,
106 .mul_generator_ct = ec_GFp_simple_mul_generator_ct,
107 .mul_single_ct = ec_GFp_simple_mul_single_ct,
108 .mul_double_nonct = ec_GFp_simple_mul_double_nonct,
109 .field_mul = ec_GFp_mont_field_mul,
110 .field_sqr = ec_GFp_mont_field_sqr,
111 .field_encode = ec_GFp_mont_field_encode,
112 .field_decode = ec_GFp_mont_field_decode,
113 .field_set_to_one = ec_GFp_mont_field_set_to_one,
114 .blind_coordinates = ec_GFp_simple_blind_coordinates,
115 };
116
117 return &ret;
118 }
119
120
121 int
ec_GFp_mont_group_init(EC_GROUP * group)122 ec_GFp_mont_group_init(EC_GROUP * group)
123 {
124 int ok;
125
126 ok = ec_GFp_simple_group_init(group);
127 group->field_data1 = NULL;
128 group->field_data2 = NULL;
129 return ok;
130 }
131
132
133 void
ec_GFp_mont_group_finish(EC_GROUP * group)134 ec_GFp_mont_group_finish(EC_GROUP * group)
135 {
136 BN_MONT_CTX_free(group->field_data1);
137 group->field_data1 = NULL;
138 BN_free(group->field_data2);
139 group->field_data2 = NULL;
140 ec_GFp_simple_group_finish(group);
141 }
142
143
144 void
ec_GFp_mont_group_clear_finish(EC_GROUP * group)145 ec_GFp_mont_group_clear_finish(EC_GROUP * group)
146 {
147 BN_MONT_CTX_free(group->field_data1);
148 group->field_data1 = NULL;
149 BN_clear_free(group->field_data2);
150 group->field_data2 = NULL;
151 ec_GFp_simple_group_clear_finish(group);
152 }
153
154
155 int
ec_GFp_mont_group_copy(EC_GROUP * dest,const EC_GROUP * src)156 ec_GFp_mont_group_copy(EC_GROUP * dest, const EC_GROUP * src)
157 {
158 BN_MONT_CTX_free(dest->field_data1);
159 dest->field_data1 = NULL;
160 BN_clear_free(dest->field_data2);
161 dest->field_data2 = NULL;
162
163 if (!ec_GFp_simple_group_copy(dest, src))
164 return 0;
165
166 if (src->field_data1 != NULL) {
167 dest->field_data1 = BN_MONT_CTX_new();
168 if (dest->field_data1 == NULL)
169 return 0;
170 if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
171 goto err;
172 }
173 if (src->field_data2 != NULL) {
174 dest->field_data2 = BN_dup(src->field_data2);
175 if (dest->field_data2 == NULL)
176 goto err;
177 }
178 return 1;
179
180 err:
181 if (dest->field_data1 != NULL) {
182 BN_MONT_CTX_free(dest->field_data1);
183 dest->field_data1 = NULL;
184 }
185 return 0;
186 }
187
188
189 int
ec_GFp_mont_group_set_curve(EC_GROUP * group,const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)190 ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
191 const BIGNUM *b, BN_CTX *ctx)
192 {
193 BN_CTX *new_ctx = NULL;
194 BN_MONT_CTX *mont = NULL;
195 BIGNUM *one = NULL;
196 int ret = 0;
197
198 BN_MONT_CTX_free(group->field_data1);
199 group->field_data1 = NULL;
200 BN_free(group->field_data2);
201 group->field_data2 = NULL;
202 if (ctx == NULL) {
203 ctx = new_ctx = BN_CTX_new();
204 if (ctx == NULL)
205 return 0;
206 }
207 mont = BN_MONT_CTX_new();
208 if (mont == NULL)
209 goto err;
210 if (!BN_MONT_CTX_set(mont, p, ctx)) {
211 ECerror(ERR_R_BN_LIB);
212 goto err;
213 }
214 one = BN_new();
215 if (one == NULL)
216 goto err;
217 if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
218 goto err;
219
220 group->field_data1 = mont;
221 mont = NULL;
222 group->field_data2 = one;
223 one = NULL;
224
225 ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
226
227 if (!ret) {
228 BN_MONT_CTX_free(group->field_data1);
229 group->field_data1 = NULL;
230 BN_free(group->field_data2);
231 group->field_data2 = NULL;
232 }
233 err:
234 BN_CTX_free(new_ctx);
235 BN_MONT_CTX_free(mont);
236 BN_free(one);
237 return ret;
238 }
239
240
241 int
ec_GFp_mont_field_mul(const EC_GROUP * group,BIGNUM * r,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)242 ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
243 const BIGNUM *b, BN_CTX *ctx)
244 {
245 if (group->field_data1 == NULL) {
246 ECerror(EC_R_NOT_INITIALIZED);
247 return 0;
248 }
249 return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
250 }
251
252
253 int
ec_GFp_mont_field_sqr(const EC_GROUP * group,BIGNUM * r,const BIGNUM * a,BN_CTX * ctx)254 ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
255 BN_CTX *ctx)
256 {
257 if (group->field_data1 == NULL) {
258 ECerror(EC_R_NOT_INITIALIZED);
259 return 0;
260 }
261 return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
262 }
263
264
265 int
ec_GFp_mont_field_encode(const EC_GROUP * group,BIGNUM * r,const BIGNUM * a,BN_CTX * ctx)266 ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
267 BN_CTX *ctx)
268 {
269 if (group->field_data1 == NULL) {
270 ECerror(EC_R_NOT_INITIALIZED);
271 return 0;
272 }
273 return BN_to_montgomery(r, a, (BN_MONT_CTX *) group->field_data1, ctx);
274 }
275
276
277 int
ec_GFp_mont_field_decode(const EC_GROUP * group,BIGNUM * r,const BIGNUM * a,BN_CTX * ctx)278 ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
279 BN_CTX *ctx)
280 {
281 if (group->field_data1 == NULL) {
282 ECerror(EC_R_NOT_INITIALIZED);
283 return 0;
284 }
285 return BN_from_montgomery(r, a, group->field_data1, ctx);
286 }
287
288
289 int
ec_GFp_mont_field_set_to_one(const EC_GROUP * group,BIGNUM * r,BN_CTX * ctx)290 ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r, BN_CTX *ctx)
291 {
292 if (group->field_data2 == NULL) {
293 ECerror(EC_R_NOT_INITIALIZED);
294 return 0;
295 }
296 if (!BN_copy(r, group->field_data2))
297 return 0;
298 return 1;
299 }
300