security/nss/lib/freebl/ecl/ecl_mult.c@6474c204b198
security/nss/lib/freebl/ecl/ecl_mult.c
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
1 /* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5 #include "mpi.h"
6 #include "mplogic.h"
7 #include "ecl.h"
8 #include "ecl-priv.h"
9 #include <stdlib.h>
11 /* Elliptic curve scalar-point multiplication. Computes R(x, y) = k * P(x,
12 * y). If x, y = NULL, then P is assumed to be the generator (base point)
13 * of the group of points on the elliptic curve. Input and output values
14 * are assumed to be NOT field-encoded. */
15 mp_err
16 ECPoint_mul(const ECGroup *group, const mp_int *k, const mp_int *px,
17 const mp_int *py, mp_int *rx, mp_int *ry)
18 {
19 mp_err res = MP_OKAY;
20 mp_int kt;
22 ARGCHK((k != NULL) && (group != NULL), MP_BADARG);
23 MP_DIGITS(&kt) = 0;
25 /* want scalar to be less than or equal to group order */
26 if (mp_cmp(k, &group->order) > 0) {
27 MP_CHECKOK(mp_init(&kt));
28 MP_CHECKOK(mp_mod(k, &group->order, &kt));
29 } else {
30 MP_SIGN(&kt) = MP_ZPOS;
31 MP_USED(&kt) = MP_USED(k);
32 MP_ALLOC(&kt) = MP_ALLOC(k);
33 MP_DIGITS(&kt) = MP_DIGITS(k);
34 }
36 if ((px == NULL) || (py == NULL)) {
37 if (group->base_point_mul) {
38 MP_CHECKOK(group->base_point_mul(&kt, rx, ry, group));
39 } else {
40 MP_CHECKOK(group->
41 point_mul(&kt, &group->genx, &group->geny, rx, ry,
42 group));
43 }
44 } else {
45 if (group->meth->field_enc) {
46 MP_CHECKOK(group->meth->field_enc(px, rx, group->meth));
47 MP_CHECKOK(group->meth->field_enc(py, ry, group->meth));
48 MP_CHECKOK(group->point_mul(&kt, rx, ry, rx, ry, group));
49 } else {
50 MP_CHECKOK(group->point_mul(&kt, px, py, rx, ry, group));
51 }
52 }
53 if (group->meth->field_dec) {
54 MP_CHECKOK(group->meth->field_dec(rx, rx, group->meth));
55 MP_CHECKOK(group->meth->field_dec(ry, ry, group->meth));
56 }
58 CLEANUP:
59 if (MP_DIGITS(&kt) != MP_DIGITS(k)) {
60 mp_clear(&kt);
61 }
62 return res;
63 }
65 /* Elliptic curve scalar-point multiplication. Computes R(x, y) = k1 * G +
66 * k2 * P(x, y), where G is the generator (base point) of the group of
67 * points on the elliptic curve. Allows k1 = NULL or { k2, P } = NULL.
68 * Input and output values are assumed to be NOT field-encoded. */
69 mp_err
70 ec_pts_mul_basic(const mp_int *k1, const mp_int *k2, const mp_int *px,
71 const mp_int *py, mp_int *rx, mp_int *ry,
72 const ECGroup *group)
73 {
74 mp_err res = MP_OKAY;
75 mp_int sx, sy;
77 ARGCHK(group != NULL, MP_BADARG);
78 ARGCHK(!((k1 == NULL)
79 && ((k2 == NULL) || (px == NULL)
80 || (py == NULL))), MP_BADARG);
82 /* if some arguments are not defined used ECPoint_mul */
83 if (k1 == NULL) {
84 return ECPoint_mul(group, k2, px, py, rx, ry);
85 } else if ((k2 == NULL) || (px == NULL) || (py == NULL)) {
86 return ECPoint_mul(group, k1, NULL, NULL, rx, ry);
87 }
89 MP_DIGITS(&sx) = 0;
90 MP_DIGITS(&sy) = 0;
91 MP_CHECKOK(mp_init(&sx));
92 MP_CHECKOK(mp_init(&sy));
94 MP_CHECKOK(ECPoint_mul(group, k1, NULL, NULL, &sx, &sy));
95 MP_CHECKOK(ECPoint_mul(group, k2, px, py, rx, ry));
97 if (group->meth->field_enc) {
98 MP_CHECKOK(group->meth->field_enc(&sx, &sx, group->meth));
99 MP_CHECKOK(group->meth->field_enc(&sy, &sy, group->meth));
100 MP_CHECKOK(group->meth->field_enc(rx, rx, group->meth));
101 MP_CHECKOK(group->meth->field_enc(ry, ry, group->meth));
102 }
104 MP_CHECKOK(group->point_add(&sx, &sy, rx, ry, rx, ry, group));
106 if (group->meth->field_dec) {
107 MP_CHECKOK(group->meth->field_dec(rx, rx, group->meth));
108 MP_CHECKOK(group->meth->field_dec(ry, ry, group->meth));
109 }
111 CLEANUP:
112 mp_clear(&sx);
113 mp_clear(&sy);
114 return res;
115 }
117 /* Elliptic curve scalar-point multiplication. Computes R(x, y) = k1 * G +
118 * k2 * P(x, y), where G is the generator (base point) of the group of
119 * points on the elliptic curve. Allows k1 = NULL or { k2, P } = NULL.
120 * Input and output values are assumed to be NOT field-encoded. Uses
121 * algorithm 15 (simultaneous multiple point multiplication) from Brown,
122 * Hankerson, Lopez, Menezes. Software Implementation of the NIST
123 * Elliptic Curves over Prime Fields. */
124 mp_err
125 ec_pts_mul_simul_w2(const mp_int *k1, const mp_int *k2, const mp_int *px,
126 const mp_int *py, mp_int *rx, mp_int *ry,
127 const ECGroup *group)
128 {
129 mp_err res = MP_OKAY;
130 mp_int precomp[4][4][2];
131 const mp_int *a, *b;
132 int i, j;
133 int ai, bi, d;
135 ARGCHK(group != NULL, MP_BADARG);
136 ARGCHK(!((k1 == NULL)
137 && ((k2 == NULL) || (px == NULL)
138 || (py == NULL))), MP_BADARG);
140 /* if some arguments are not defined used ECPoint_mul */
141 if (k1 == NULL) {
142 return ECPoint_mul(group, k2, px, py, rx, ry);
143 } else if ((k2 == NULL) || (px == NULL) || (py == NULL)) {
144 return ECPoint_mul(group, k1, NULL, NULL, rx, ry);
145 }
147 /* initialize precomputation table */
148 for (i = 0; i < 4; i++) {
149 for (j = 0; j < 4; j++) {
150 MP_DIGITS(&precomp[i][j][0]) = 0;
151 MP_DIGITS(&precomp[i][j][1]) = 0;
152 }
153 }
154 for (i = 0; i < 4; i++) {
155 for (j = 0; j < 4; j++) {
156 MP_CHECKOK( mp_init_size(&precomp[i][j][0],
157 ECL_MAX_FIELD_SIZE_DIGITS) );
158 MP_CHECKOK( mp_init_size(&precomp[i][j][1],
159 ECL_MAX_FIELD_SIZE_DIGITS) );
160 }
161 }
163 /* fill precomputation table */
164 /* assign {k1, k2} = {a, b} such that len(a) >= len(b) */
165 if (mpl_significant_bits(k1) < mpl_significant_bits(k2)) {
166 a = k2;
167 b = k1;
168 if (group->meth->field_enc) {
169 MP_CHECKOK(group->meth->
170 field_enc(px, &precomp[1][0][0], group->meth));
171 MP_CHECKOK(group->meth->
172 field_enc(py, &precomp[1][0][1], group->meth));
173 } else {
174 MP_CHECKOK(mp_copy(px, &precomp[1][0][0]));
175 MP_CHECKOK(mp_copy(py, &precomp[1][0][1]));
176 }
177 MP_CHECKOK(mp_copy(&group->genx, &precomp[0][1][0]));
178 MP_CHECKOK(mp_copy(&group->geny, &precomp[0][1][1]));
179 } else {
180 a = k1;
181 b = k2;
182 MP_CHECKOK(mp_copy(&group->genx, &precomp[1][0][0]));
183 MP_CHECKOK(mp_copy(&group->geny, &precomp[1][0][1]));
184 if (group->meth->field_enc) {
185 MP_CHECKOK(group->meth->
186 field_enc(px, &precomp[0][1][0], group->meth));
187 MP_CHECKOK(group->meth->
188 field_enc(py, &precomp[0][1][1], group->meth));
189 } else {
190 MP_CHECKOK(mp_copy(px, &precomp[0][1][0]));
191 MP_CHECKOK(mp_copy(py, &precomp[0][1][1]));
192 }
193 }
194 /* precompute [*][0][*] */
195 mp_zero(&precomp[0][0][0]);
196 mp_zero(&precomp[0][0][1]);
197 MP_CHECKOK(group->
198 point_dbl(&precomp[1][0][0], &precomp[1][0][1],
199 &precomp[2][0][0], &precomp[2][0][1], group));
200 MP_CHECKOK(group->
201 point_add(&precomp[1][0][0], &precomp[1][0][1],
202 &precomp[2][0][0], &precomp[2][0][1],
203 &precomp[3][0][0], &precomp[3][0][1], group));
204 /* precompute [*][1][*] */
205 for (i = 1; i < 4; i++) {
206 MP_CHECKOK(group->
207 point_add(&precomp[0][1][0], &precomp[0][1][1],
208 &precomp[i][0][0], &precomp[i][0][1],
209 &precomp[i][1][0], &precomp[i][1][1], group));
210 }
211 /* precompute [*][2][*] */
212 MP_CHECKOK(group->
213 point_dbl(&precomp[0][1][0], &precomp[0][1][1],
214 &precomp[0][2][0], &precomp[0][2][1], group));
215 for (i = 1; i < 4; i++) {
216 MP_CHECKOK(group->
217 point_add(&precomp[0][2][0], &precomp[0][2][1],
218 &precomp[i][0][0], &precomp[i][0][1],
219 &precomp[i][2][0], &precomp[i][2][1], group));
220 }
221 /* precompute [*][3][*] */
222 MP_CHECKOK(group->
223 point_add(&precomp[0][1][0], &precomp[0][1][1],
224 &precomp[0][2][0], &precomp[0][2][1],
225 &precomp[0][3][0], &precomp[0][3][1], group));
226 for (i = 1; i < 4; i++) {
227 MP_CHECKOK(group->
228 point_add(&precomp[0][3][0], &precomp[0][3][1],
229 &precomp[i][0][0], &precomp[i][0][1],
230 &precomp[i][3][0], &precomp[i][3][1], group));
231 }
233 d = (mpl_significant_bits(a) + 1) / 2;
235 /* R = inf */
236 mp_zero(rx);
237 mp_zero(ry);
239 for (i = d - 1; i >= 0; i--) {
240 ai = MP_GET_BIT(a, 2 * i + 1);
241 ai <<= 1;
242 ai |= MP_GET_BIT(a, 2 * i);
243 bi = MP_GET_BIT(b, 2 * i + 1);
244 bi <<= 1;
245 bi |= MP_GET_BIT(b, 2 * i);
246 /* R = 2^2 * R */
247 MP_CHECKOK(group->point_dbl(rx, ry, rx, ry, group));
248 MP_CHECKOK(group->point_dbl(rx, ry, rx, ry, group));
249 /* R = R + (ai * A + bi * B) */
250 MP_CHECKOK(group->
251 point_add(rx, ry, &precomp[ai][bi][0],
252 &precomp[ai][bi][1], rx, ry, group));
253 }
255 if (group->meth->field_dec) {
256 MP_CHECKOK(group->meth->field_dec(rx, rx, group->meth));
257 MP_CHECKOK(group->meth->field_dec(ry, ry, group->meth));
258 }
260 CLEANUP:
261 for (i = 0; i < 4; i++) {
262 for (j = 0; j < 4; j++) {
263 mp_clear(&precomp[i][j][0]);
264 mp_clear(&precomp[i][j][1]);
265 }
266 }
267 return res;
268 }
270 /* Elliptic curve scalar-point multiplication. Computes R(x, y) = k1 * G +
271 * k2 * P(x, y), where G is the generator (base point) of the group of
272 * points on the elliptic curve. Allows k1 = NULL or { k2, P } = NULL.
273 * Input and output values are assumed to be NOT field-encoded. */
274 mp_err
275 ECPoints_mul(const ECGroup *group, const mp_int *k1, const mp_int *k2,
276 const mp_int *px, const mp_int *py, mp_int *rx, mp_int *ry)
277 {
278 mp_err res = MP_OKAY;
279 mp_int k1t, k2t;
280 const mp_int *k1p, *k2p;
282 MP_DIGITS(&k1t) = 0;
283 MP_DIGITS(&k2t) = 0;
285 ARGCHK(group != NULL, MP_BADARG);
287 /* want scalar to be less than or equal to group order */
288 if (k1 != NULL) {
289 if (mp_cmp(k1, &group->order) >= 0) {
290 MP_CHECKOK(mp_init(&k1t));
291 MP_CHECKOK(mp_mod(k1, &group->order, &k1t));
292 k1p = &k1t;
293 } else {
294 k1p = k1;
295 }
296 } else {
297 k1p = k1;
298 }
299 if (k2 != NULL) {
300 if (mp_cmp(k2, &group->order) >= 0) {
301 MP_CHECKOK(mp_init(&k2t));
302 MP_CHECKOK(mp_mod(k2, &group->order, &k2t));
303 k2p = &k2t;
304 } else {
305 k2p = k2;
306 }
307 } else {
308 k2p = k2;
309 }
311 /* if points_mul is defined, then use it */
312 if (group->points_mul) {
313 res = group->points_mul(k1p, k2p, px, py, rx, ry, group);
314 } else {
315 res = ec_pts_mul_simul_w2(k1p, k2p, px, py, rx, ry, group);
316 }
318 CLEANUP:
319 mp_clear(&k1t);
320 mp_clear(&k2t);
321 return res;
322 }
