1 /*
2 * ***** BEGIN LICENSE BLOCK *****
3 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 *
5 * The contents of this file are subject to the Mozilla Public License Version
6 * 1.1 (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 * http://www.mozilla.org/MPL/
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 *
15 * The Original Code is the elliptic curve math library for prime field curves.
16 *
17 * The Initial Developer of the Original Code is
18 * Sun Microsystems, Inc.
19 * Portions created by the Initial Developer are Copyright (C) 2003
20 * the Initial Developer. All Rights Reserved.
21 *
22 * Contributor(s):
23 * Douglas Stebila <douglas@stebila.ca>
24 *
25 * Alternatively, the contents of this file may be used under the terms of
26 * either the GNU General Public License Version 2 or later (the "GPL"), or
27 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 * in which case the provisions of the GPL or the LGPL are applicable instead
29 * of those above. If you wish to allow use of your version of this file only
30 * under the terms of either the GPL or the LGPL, and not to allow others to
31 * use your version of this file under the terms of the MPL, indicate your
32 * decision by deleting the provisions above and replace them with the notice
33 * and other provisions required by the GPL or the LGPL. If you do not delete
34 * the provisions above, a recipient may use your version of this file under
35 * the terms of any one of the MPL, the GPL or the LGPL.
36 *
37 * ***** END LICENSE BLOCK ***** */
38 /*
39 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
40 * Use is subject to license terms.
41 *
42 * Sun elects to use this software under the MPL license.
43 */
44
45 #pragma ident "%Z%%M% %I% %E% SMI"
46
47 #include "ecp.h"
48 #include "mpi.h"
49 #include "mplogic.h"
50 #include "mpi-priv.h"
51 #ifndef _KERNEL
52 #include <stdlib.h>
53 #endif
54
55 /* Fast modular reduction for p384 = 2^384 - 2^128 - 2^96 + 2^32 - 1. a can be r.
56 * Uses algorithm 2.30 from Hankerson, Menezes, Vanstone. Guide to
57 * Elliptic Curve Cryptography. */
58 mp_err
ec_GFp_nistp384_mod(const mp_int * a,mp_int * r,const GFMethod * meth)59 ec_GFp_nistp384_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
60 {
61 mp_err res = MP_OKAY;
62 int a_bits = mpl_significant_bits(a);
63 int i;
64
65 /* m1, m2 are statically-allocated mp_int of exactly the size we need */
66 mp_int m[10];
67
68 #ifdef ECL_THIRTY_TWO_BIT
69 mp_digit s[10][12];
70 for (i = 0; i < 10; i++) {
71 MP_SIGN(&m[i]) = MP_ZPOS;
72 MP_ALLOC(&m[i]) = 12;
73 MP_USED(&m[i]) = 12;
74 MP_DIGITS(&m[i]) = s[i];
75 }
76 #else
77 mp_digit s[10][6];
78 for (i = 0; i < 10; i++) {
79 MP_SIGN(&m[i]) = MP_ZPOS;
80 MP_ALLOC(&m[i]) = 6;
81 MP_USED(&m[i]) = 6;
82 MP_DIGITS(&m[i]) = s[i];
83 }
84 #endif
85
86 #ifdef ECL_THIRTY_TWO_BIT
87 /* for polynomials larger than twice the field size or polynomials
88 * not using all words, use regular reduction */
89 if ((a_bits > 768) || (a_bits <= 736)) {
90 MP_CHECKOK(mp_mod(a, &meth->irr, r));
91 } else {
92 for (i = 0; i < 12; i++) {
93 s[0][i] = MP_DIGIT(a, i);
94 }
95 s[1][0] = 0;
96 s[1][1] = 0;
97 s[1][2] = 0;
98 s[1][3] = 0;
99 s[1][4] = MP_DIGIT(a, 21);
100 s[1][5] = MP_DIGIT(a, 22);
101 s[1][6] = MP_DIGIT(a, 23);
102 s[1][7] = 0;
103 s[1][8] = 0;
104 s[1][9] = 0;
105 s[1][10] = 0;
106 s[1][11] = 0;
107 for (i = 0; i < 12; i++) {
108 s[2][i] = MP_DIGIT(a, i+12);
109 }
110 s[3][0] = MP_DIGIT(a, 21);
111 s[3][1] = MP_DIGIT(a, 22);
112 s[3][2] = MP_DIGIT(a, 23);
113 for (i = 3; i < 12; i++) {
114 s[3][i] = MP_DIGIT(a, i+9);
115 }
116 s[4][0] = 0;
117 s[4][1] = MP_DIGIT(a, 23);
118 s[4][2] = 0;
119 s[4][3] = MP_DIGIT(a, 20);
120 for (i = 4; i < 12; i++) {
121 s[4][i] = MP_DIGIT(a, i+8);
122 }
123 s[5][0] = 0;
124 s[5][1] = 0;
125 s[5][2] = 0;
126 s[5][3] = 0;
127 s[5][4] = MP_DIGIT(a, 20);
128 s[5][5] = MP_DIGIT(a, 21);
129 s[5][6] = MP_DIGIT(a, 22);
130 s[5][7] = MP_DIGIT(a, 23);
131 s[5][8] = 0;
132 s[5][9] = 0;
133 s[5][10] = 0;
134 s[5][11] = 0;
135 s[6][0] = MP_DIGIT(a, 20);
136 s[6][1] = 0;
137 s[6][2] = 0;
138 s[6][3] = MP_DIGIT(a, 21);
139 s[6][4] = MP_DIGIT(a, 22);
140 s[6][5] = MP_DIGIT(a, 23);
141 s[6][6] = 0;
142 s[6][7] = 0;
143 s[6][8] = 0;
144 s[6][9] = 0;
145 s[6][10] = 0;
146 s[6][11] = 0;
147 s[7][0] = MP_DIGIT(a, 23);
148 for (i = 1; i < 12; i++) {
149 s[7][i] = MP_DIGIT(a, i+11);
150 }
151 s[8][0] = 0;
152 s[8][1] = MP_DIGIT(a, 20);
153 s[8][2] = MP_DIGIT(a, 21);
154 s[8][3] = MP_DIGIT(a, 22);
155 s[8][4] = MP_DIGIT(a, 23);
156 s[8][5] = 0;
157 s[8][6] = 0;
158 s[8][7] = 0;
159 s[8][8] = 0;
160 s[8][9] = 0;
161 s[8][10] = 0;
162 s[8][11] = 0;
163 s[9][0] = 0;
164 s[9][1] = 0;
165 s[9][2] = 0;
166 s[9][3] = MP_DIGIT(a, 23);
167 s[9][4] = MP_DIGIT(a, 23);
168 s[9][5] = 0;
169 s[9][6] = 0;
170 s[9][7] = 0;
171 s[9][8] = 0;
172 s[9][9] = 0;
173 s[9][10] = 0;
174 s[9][11] = 0;
175
176 MP_CHECKOK(mp_add(&m[0], &m[1], r));
177 MP_CHECKOK(mp_add(r, &m[1], r));
178 MP_CHECKOK(mp_add(r, &m[2], r));
179 MP_CHECKOK(mp_add(r, &m[3], r));
180 MP_CHECKOK(mp_add(r, &m[4], r));
181 MP_CHECKOK(mp_add(r, &m[5], r));
182 MP_CHECKOK(mp_add(r, &m[6], r));
183 MP_CHECKOK(mp_sub(r, &m[7], r));
184 MP_CHECKOK(mp_sub(r, &m[8], r));
185 MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
186 s_mp_clamp(r);
187 }
188 #else
189 /* for polynomials larger than twice the field size or polynomials
190 * not using all words, use regular reduction */
191 if ((a_bits > 768) || (a_bits <= 736)) {
192 MP_CHECKOK(mp_mod(a, &meth->irr, r));
193 } else {
194 for (i = 0; i < 6; i++) {
195 s[0][i] = MP_DIGIT(a, i);
196 }
197 s[1][0] = 0;
198 s[1][1] = 0;
199 s[1][2] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
200 s[1][3] = MP_DIGIT(a, 11) >> 32;
201 s[1][4] = 0;
202 s[1][5] = 0;
203 for (i = 0; i < 6; i++) {
204 s[2][i] = MP_DIGIT(a, i+6);
205 }
206 s[3][0] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
207 s[3][1] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
208 for (i = 2; i < 6; i++) {
209 s[3][i] = (MP_DIGIT(a, i+4) >> 32) | (MP_DIGIT(a, i+5) << 32);
210 }
211 s[4][0] = (MP_DIGIT(a, 11) >> 32) << 32;
212 s[4][1] = MP_DIGIT(a, 10) << 32;
213 for (i = 2; i < 6; i++) {
214 s[4][i] = MP_DIGIT(a, i+4);
215 }
216 s[5][0] = 0;
217 s[5][1] = 0;
218 s[5][2] = MP_DIGIT(a, 10);
219 s[5][3] = MP_DIGIT(a, 11);
220 s[5][4] = 0;
221 s[5][5] = 0;
222 s[6][0] = (MP_DIGIT(a, 10) << 32) >> 32;
223 s[6][1] = (MP_DIGIT(a, 10) >> 32) << 32;
224 s[6][2] = MP_DIGIT(a, 11);
225 s[6][3] = 0;
226 s[6][4] = 0;
227 s[6][5] = 0;
228 s[7][0] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
229 for (i = 1; i < 6; i++) {
230 s[7][i] = (MP_DIGIT(a, i+5) >> 32) | (MP_DIGIT(a, i+6) << 32);
231 }
232 s[8][0] = MP_DIGIT(a, 10) << 32;
233 s[8][1] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
234 s[8][2] = MP_DIGIT(a, 11) >> 32;
235 s[8][3] = 0;
236 s[8][4] = 0;
237 s[8][5] = 0;
238 s[9][0] = 0;
239 s[9][1] = (MP_DIGIT(a, 11) >> 32) << 32;
240 s[9][2] = MP_DIGIT(a, 11) >> 32;
241 s[9][3] = 0;
242 s[9][4] = 0;
243 s[9][5] = 0;
244
245 MP_CHECKOK(mp_add(&m[0], &m[1], r));
246 MP_CHECKOK(mp_add(r, &m[1], r));
247 MP_CHECKOK(mp_add(r, &m[2], r));
248 MP_CHECKOK(mp_add(r, &m[3], r));
249 MP_CHECKOK(mp_add(r, &m[4], r));
250 MP_CHECKOK(mp_add(r, &m[5], r));
251 MP_CHECKOK(mp_add(r, &m[6], r));
252 MP_CHECKOK(mp_sub(r, &m[7], r));
253 MP_CHECKOK(mp_sub(r, &m[8], r));
254 MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
255 s_mp_clamp(r);
256 }
257 #endif
258
259 CLEANUP:
260 return res;
261 }
262
263 /* Compute the square of polynomial a, reduce modulo p384. Store the
264 * result in r. r could be a. Uses optimized modular reduction for p384.
265 */
266 mp_err
ec_GFp_nistp384_sqr(const mp_int * a,mp_int * r,const GFMethod * meth)267 ec_GFp_nistp384_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
268 {
269 mp_err res = MP_OKAY;
270
271 MP_CHECKOK(mp_sqr(a, r));
272 MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
273 CLEANUP:
274 return res;
275 }
276
277 /* Compute the product of two polynomials a and b, reduce modulo p384.
278 * Store the result in r. r could be a or b; a could be b. Uses
279 * optimized modular reduction for p384. */
280 mp_err
ec_GFp_nistp384_mul(const mp_int * a,const mp_int * b,mp_int * r,const GFMethod * meth)281 ec_GFp_nistp384_mul(const mp_int *a, const mp_int *b, mp_int *r,
282 const GFMethod *meth)
283 {
284 mp_err res = MP_OKAY;
285
286 MP_CHECKOK(mp_mul(a, b, r));
287 MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
288 CLEANUP:
289 return res;
290 }
291
292 /* Wire in fast field arithmetic and precomputation of base point for
293 * named curves. */
294 mp_err
ec_group_set_gfp384(ECGroup * group,ECCurveName name)295 ec_group_set_gfp384(ECGroup *group, ECCurveName name)
296 {
297 if (name == ECCurve_NIST_P384) {
298 group->meth->field_mod = &ec_GFp_nistp384_mod;
299 group->meth->field_mul = &ec_GFp_nistp384_mul;
300 group->meth->field_sqr = &ec_GFp_nistp384_sqr;
301 }
302 return MP_OKAY;
303 }
304