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 #include "ecp.h"
46 #include "mpi.h"
47 #include "mplogic.h"
48 #include "mpi-priv.h"
49 #ifndef _KERNEL
50 #include <stdlib.h>
51 #endif
52
53 /* Fast modular reduction for p384 = 2^384 - 2^128 - 2^96 + 2^32 - 1. a can be r.
54 * Uses algorithm 2.30 from Hankerson, Menezes, Vanstone. Guide to
55 * Elliptic Curve Cryptography. */
56 mp_err
ec_GFp_nistp384_mod(const mp_int * a,mp_int * r,const GFMethod * meth)57 ec_GFp_nistp384_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
58 {
59 mp_err res = MP_OKAY;
60 int a_bits = mpl_significant_bits(a);
61 int i;
62
63 /* m1, m2 are statically-allocated mp_int of exactly the size we need */
64 mp_int m[10];
65
66 #ifdef ECL_THIRTY_TWO_BIT
67 mp_digit s[10][12];
68 for (i = 0; i < 10; i++) {
69 MP_SIGN(&m[i]) = MP_ZPOS;
70 MP_ALLOC(&m[i]) = 12;
71 MP_USED(&m[i]) = 12;
72 MP_DIGITS(&m[i]) = s[i];
73 }
74 #else
75 mp_digit s[10][6];
76 for (i = 0; i < 10; i++) {
77 MP_SIGN(&m[i]) = MP_ZPOS;
78 MP_ALLOC(&m[i]) = 6;
79 MP_USED(&m[i]) = 6;
80 MP_DIGITS(&m[i]) = s[i];
81 }
82 #endif
83
84 #ifdef ECL_THIRTY_TWO_BIT
85 /* for polynomials larger than twice the field size or polynomials
86 * not using all words, use regular reduction */
87 if ((a_bits > 768) || (a_bits <= 736)) {
88 MP_CHECKOK(mp_mod(a, &meth->irr, r));
89 } else {
90 for (i = 0; i < 12; i++) {
91 s[0][i] = MP_DIGIT(a, i);
92 }
93 s[1][0] = 0;
94 s[1][1] = 0;
95 s[1][2] = 0;
96 s[1][3] = 0;
97 s[1][4] = MP_DIGIT(a, 21);
98 s[1][5] = MP_DIGIT(a, 22);
99 s[1][6] = MP_DIGIT(a, 23);
100 s[1][7] = 0;
101 s[1][8] = 0;
102 s[1][9] = 0;
103 s[1][10] = 0;
104 s[1][11] = 0;
105 for (i = 0; i < 12; i++) {
106 s[2][i] = MP_DIGIT(a, i+12);
107 }
108 s[3][0] = MP_DIGIT(a, 21);
109 s[3][1] = MP_DIGIT(a, 22);
110 s[3][2] = MP_DIGIT(a, 23);
111 for (i = 3; i < 12; i++) {
112 s[3][i] = MP_DIGIT(a, i+9);
113 }
114 s[4][0] = 0;
115 s[4][1] = MP_DIGIT(a, 23);
116 s[4][2] = 0;
117 s[4][3] = MP_DIGIT(a, 20);
118 for (i = 4; i < 12; i++) {
119 s[4][i] = MP_DIGIT(a, i+8);
120 }
121 s[5][0] = 0;
122 s[5][1] = 0;
123 s[5][2] = 0;
124 s[5][3] = 0;
125 s[5][4] = MP_DIGIT(a, 20);
126 s[5][5] = MP_DIGIT(a, 21);
127 s[5][6] = MP_DIGIT(a, 22);
128 s[5][7] = MP_DIGIT(a, 23);
129 s[5][8] = 0;
130 s[5][9] = 0;
131 s[5][10] = 0;
132 s[5][11] = 0;
133 s[6][0] = MP_DIGIT(a, 20);
134 s[6][1] = 0;
135 s[6][2] = 0;
136 s[6][3] = MP_DIGIT(a, 21);
137 s[6][4] = MP_DIGIT(a, 22);
138 s[6][5] = MP_DIGIT(a, 23);
139 s[6][6] = 0;
140 s[6][7] = 0;
141 s[6][8] = 0;
142 s[6][9] = 0;
143 s[6][10] = 0;
144 s[6][11] = 0;
145 s[7][0] = MP_DIGIT(a, 23);
146 for (i = 1; i < 12; i++) {
147 s[7][i] = MP_DIGIT(a, i+11);
148 }
149 s[8][0] = 0;
150 s[8][1] = MP_DIGIT(a, 20);
151 s[8][2] = MP_DIGIT(a, 21);
152 s[8][3] = MP_DIGIT(a, 22);
153 s[8][4] = MP_DIGIT(a, 23);
154 s[8][5] = 0;
155 s[8][6] = 0;
156 s[8][7] = 0;
157 s[8][8] = 0;
158 s[8][9] = 0;
159 s[8][10] = 0;
160 s[8][11] = 0;
161 s[9][0] = 0;
162 s[9][1] = 0;
163 s[9][2] = 0;
164 s[9][3] = MP_DIGIT(a, 23);
165 s[9][4] = MP_DIGIT(a, 23);
166 s[9][5] = 0;
167 s[9][6] = 0;
168 s[9][7] = 0;
169 s[9][8] = 0;
170 s[9][9] = 0;
171 s[9][10] = 0;
172 s[9][11] = 0;
173
174 MP_CHECKOK(mp_add(&m[0], &m[1], r));
175 MP_CHECKOK(mp_add(r, &m[1], r));
176 MP_CHECKOK(mp_add(r, &m[2], r));
177 MP_CHECKOK(mp_add(r, &m[3], r));
178 MP_CHECKOK(mp_add(r, &m[4], r));
179 MP_CHECKOK(mp_add(r, &m[5], r));
180 MP_CHECKOK(mp_add(r, &m[6], r));
181 MP_CHECKOK(mp_sub(r, &m[7], r));
182 MP_CHECKOK(mp_sub(r, &m[8], r));
183 MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
184 s_mp_clamp(r);
185 }
186 #else
187 /* for polynomials larger than twice the field size or polynomials
188 * not using all words, use regular reduction */
189 if ((a_bits > 768) || (a_bits <= 736)) {
190 MP_CHECKOK(mp_mod(a, &meth->irr, r));
191 } else {
192 for (i = 0; i < 6; i++) {
193 s[0][i] = MP_DIGIT(a, i);
194 }
195 s[1][0] = 0;
196 s[1][1] = 0;
197 s[1][2] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
198 s[1][3] = MP_DIGIT(a, 11) >> 32;
199 s[1][4] = 0;
200 s[1][5] = 0;
201 for (i = 0; i < 6; i++) {
202 s[2][i] = MP_DIGIT(a, i+6);
203 }
204 s[3][0] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
205 s[3][1] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
206 for (i = 2; i < 6; i++) {
207 s[3][i] = (MP_DIGIT(a, i+4) >> 32) | (MP_DIGIT(a, i+5) << 32);
208 }
209 s[4][0] = (MP_DIGIT(a, 11) >> 32) << 32;
210 s[4][1] = MP_DIGIT(a, 10) << 32;
211 for (i = 2; i < 6; i++) {
212 s[4][i] = MP_DIGIT(a, i+4);
213 }
214 s[5][0] = 0;
215 s[5][1] = 0;
216 s[5][2] = MP_DIGIT(a, 10);
217 s[5][3] = MP_DIGIT(a, 11);
218 s[5][4] = 0;
219 s[5][5] = 0;
220 s[6][0] = (MP_DIGIT(a, 10) << 32) >> 32;
221 s[6][1] = (MP_DIGIT(a, 10) >> 32) << 32;
222 s[6][2] = MP_DIGIT(a, 11);
223 s[6][3] = 0;
224 s[6][4] = 0;
225 s[6][5] = 0;
226 s[7][0] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
227 for (i = 1; i < 6; i++) {
228 s[7][i] = (MP_DIGIT(a, i+5) >> 32) | (MP_DIGIT(a, i+6) << 32);
229 }
230 s[8][0] = MP_DIGIT(a, 10) << 32;
231 s[8][1] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
232 s[8][2] = MP_DIGIT(a, 11) >> 32;
233 s[8][3] = 0;
234 s[8][4] = 0;
235 s[8][5] = 0;
236 s[9][0] = 0;
237 s[9][1] = (MP_DIGIT(a, 11) >> 32) << 32;
238 s[9][2] = MP_DIGIT(a, 11) >> 32;
239 s[9][3] = 0;
240 s[9][4] = 0;
241 s[9][5] = 0;
242
243 MP_CHECKOK(mp_add(&m[0], &m[1], r));
244 MP_CHECKOK(mp_add(r, &m[1], r));
245 MP_CHECKOK(mp_add(r, &m[2], r));
246 MP_CHECKOK(mp_add(r, &m[3], r));
247 MP_CHECKOK(mp_add(r, &m[4], r));
248 MP_CHECKOK(mp_add(r, &m[5], r));
249 MP_CHECKOK(mp_add(r, &m[6], r));
250 MP_CHECKOK(mp_sub(r, &m[7], r));
251 MP_CHECKOK(mp_sub(r, &m[8], r));
252 MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
253 s_mp_clamp(r);
254 }
255 #endif
256
257 CLEANUP:
258 return res;
259 }
260
261 /* Compute the square of polynomial a, reduce modulo p384. Store the
262 * result in r. r could be a. Uses optimized modular reduction for p384.
263 */
264 mp_err
ec_GFp_nistp384_sqr(const mp_int * a,mp_int * r,const GFMethod * meth)265 ec_GFp_nistp384_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
266 {
267 mp_err res = MP_OKAY;
268
269 MP_CHECKOK(mp_sqr(a, r));
270 MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
271 CLEANUP:
272 return res;
273 }
274
275 /* Compute the product of two polynomials a and b, reduce modulo p384.
276 * Store the result in r. r could be a or b; a could be b. Uses
277 * optimized modular reduction for p384. */
278 mp_err
ec_GFp_nistp384_mul(const mp_int * a,const mp_int * b,mp_int * r,const GFMethod * meth)279 ec_GFp_nistp384_mul(const mp_int *a, const mp_int *b, mp_int *r,
280 const GFMethod *meth)
281 {
282 mp_err res = MP_OKAY;
283
284 MP_CHECKOK(mp_mul(a, b, r));
285 MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
286 CLEANUP:
287 return res;
288 }
289
290 /* Wire in fast field arithmetic and precomputation of base point for
291 * named curves. */
292 mp_err
ec_group_set_gfp384(ECGroup * group,ECCurveName name)293 ec_group_set_gfp384(ECGroup *group, ECCurveName name)
294 {
295 if (name == ECCurve_NIST_P384) {
296 group->meth->field_mod = &ec_GFp_nistp384_mod;
297 group->meth->field_mul = &ec_GFp_nistp384_mul;
298 group->meth->field_sqr = &ec_GFp_nistp384_sqr;
299 }
300 return MP_OKAY;
301 }
302