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 binary polynomial 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 * Sheueling Chang-Shantz <sheueling.chang@sun.com>,
24 * Stephen Fung <fungstep@hotmail.com>, and
25 * Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
26 *
27 * Alternatively, the contents of this file may be used under the terms of
28 * either the GNU General Public License Version 2 or later (the "GPL"), or
29 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
30 * in which case the provisions of the GPL or the LGPL are applicable instead
31 * of those above. If you wish to allow use of your version of this file only
32 * under the terms of either the GPL or the LGPL, and not to allow others to
33 * use your version of this file under the terms of the MPL, indicate your
34 * decision by deleting the provisions above and replace them with the notice
35 * and other provisions required by the GPL or the LGPL. If you do not delete
36 * the provisions above, a recipient may use your version of this file under
37 * the terms of any one of the MPL, the GPL or the LGPL.
38 *
39 * ***** END LICENSE BLOCK ***** */
40 /*
41 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
42 * Use is subject to license terms.
43 *
44 * Sun elects to use this software under the MPL license.
45 */
46
47 #include "ec2.h"
48 #include "mp_gf2m.h"
49 #include "mp_gf2m-priv.h"
50 #include "mpi.h"
51 #include "mpi-priv.h"
52 #ifndef _KERNEL
53 #include <stdlib.h>
54 #endif
55
56 /* Fast reduction for polynomials over a 193-bit curve. Assumes reduction
57 * polynomial with terms {193, 15, 0}. */
58 mp_err
ec_GF2m_193_mod(const mp_int * a,mp_int * r,const GFMethod * meth)59 ec_GF2m_193_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
60 {
61 mp_err res = MP_OKAY;
62 mp_digit *u, z;
63
64 if (a != r) {
65 MP_CHECKOK(mp_copy(a, r));
66 }
67 #ifdef ECL_SIXTY_FOUR_BIT
68 if (MP_USED(r) < 7) {
69 MP_CHECKOK(s_mp_pad(r, 7));
70 }
71 u = MP_DIGITS(r);
72 MP_USED(r) = 7;
73
74 /* u[6] only has 2 significant bits */
75 z = u[6];
76 u[3] ^= (z << 14) ^ (z >> 1);
77 u[2] ^= (z << 63);
78 z = u[5];
79 u[3] ^= (z >> 50);
80 u[2] ^= (z << 14) ^ (z >> 1);
81 u[1] ^= (z << 63);
82 z = u[4];
83 u[2] ^= (z >> 50);
84 u[1] ^= (z << 14) ^ (z >> 1);
85 u[0] ^= (z << 63);
86 z = u[3] >> 1; /* z only has 63 significant bits */
87 u[1] ^= (z >> 49);
88 u[0] ^= (z << 15) ^ z;
89 /* clear bits above 193 */
90 u[6] = u[5] = u[4] = 0;
91 u[3] ^= z << 1;
92 #else
93 if (MP_USED(r) < 13) {
94 MP_CHECKOK(s_mp_pad(r, 13));
95 }
96 u = MP_DIGITS(r);
97 MP_USED(r) = 13;
98
99 /* u[12] only has 2 significant bits */
100 z = u[12];
101 u[6] ^= (z << 14) ^ (z >> 1);
102 u[5] ^= (z << 31);
103 z = u[11];
104 u[6] ^= (z >> 18);
105 u[5] ^= (z << 14) ^ (z >> 1);
106 u[4] ^= (z << 31);
107 z = u[10];
108 u[5] ^= (z >> 18);
109 u[4] ^= (z << 14) ^ (z >> 1);
110 u[3] ^= (z << 31);
111 z = u[9];
112 u[4] ^= (z >> 18);
113 u[3] ^= (z << 14) ^ (z >> 1);
114 u[2] ^= (z << 31);
115 z = u[8];
116 u[3] ^= (z >> 18);
117 u[2] ^= (z << 14) ^ (z >> 1);
118 u[1] ^= (z << 31);
119 z = u[7];
120 u[2] ^= (z >> 18);
121 u[1] ^= (z << 14) ^ (z >> 1);
122 u[0] ^= (z << 31);
123 z = u[6] >> 1; /* z only has 31 significant bits */
124 u[1] ^= (z >> 17);
125 u[0] ^= (z << 15) ^ z;
126 /* clear bits above 193 */
127 u[12] = u[11] = u[10] = u[9] = u[8] = u[7] = 0;
128 u[6] ^= z << 1;
129 #endif
130 s_mp_clamp(r);
131
132 CLEANUP:
133 return res;
134 }
135
136 /* Fast squaring for polynomials over a 193-bit curve. Assumes reduction
137 * polynomial with terms {193, 15, 0}. */
138 mp_err
ec_GF2m_193_sqr(const mp_int * a,mp_int * r,const GFMethod * meth)139 ec_GF2m_193_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
140 {
141 mp_err res = MP_OKAY;
142 mp_digit *u, *v;
143
144 v = MP_DIGITS(a);
145
146 #ifdef ECL_SIXTY_FOUR_BIT
147 if (MP_USED(a) < 4) {
148 return mp_bsqrmod(a, meth->irr_arr, r);
149 }
150 if (MP_USED(r) < 7) {
151 MP_CHECKOK(s_mp_pad(r, 7));
152 }
153 MP_USED(r) = 7;
154 #else
155 if (MP_USED(a) < 7) {
156 return mp_bsqrmod(a, meth->irr_arr, r);
157 }
158 if (MP_USED(r) < 13) {
159 MP_CHECKOK(s_mp_pad(r, 13));
160 }
161 MP_USED(r) = 13;
162 #endif
163 u = MP_DIGITS(r);
164
165 #ifdef ECL_THIRTY_TWO_BIT
166 u[12] = gf2m_SQR0(v[6]);
167 u[11] = gf2m_SQR1(v[5]);
168 u[10] = gf2m_SQR0(v[5]);
169 u[9] = gf2m_SQR1(v[4]);
170 u[8] = gf2m_SQR0(v[4]);
171 u[7] = gf2m_SQR1(v[3]);
172 #endif
173 u[6] = gf2m_SQR0(v[3]);
174 u[5] = gf2m_SQR1(v[2]);
175 u[4] = gf2m_SQR0(v[2]);
176 u[3] = gf2m_SQR1(v[1]);
177 u[2] = gf2m_SQR0(v[1]);
178 u[1] = gf2m_SQR1(v[0]);
179 u[0] = gf2m_SQR0(v[0]);
180 return ec_GF2m_193_mod(r, r, meth);
181
182 CLEANUP:
183 return res;
184 }
185
186 /* Fast multiplication for polynomials over a 193-bit curve. Assumes
187 * reduction polynomial with terms {193, 15, 0}. */
188 mp_err
ec_GF2m_193_mul(const mp_int * a,const mp_int * b,mp_int * r,const GFMethod * meth)189 ec_GF2m_193_mul(const mp_int *a, const mp_int *b, mp_int *r,
190 const GFMethod *meth)
191 {
192 mp_err res = MP_OKAY;
193 mp_digit a3 = 0, a2 = 0, a1 = 0, a0, b3 = 0, b2 = 0, b1 = 0, b0;
194
195 #ifdef ECL_THIRTY_TWO_BIT
196 mp_digit a6 = 0, a5 = 0, a4 = 0, b6 = 0, b5 = 0, b4 = 0;
197 mp_digit rm[8];
198 #endif
199
200 if (a == b) {
201 return ec_GF2m_193_sqr(a, r, meth);
202 } else {
203 switch (MP_USED(a)) {
204 #ifdef ECL_THIRTY_TWO_BIT
205 case 7:
206 a6 = MP_DIGIT(a, 6);
207 /* FALLTHROUGH */
208 case 6:
209 a5 = MP_DIGIT(a, 5);
210 /* FALLTHROUGH */
211 case 5:
212 a4 = MP_DIGIT(a, 4);
213 #endif
214 /* FALLTHROUGH */
215 case 4:
216 a3 = MP_DIGIT(a, 3);
217 /* FALLTHROUGH */
218 case 3:
219 a2 = MP_DIGIT(a, 2);
220 /* FALLTHROUGH */
221 case 2:
222 a1 = MP_DIGIT(a, 1);
223 /* FALLTHROUGH */
224 default:
225 a0 = MP_DIGIT(a, 0);
226 }
227 switch (MP_USED(b)) {
228 #ifdef ECL_THIRTY_TWO_BIT
229 case 7:
230 b6 = MP_DIGIT(b, 6);
231 /* FALLTHROUGH */
232 case 6:
233 b5 = MP_DIGIT(b, 5);
234 /* FALLTHROUGH */
235 case 5:
236 b4 = MP_DIGIT(b, 4);
237 #endif
238 /* FALLTHROUGH */
239 case 4:
240 b3 = MP_DIGIT(b, 3);
241 /* FALLTHROUGH */
242 case 3:
243 b2 = MP_DIGIT(b, 2);
244 /* FALLTHROUGH */
245 case 2:
246 b1 = MP_DIGIT(b, 1);
247 /* FALLTHROUGH */
248 default:
249 b0 = MP_DIGIT(b, 0);
250 }
251 #ifdef ECL_SIXTY_FOUR_BIT
252 MP_CHECKOK(s_mp_pad(r, 8));
253 s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
254 MP_USED(r) = 8;
255 s_mp_clamp(r);
256 #else
257 MP_CHECKOK(s_mp_pad(r, 14));
258 s_bmul_3x3(MP_DIGITS(r) + 8, a6, a5, a4, b6, b5, b4);
259 s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
260 s_bmul_4x4(rm, a3, a6 ^ a2, a5 ^ a1, a4 ^ a0, b3, b6 ^ b2, b5 ^ b1,
261 b4 ^ b0);
262 rm[7] ^= MP_DIGIT(r, 7);
263 rm[6] ^= MP_DIGIT(r, 6);
264 rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 13);
265 rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 12);
266 rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 11);
267 rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 10);
268 rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 9);
269 rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 8);
270 MP_DIGIT(r, 11) ^= rm[7];
271 MP_DIGIT(r, 10) ^= rm[6];
272 MP_DIGIT(r, 9) ^= rm[5];
273 MP_DIGIT(r, 8) ^= rm[4];
274 MP_DIGIT(r, 7) ^= rm[3];
275 MP_DIGIT(r, 6) ^= rm[2];
276 MP_DIGIT(r, 5) ^= rm[1];
277 MP_DIGIT(r, 4) ^= rm[0];
278 MP_USED(r) = 14;
279 s_mp_clamp(r);
280 #endif
281 return ec_GF2m_193_mod(r, r, meth);
282 }
283
284 CLEANUP:
285 return res;
286 }
287
288 /* Wire in fast field arithmetic for 193-bit curves. */
289 mp_err
ec_group_set_gf2m193(ECGroup * group,ECCurveName name)290 ec_group_set_gf2m193(ECGroup *group, ECCurveName name)
291 {
292 group->meth->field_mod = &ec_GF2m_193_mod;
293 group->meth->field_mul = &ec_GF2m_193_mul;
294 group->meth->field_sqr = &ec_GF2m_193_sqr;
295 return MP_OKAY;
296 }
297