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 #pragma ident "%Z%%M% %I% %E% SMI"
48
49 #include "ec2.h"
50 #include "mp_gf2m.h"
51 #include "mp_gf2m-priv.h"
52 #include "mpi.h"
53 #include "mpi-priv.h"
54 #ifndef _KERNEL
55 #include <stdlib.h>
56 #endif
57
58 /* Fast reduction for polynomials over a 193-bit curve. Assumes reduction
59 * polynomial with terms {193, 15, 0}. */
60 mp_err
ec_GF2m_193_mod(const mp_int * a,mp_int * r,const GFMethod * meth)61 ec_GF2m_193_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
62 {
63 mp_err res = MP_OKAY;
64 mp_digit *u, z;
65
66 if (a != r) {
67 MP_CHECKOK(mp_copy(a, r));
68 }
69 #ifdef ECL_SIXTY_FOUR_BIT
70 if (MP_USED(r) < 7) {
71 MP_CHECKOK(s_mp_pad(r, 7));
72 }
73 u = MP_DIGITS(r);
74 MP_USED(r) = 7;
75
76 /* u[6] only has 2 significant bits */
77 z = u[6];
78 u[3] ^= (z << 14) ^ (z >> 1);
79 u[2] ^= (z << 63);
80 z = u[5];
81 u[3] ^= (z >> 50);
82 u[2] ^= (z << 14) ^ (z >> 1);
83 u[1] ^= (z << 63);
84 z = u[4];
85 u[2] ^= (z >> 50);
86 u[1] ^= (z << 14) ^ (z >> 1);
87 u[0] ^= (z << 63);
88 z = u[3] >> 1; /* z only has 63 significant bits */
89 u[1] ^= (z >> 49);
90 u[0] ^= (z << 15) ^ z;
91 /* clear bits above 193 */
92 u[6] = u[5] = u[4] = 0;
93 u[3] ^= z << 1;
94 #else
95 if (MP_USED(r) < 13) {
96 MP_CHECKOK(s_mp_pad(r, 13));
97 }
98 u = MP_DIGITS(r);
99 MP_USED(r) = 13;
100
101 /* u[12] only has 2 significant bits */
102 z = u[12];
103 u[6] ^= (z << 14) ^ (z >> 1);
104 u[5] ^= (z << 31);
105 z = u[11];
106 u[6] ^= (z >> 18);
107 u[5] ^= (z << 14) ^ (z >> 1);
108 u[4] ^= (z << 31);
109 z = u[10];
110 u[5] ^= (z >> 18);
111 u[4] ^= (z << 14) ^ (z >> 1);
112 u[3] ^= (z << 31);
113 z = u[9];
114 u[4] ^= (z >> 18);
115 u[3] ^= (z << 14) ^ (z >> 1);
116 u[2] ^= (z << 31);
117 z = u[8];
118 u[3] ^= (z >> 18);
119 u[2] ^= (z << 14) ^ (z >> 1);
120 u[1] ^= (z << 31);
121 z = u[7];
122 u[2] ^= (z >> 18);
123 u[1] ^= (z << 14) ^ (z >> 1);
124 u[0] ^= (z << 31);
125 z = u[6] >> 1; /* z only has 31 significant bits */
126 u[1] ^= (z >> 17);
127 u[0] ^= (z << 15) ^ z;
128 /* clear bits above 193 */
129 u[12] = u[11] = u[10] = u[9] = u[8] = u[7] = 0;
130 u[6] ^= z << 1;
131 #endif
132 s_mp_clamp(r);
133
134 CLEANUP:
135 return res;
136 }
137
138 /* Fast squaring for polynomials over a 193-bit curve. Assumes reduction
139 * polynomial with terms {193, 15, 0}. */
140 mp_err
ec_GF2m_193_sqr(const mp_int * a,mp_int * r,const GFMethod * meth)141 ec_GF2m_193_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
142 {
143 mp_err res = MP_OKAY;
144 mp_digit *u, *v;
145
146 v = MP_DIGITS(a);
147
148 #ifdef ECL_SIXTY_FOUR_BIT
149 if (MP_USED(a) < 4) {
150 return mp_bsqrmod(a, meth->irr_arr, r);
151 }
152 if (MP_USED(r) < 7) {
153 MP_CHECKOK(s_mp_pad(r, 7));
154 }
155 MP_USED(r) = 7;
156 #else
157 if (MP_USED(a) < 7) {
158 return mp_bsqrmod(a, meth->irr_arr, r);
159 }
160 if (MP_USED(r) < 13) {
161 MP_CHECKOK(s_mp_pad(r, 13));
162 }
163 MP_USED(r) = 13;
164 #endif
165 u = MP_DIGITS(r);
166
167 #ifdef ECL_THIRTY_TWO_BIT
168 u[12] = gf2m_SQR0(v[6]);
169 u[11] = gf2m_SQR1(v[5]);
170 u[10] = gf2m_SQR0(v[5]);
171 u[9] = gf2m_SQR1(v[4]);
172 u[8] = gf2m_SQR0(v[4]);
173 u[7] = gf2m_SQR1(v[3]);
174 #endif
175 u[6] = gf2m_SQR0(v[3]);
176 u[5] = gf2m_SQR1(v[2]);
177 u[4] = gf2m_SQR0(v[2]);
178 u[3] = gf2m_SQR1(v[1]);
179 u[2] = gf2m_SQR0(v[1]);
180 u[1] = gf2m_SQR1(v[0]);
181 u[0] = gf2m_SQR0(v[0]);
182 return ec_GF2m_193_mod(r, r, meth);
183
184 CLEANUP:
185 return res;
186 }
187
188 /* Fast multiplication for polynomials over a 193-bit curve. Assumes
189 * reduction polynomial with terms {193, 15, 0}. */
190 mp_err
ec_GF2m_193_mul(const mp_int * a,const mp_int * b,mp_int * r,const GFMethod * meth)191 ec_GF2m_193_mul(const mp_int *a, const mp_int *b, mp_int *r,
192 const GFMethod *meth)
193 {
194 mp_err res = MP_OKAY;
195 mp_digit a3 = 0, a2 = 0, a1 = 0, a0, b3 = 0, b2 = 0, b1 = 0, b0;
196
197 #ifdef ECL_THIRTY_TWO_BIT
198 mp_digit a6 = 0, a5 = 0, a4 = 0, b6 = 0, b5 = 0, b4 = 0;
199 mp_digit rm[8];
200 #endif
201
202 if (a == b) {
203 return ec_GF2m_193_sqr(a, r, meth);
204 } else {
205 switch (MP_USED(a)) {
206 #ifdef ECL_THIRTY_TWO_BIT
207 case 7:
208 a6 = MP_DIGIT(a, 6);
209 case 6:
210 a5 = MP_DIGIT(a, 5);
211 case 5:
212 a4 = MP_DIGIT(a, 4);
213 #endif
214 case 4:
215 a3 = MP_DIGIT(a, 3);
216 case 3:
217 a2 = MP_DIGIT(a, 2);
218 case 2:
219 a1 = MP_DIGIT(a, 1);
220 default:
221 a0 = MP_DIGIT(a, 0);
222 }
223 switch (MP_USED(b)) {
224 #ifdef ECL_THIRTY_TWO_BIT
225 case 7:
226 b6 = MP_DIGIT(b, 6);
227 case 6:
228 b5 = MP_DIGIT(b, 5);
229 case 5:
230 b4 = MP_DIGIT(b, 4);
231 #endif
232 case 4:
233 b3 = MP_DIGIT(b, 3);
234 case 3:
235 b2 = MP_DIGIT(b, 2);
236 case 2:
237 b1 = MP_DIGIT(b, 1);
238 default:
239 b0 = MP_DIGIT(b, 0);
240 }
241 #ifdef ECL_SIXTY_FOUR_BIT
242 MP_CHECKOK(s_mp_pad(r, 8));
243 s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
244 MP_USED(r) = 8;
245 s_mp_clamp(r);
246 #else
247 MP_CHECKOK(s_mp_pad(r, 14));
248 s_bmul_3x3(MP_DIGITS(r) + 8, a6, a5, a4, b6, b5, b4);
249 s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
250 s_bmul_4x4(rm, a3, a6 ^ a2, a5 ^ a1, a4 ^ a0, b3, b6 ^ b2, b5 ^ b1,
251 b4 ^ b0);
252 rm[7] ^= MP_DIGIT(r, 7);
253 rm[6] ^= MP_DIGIT(r, 6);
254 rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 13);
255 rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 12);
256 rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 11);
257 rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 10);
258 rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 9);
259 rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 8);
260 MP_DIGIT(r, 11) ^= rm[7];
261 MP_DIGIT(r, 10) ^= rm[6];
262 MP_DIGIT(r, 9) ^= rm[5];
263 MP_DIGIT(r, 8) ^= rm[4];
264 MP_DIGIT(r, 7) ^= rm[3];
265 MP_DIGIT(r, 6) ^= rm[2];
266 MP_DIGIT(r, 5) ^= rm[1];
267 MP_DIGIT(r, 4) ^= rm[0];
268 MP_USED(r) = 14;
269 s_mp_clamp(r);
270 #endif
271 return ec_GF2m_193_mod(r, r, meth);
272 }
273
274 CLEANUP:
275 return res;
276 }
277
278 /* Wire in fast field arithmetic for 193-bit curves. */
279 mp_err
ec_group_set_gf2m193(ECGroup * group,ECCurveName name)280 ec_group_set_gf2m193(ECGroup *group, ECCurveName name)
281 {
282 group->meth->field_mod = &ec_GF2m_193_mod;
283 group->meth->field_mul = &ec_GF2m_193_mul;
284 group->meth->field_sqr = &ec_GF2m_193_sqr;
285 return MP_OKAY;
286 }
287