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 163-bit curve. Assumes reduction
57 * polynomial with terms {163, 7, 6, 3, 0}. */
58 mp_err
ec_GF2m_163_mod(const mp_int * a,mp_int * r,const GFMethod * meth)59 ec_GF2m_163_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) < 6) {
69 MP_CHECKOK(s_mp_pad(r, 6));
70 }
71 u = MP_DIGITS(r);
72 MP_USED(r) = 6;
73
74 /* u[5] only has 6 significant bits */
75 z = u[5];
76 u[2] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
77 z = u[4];
78 u[2] ^= (z >> 28) ^ (z >> 29) ^ (z >> 32) ^ (z >> 35);
79 u[1] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
80 z = u[3];
81 u[1] ^= (z >> 28) ^ (z >> 29) ^ (z >> 32) ^ (z >> 35);
82 u[0] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
83 z = u[2] >> 35; /* z only has 29 significant bits */
84 u[0] ^= (z << 7) ^ (z << 6) ^ (z << 3) ^ z;
85 /* clear bits above 163 */
86 u[5] = u[4] = u[3] = 0;
87 u[2] ^= z << 35;
88 #else
89 if (MP_USED(r) < 11) {
90 MP_CHECKOK(s_mp_pad(r, 11));
91 }
92 u = MP_DIGITS(r);
93 MP_USED(r) = 11;
94
95 /* u[11] only has 6 significant bits */
96 z = u[10];
97 u[5] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
98 u[4] ^= (z << 29);
99 z = u[9];
100 u[5] ^= (z >> 28) ^ (z >> 29);
101 u[4] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
102 u[3] ^= (z << 29);
103 z = u[8];
104 u[4] ^= (z >> 28) ^ (z >> 29);
105 u[3] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
106 u[2] ^= (z << 29);
107 z = u[7];
108 u[3] ^= (z >> 28) ^ (z >> 29);
109 u[2] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
110 u[1] ^= (z << 29);
111 z = u[6];
112 u[2] ^= (z >> 28) ^ (z >> 29);
113 u[1] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
114 u[0] ^= (z << 29);
115 z = u[5] >> 3; /* z only has 29 significant bits */
116 u[1] ^= (z >> 25) ^ (z >> 26);
117 u[0] ^= (z << 7) ^ (z << 6) ^ (z << 3) ^ z;
118 /* clear bits above 163 */
119 u[11] = u[10] = u[9] = u[8] = u[7] = u[6] = 0;
120 u[5] ^= z << 3;
121 #endif
122 s_mp_clamp(r);
123
124 CLEANUP:
125 return res;
126 }
127
128 /* Fast squaring for polynomials over a 163-bit curve. Assumes reduction
129 * polynomial with terms {163, 7, 6, 3, 0}. */
130 mp_err
ec_GF2m_163_sqr(const mp_int * a,mp_int * r,const GFMethod * meth)131 ec_GF2m_163_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
132 {
133 mp_err res = MP_OKAY;
134 mp_digit *u, *v;
135
136 v = MP_DIGITS(a);
137
138 #ifdef ECL_SIXTY_FOUR_BIT
139 if (MP_USED(a) < 3) {
140 return mp_bsqrmod(a, meth->irr_arr, r);
141 }
142 if (MP_USED(r) < 6) {
143 MP_CHECKOK(s_mp_pad(r, 6));
144 }
145 MP_USED(r) = 6;
146 #else
147 if (MP_USED(a) < 6) {
148 return mp_bsqrmod(a, meth->irr_arr, r);
149 }
150 if (MP_USED(r) < 12) {
151 MP_CHECKOK(s_mp_pad(r, 12));
152 }
153 MP_USED(r) = 12;
154 #endif
155 u = MP_DIGITS(r);
156
157 #ifdef ECL_THIRTY_TWO_BIT
158 u[11] = gf2m_SQR1(v[5]);
159 u[10] = gf2m_SQR0(v[5]);
160 u[9] = gf2m_SQR1(v[4]);
161 u[8] = gf2m_SQR0(v[4]);
162 u[7] = gf2m_SQR1(v[3]);
163 u[6] = gf2m_SQR0(v[3]);
164 #endif
165 u[5] = gf2m_SQR1(v[2]);
166 u[4] = gf2m_SQR0(v[2]);
167 u[3] = gf2m_SQR1(v[1]);
168 u[2] = gf2m_SQR0(v[1]);
169 u[1] = gf2m_SQR1(v[0]);
170 u[0] = gf2m_SQR0(v[0]);
171 return ec_GF2m_163_mod(r, r, meth);
172
173 CLEANUP:
174 return res;
175 }
176
177 /* Fast multiplication for polynomials over a 163-bit curve. Assumes
178 * reduction polynomial with terms {163, 7, 6, 3, 0}. */
179 mp_err
ec_GF2m_163_mul(const mp_int * a,const mp_int * b,mp_int * r,const GFMethod * meth)180 ec_GF2m_163_mul(const mp_int *a, const mp_int *b, mp_int *r,
181 const GFMethod *meth)
182 {
183 mp_err res = MP_OKAY;
184 mp_digit a2 = 0, a1 = 0, a0, b2 = 0, b1 = 0, b0;
185
186 #ifdef ECL_THIRTY_TWO_BIT
187 mp_digit a5 = 0, a4 = 0, a3 = 0, b5 = 0, b4 = 0, b3 = 0;
188 mp_digit rm[6];
189 #endif
190
191 if (a == b) {
192 return ec_GF2m_163_sqr(a, r, meth);
193 } else {
194 switch (MP_USED(a)) {
195 #ifdef ECL_THIRTY_TWO_BIT
196 case 6:
197 a5 = MP_DIGIT(a, 5);
198 /* FALLTHROUGH */
199 case 5:
200 a4 = MP_DIGIT(a, 4);
201 /* FALLTHROUGH */
202 case 4:
203 a3 = MP_DIGIT(a, 3);
204 #endif
205 /* FALLTHROUGH */
206 case 3:
207 a2 = MP_DIGIT(a, 2);
208 /* FALLTHROUGH */
209 case 2:
210 a1 = MP_DIGIT(a, 1);
211 /* FALLTHROUGH */
212 default:
213 a0 = MP_DIGIT(a, 0);
214 }
215 switch (MP_USED(b)) {
216 #ifdef ECL_THIRTY_TWO_BIT
217 case 6:
218 b5 = MP_DIGIT(b, 5);
219 /* FALLTHROUGH */
220 case 5:
221 b4 = MP_DIGIT(b, 4);
222 /* FALLTHROUGH */
223 case 4:
224 b3 = MP_DIGIT(b, 3);
225 #endif
226 /* FALLTHROUGH */
227 case 3:
228 b2 = MP_DIGIT(b, 2);
229 /* FALLTHROUGH */
230 case 2:
231 b1 = MP_DIGIT(b, 1);
232 /* FALLTHROUGH */
233 default:
234 b0 = MP_DIGIT(b, 0);
235 }
236 #ifdef ECL_SIXTY_FOUR_BIT
237 MP_CHECKOK(s_mp_pad(r, 6));
238 s_bmul_3x3(MP_DIGITS(r), a2, a1, a0, b2, b1, b0);
239 MP_USED(r) = 6;
240 s_mp_clamp(r);
241 #else
242 MP_CHECKOK(s_mp_pad(r, 12));
243 s_bmul_3x3(MP_DIGITS(r) + 6, a5, a4, a3, b5, b4, b3);
244 s_bmul_3x3(MP_DIGITS(r), a2, a1, a0, b2, b1, b0);
245 s_bmul_3x3(rm, a5 ^ a2, a4 ^ a1, a3 ^ a0, b5 ^ b2, b4 ^ b1,
246 b3 ^ b0);
247 rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 11);
248 rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 10);
249 rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 9);
250 rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 8);
251 rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 7);
252 rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 6);
253 MP_DIGIT(r, 8) ^= rm[5];
254 MP_DIGIT(r, 7) ^= rm[4];
255 MP_DIGIT(r, 6) ^= rm[3];
256 MP_DIGIT(r, 5) ^= rm[2];
257 MP_DIGIT(r, 4) ^= rm[1];
258 MP_DIGIT(r, 3) ^= rm[0];
259 MP_USED(r) = 12;
260 s_mp_clamp(r);
261 #endif
262 return ec_GF2m_163_mod(r, r, meth);
263 }
264
265 CLEANUP:
266 return res;
267 }
268
269 /* Wire in fast field arithmetic for 163-bit curves. */
270 mp_err
ec_group_set_gf2m163(ECGroup * group,ECCurveName name)271 ec_group_set_gf2m163(ECGroup *group, ECCurveName name)
272 {
273 group->meth->field_mod = &ec_GF2m_163_mod;
274 group->meth->field_mul = &ec_GF2m_163_mul;
275 group->meth->field_sqr = &ec_GF2m_163_sqr;
276 return MP_OKAY;
277 }
278