1/*
2 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
3 * Use is subject to license terms.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public License
16 * along with this library; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24/* *********************************************************************
25 *
26 * The Original Code is the elliptic curve math library for binary polynomial field curves.
27 *
28 * The Initial Developer of the Original Code is
29 * Sun Microsystems, Inc.
30 * Portions created by the Initial Developer are Copyright (C) 2003
31 * the Initial Developer. All Rights Reserved.
32 *
33 * Contributor(s):
34 *   Sheueling Chang-Shantz <sheueling.chang@sun.com>,
35 *   Stephen Fung <fungstep@hotmail.com>, and
36 *   Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
37 *
38 *********************************************************************** */
39
40#include "ec2.h"
41#include "mp_gf2m.h"
42#include "mp_gf2m-priv.h"
43#include "mpi.h"
44#include "mpi-priv.h"
45#ifndef _KERNEL
46#include <stdlib.h>
47#endif
48
49/* Fast reduction for polynomials over a 193-bit curve. Assumes reduction
50 * polynomial with terms {193, 15, 0}. */
51mp_err
52ec_GF2m_193_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
53{
54        mp_err res = MP_OKAY;
55        mp_digit *u, z;
56
57        if (a != r) {
58                MP_CHECKOK(mp_copy(a, r));
59        }
60#ifdef ECL_SIXTY_FOUR_BIT
61        if (MP_USED(r) < 7) {
62                MP_CHECKOK(s_mp_pad(r, 7));
63        }
64        u = MP_DIGITS(r);
65        MP_USED(r) = 7;
66
67        /* u[6] only has 2 significant bits */
68        z = u[6];
69        u[3] ^= (z << 14) ^ (z >> 1);
70        u[2] ^= (z << 63);
71        z = u[5];
72        u[3] ^= (z >> 50);
73        u[2] ^= (z << 14) ^ (z >> 1);
74        u[1] ^= (z << 63);
75        z = u[4];
76        u[2] ^= (z >> 50);
77        u[1] ^= (z << 14) ^ (z >> 1);
78        u[0] ^= (z << 63);
79        z = u[3] >> 1;                          /* z only has 63 significant bits */
80        u[1] ^= (z >> 49);
81        u[0] ^= (z << 15) ^ z;
82        /* clear bits above 193 */
83        u[6] = u[5] = u[4] = 0;
84        u[3] ^= z << 1;
85#else
86        if (MP_USED(r) < 13) {
87                MP_CHECKOK(s_mp_pad(r, 13));
88        }
89        u = MP_DIGITS(r);
90        MP_USED(r) = 13;
91
92        /* u[12] only has 2 significant bits */
93        z = u[12];
94        u[6] ^= (z << 14) ^ (z >> 1);
95        u[5] ^= (z << 31);
96        z = u[11];
97        u[6] ^= (z >> 18);
98        u[5] ^= (z << 14) ^ (z >> 1);
99        u[4] ^= (z << 31);
100        z = u[10];
101        u[5] ^= (z >> 18);
102        u[4] ^= (z << 14) ^ (z >> 1);
103        u[3] ^= (z << 31);
104        z = u[9];
105        u[4] ^= (z >> 18);
106        u[3] ^= (z << 14) ^ (z >> 1);
107        u[2] ^= (z << 31);
108        z = u[8];
109        u[3] ^= (z >> 18);
110        u[2] ^= (z << 14) ^ (z >> 1);
111        u[1] ^= (z << 31);
112        z = u[7];
113        u[2] ^= (z >> 18);
114        u[1] ^= (z << 14) ^ (z >> 1);
115        u[0] ^= (z << 31);
116        z = u[6] >> 1;                          /* z only has 31 significant bits */
117        u[1] ^= (z >> 17);
118        u[0] ^= (z << 15) ^ z;
119        /* clear bits above 193 */
120        u[12] = u[11] = u[10] = u[9] = u[8] = u[7] = 0;
121        u[6] ^= z << 1;
122#endif
123        s_mp_clamp(r);
124
125  CLEANUP:
126        return res;
127}
128
129/* Fast squaring for polynomials over a 193-bit curve. Assumes reduction
130 * polynomial with terms {193, 15, 0}. */
131mp_err
132ec_GF2m_193_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
133{
134        mp_err res = MP_OKAY;
135        mp_digit *u, *v;
136
137        v = MP_DIGITS(a);
138
139#ifdef ECL_SIXTY_FOUR_BIT
140        if (MP_USED(a) < 4) {
141                return mp_bsqrmod(a, meth->irr_arr, r);
142        }
143        if (MP_USED(r) < 7) {
144                MP_CHECKOK(s_mp_pad(r, 7));
145        }
146        MP_USED(r) = 7;
147#else
148        if (MP_USED(a) < 7) {
149                return mp_bsqrmod(a, meth->irr_arr, r);
150        }
151        if (MP_USED(r) < 13) {
152                MP_CHECKOK(s_mp_pad(r, 13));
153        }
154        MP_USED(r) = 13;
155#endif
156        u = MP_DIGITS(r);
157
158#ifdef ECL_THIRTY_TWO_BIT
159        u[12] = gf2m_SQR0(v[6]);
160        u[11] = gf2m_SQR1(v[5]);
161        u[10] = gf2m_SQR0(v[5]);
162        u[9] = gf2m_SQR1(v[4]);
163        u[8] = gf2m_SQR0(v[4]);
164        u[7] = gf2m_SQR1(v[3]);
165#endif
166        u[6] = gf2m_SQR0(v[3]);
167        u[5] = gf2m_SQR1(v[2]);
168        u[4] = gf2m_SQR0(v[2]);
169        u[3] = gf2m_SQR1(v[1]);
170        u[2] = gf2m_SQR0(v[1]);
171        u[1] = gf2m_SQR1(v[0]);
172        u[0] = gf2m_SQR0(v[0]);
173        return ec_GF2m_193_mod(r, r, meth);
174
175  CLEANUP:
176        return res;
177}
178
179/* Fast multiplication for polynomials over a 193-bit curve. Assumes
180 * reduction polynomial with terms {193, 15, 0}. */
181mp_err
182ec_GF2m_193_mul(const mp_int *a, const mp_int *b, mp_int *r,
183                                const GFMethod *meth)
184{
185        mp_err res = MP_OKAY;
186        mp_digit a3 = 0, a2 = 0, a1 = 0, a0, b3 = 0, b2 = 0, b1 = 0, b0;
187
188#ifdef ECL_THIRTY_TWO_BIT
189        mp_digit a6 = 0, a5 = 0, a4 = 0, b6 = 0, b5 = 0, b4 = 0;
190        mp_digit rm[8];
191#endif
192
193        if (a == b) {
194                return ec_GF2m_193_sqr(a, r, meth);
195        } else {
196                switch (MP_USED(a)) {
197#ifdef ECL_THIRTY_TWO_BIT
198                case 7:
199                        a6 = MP_DIGIT(a, 6);
200                case 6:
201                        a5 = MP_DIGIT(a, 5);
202                case 5:
203                        a4 = MP_DIGIT(a, 4);
204#endif
205                case 4:
206                        a3 = MP_DIGIT(a, 3);
207                case 3:
208                        a2 = MP_DIGIT(a, 2);
209                case 2:
210                        a1 = MP_DIGIT(a, 1);
211                default:
212                        a0 = MP_DIGIT(a, 0);
213                }
214                switch (MP_USED(b)) {
215#ifdef ECL_THIRTY_TWO_BIT
216                case 7:
217                        b6 = MP_DIGIT(b, 6);
218                case 6:
219                        b5 = MP_DIGIT(b, 5);
220                case 5:
221                        b4 = MP_DIGIT(b, 4);
222#endif
223                case 4:
224                        b3 = MP_DIGIT(b, 3);
225                case 3:
226                        b2 = MP_DIGIT(b, 2);
227                case 2:
228                        b1 = MP_DIGIT(b, 1);
229                default:
230                        b0 = MP_DIGIT(b, 0);
231                }
232#ifdef ECL_SIXTY_FOUR_BIT
233                MP_CHECKOK(s_mp_pad(r, 8));
234                s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
235                MP_USED(r) = 8;
236                s_mp_clamp(r);
237#else
238                MP_CHECKOK(s_mp_pad(r, 14));
239                s_bmul_3x3(MP_DIGITS(r) + 8, a6, a5, a4, b6, b5, b4);
240                s_bmul_4x4(MP_DIGITS(r), a3, a2, a1, a0, b3, b2, b1, b0);
241                s_bmul_4x4(rm, a3, a6 ^ a2, a5 ^ a1, a4 ^ a0, b3, b6 ^ b2, b5 ^ b1,
242                                   b4 ^ b0);
243                rm[7] ^= MP_DIGIT(r, 7);
244                rm[6] ^= MP_DIGIT(r, 6);
245                rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 13);
246                rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 12);
247                rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 11);
248                rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 10);
249                rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 9);
250                rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 8);
251                MP_DIGIT(r, 11) ^= rm[7];
252                MP_DIGIT(r, 10) ^= rm[6];
253                MP_DIGIT(r, 9) ^= rm[5];
254                MP_DIGIT(r, 8) ^= rm[4];
255                MP_DIGIT(r, 7) ^= rm[3];
256                MP_DIGIT(r, 6) ^= rm[2];
257                MP_DIGIT(r, 5) ^= rm[1];
258                MP_DIGIT(r, 4) ^= rm[0];
259                MP_USED(r) = 14;
260                s_mp_clamp(r);
261#endif
262                return ec_GF2m_193_mod(r, r, meth);
263        }
264
265  CLEANUP:
266        return res;
267}
268
269/* Wire in fast field arithmetic for 193-bit curves. */
270mp_err
271ec_group_set_gf2m193(ECGroup *group, ECCurveName name)
272{
273        group->meth->field_mod = &ec_GF2m_193_mod;
274        group->meth->field_mul = &ec_GF2m_193_mul;
275        group->meth->field_sqr = &ec_GF2m_193_sqr;
276        return MP_OKAY;
277}
278