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General utilities cleanup. Add signature support to catcrypt. Throw in
[u/mdw/catacomb] / mpbarrett-mexp.c
CommitLineData
ab0350a6 1/* -*-c-*-
2 *
b817bfc6 3 * $Id: mpbarrett-mexp.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
ab0350a6 4 *
5 * Multiple simultaneous exponentiations
6 *
7 * (c) 1999 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Catacomb.
13 *
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
ab0350a6 30/*----- Header files ------------------------------------------------------*/
31
32#include "mp.h"
33#include "mpbarrett.h"
34
35#define EXP_WINSZ 3
36#include "mpbarrett-exp.h"
37
38/*----- Main code ---------------------------------------------------------*/
39
40/* --- @mpbarrett_mexp@ --- *
41 *
42 * Arguments: @mpbarrett *mb@ = pointer to Barrett reduction context
43 * @mp *d@ = fake destination
34e4f738 44 * @const mp_expfactor *f@ = pointer to array of factors
ab0350a6 45 * @size_t n@ = number of factors supplied
46 *
47 * Returns: If the bases are %$g_0, g_1, \ldots, g_{n-1}$% and the
48 * exponents are %$e_0, e_1, \ldots, e_{n-1}$% then the result
49 * is:
50 *
51 * %$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$%
52 */
53
34e4f738 54mp *mpbarrett_mexp(mpbarrett *mb, mp *d, const mp_expfactor *f, size_t n)
ab0350a6 55{
34e4f738 56 mp_expfactor *ff = xmalloc(n * sizeof(mp_expfactor));
ab0350a6 57 mp *a = MP_ONE;
58 mp *spare;
34e4f738 59 mp *g = MP_NEW;
ab0350a6 60 size_t i;
61
62 spare = MP_NEW;
63 for (i = 0; i < n; i++) {
34e4f738 64 if (f[i].exp->f & MP_BURN)
ab0350a6 65 spare = MP_NEWSEC;
34e4f738 66 if (!(f[i].exp->f & MP_NEG))
67 ff[i].base = MP_COPY(f[i].base);
b817bfc6 68 else
69 ff[i].base = mp_modinv(MP_NEW, f[i].base, mb->m);
34e4f738 70 ff[i].exp = f[i].exp;
ab0350a6 71 }
34e4f738 72 mp_drop(g);
73 EXP_SIMUL(a, ff, n);
ab0350a6 74 mp_drop(d);
75 mp_drop(spare);
34e4f738 76 for (i = 0; i < n; i++)
77 mp_drop(ff[i].base);
78 xfree(ff);
ab0350a6 79 return (a);
80}
81
82/*----- Test rig ----------------------------------------------------------*/
83
84#ifdef TEST_RIG
85
86#include <mLib/testrig.h>
87
88static int verify(size_t n, dstr *v)
89{
90 mp *m = *(mp **)v[0].buf;
91 mp_expfactor *f = xmalloc(n * sizeof(*f));
92 mp *r, *rr;
93 size_t i, j;
94 mpbarrett mb;
95 int ok = 1;
96
97 j = 1;
98 for (i = 0; i < n; i++) {
99 f[i].base = *(mp **)v[j++].buf;
100 f[i].exp = *(mp **)v[j++].buf;
101 }
102
103 rr = *(mp **)v[j].buf;
104 mpbarrett_create(&mb, m);
105 r = mpbarrett_mexp(&mb, MP_NEW, f, n);
106 if (!MP_EQ(r, rr)) {
107 fputs("\n*** mexp failed\n", stderr);
108 fputs("m = ", stderr); mp_writefile(m, stderr, 10);
109 for (i = 0; i < n; i++) {
110 fprintf(stderr, "\ng_%u = ", i);
111 mp_writefile(f[i].base, stderr, 10);
112 fprintf(stderr, "\ne_%u = ", i);
113 mp_writefile(f[i].exp, stderr, 10);
114 }
115 fputs("\nr = ", stderr); mp_writefile(r, stderr, 10);
116 fputs("\nR = ", stderr); mp_writefile(rr, stderr, 10);
117 fputc('\n', stderr);
118 ok = 0;
119 }
120
121 for (i = 0; i < n; i++) {
122 MP_DROP(f[i].base);
123 MP_DROP(f[i].exp);
124 }
125 MP_DROP(m);
126 MP_DROP(r);
127 MP_DROP(rr);
128 mpbarrett_destroy(&mb);
129 assert(mparena_count(MPARENA_GLOBAL) == 0);
130 return (ok);
131}
132
133static int t1(dstr *v) { return verify(1, v); }
134static int t2(dstr *v) { return verify(2, v); }
135static int t3(dstr *v) { return verify(3, v); }
136static int t4(dstr *v) { return verify(4, v); }
137static int t5(dstr *v) { return verify(5, v); }
138
139static test_chunk tests[] = {
140 { "mexp-1", t1, { &type_mp,
141 &type_mp, &type_mp,
142 &type_mp, 0 } },
143 { "mexp-2", t2, { &type_mp,
144 &type_mp, &type_mp,
145 &type_mp, &type_mp,
146 &type_mp, 0 } },
147 { "mexp-3", t3, { &type_mp,
148 &type_mp, &type_mp,
149 &type_mp, &type_mp,
150 &type_mp, &type_mp,
151 &type_mp, 0 } },
152 { "mexp-4", t4, { &type_mp,
153 &type_mp, &type_mp,
154 &type_mp, &type_mp,
155 &type_mp, &type_mp,
156 &type_mp, &type_mp,
157 &type_mp, 0 } },
158 { "mexp-5", t5, { &type_mp,
159 &type_mp, &type_mp,
160 &type_mp, &type_mp,
161 &type_mp, &type_mp,
162 &type_mp, &type_mp,
163 &type_mp, &type_mp,
164 &type_mp, 0 } },
165 { 0, 0, { 0 } }
166};
167
168int main(int argc, char *argv[])
169{
170 sub_init();
171 test_run(argc, argv, tests, SRCDIR "/tests/mpbarrett");
172 return (0);
173}
174
175#endif
176
177/*----- That's all, folks -------------------------------------------------*/
Catacomb cryptographic library (downstream of http://git.distorted.org.uk/~mdw/catacomb/)