3 * $Id: mpbarrett-mexp.c,v 1.2 2004/04/01 12:50:09 mdw Exp $
5 * Multiple simultaneous exponentiations
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
32 * $Log: mpbarrett-mexp.c,v $
33 * Revision 1.2 2004/04/01 12:50:09 mdw
34 * Add cyclic group abstraction, with test code. Separate off exponentation
35 * functions for better static linking. Fix a buttload of bugs on the way.
36 * Generally ensure that negative exponents do inversion correctly. Add
37 * table of standard prime-field subgroups. (Binary field subgroups are
38 * currently unimplemented but easy to add if anyone ever finds a good one.)
40 * Revision 1.1 2001/06/16 12:58:34 mdw
41 * Added simultaneous exponentiation with Barrett reduction.
45 /*----- Header files ------------------------------------------------------*/
48 #include "mpbarrett.h"
51 #include "mpbarrett-exp.h"
53 /*----- Main code ---------------------------------------------------------*/
55 /* --- @mpbarrett_mexp@ --- *
57 * Arguments: @mpbarrett *mb@ = pointer to Barrett reduction context
58 * @mp *d@ = fake destination
59 * @const mp_expfactor *f@ = pointer to array of factors
60 * @size_t n@ = number of factors supplied
62 * Returns: If the bases are %$g_0, g_1, \ldots, g_{n-1}$% and the
63 * exponents are %$e_0, e_1, \ldots, e_{n-1}$% then the result
66 * %$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$%
69 mp *mpbarrett_mexp(mpbarrett *mb, mp *d, const mp_expfactor *f, size_t n)
71 mp_expfactor *ff = xmalloc(n * sizeof(mp_expfactor));
78 for (i = 0; i < n; i++) {
79 if (f[i].exp->f & MP_BURN)
81 if (!(f[i].exp->f & MP_NEG))
82 ff[i].base = MP_COPY(f[i].base);
85 mp_gcd(&g, 0, &ff[i].base, mb->m, f[i].base);
86 assert(MP_EQ(g, MP_ONE));
94 for (i = 0; i < n; i++)
100 /*----- Test rig ----------------------------------------------------------*/
104 #include <mLib/testrig.h>
106 static int verify(size_t n, dstr *v)
108 mp *m = *(mp **)v[0].buf;
109 mp_expfactor *f = xmalloc(n * sizeof(*f));
116 for (i = 0; i < n; i++) {
117 f[i].base = *(mp **)v[j++].buf;
118 f[i].exp = *(mp **)v[j++].buf;
121 rr = *(mp **)v[j].buf;
122 mpbarrett_create(&mb, m);
123 r = mpbarrett_mexp(&mb, MP_NEW, f, n);
125 fputs("\n*** mexp failed\n", stderr);
126 fputs("m = ", stderr); mp_writefile(m, stderr, 10);
127 for (i = 0; i < n; i++) {
128 fprintf(stderr, "\ng_%u = ", i);
129 mp_writefile(f[i].base, stderr, 10);
130 fprintf(stderr, "\ne_%u = ", i);
131 mp_writefile(f[i].exp, stderr, 10);
133 fputs("\nr = ", stderr); mp_writefile(r, stderr, 10);
134 fputs("\nR = ", stderr); mp_writefile(rr, stderr, 10);
139 for (i = 0; i < n; i++) {
146 mpbarrett_destroy(&mb);
147 assert(mparena_count(MPARENA_GLOBAL) == 0);
151 static int t1(dstr *v) { return verify(1, v); }
152 static int t2(dstr *v) { return verify(2, v); }
153 static int t3(dstr *v) { return verify(3, v); }
154 static int t4(dstr *v) { return verify(4, v); }
155 static int t5(dstr *v) { return verify(5, v); }
157 static test_chunk tests[] = {
158 { "mexp-1", t1, { &type_mp,
161 { "mexp-2", t2, { &type_mp,
165 { "mexp-3", t3, { &type_mp,
170 { "mexp-4", t4, { &type_mp,
176 { "mexp-5", t5, { &type_mp,
186 int main(int argc, char *argv[])
189 test_run(argc, argv, tests, SRCDIR "/tests/mpbarrett");
195 /*----- That's all, folks -------------------------------------------------*/