5 * General-purpose modular exponentiation
7 * (c) 2006 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 /*----- Header files ------------------------------------------------------*/
33 #include "mpbarrett.h"
36 /*----- Main code ---------------------------------------------------------*/
38 /* --- @mp_modexp@ --- *
40 * Arguments: @mp *d@ = fake destination
41 * @mp *x@ = base of exponentiation
43 * @mp *n@ = modulus (must be positive)
45 * Returns: The value %$x^e \bmod n$%.
48 mp *mp_modexp(mp *d, mp *x, mp *e, mp *n)
52 mpmont_create(&mm, n);
53 d = mpmont_exp(&mm, d, x, e);
57 mpbarrett_create(&mb, n);
58 d = mpbarrett_exp(&mb, d, x, e);
59 mpbarrett_destroy(&mb);
64 /*----- Test rig ----------------------------------------------------------*/
68 static int tmodexp(dstr *v)
70 mp *a = *(mp **)v[0].buf;
71 mp *b = *(mp **)v[1].buf;
72 mp *m = *(mp **)v[2].buf;
73 mp *r = *(mp **)v[3].buf;
77 mr = mp_modexp(MP_NEW, a, b, m);
80 fputs("\n*** modexp failed", stderr);
81 fputs("\n a = ", stderr); mp_writefile(a, stderr, 10);
82 fputs("\n e = ", stderr); mp_writefile(b, stderr, 10);
83 fputs("\n m = ", stderr); mp_writefile(m, stderr, 10);
84 fputs("\n r = ", stderr); mp_writefile(r, stderr, 10);
85 fputs("\nmr = ", stderr); mp_writefile(mr, stderr, 10);
95 assert(mparena_count(MPARENA_GLOBAL) == 0);
99 static test_chunk tests[] = {
100 { "modexp", tmodexp, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
104 int main(int argc, char *argv[])
107 test_run(argc, argv, tests, SRCDIR "/tests/mp");
113 /*----- That's all, folks -------------------------------------------------*/