projects / u / mdw / catacomb / blame
| Commit | Line | Data |
|---|---|---|
| ffec4880 MW |
1 | /* -*-c-*- |
| 2 | * | |
| 3 | * $Id$ | |
| 4 | * | |
| 5 | * General-purpose modular exponentiation | |
| 6 | * | |
| 7 | * (c) 2006 Straylight/Edgeware | |
| 8 | */ | |
| 9 | ||
| 45c0fd36 | 10 | /*----- Licensing notice --------------------------------------------------* |
| ffec4880 MW |
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. | |
| 45c0fd36 | 18 | * |
| ffec4880 MW |
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. | |
| 45c0fd36 | 23 | * |
| ffec4880 MW |
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 | ||
| 30 | /*----- Header files ------------------------------------------------------*/ | |
| 31 | ||
| 32 | #include "mp.h" | |
| 33 | #include "mpbarrett.h" | |
| 34 | #include "mpmont.h" | |
| 35 | ||
| 36 | /*----- Main code ---------------------------------------------------------*/ | |
| 37 | ||
| 38 | /* --- @mp_modexp@ --- * | |
| 39 | * | |
| 40 | * Arguments: @mp *d@ = fake destination | |
| 41 | * @mp *x@ = base of exponentiation | |
| 42 | * @mp *e@ = exponent | |
| 43 | * @mp *n@ = modulus (must be positive) | |
| 44 | * | |
| 45 | * Returns: The value %$x^e \bmod n$%. | |
| 46 | */ | |
| 47 | ||
| 48 | mp *mp_modexp(mp *d, mp *x, mp *e, mp *n) | |
| 49 | { | |
| 50 | if (MP_ODDP(n)) { | |
| 51 | mpmont mm; | |
| 52 | mpmont_create(&mm, n); | |
| 53 | d = mpmont_exp(&mm, d, x, e); | |
| 54 | mpmont_destroy(&mm); | |
| 55 | } else { | |
| 56 | mpbarrett mb; | |
| 57 | mpbarrett_create(&mb, n); | |
| 58 | d = mpbarrett_exp(&mb, d, x, e); | |
| 59 | mpbarrett_destroy(&mb); | |
| 60 | } | |
| 61 | return (d); | |
| 62 | } | |
| 63 | ||
| 64 | /*----- Test rig ----------------------------------------------------------*/ | |
| 65 | ||
| 66 | #ifdef TEST_RIG | |
| 67 | ||
| 68 | static int tmodexp(dstr *v) | |
| 69 | { | |
| 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; | |
| 74 | mp *mr; | |
| 75 | int ok = 1; | |
| 76 | ||
| 77 | mr = mp_modexp(MP_NEW, a, b, m); | |
| 78 | ||
| 79 | if (!MP_EQ(mr, r)) { | |
| 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); | |
| 86 | fputc('\n', stderr); | |
| 87 | ok = 0; | |
| 88 | } | |
| 89 | ||
| 90 | MP_DROP(m); | |
| 91 | MP_DROP(a); | |
| 92 | MP_DROP(b); | |
| 93 | MP_DROP(r); | |
| 94 | MP_DROP(mr); | |
| 95 | assert(mparena_count(MPARENA_GLOBAL) == 0); | |
| 96 | return ok; | |
| 97 | } | |
| 98 | ||
| 99 | static test_chunk tests[] = { | |
| 100 | { "modexp", tmodexp, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } }, | |
| 101 | { 0, 0, { 0 } } | |
| 102 | }; | |
| 103 | ||
| 104 | int main(int argc, char *argv[]) | |
| 105 | { | |
| 106 | sub_init(); | |
| 107 | test_run(argc, argv, tests, SRCDIR "/tests/mp"); | |
| 108 | return (0); | |
| 109 | } | |
| 110 | ||
| 111 | #endif | |
| 112 | ||
| 113 | /*----- That's all, folks -------------------------------------------------*/ |