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