git.distorted.org.uk Git - u/mdw/catacomb/blob - mpmont-mexp.c

   1 /* -*-c-*-
   2  *
   3  * $Id: mpmont-mexp.c,v 1.6 2001/06/16 13:00:20 mdw Exp $
   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
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: mpmont-mexp.c,v $
  33  * Revision 1.6  2001/06/16 13:00:20  mdw
  34  * Use the generic exponentiation functions.
  35  *
  36  * Revision 1.5  2000/10/08 12:11:22  mdw
  37  * Use @MP_EQ@ instead of @MP_CMP@.
  38  *
  39  * Revision 1.4  2000/06/17 11:45:09  mdw
  40  * Major memory management overhaul.  Added arena support.  Use the secure
  41  * arena for secret integers.  Replace and improve the MP management macros
  42  * (e.g., replace MP_MODIFY by MP_DEST).
  43  *
  44  * Revision 1.3  1999/12/10 23:18:39  mdw
  45  * Change interface for suggested destinations.
  46  *
  47  * Revision 1.2  1999/11/21 11:35:10  mdw
  48  * Performance improvement: use @mp_sqr@ and @mpmont_reduce@ instead of
  49  * @mpmont_mul@ for squaring in exponentiation.
  50  *
  51  * Revision 1.1  1999/11/19 13:19:29  mdw
  52  * Simultaneous exponentiation support.
  53  *
  54  */
  55
  56 /*----- Header files ------------------------------------------------------*/
  57
  58 #include "mp.h"
  59 #include "mpmont.h"
  60
  61 #define EXP_WINSZ 3
  62 #include "mpmont-exp.h"
  63
  64 /*----- Main code ---------------------------------------------------------*/
  65
  66 /* --- @mpmont_mexpr@ --- *
  67  *
  68  * Arguments:   @mpmont *mm@ = pointer to Montgomery reduction context
  69  *              @mp *d@ = fake destination
  70  *              @mp_expfactor *f@ = pointer to array of factors
  71  *              @size_t n@ = number of factors supplied
  72  *
  73  * Returns:     If the bases are %$g_0, g_1, \ldots, g_{n-1}$% and the
  74  *              exponents are %$e_0, e_1, \ldots, e_{n-1}$% then the result
  75  *              is:
  76  *
  77  *              %$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$%
  78  *
  79  *              except that the %$g_i$% and result are in Montgomery form.
  80  */
  81
  82 mp *mpmont_mexpr(mpmont *mm, mp *d, mp_expfactor *f, size_t n)
  83 {
  84   mp *a = mp_copy(mm->r);
  85   mp *spare;
  86   size_t i;
  87
  88   spare = MP_NEW;
  89   for (i = 0; i < n; i++) {
  90     if (f[i].exp->f & MP_BURN) {
  91       spare = MP_NEWSEC;
  92       break;
  93     }
  94   }
  95
  96   EXP_SIMUL(a, f, n);
  97   mp_drop(d);
  98   mp_drop(spare);
  99   return (a);
 100 }
 101
 102 /* --- @mpmont_mexp@ --- *
 103  *
 104  * Arguments:   @mpmont *mm@ = pointer to Montgomery reduction context
 105  *              @mp *d@ = fake destination
 106  *              @mp_expfactor *f@ = pointer to array of factors
 107  *              @size_t n@ = number of factors supplied
 108  *
 109  * Returns:     Product of bases raised to exponents, all mod @m@.
 110  *
 111  * Use:         Convenient interface over @mpmont_mexpr@.
 112  */
 113
 114 mp *mpmont_mexp(mpmont *mm, mp *d, mp_expfactor *f, size_t n)
 115 {
 116   mp_expfactor *v = xmalloc(sizeof(*v) * n);
 117   size_t i;
 118
 119   for (i = 0; i < n; i++) {
 120     v[i].base = mpmont_mul(mm, MP_NEW, f[i].base, mm->r2);
 121     v[i].exp = f[i].exp;
 122   }
 123   d = mpmont_mexpr(mm, d, v, n);
 124   for (i = 0; i < n; i++)
 125     MP_DROP(v[i].base);
 126   xfree(v);
 127   d = mpmont_reduce(mm, d, d);
 128   return (d);
 129 }
 130
 131 /*----- Test rig ----------------------------------------------------------*/
 132
 133 #ifdef TEST_RIG
 134
 135 #include <mLib/testrig.h>
 136
 137 static int verify(size_t n, dstr *v)
 138 {
 139   mp *m = *(mp **)v[0].buf;
 140   mp_expfactor *f = xmalloc(n * sizeof(*f));
 141   mp *r, *rr;
 142   size_t i, j;
 143   mpmont mm;
 144   int ok = 1;
 145
 146   j = 1;
 147   for (i = 0; i < n; i++) {
 148     f[i].base = *(mp **)v[j++].buf;
 149     f[i].exp = *(mp **)v[j++].buf;
 150   }
 151
 152   rr = *(mp **)v[j].buf;
 153   mpmont_create(&mm, m);
 154   r = mpmont_mexp(&mm, MP_NEW, f, n);
 155   if (!MP_EQ(r, rr)) {
 156     fputs("\n*** mexp failed\n", stderr);
 157     fputs("m = ", stderr); mp_writefile(m, stderr, 10);
 158     for (i = 0; i < n; i++) {
 159       fprintf(stderr, "\ng_%u = ", i);
 160       mp_writefile(f[i].base, stderr, 10);
 161       fprintf(stderr, "\ne_%u = ", i);
 162       mp_writefile(f[i].exp, stderr, 10);
 163     }
 164     fputs("\nr = ", stderr); mp_writefile(r, stderr, 10);
 165     fputs("\nR = ", stderr); mp_writefile(rr, stderr, 10);
 166     fputc('\n', stderr);
 167     ok = 0;
 168   }
 169
 170   for (i = 0; i < n; i++) {
 171     MP_DROP(f[i].base);
 172     MP_DROP(f[i].exp);
 173   }
 174   MP_DROP(m);
 175   MP_DROP(r);
 176   MP_DROP(rr);
 177   mpmont_destroy(&mm);
 178   assert(mparena_count(MPARENA_GLOBAL) == 0);
 179   return (ok);
 180 }
 181
 182 static int t1(dstr *v) { return verify(1, v); }
 183 static int t2(dstr *v) { return verify(2, v); }
 184 static int t3(dstr *v) { return verify(3, v); }
 185 static int t4(dstr *v) { return verify(4, v); }
 186 static int t5(dstr *v) { return verify(5, v); }
 187
 188 static test_chunk tests[] = {
 189   { "mexp-1", t1, { &type_mp,
 190                     &type_mp, &type_mp,
 191                     &type_mp, 0 } },
 192   { "mexp-2", t2, { &type_mp,
 193                     &type_mp, &type_mp,
 194                     &type_mp, &type_mp,
 195                     &type_mp, 0 } },
 196   { "mexp-3", t3, { &type_mp,
 197                     &type_mp, &type_mp,
 198                     &type_mp, &type_mp,
 199                     &type_mp, &type_mp,
 200                     &type_mp, 0 } },
 201   { "mexp-4", t4, { &type_mp,
 202                     &type_mp, &type_mp,
 203                     &type_mp, &type_mp,
 204                     &type_mp, &type_mp,
 205                     &type_mp, &type_mp,
 206                     &type_mp, 0 } },
 207   { "mexp-5", t5, { &type_mp,
 208                     &type_mp, &type_mp,
 209                     &type_mp, &type_mp,
 210                     &type_mp, &type_mp,
 211                     &type_mp, &type_mp,
 212                     &type_mp, &type_mp,
 213                     &type_mp, 0 } },
 214   { 0, 0, { 0 } }
 215 };
 216
 217 int main(int argc, char *argv[])
 218 {
 219   sub_init();
 220   test_run(argc, argv, tests, SRCDIR "/tests/mpmont");
 221   return (0);
 222 }
 223
 224 #endif
 225
 226 /*----- That's all, folks -------------------------------------------------*/