git.distorted.org.uk Git - u/mdw/catacomb/blob - dh-param.c

   1 /* -*-c-*-
   2  *
   3  * $Id: dh-param.c,v 1.1 2004/04/01 12:50:09 mdw Exp $
   4  *
   5  * Reading Diffie-Hellman parameters
   6  *
   7  * (c) 2004 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: dh-param.c,v $
  33  * Revision 1.1  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.)
  39  *
  40  */
  41
  42 /*----- Header files ------------------------------------------------------*/
  43
  44 #include "dh.h"
  45 #include "ptab.h"
  46
  47 /*----- Main code ---------------------------------------------------------*/
  48
  49 /* --- @dh_parse@ --- *
  50  *
  51  * Arguments:   @qd_parse *qd@ = parser context
  52  *              @dh_param *dp@ = parameters to fill in
  53  *
  54  * Returns:     Zero if OK, nonzero on error.
  55  *
  56  * Use:         Parses a prime group string.  This is either one of the
  57  *              standard group strings, or a %$p$%, %$q$%, %$g$% triple
  58  *              separated by commas.
  59  */
  60
  61 static void getinfo(dh_param *dp, pdata *pd)
  62   { dp->p = &pd->p; dp->q = &pd->q; dp->g = &pd->g; }
  63
  64 int dh_parse(qd_parse *qd, dh_param *dp)
  65 {
  66   mp *p = MP_NEW, *q = MP_NEW, *g = MP_NEW;
  67   const pentry *pe;
  68
  69   for (pe = ptab; pe->name; pe++) {
  70     if (qd_enum(qd, pe->name) >= 0) {
  71       getinfo(dp, pe->data);
  72       goto found;
  73     }
  74   }
  75   if ((p = qd_getmp(qd)) == 0) goto fail;
  76   qd_delim(qd, ','); if ((q = qd_getmp(qd)) == 0) goto fail;
  77   qd_delim(qd, ','); if ((g = qd_getmp(qd)) == 0) goto fail;
  78   dp->p = p; dp->q = q; dp->g = g;
  79 found:
  80   return (0);
  81
  82 fail:
  83   mp_drop(p); mp_drop(q); mp_drop(g);
  84   return (-1);
  85 }
  86
  87 /*----- Test rig ----------------------------------------------------------*/
  88
  89 #ifdef TEST_RIG
  90
  91 #include "fibrand.h"
  92
  93 int main(void)
  94 {
  95   const pentry *pe;
  96   const char *e;
  97   int ok = 1;
  98   grand *gr;
  99
 100   gr = fibrand_create(0);
 101   fputs("checking standard prime fields: ", stdout);
 102   for (pe = ptab; pe->name; pe++) {
 103     dh_param dp;
 104     group *g;
 105     getinfo(&dp, pe->data);
 106     g = group_prime(&dp);
 107     e = G_CHECK(g, gr);
 108     G_DESTROYGROUP(g);
 109     dh_paramfree(&dp);
 110     if (e) {
 111       fprintf(stderr, "\n*** group %s fails: %s\n", pe->name, e);
 112       ok = 0;
 113     }
 114     putchar('.');
 115     fflush(stdout);
 116   }
 117   gr->ops->destroy(gr);
 118   fputs(ok ? " ok\n" : " failed\n", stdout);
 119   return (!ok);
 120 }
 121
 122 #endif
 123
 124 /*----- That's all, folks -------------------------------------------------*/