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   1 /* -*-c-*-
   2  *
   3  * $Id: gdsa.h,v 1.1 2004/04/04 19:42:59 mdw Exp $
   4  *
   5  * Generalized version of DSA
   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: gdsa.h,v $
  33  * Revision 1.1  2004/04/04 19:42:59  mdw
  34  * Add set -e.
  35  *
  36  */
  37
  38 #ifndef CATACOMB_GDSA_H
  39 #define CATACOMB_GDSA_H
  40
  41 #ifdef __cplusplus
  42   extern "C" {
  43 #endif
  44
  45 /*----- Header files ------------------------------------------------------*/
  46
  47 #ifndef CATACOMB_GHASH_H
  48 #  include "ghash.h"
  49 #endif
  50
  51 #ifndef CATACOMB_GROUP_H
  52 #  include "group.h"
  53 #endif
  54
  55 /*----- Data structures ---------------------------------------------------*/
  56
  57 /* --- GDSA context --- *
  58  *
  59  * You don't need to fill in all of this stuff.  See the description of the
  60  * function you want to use to find out what members are needed.
  61  */
  62
  63 typedef struct gdsa {
  64   group *g;                             /* The group we work in */
  65   mp *u;                                /* Private key, for signing */
  66   ge *p;                                /* Public key, for verifying */
  67   grand *r;                             /* Random number source */
  68   const gchash *h;                      /* Hash function */
  69 } gdsa;
  70
  71 /* --- GDSA signatures --- */
  72
  73 typedef struct gdsa_sig { mp *r, *s; } gdsa_sig;
  74 #define GDSA_SIG_INIT { MP_NEW, MP_NEW }
  75
  76 /*----- Functions provided ------------------------------------------------*/
  77
  78 /* --- @gdsa_beginhash@ --- *
  79  *
  80  * Arguments:   @const gdsa *c@ = pointer to the context structure
  81  *
  82  * Returns:     A hashing context for you to hash the message.
  83  *
  84  * Use:         Initializes a hash function correctly for you to hash a
  85  *              message.  Requires @h@.
  86  */
  87
  88 extern ghash *gdsa_beginhash(const gdsa */*c*/);
  89
  90 /* --- @gdsa_endhash@ --- *
  91  *
  92  * Arguments:   @const gdsa *c@ = pointer to the context structure
  93  *              @ghash *h@ = the hashing context
  94  *
  95  * Returns:     ---
  96  *
  97  * Use:         Does any final thing that DSA wants to do when hashing a
  98  *              message.  (Actually, there's nothing.)  The hashing context
  99  *              isn't finalized.
 100  */
 101
 102 extern void gdsa_endhash(gdsa */*c*/, ghash */*h*/);
 103
 104 /* --- @gdsa_sign@ --- *
 105  *
 106  * Arguments:   @const gdsa *c@ = my context structure
 107  *              @gdsa_sig *s@ = where to put the signature (initialized)
 108  *              @const void *m@ = pointer to message hash
 109  *              @mp *k@ = random exponent for this message or null
 110  *
 111  * Returns:     ---
 112  *
 113  * Use:         Signs a message.  Requires @g@, @u@, @h@, and @r@ if @k@ is
 114  *              null.  This is a better idea than inventing @k@ yourself.
 115  */
 116
 117 extern void gdsa_sign(const gdsa */*c*/, gdsa_sig */*s*/,
 118                       const void */*m*/, mp */*k*/);
 119
 120 /* --- @gdsa_verify@ --- *
 121  *
 122  * Arguments:   @const gdsa *c@ = my context structure
 123  *              @const gdsa_sig *s@ = the signature to verify
 124  *              @const void *m@ = pointer to message hash
 125  *
 126  * Returns:     Zero if OK, negative on failure.
 127  *
 128  * Use:         Checks a signature on a message,  Requires @g@, @p@, @h@.
 129  */
 130
 131 extern int gdsa_verify(const gdsa */*c*/, const gdsa_sig */*s*/,
 132                        const void */*m*/);
 133
 134 /*----- That's all, folks -------------------------------------------------*/
 135
 136 #ifdef __cplusplus
 137   }
 138 #endif
 139
 140 #endif