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

   1 /* -*-c-*-
   2  *
   3  * $Id: dh.h,v 1.6 2000/07/29 10:01:16 mdw Exp $
   4  *
   5  * Diffie-Hellman and related public-key systems
   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: dh.h,v $
  33  * Revision 1.6  2000/07/29 10:01:16  mdw
  34  * Supply commentry for the Diffie-Hellman parameters.  Add Lim-Lee
  35  * parameter generation.
  36  *
  37  * Revision 1.5  2000/07/01 11:20:51  mdw
  38  * New functions for freeing public and private keys.
  39  *
  40  * Revision 1.4  2000/06/17 10:52:47  mdw
  41  * Minor changes for key fetching.
  42  *
  43  * Revision 1.3  2000/02/12 18:21:02  mdw
  44  * Overhaul of key management (again).
  45  *
  46  */
  47
  48 #ifndef CATACOMB_DH_H
  49 #define CATACOMB_DH_H
  50
  51 #ifdef __cplusplus
  52   extern "C" {
  53 #endif
  54
  55 /*----- Header files ------------------------------------------------------*/
  56
  57 #ifndef CATACOMB_GRAND_H
  58 #  include "grand.h"
  59 #endif
  60
  61 #ifndef CATACOMB_KEY_H
  62 #  include "key.h"
  63 #endif
  64
  65 #ifndef CATACOMB_PGEN_H
  66 #  include "pgen.h"
  67 #endif
  68
  69 /*----- Data structures ---------------------------------------------------*/
  70
  71 typedef struct dh_param {               /* Prime numbers %$p$% and %$q$% */
  72   mp *p, *q;                            /* Generates order-%$q$% subgroup */
  73   mp *g;
  74 } dh_param;
  75
  76 typedef struct dh_pub {                 /* Shared parameters */
  77   dh_param dp;                          /* Public key */
  78   mp *y;
  79 } dh_pub;
  80
  81 typedef struct dh_priv {                /* Shared parameters */
  82   dh_param dp;                          /* Private key */
  83   mp *x;                                /* %$y \equiv g^x \pmod{p}$% */
  84   mp *y;
  85 } dh_priv;
  86
  87 /*----- Key fetching ------------------------------------------------------*/
  88
  89 extern const key_fetchdef dh_paramfetch[];
  90 #define DH_PARAMFETCHSZ 5
  91
  92 extern const key_fetchdef dh_pubfetch[];
  93 #define DH_PUBFETCHSZ 6
  94
  95 extern const key_fetchdef dh_privfetch[];
  96 #define DH_PRIVFETCHSZ 9
  97
  98 /* --- @dh_paramfree@, @dh_pubfree@, @dh_privfree@ --- *
  99  *
 100  * Arguments:   @dh_param *dp@, @dh_pub *dp@, @dh_priv *dp@ = pointer to
 101  *                      key block to free
 102  *
 103  * Returns:     ---
 104  *
 105  * Use:         Frees a Diffie-Hellman key block.
 106  */
 107
 108 extern void dh_paramfree(dh_param */*dp*/);
 109 extern void dh_pubfree(dh_pub */*dp*/);
 110 extern void dh_privfree(dh_priv */*dp*/);
 111
 112 /*----- Functions provided ------------------------------------------------*/
 113
 114 /* --- @dh_gen@ --- *
 115  *
 116  * Arguments:   @dh_param *dp@ = pointer to output parameter block
 117  *              @unsigned ql@ = length of %$q$% in bits, or zero
 118  *              @unsigned pl@ = length of %$p$% in bits
 119  *              @unsigned steps@ = number of steps to go
 120  *              @grand *r@ = random number source
 121  *              @pgen_proc *event@ = event handler function
 122  *              @void *ectx@ = argument for the event handler
 123  *
 124  * Returns:     @PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
 125  *
 126  * Use:         Generates Diffie-Hellman parameters.
 127  *
 128  *              The parameters are a prime %$q$%, relatively small, and a
 129  *              large prime %$p = kq + 1$% for some %$k$%, together with a
 130  *              generator %$g$% of the cyclic subgroup of order %$q$%.  These
 131  *              are actually the same as the DSA parameter set, but the
 132  *              generation algorithm is different.  Also, if @ql@ is zero,
 133  *              this algorithm forces %$k = 2$%, and chooses %$g = 4$%.  Make
 134  *              sure you have something interesting to do if you choose this
 135  *              option.
 136  */
 137
 138 extern int dh_gen(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 139                   unsigned /*steps*/, grand */*r*/, pgen_proc */*event*/,
 140                   void */*ectx*/);
 141
 142 /* --- @dh_limlee@ --- *
 143  *
 144  * Arguments:   @dh_param *dp@ = pointer to output parameter block
 145  *              @unsigned ql@ = length of smallest factor of %$(p - 1)/2$%
 146  *              @unsigned pl@ = length of %$p$% in bits
 147  *              @unsigned flags@ = other generation flags
 148  *              @unsigned steps@ = number of steps to go
 149  *              @grand *r@ = random number source
 150  *              @pgen_proc *oev@ = outer event handler function
 151  *              @void *oec@ = argument for the outer event handler
 152  *              @pgen_proc *iev@ = inner event handler function
 153  *              @void *iec@ = argument for the inner event handler
 154  *              @size_t *nf@, @mp ***f@ = output array for factors
 155  *
 156  * Returns:     @PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
 157  *
 158  * Use:         Generates Diffie-Hellman parameters based on a Lim-Lee prime.
 159  *
 160  *              The modulus is a large prime %$p = 2 \prod q_i + 1$%, @pl@
 161  *              bits long, where the %$q_i$% are smaller primes each at least
 162  *              @ql@ bits long.  It is safe to set @nf@ and @f@ to zero if
 163  *              you're not interested in the factor values.
 164  *
 165  *              The returned %$g$% generates a subgroup of order %$q_0$% (the
 166  *              first factor, returned as @f[0]@), if the flag @DH_SUBGROUP@
 167  *              is set on entry; otherwise %$g$% will have order
 168  *              %$(p - 1)/2$%.
 169  */
 170
 171 #define DH_SUBGROUP 1u
 172
 173 extern int dh_limlee(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 174                      unsigned /*flags*/, unsigned /*steps*/, grand */*r*/,
 175                      pgen_proc */*oev*/, void */*oec*/, pgen_proc */*iev*/,
 176                      void */*iec*/, size_t */*nf*/, mp ***/*f*/);
 177
 178 /*----- That's all, folks -------------------------------------------------*/
 179
 180 #ifdef __cplusplus
 181   }
 182 #endif
 183
 184 #endif