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

   1 /* -*-c-*-
   2  *
   3  * $Id: dh.h,v 1.7 2001/02/03 16:08:24 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 1.7  2001/02/03 16:08:24  mdw
  34  * Add consistency checking for public keys.
  35  *
  36  * Revision 1.6  2000/07/29 10:01:16  mdw
  37  * Supply commentry for the Diffie-Hellman parameters.  Add Lim-Lee
  38  * parameter generation.
  39  *
  40  * Revision 1.5  2000/07/01 11:20:51  mdw
  41  * New functions for freeing public and private keys.
  42  *
  43  * Revision 1.4  2000/06/17 10:52:47  mdw
  44  * Minor changes for key fetching.
  45  *
  46  * Revision 1.3  2000/02/12 18:21:02  mdw
  47  * Overhaul of key management (again).
  48  *
  49  */
  50
  51 #ifndef CATACOMB_DH_H
  52 #define CATACOMB_DH_H
  53
  54 #ifdef __cplusplus
  55   extern "C" {
  56 #endif
  57
  58 /*----- Header files ------------------------------------------------------*/
  59
  60 #ifndef CATACOMB_GRAND_H
  61 #  include "grand.h"
  62 #endif
  63
  64 #ifndef CATACOMB_KEY_H
  65 #  include "key.h"
  66 #endif
  67
  68 #ifndef CATACOMB_KEYCHECK_H
  69 #  include "keycheck.h"
  70 #endif
  71
  72 #ifndef CATACOMB_PGEN_H
  73 #  include "pgen.h"
  74 #endif
  75
  76 /*----- Data structures ---------------------------------------------------*/
  77
  78 typedef struct dh_param {
  79   mp *p, *q;                            /* Prime numbers %$p$% and %$q$% */
  80   mp *g;                                /* Generates order-%$q$% subgroup */
  81 } dh_param;
  82
  83 typedef struct dh_pub {
  84   dh_param dp;                          /* Shared parameters */
  85   mp *y;                                /* Public key */
  86 } dh_pub;
  87
  88 typedef struct dh_priv {
  89   dh_param dp;                          /* Shared parameters */
  90   mp *x;                                /* Private key */
  91   mp *y;                                /* %$y \equiv g^x \pmod{p}$% */
  92 } dh_priv;
  93
  94 /*----- Key fetching ------------------------------------------------------*/
  95
  96 extern const key_fetchdef dh_paramfetch[];
  97 #define DH_PARAMFETCHSZ 5
  98
  99 extern const key_fetchdef dh_pubfetch[];
 100 #define DH_PUBFETCHSZ 6
 101
 102 extern const key_fetchdef dh_privfetch[];
 103 #define DH_PRIVFETCHSZ 9
 104
 105 /* --- @dh_paramfree@, @dh_pubfree@, @dh_privfree@ --- *
 106  *
 107  * Arguments:   @dh_param *dp@, @dh_pub *dp@, @dh_priv *dp@ = pointer to
 108  *                      key block to free
 109  *
 110  * Returns:     ---
 111  *
 112  * Use:         Frees a Diffie-Hellman key block.
 113  */
 114
 115 extern void dh_paramfree(dh_param */*dp*/);
 116 extern void dh_pubfree(dh_pub */*dp*/);
 117 extern void dh_privfree(dh_priv */*dp*/);
 118
 119 /*----- Functions provided ------------------------------------------------*/
 120
 121 /* --- @dh_gen@ --- *
 122  *
 123  * Arguments:   @dh_param *dp@ = pointer to output parameter block
 124  *              @unsigned ql@ = length of %$q$% in bits, or zero
 125  *              @unsigned pl@ = length of %$p$% in bits
 126  *              @unsigned steps@ = number of steps to go
 127  *              @grand *r@ = random number source
 128  *              @pgen_proc *event@ = event handler function
 129  *              @void *ectx@ = argument for the event handler
 130  *
 131  * Returns:     @PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
 132  *
 133  * Use:         Generates Diffie-Hellman parameters.
 134  *
 135  *              The parameters are a prime %$q$%, relatively small, and a
 136  *              large prime %$p = kq + 1$% for some %$k$%, together with a
 137  *              generator %$g$% of the cyclic subgroup of order %$q$%.  These
 138  *              are actually the same as the DSA parameter set, but the
 139  *              generation algorithm is different.  Also, if @ql@ is zero,
 140  *              this algorithm forces %$k = 2$%, and chooses %$g = 4$%.  Make
 141  *              sure you have something interesting to do if you choose this
 142  *              option.
 143  */
 144
 145 extern int dh_gen(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 146                   unsigned /*steps*/, grand */*r*/, pgen_proc */*event*/,
 147                   void */*ectx*/);
 148
 149 /* --- @dh_limlee@ --- *
 150  *
 151  * Arguments:   @dh_param *dp@ = pointer to output parameter block
 152  *              @unsigned ql@ = length of smallest factor of %$(p - 1)/2$%
 153  *              @unsigned pl@ = length of %$p$% in bits
 154  *              @unsigned flags@ = other generation flags
 155  *              @unsigned steps@ = number of steps to go
 156  *              @grand *r@ = random number source
 157  *              @pgen_proc *oev@ = outer event handler function
 158  *              @void *oec@ = argument for the outer event handler
 159  *              @pgen_proc *iev@ = inner event handler function
 160  *              @void *iec@ = argument for the inner event handler
 161  *              @size_t *nf@, @mp ***f@ = output array for factors
 162  *
 163  * Returns:     @PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
 164  *
 165  * Use:         Generates Diffie-Hellman parameters based on a Lim-Lee prime.
 166  *
 167  *              The modulus is a large prime %$p = 2 \prod q_i + 1$%, @pl@
 168  *              bits long, where the %$q_i$% are smaller primes each at least
 169  *              @ql@ bits long.  It is safe to set @nf@ and @f@ to zero if
 170  *              you're not interested in the factor values.
 171  *
 172  *              The returned %$g$% generates a subgroup of order %$q_0$% (the
 173  *              first factor, returned as @f[0]@), if the flag @DH_SUBGROUP@
 174  *              is set on entry; otherwise %$g$% will have order
 175  *              %$(p - 1)/2$%.
 176  */
 177
 178 #define DH_SUBGROUP 1u
 179
 180 extern int dh_limlee(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 181                      unsigned /*flags*/, unsigned /*steps*/, grand */*r*/,
 182                      pgen_proc */*oev*/, void */*oec*/, pgen_proc */*iev*/,
 183                      void */*iec*/, size_t */*nf*/, mp ***/*f*/);
 184
 185 /* --- @dh_checkparam@ --- *
 186  *
 187  * Arguments:   @keycheck *kc@ = keycheck state
 188  *              @const dh_param *dp@ = pointer to the parameter set
 189  *              @mp **v@ = optional vector of factors
 190  *              @size_t n@ = size of vector
 191  *
 192  * Returns:     Zero if all OK, or return status from function.
 193  *
 194  * Use:         Checks a set of Diffie-Hellman parameters for consistency and
 195  *              security.
 196  */
 197
 198 extern int dh_checkparam(keycheck */*kc*/, const dh_param */*dp*/,
 199                          mp **/*v*/, size_t /*n*/);
 200
 201 /*----- That's all, folks -------------------------------------------------*/
 202
 203 #ifdef __cplusplus
 204   }
 205 #endif
 206
 207 #endif