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

   1 /* -*-c-*-
   2  *
   3  * $Id$
   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 #ifndef CATACOMB_DH_H
  31 #define CATACOMB_DH_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #ifndef CATACOMB_GROUP_H
  40 #  include "group.h"
  41 #endif
  42
  43 #ifndef CATACOMB_GRAND_H
  44 #  include "grand.h"
  45 #endif
  46
  47 #ifndef CATACOMB_KEY_H
  48 #  include "key.h"
  49 #endif
  50
  51 #ifndef CATACOMB_KEYCHECK_H
  52 #  include "keycheck.h"
  53 #endif
  54
  55 #ifndef CATACOMB_PGEN_H
  56 #  include "pgen.h"
  57 #endif
  58
  59 #ifndef CATACOMB_QDPARSE_H
  60 #  include "qdparse.h"
  61 #endif
  62
  63 /*----- Data structures ---------------------------------------------------*/
  64
  65 typedef gprime_param dh_param;          /* Group parameters */
  66
  67 typedef struct dh_pub {
  68   dh_param dp;                          /* Shared parameters */
  69   mp *y;                                /* Public key */
  70 } dh_pub;
  71
  72 typedef struct dh_priv {
  73   dh_param dp;                          /* Shared parameters */
  74   mp *x;                                /* Private key */
  75   mp *y;                                /* %$y \equiv g^x \pmod{p}$% */
  76 } dh_priv;
  77
  78 /*----- Key fetching ------------------------------------------------------*/
  79
  80 extern const key_fetchdef dh_paramfetch[];
  81 #define DH_PARAMFETCHSZ 5
  82
  83 extern const key_fetchdef dh_pubfetch[];
  84 #define DH_PUBFETCHSZ 6
  85
  86 extern const key_fetchdef dh_privfetch[];
  87 #define DH_PRIVFETCHSZ 9
  88
  89 /* --- @dh_paramfree@, @dh_pubfree@, @dh_privfree@ --- *
  90  *
  91  * Arguments:   @dh_param *dp@, @dh_pub *dp@, @dh_priv *dp@ = pointer to
  92  *                      key block to free
  93  *
  94  * Returns:     ---
  95  *
  96  * Use:         Frees a Diffie-Hellman key block.
  97  */
  98
  99 extern void dh_paramfree(dh_param */*dp*/);
 100 extern void dh_pubfree(dh_pub */*dp*/);
 101 extern void dh_privfree(dh_priv */*dp*/);
 102
 103 /*----- Functions provided ------------------------------------------------*/
 104
 105 /* --- @dh_gen@ --- *
 106  *
 107  * Arguments:   @dh_param *dp@ = pointer to output parameter block
 108  *              @unsigned ql@ = length of %$q$% in bits, or zero
 109  *              @unsigned pl@ = length of %$p$% in bits
 110  *              @unsigned steps@ = number of steps to go
 111  *              @grand *r@ = random number source
 112  *              @pgen_proc *event@ = event handler function
 113  *              @void *ectx@ = argument for the event handler
 114  *
 115  * Returns:     @PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
 116  *
 117  * Use:         Generates Diffie-Hellman parameters.
 118  *
 119  *              The parameters are a prime %$q$%, relatively small, and a
 120  *              large prime %$p = kq + 1$% for some %$k$%, together with a
 121  *              generator %$g$% of the cyclic subgroup of order %$q$%.  These
 122  *              are actually the same as the DSA parameter set, but the
 123  *              generation algorithm is different.  Also, if @ql@ is zero,
 124  *              this algorithm forces %$k = 2$%, and chooses %$g = 4$%.  Make
 125  *              sure you have something interesting to do if you choose this
 126  *              option.
 127  */
 128
 129 extern int dh_gen(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 130                   unsigned /*steps*/, grand */*r*/, pgen_proc */*event*/,
 131                   void */*ectx*/);
 132
 133 /* --- @dh_limlee@ --- *
 134  *
 135  * Arguments:   @dh_param *dp@ = pointer to output parameter block
 136  *              @unsigned ql@ = length of smallest factor of %$(p - 1)/2$%
 137  *              @unsigned pl@ = length of %$p$% in bits
 138  *              @unsigned flags@ = other generation flags
 139  *              @unsigned steps@ = number of steps to go
 140  *              @grand *r@ = random number source
 141  *              @pgen_proc *oev@ = outer event handler function
 142  *              @void *oec@ = argument for the outer event handler
 143  *              @pgen_proc *iev@ = inner event handler function
 144  *              @void *iec@ = argument for the inner event handler
 145  *              @size_t *nf@, @mp ***f@ = output array for factors
 146  *
 147  * Returns:     @PGEN_DONE@ if it worked, @PGEN_ABORT@ if it didn't.
 148  *
 149  * Use:         Generates Diffie-Hellman parameters based on a Lim-Lee prime.
 150  *
 151  *              The modulus is a large prime %$p = 2 \prod q_i + 1$%, @pl@
 152  *              bits long, where the %$q_i$% are smaller primes each at least
 153  *              @ql@ bits long.  It is safe to set @nf@ and @f@ to zero if
 154  *              you're not interested in the factor values.
 155  *
 156  *              The returned %$g$% generates a subgroup of order %$q_0$% (the
 157  *              first factor, returned as @f[0]@), if the flag @DH_SUBGROUP@
 158  *              is set on entry; otherwise %$g$% will have order
 159  *              %$(p - 1)/2$%.
 160  */
 161
 162 #define DH_SUBGROUP 1u
 163
 164 extern int dh_limlee(dh_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/,
 165                      unsigned /*flags*/, unsigned /*steps*/, grand */*r*/,
 166                      pgen_proc */*oev*/, void */*oec*/, pgen_proc */*iev*/,
 167                      void */*iec*/, size_t */*nf*/, mp ***/*f*/);
 168
 169 /* --- @dh_checkparam@ --- *
 170  *
 171  * Arguments:   @keycheck *kc@ = keycheck state
 172  *              @const dh_param *dp@ = pointer to the parameter set
 173  *              @mp **v@ = optional vector of factors
 174  *              @size_t n@ = size of vector
 175  *
 176  * Returns:     Zero if all OK, or return status from function.
 177  *
 178  * Use:         Checks a set of Diffie-Hellman parameters for consistency and
 179  *              security.
 180  */
 181
 182 extern int dh_checkparam(keycheck */*kc*/, const dh_param */*dp*/,
 183                          mp **/*v*/, size_t /*n*/);
 184
 185 /* ---- @dh_infofromdata@ --- *
 186  *
 187  * Arguments:   @dh_param *dp@ = parameters to fill in
 188  *              @pdata *pd@ = packed data structure
 189  *
 190  * Returns:     ---
 191  *
 192  * Use:         Fills in a parameters structure from a packed data block.
 193  */
 194
 195 struct pdata;
 196 extern void dh_infofromdata(dh_param */*dp*/, struct pdata */*pd*/);
 197
 198 /* --- @dh_parse@, @dhbin_parse@ --- *
 199  *
 200  * Arguments:   @qd_parse *qd@ = parser context
 201  *              @dh_param *dp@ = parameters to fill in
 202  *
 203  * Returns:     Zero if OK, nonzero on error.
 204  *
 205  * Use:         Parses a prime/binary group string.  This is either one of
 206  *              the standard group strings, or a %$p$%, %$q$%, %$g$% triple
 207  *              separated by commas.
 208  */
 209
 210 extern int dh_parse(qd_parse */*qd*/, dh_param */*dp*/);
 211 extern int dhbin_parse(qd_parse */*qd*/, gbin_param */*gb*/);
 212
 213 /*----- That's all, folks -------------------------------------------------*/
 214
 215 #ifdef __cplusplus
 216   }
 217 #endif
 218
 219 #endif