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

   1 /* -*-c-*-
   2  *
   3  * $Id: pgen.h,v 1.9 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Prime generation glue
   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_PGEN_H
  31 #define CATACOMB_PGEN_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #ifndef CATACOMB_GRAND_H
  40 #  include "grand.h"
  41 #endif
  42
  43 #ifndef CATACOMB_MP_H
  44 #  include "mp.h"
  45 #endif
  46
  47 #ifndef CATACOMB_PFILT_H
  48 #  include "pfilt.h"
  49 #endif
  50
  51 #ifndef CATACOMB_RABIN_H
  52 #  include "rabin.h"
  53 #endif
  54
  55 /*----- Event handling ----------------------------------------------------*
  56  *
  57  * Different programs and architectures will want to show progress of prime
  58  * searches and similar processes in different ways.  Of course, for simple
  59  * searches, it's possible to use the @pfilt@ and @rabin@ functions and
  60  * maintain control over the general control flow throughout the search.
  61  *
  62  * For more complex cases, this sort of control is undesirable.  It's
  63  * possible to specify an event handler which is informed in abstract about
  64  * the search.  The event handler can also request the search be aborted.
  65  */
  66
  67 /* --- Event code constants --- *
  68  *
  69  * You're allowed to rely on the values of @PGEN_DONE@ and @PGEN_ABORT@.
  70  */
  71
  72 enum {
  73   PGEN_BEGIN = 1,                       /* Search for value begins */
  74   PGEN_TRY,                             /* A new candidate has appeared */
  75   PGEN_FAIL,                            /* The candidate failed the test */
  76   PGEN_PASS,                            /* The candidate passed a test */
  77   PGEN_DONE = 0,                        /* A good value has been found */
  78   PGEN_ABORT = -1                       /* The search has been aborted */
  79 };
  80
  81 /* --- Event information --- *
  82  *
  83  * Note that the pseudorandom number generator supplied is not
  84  * cryptographically strong.
  85  */
  86
  87 typedef struct pgen_event {
  88   const char *name;                     /* Which quantity is being found */
  89   mp *m;                                /* Current value under test */
  90   unsigned steps;                       /* Number of candidates left */
  91   unsigned tests;                       /* Tests left before passing */
  92   grand *r;                             /* Source of random numbers */
  93 } pgen_event;
  94
  95 /*----- Prime search parameters -------------------------------------------*
  96  *
  97  * The prime search is parameterized in a large number of ways, although this
  98  * isn't so much of a surprise given the different sorts of properties
  99  * required from prime numbers in cryptographic applications.
 100  *
 101  * There are two main things which need to be configured: stepping, and
 102  * testing.  (Filtering is done as part of stepping.)
 103  *
 104  * The functions here provide a toolkit for constructing stepping and testing
 105  * routines.  In a lot of cases, the functions can be used directly; in
 106  * others, simple bits of glue need be written.
 107  *
 108  * Two types of functions are defined: steppers and testers, but their
 109  * interfaces are substantially similar.  Each is given a request code, a
 110  * context block and an event block.  It is meant to update its context and
 111  * the event block and return an event code.
 112  *
 113  * A call with a request of @PGEN_BEGIN@ asks the stepper or tester to
 114  * initialize itself using the information in its event block and context.  A
 115  * return of @PGEN_FAIL@ reports an immediate failure; @PGEN_ABORT@ reports a
 116  * fatal problem; @PGEN_DONE@ reports immediate success.  @PGEN_TRY@ reports
 117  * successful initialization and requests test iterations.
 118  *
 119  * A call to a stepper with a request of @PGEN_TRY@ asks it to step to the
 120  * next possible candidate, replacing the value @m@ in the event block with
 121  * the new candidate.  A call to a tester with a request of @PGEN_TRY@
 122  * runs one pass of the test.  It should return @PGEN_FAIL@ to report a
 123  * failure, @PGEN_PASS@ to report a success and request another iteration,
 124  * @PGEN_DONE@ to report final acceptance and @PGEN_ABORT@ to terminate the
 125  * search unsuccessfully.  Note that even if the search is aborted, a
 126  * shutdown request is still made.
 127  *
 128  * A call with a request of @PGEN_DONE@ closes down the stepper or tester.
 129  * After a successful initialization (i.e., a return of something other than
 130  * @PGEN_ABORT@), a shutdown call is guaranteed.  The return code is ignored.
 131  */
 132
 133 typedef int pgen_proc(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 134
 135 /*----- Simple handler functions ------------------------------------------*/
 136
 137 /* --- @pgen_filter@ --- *
 138  *
 139  * A prime generation context contains the information required for the
 140  * simple prime filter and tester presented here.
 141  */
 142
 143 typedef struct pgen_filterctx {
 144   unsigned step;                        /* Step size (set by client) */
 145   pfilt f;                              /* The rapid prime filter */
 146 } pgen_filterctx;
 147
 148 extern int pgen_filter(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 149
 150 /* --- @pgen_jump@ --- *
 151  *
 152  * Similar to the standard @pgen_filter@, but jumps in large steps rather
 153  * than small ones.
 154  */
 155
 156 typedef struct pgen_jumpctx {
 157   const pfilt *j;
 158   pfilt f;
 159 } pgen_jumpctx;
 160
 161 extern int pgen_jump(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 162
 163 /* --- @pgen_test@ --- *
 164  *
 165  * Runs the Rabin-Miller primality test.  The context block is simply a
 166  * @rabin@ context.
 167  */
 168
 169 extern int pgen_test(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 170
 171 /*----- Safe prime functions ----------------------------------------------*/
 172
 173 /* --- @pgen_safestep@ --- *
 174  *
 175  * Steps two numbers, %$q$% and %$p = 2q + 1$%, such that neither has any
 176  * small factors.  %$p$% is put in the event block.
 177  */
 178
 179 typedef struct pgen_safestepctx {
 180   pfilt q, p;
 181 } pgen_safestepctx;
 182
 183 extern int pgen_safestep(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 184
 185 /* --- @pgen_safejump@ --- *
 186  *
 187  * Jumps two numbers, %$q$% and %$p = 2q + 1$% such that neither has any
 188  * small factors.
 189  */
 190
 191 typedef struct pgen_safejumpctx {
 192   pfilt q, jq;
 193   pfilt p, jp;
 194 } pgen_safejumpctx;
 195
 196 extern int pgen_safejump(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 197
 198 /* --- @pgen_safetest@ --- *
 199  *
 200  * Applies Rabin-Miller tests to %$p$% and %$(p - 1)/2$%.
 201  */
 202
 203 typedef struct pgen_safetestctx {
 204   pgen_safestepctx c;
 205   rabin q, p;
 206 } pgen_safetestctx;
 207
 208 extern int pgen_safetest(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 209
 210 /*----- Miscellaneous steppers and testers --------------------------------*/
 211
 212 typedef struct pgen_gcdstepctx {
 213   pfilt p, jp;                          /* Prime filter and step filter */
 214   mp *q, *jq;                           /* %$p - 1$%, and a step value*/
 215   mp *r;                                /* Other argument for GCD */
 216   mp *g;                                /* GCD output (must be inited) */
 217   mp *max;                              /* Maximum permissible GCD */
 218 } pgen_gcdstepctx;
 219
 220 /* --- @pgen_gcdstep@ --- *
 221  *
 222  * Steps @p@ and @q@, until @p@ has no small factors, and
 223  * %$\gcd(p, r) \le max$%.
 224  */
 225
 226 extern int pgen_gcdstep(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 227
 228 /*----- Standard event handlers -------------------------------------------*/
 229
 230 /* --- @pgen_evspin@ --- *
 231  *
 232  * Displays a spinning baton to show progress.
 233  */
 234
 235 extern int pgen_evspin(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 236
 237 /* --- @pgen_ev@ --- *
 238  *
 239  * Traditional event handler, shows dots for each test.
 240  */
 241
 242 extern int pgen_ev(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 243
 244 /* --- @pgen_subev@ --- *
 245  *
 246  * Subsidiary event handler, mainly for Lim-Lee searches and so on.
 247  */
 248
 249 extern int pgen_subev(int /*rq*/, pgen_event */*ev*/, void */*p*/);
 250
 251 /*----- The main driver ---------------------------------------------------*/
 252
 253 /* --- @pgen@ --- *
 254  *
 255  * Arguments:   @const char *name@ = name of the value being searched for
 256  *              @mp *d@ = destination for resulting integer
 257  *              @mp *m@ = start value to pass to stepper
 258  *              @pgen_proc *event@ = event handler function
 259  *              @void *ectx@ = context argument for event andler
 260  *              @unsigned steps@ = number of steps to take in search
 261  *              @pgen_proc *step@ = stepper function to use
 262  *              @void *sctx@ = context argument for stepper
 263  *              @unsigned tests@ = number of tests to make
 264  *              @pgen_proc *test@ = tester function to use
 265  *              @void *tctx@ = context argument for tester
 266  *
 267  * Returns:     If successful, @PGEN_DONE@; otherwise @PGEN_ABORT@.
 268  *
 269  * Use:         A generalized prime-number search skeleton.  Yes, that's a
 270  *              scary number of arguments.
 271  */
 272
 273 extern mp *pgen(const char */*name*/, mp */*d*/, mp */*m*/,
 274                 pgen_proc */*event*/, void */*ectx*/,
 275                 unsigned /*steps*/, pgen_proc */*step*/, void */*sctx*/,
 276                 unsigned /*tests*/, pgen_proc */*test*/, void */*tctx*/);
 277
 278 /* --- @pgen_primep@ --- *
 279  *
 280  * Arguments:   @mp *p@ = a number to check
 281  *              @grand *gr@ = a random number source
 282  *
 283  * Returns:     Nonzero if @p@ is really prime.
 284  */
 285
 286 extern int pgen_primep(mp */*p*/, grand */*gr*/);
 287
 288 /*----- That's all, folks -------------------------------------------------*/
 289
 290 #ifdef __cplusplus
 291   }
 292 #endif
 293
 294 #endif