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   1 /* -*-c-*-
   2  *
   3  * $Id: pgen.h,v 1.3 1999/12/10 23:29:48 mdw Exp $
   4  *
   5  * Finding and testing prime numbers
   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: pgen.h,v $
  33  * Revision 1.3  1999/12/10 23:29:48  mdw
  34  * Change header file guard names.
  35  *
  36  * Revision 1.2  1999/11/20 22:23:05  mdw
  37  * Add multiply-and-add function for Diffie-Hellman safe prime generation.
  38  *
  39  * Revision 1.1  1999/11/19 13:17:57  mdw
  40  * Prime number generator and tester.
  41  *
  42  */
  43
  44 #ifndef CATACOMB_PGEN_H
  45 #define CATACOMB_PGEN_H
  46
  47 #ifdef __cplusplus
  48   extern "C" {
  49 #endif
  50
  51 /*----- Header files ------------------------------------------------------*/
  52
  53 #ifndef CATACOMB_MP_H
  54 #  include "mp.h"
  55 #endif
  56
  57 #ifndef CATACOMB_PTAB_H
  58 #  include "ptab.h"
  59 #endif
  60
  61 /*----- Constants ---------------------------------------------------------*/
  62
  63 #define PGEN_COMPOSITE (-1)             /* Number is definitely composite */
  64 #define PGEN_MAYBE (0)                  /* Number may be prime */
  65 #define PGEN_PRIME (1)                  /* Number is definitely prime */
  66
  67 /*----- Data structures ---------------------------------------------------*/
  68
  69 typedef struct pgen {
  70   mp *m;
  71   unsigned char r[NPRIME];
  72 } pgen;
  73
  74 /*----- Functions provided ------------------------------------------------*/
  75
  76 /* --- @pgen_create@ --- *
  77  *
  78  * Arguments:   @pgen *p@ = pointer to prime generation context
  79  *              @mp *m@ = pointer to initial number to test
  80  *
  81  * Returns:     One of the @PGEN@ constants above.
  82  *
  83  * Use:         Tests an initial number for primality by computing its
  84  *              residue modulo various small prime numbers.  This is fairly
  85  *              quick, but not particularly certain.  If a @PGEN_MAYBE@
  86  *              result is returned, perform Rabin-Miller tests to confirm.
  87  */
  88
  89 extern int pgen_create(pgen */*p*/, mp */*m*/);
  90
  91 /* --- @pgen_destroy@ --- *
  92  *
  93  * Arguments:   @pgen *p@ = pointer to prime generation context
  94  *
  95  * Returns:     ---
  96  *
  97  * Use:         Discards a context and all the resources it holds.
  98  */
  99
 100 extern void pgen_destroy(pgen */*p*/);
 101
 102 /* --- @pgen_step@ --- *
 103  *
 104  * Arguments:   @pgen *p@ = pointer to prime generation context
 105  *              @mpw step@ = how much to step the number
 106  *
 107  * Returns:     One of the @PGEN@ constants above.
 108  *
 109  * Use:         Steps a number by a small amount.  Stepping is much faster
 110  *              than initializing with a new number.  The test performed is
 111  *              the same simple one used by @ptab_create@, so @PGEN_MAYBE@
 112  *              results should be followed up by a Rabin-Miller test.
 113  */
 114
 115 extern int pgen_step(pgen */*p*/, mpw /*step*/);
 116
 117 /* --- @pgen_muladd@ --- *
 118  *
 119  * Arguments:   @pgen *p@ = destination prime generation context
 120  *              @const pgen *q@ = source prime generation context
 121  *              @mpw m@ = number to multiply by
 122  *              @mpw a@ = number to add
 123  *
 124  * Returns:     One of the @PGEN@ constants above.
 125  *
 126  * Use:         Multiplies the number in a prime generation context by a
 127  *              small value and then adds a small value.  The destination
 128  *              should either be uninitialized or the same as the source.
 129  *
 130  *              Common things to do include multiplying by 2 and adding 0 to
 131  *              turn a prime into a jump for finding other primes with @q@ as
 132  *              a factor of @p - 1@, or multiplying by 2 and adding 1.
 133  */
 134
 135 extern int pgen_muladd(pgen */*p*/, const pgen */*q*/, mpw /*m*/, mpw /*a*/);
 136
 137 /* --- @pgen_jump@ --- *
 138  *
 139  * Arguments:   @pgen *p@ = pointer to prime generation context
 140  *              @pgen *j@ = pointer to another generation context
 141  *
 142  * Returns:     One of the @PGEN@ constants above.
 143  *
 144  * Use:         Steps a number by a large amount.  Even so, jumping is much
 145  *              faster than initializing a new number.  The test peformed is
 146  *              the same simple one used by @ptab_create@, so @PGEN_MAYBE@
 147  *              results should be followed up by a Rabin-Miller test.
 148  *
 149  *              Note that the number stored in the @j@ context is probably
 150  *              better off being even than prime.  The important thing is
 151  *              that all of the residues for the number have already been
 152  *              computed.
 153  */
 154
 155 extern int pgen_jump(pgen */*p*/, pgen */*j*/);
 156
 157 /*----- That's all, folks -------------------------------------------------*/
 158
 159 #ifdef __cplusplus
 160   }
 161 #endif
 162
 163 #endif