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