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

   1 /* -*-c-*-
   2  *
   3  * Miller-Rabin primality test
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef CATACOMB_RABIN_H
  29 #define CATACOMB_RABIN_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #ifndef CATACOMB_MP_H
  38 #  include "mp.h"
  39 #endif
  40
  41 #ifndef CATACOMB_MPMONT_H
  42 #  include "mpmont.h"
  43 #endif
  44
  45 #ifndef CATACOMB_PFILT_H
  46 #  include "pfilt.h"
  47 #endif
  48
  49 /*----- Data structures ---------------------------------------------------*/
  50
  51 typedef struct rabin {
  52   mpmont mm;                            /* Montgomery arithmetic context */
  53   size_t s;                             /* %$m = 2^s r + 1$% */
  54   mp *r;                                /* %$m = 2^s r + 1$% */
  55   mp *m1;                               /* %$(m - 1)R \bmod m$% */
  56 } rabin;
  57
  58 /*----- Functions provided ------------------------------------------------*/
  59
  60 /* --- @rabin_create@ --- *
  61  *
  62  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  63  *              @mp *m@ = pointer to number to test
  64  *
  65  * Returns:     Zero on success, nonzero for failure.
  66  *
  67  * Use:         Precomputes some useful values for performing the
  68  *              Miller-Rabin probabilistic primality test.
  69  */
  70
  71 extern int rabin_create(rabin */*r*/, mp */*m*/);
  72
  73 /* --- @rabin_destroy@ --- *
  74  *
  75  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  76  *
  77  * Returns:     ---
  78  *
  79  * Use:         Disposes of a Rabin-Miller context when it's no longer
  80  *              needed.
  81  */
  82
  83 extern void rabin_destroy(rabin */*r*/);
  84
  85 /* --- @rabin_test@, @rabin_rtest@ --- *
  86  *
  87  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  88  *              @mp *g@ = base to test the number against
  89  *
  90  * Returns:     Either @PGEN_FAIL@ if the test failed, or @PGEN_PASS@
  91  *              if it succeeded.
  92  *
  93  * Use:         Performs a single iteration of the Rabin-Miller primality
  94  *              test.  The @rtest@ variant assumes that %$g$% is either
  95  *              already in Montgomery representation, or you don't care.
  96  */
  97
  98 extern int rabin_rtest(rabin */*r*/, mp */*g*/);
  99 extern int rabin_test(rabin */*r*/, mp */*g*/);
 100
 101 /* --- @rabin_iters@ --- *
 102  *
 103  * Arguments:   @unsigned len@ = number of bits in value
 104  *
 105  * Returns:     Number of iterations recommended.
 106  *
 107  * Use:         Returns the recommended number of iterations to ensure that a
 108  *              number with @len@ bits is really prime.
 109  */
 110
 111 extern int rabin_iters(unsigned /*len*/);
 112
 113 /*----- That's all, folks -------------------------------------------------*/
 114
 115 #ifdef __cplusplus
 116   }
 117 #endif
 118
 119 #endif