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

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Miller-Rabin primality test
   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_RABIN_H
  31 #define CATACOMB_RABIN_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #ifndef CATACOMB_MP_H
  40 #  include "mp.h"
  41 #endif
  42
  43 #ifndef CATACOMB_MPMONT_H
  44 #  include "mpmont.h"
  45 #endif
  46
  47 #ifndef CATACOMB_PFILT_H
  48 #  include "pfilt.h"
  49 #endif
  50
  51 /*----- Data structures ---------------------------------------------------*/
  52
  53 typedef struct rabin {
  54   mpmont mm;                            /* Montgomery arithmetic context */
  55   size_t s;                             /* %$m = 2^s r + 1$% */
  56   mp *r;                                /* %$m = 2^s r + 1$% */
  57   mp *m1;                               /* %$(m - 1)R \bmod m$% */
  58 } rabin;
  59
  60 /*----- Functions provided ------------------------------------------------*/
  61
  62 /* --- @rabin_create@ --- *
  63  *
  64  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  65  *              @mp *m@ = pointer to number to test
  66  *
  67  * Returns:     Zero on success, nonzero for failure.
  68  *
  69  * Use:         Precomputes some useful values for performing the
  70  *              Miller-Rabin probabilistic primality test.
  71  */
  72
  73 extern int rabin_create(rabin */*r*/, mp */*m*/);
  74
  75 /* --- @rabin_destroy@ --- *
  76  *
  77  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  78  *
  79  * Returns:     ---
  80  *
  81  * Use:         Disposes of a Rabin-Miller context when it's no longer
  82  *              needed.
  83  */
  84
  85 extern void rabin_destroy(rabin */*r*/);
  86
  87 /* --- @rabin_test@, @rabin_rtest@ --- *
  88  *
  89  * Arguments:   @rabin *r@ = pointer to Rabin-Miller context
  90  *              @mp *g@ = base to test the number against
  91  *
  92  * Returns:     Either @PGEN_FAIL@ if the test failed, or @PGEN_PASS@
  93  *              if it succeeded.
  94  *
  95  * Use:         Performs a single iteration of the Rabin-Miller primality
  96  *              test.  The @rtest@ variant assumes that %$g$% is either
  97  *              already in Montgomery representation, or you don't care.
  98  */
  99
 100 extern int rabin_rtest(rabin */*r*/, mp */*g*/);
 101 extern int rabin_test(rabin */*r*/, mp */*g*/);
 102
 103 /* --- @rabin_iters@ --- *
 104  *
 105  * Arguments:   @unsigned len@ = number of bits in value
 106  *
 107  * Returns:     Number of iterations recommended.
 108  *
 109  * Use:         Returns the recommended number of iterations to ensure that a
 110  *              number with @len@ bits is really prime.
 111  */
 112
 113 extern int rabin_iters(unsigned /*len*/);
 114
 115 /*----- That's all, folks -------------------------------------------------*/
 116
 117 #ifdef __cplusplus
 118   }
 119 #endif
 120
 121 #endif