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

   1 /* -*-c-*-
   2  *
   3  * $Id: field.h,v 1.1 2001/04/29 18:12:33 mdw Exp $
   4  *
   5  * Definitions for field arithmetic
   6  *
   7  * (c) 2000 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: field.h,v $
  33  * Revision 1.1  2001/04/29 18:12:33  mdw
  34  * Prototype version.
  35  *
  36  */
  37
  38 #ifndef CATACOMB_FIELD_H
  39 #define CATACOMB_FIELD_H
  40
  41 #ifdef __cplusplus
  42   extern "C" {
  43 #endif
  44
  45 /*----- Header files ------------------------------------------------------*/
  46
  47 #ifndef CATACOMB_MP_H
  48 #  include "mp.h"
  49 #endif
  50
  51 /*----- Data structures ---------------------------------------------------*/
  52
  53 typedef struct field {
  54   const struct field_ops *ops;          /* Field operations */
  55   mp *zero, *one;                       /* Identities in the field */
  56 } field;
  57
  58 typedef struct field_ops {
  59
  60   /* --- Universal operations --- */
  61
  62   void (*destroy)(field */*f*/);
  63
  64   mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/);
  65   mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/);
  66
  67   mp *(*add)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  68   mp *(*sub)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  69   mp *(*mul)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  70   mp *(*sqr)(field */*f*/, mp */*d*/, mp */*x*/);
  71   mp *(*inv)(field */*f*/, mp */*d*/, mp */*x*/);
  72   mp *(*reduce)(field */*f*/, mp */*d*/, mp */*x*/);
  73
  74   /* --- Operations for prime fields only --- */
  75
  76   mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/);
  77   mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/);
  78   mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/);
  79
  80 } field_ops;
  81
  82 #define F_DESTROY(f)            (f)->ops->destroy((f))
  83
  84 #define F_IN(f, d, x)           (f)->ops->in((f), (d), (x))
  85 #define F_OUT(f, d, x)          (f)->ops->out((f), (d), (x))
  86 #define F_ADD(f, d, x, y)       (f)->ops->add((f), (d), (x), (y))
  87 #define F_SUB(f, d, x, y)       (f)->ops->sub((f), (d), (x), (y))
  88 #define F_MUL(f, d, x, y)       (f)->ops->mul((f), (d), (x), (y))
  89 #define F_SQR(f, d, x)          (f)->ops->sqr((f), (d), (x))
  90 #define F_INV(f, d, x)          (f)->ops->inv((f), (d), (x))
  91 #define F_REDUCE(f, d, x)       (f)->ops->reduce((f), (d), (x))
  92
  93 #define F_DBL(f, d, x)          (f)->ops->dbl((f), (d), (x))
  94 #define F_TPL(f, d, x)          (f)->ops->tpl((f), (d), (x))
  95 #define F_SQRT(f, d, x)         (f)->ops->sqrt((f), (d), (x))
  96
  97 /*----- Creating fields ---------------------------------------------------*/
  98
  99 /* --- @field_prime@ --- *
 100  *
 101  * Arguments:   @mp *p@ = the characteristic of the field
 102  *
 103  * Returns:     A pointer to the field.
 104  *
 105  * Use:         Creates a field structure for a prime field of size %$p$%,
 106  *              using Montgomery reduction for arithmetic.
 107  */
 108
 109 extern field *field_prime(mp */*p*/);
 110
 111 /* --- @field_binpoly@ --- *
 112  *
 113  * Arguments:   @mp *p@ = an irreducible polynomial over %$\gf{2}$%
 114  *
 115  * Returns:     A pointer to the field.
 116  *
 117  * Use:         Creates a field structure for a binary field using naive
 118  *              arithmetic.
 119  */
 120
 121 extern field *field_binpoly(mp */*p*/);
 122
 123 /* --- @field_binsparsepoly@ --- *
 124  *
 125  * Arguments:   @unsigned deg@ = the degree of the field polynomial
 126  *              @const unsigned *c@ = degrees of nonzero coefficients
 127  *
 128  * Returns:     A pointer to the field.
 129  *
 130  * Use:         Creates a field structure for a binary field taking advantage
 131  *              of the sparseness of the given polynomial to improve
 132  *              reduction performance.
 133  */
 134
 135 extern field *field_binsparsepoly(unsigned /*deg*/, const unsigned */*c*/);
 136
 137 /*----- That's all, folks -------------------------------------------------*/
 138
 139 #ifdef __cplusplus
 140   }
 141 #endif
 142
 143 #endif