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

   1 /* -*-c-*-
   2  *
   3  * $Id: field.h,v 1.3.4.2 2004/03/21 22:39:46 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 1.3.4.2  2004/03/21 22:39:46  mdw
  34  * Elliptic curves on binary fields work.
  35  *
  36  * Revision 1.3.4.1  2004/03/20 00:13:31  mdw
  37  * Projective coordinates for prime curves
  38  *
  39  * Revision 1.3  2002/01/13 13:48:44  mdw
  40  * Further progress.
  41  *
  42  * Revision 1.2  2001/05/07 17:30:13  mdw
  43  * Add an internal-representation no-op function.
  44  *
  45  * Revision 1.1  2001/04/29 18:12:33  mdw
  46  * Prototype version.
  47  *
  48  */
  49
  50 #ifndef CATACOMB_FIELD_H
  51 #define CATACOMB_FIELD_H
  52
  53 #ifdef __cplusplus
  54   extern "C" {
  55 #endif
  56
  57 /*----- Header files ------------------------------------------------------*/
  58
  59 #ifndef CATACOMB_MP_H
  60 #  include "mp.h"
  61 #endif
  62
  63 /*----- Data structures ---------------------------------------------------*/
  64
  65 typedef struct field {
  66   const struct field_ops *ops;          /* Field operations */
  67   mp *zero, *one;                       /* Identities in the field */
  68 } field;
  69
  70 typedef struct field_ops {
  71
  72   /* --- Universal operations --- */
  73
  74   void (*destroy)(field */*f*/);
  75
  76   mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/);
  77   mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/);
  78
  79   int (*zerop)(field */*f*/, mp */*x*/);
  80   mp *(*neg)(field */*f*/, mp */*d*/, mp */*x*/);
  81   mp *(*add)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  82   mp *(*sub)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  83   mp *(*mul)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  84   mp *(*sqr)(field */*f*/, mp */*d*/, mp */*x*/);
  85   mp *(*inv)(field */*f*/, mp */*d*/, mp */*x*/);
  86   mp *(*reduce)(field */*f*/, mp */*d*/, mp */*x*/);
  87   mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/);
  88
  89   /* --- Operations for binary fields only --- */
  90
  91   mp *(*quadsolve)(field */*f*/, mp */*d*/, mp */*x*/);
  92
  93   /* --- Operations for prime fields only --- */
  94
  95   mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/);
  96   mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/);
  97   mp *(*qdl)(field */*f*/, mp */*d*/, mp */*x*/);
  98   mp *(*hlv)(field */*f*/, mp */*d*/, mp */*x*/);
  99
 100 } field_ops;
 101
 102 #define F_DESTROY(f)            (f)->ops->destroy((f))
 103
 104 #define F_IN(f, d, x)           (f)->ops->in((f), (d), (x))
 105 #define F_OUT(f, d, x)          (f)->ops->out((f), (d), (x))
 106
 107 #define F_ZEROP(f, x)           (f)->ops->zerop((f), (x))
 108 #define F_NEG(f, d, x)          (f)->ops->neg((f), (d), (x))
 109 #define F_ADD(f, d, x, y)       (f)->ops->add((f), (d), (x), (y))
 110 #define F_SUB(f, d, x, y)       (f)->ops->sub((f), (d), (x), (y))
 111 #define F_MUL(f, d, x, y)       (f)->ops->mul((f), (d), (x), (y))
 112 #define F_SQR(f, d, x)          (f)->ops->sqr((f), (d), (x))
 113 #define F_INV(f, d, x)          (f)->ops->inv((f), (d), (x))
 114 #define F_REDUCE(f, d, x)       (f)->ops->reduce((f), (d), (x))
 115 #define F_SQRT(f, d, x)         (f)->ops->sqrt((f), (d), (x))
 116
 117 #define F_QUADSOLVE(f, d, x)    (f)->ops->quadsolve((f), (d), (x))
 118
 119 #define F_DBL(f, d, x)          (f)->ops->dbl((f), (d), (x))
 120 #define F_TPL(f, d, x)          (f)->ops->tpl((f), (d), (x))
 121 #define F_QDL(f, d, x)          (f)->ops->qdl((f), (d), (x))
 122 #define F_HLV(f, d, x)          (f)->ops->hlv((f), (d), (x))
 123
 124 /*----- Helpful field operations ------------------------------------------*/
 125
 126 /* --- @field_id@ --- *
 127  *
 128  * Arguments:   @field *f@ = pointer to a field
 129  *              @mp *d@ = a destination element
 130  *              @mp *x@ = a source element
 131  *
 132  * Returns:     The result element.
 133  *
 134  * Use:         An identity operation which can be used if your field has no
 135  *              internal representation.
 136  */
 137
 138 extern mp *field_id(field */*f*/, mp */*d*/, mp */*x*/);
 139
 140 /*----- Creating fields ---------------------------------------------------*/
 141
 142 /* --- @field_prime@ --- *
 143  *
 144  * Arguments:   @mp *p@ = the characteristic of the field
 145  *
 146  * Returns:     A pointer to the field.
 147  *
 148  * Use:         Creates a field structure for a prime field of size %$p$%,
 149  *              using Montgomery reduction for arithmetic.
 150  */
 151
 152 extern field *field_prime(mp */*p*/);
 153
 154 /* --- @field_binpoly@ --- *
 155  *
 156  * Arguments:   @mp *p@ = an irreducible polynomial over %$\gf{2}$%
 157  *
 158  * Returns:     A pointer to the field.
 159  *
 160  * Use:         Creates a field structure for a binary field using naive
 161  *              arithmetic.
 162  */
 163
 164 extern field *field_binpoly(mp */*p*/);
 165
 166 /*----- That's all, folks -------------------------------------------------*/
 167
 168 #ifdef __cplusplus
 169   }
 170 #endif
 171
 172 #endif