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

   1 /* -*-c-*-
   2  *
   3  * $Id: field.h,v 1.5 2004/03/23 12:08:26 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 1.5  2004/03/23 12:08:26  mdw
  34  * Random field-element selection.
  35  *
  36  * Revision 1.4  2004/03/21 22:52:06  mdw
  37  * Merge and close elliptic curve branch.
  38  *
  39  * Revision 1.3.4.2  2004/03/21 22:39:46  mdw
  40  * Elliptic curves on binary fields work.
  41  *
  42  * Revision 1.3.4.1  2004/03/20 00:13:31  mdw
  43  * Projective coordinates for prime curves
  44  *
  45  * Revision 1.3  2002/01/13 13:48:44  mdw
  46  * Further progress.
  47  *
  48  * Revision 1.2  2001/05/07 17:30:13  mdw
  49  * Add an internal-representation no-op function.
  50  *
  51  * Revision 1.1  2001/04/29 18:12:33  mdw
  52  * Prototype version.
  53  *
  54  */
  55
  56 #ifndef CATACOMB_FIELD_H
  57 #define CATACOMB_FIELD_H
  58
  59 #ifdef __cplusplus
  60   extern "C" {
  61 #endif
  62
  63 /*----- Header files ------------------------------------------------------*/
  64
  65 #ifndef CATACOMB_GRAND_H
  66 #  include "grand.h"
  67 #endif
  68
  69 #ifndef CATACOMB_MP_H
  70 #  include "mp.h"
  71 #endif
  72
  73 /*----- Data structures ---------------------------------------------------*/
  74
  75 typedef struct field {
  76   const struct field_ops *ops;          /* Field operations */
  77   mp *zero, *one;                       /* Identities in the field */
  78 } field;
  79
  80 typedef struct field_ops {
  81
  82   /* --- Universal operations --- */
  83
  84   void (*destroy)(field */*f*/);
  85   mp *(*rand)(field */*f*/, mp */*d*/, grand */*r*/);
  86
  87   mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/);
  88   mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/);
  89
  90   int (*zerop)(field */*f*/, mp */*x*/);
  91   mp *(*neg)(field */*f*/, mp */*d*/, mp */*x*/);
  92   mp *(*add)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  93   mp *(*sub)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  94   mp *(*mul)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
  95   mp *(*sqr)(field */*f*/, mp */*d*/, mp */*x*/);
  96   mp *(*inv)(field */*f*/, mp */*d*/, mp */*x*/);
  97   mp *(*reduce)(field */*f*/, mp */*d*/, mp */*x*/);
  98   mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/);
  99
 100   /* --- Operations for binary fields only --- */
 101
 102   mp *(*quadsolve)(field */*f*/, mp */*d*/, mp */*x*/);
 103
 104   /* --- Operations for prime fields only --- */
 105
 106   mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/);
 107   mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/);
 108   mp *(*qdl)(field */*f*/, mp */*d*/, mp */*x*/);
 109   mp *(*hlv)(field */*f*/, mp */*d*/, mp */*x*/);
 110
 111 } field_ops;
 112
 113 #define F_DESTROY(f)            (f)->ops->destroy((f))
 114
 115 #define F_IN(f, d, x)           (f)->ops->in((f), (d), (x))
 116 #define F_OUT(f, d, x)          (f)->ops->out((f), (d), (x))
 117
 118 #define F_ZEROP(f, x)           (f)->ops->zerop((f), (x))
 119 #define F_NEG(f, d, x)          (f)->ops->neg((f), (d), (x))
 120 #define F_ADD(f, d, x, y)       (f)->ops->add((f), (d), (x), (y))
 121 #define F_SUB(f, d, x, y)       (f)->ops->sub((f), (d), (x), (y))
 122 #define F_MUL(f, d, x, y)       (f)->ops->mul((f), (d), (x), (y))
 123 #define F_SQR(f, d, x)          (f)->ops->sqr((f), (d), (x))
 124 #define F_INV(f, d, x)          (f)->ops->inv((f), (d), (x))
 125 #define F_REDUCE(f, d, x)       (f)->ops->reduce((f), (d), (x))
 126 #define F_SQRT(f, d, x)         (f)->ops->sqrt((f), (d), (x))
 127
 128 #define F_QUADSOLVE(f, d, x)    (f)->ops->quadsolve((f), (d), (x))
 129
 130 #define F_DBL(f, d, x)          (f)->ops->dbl((f), (d), (x))
 131 #define F_TPL(f, d, x)          (f)->ops->tpl((f), (d), (x))
 132 #define F_QDL(f, d, x)          (f)->ops->qdl((f), (d), (x))
 133 #define F_HLV(f, d, x)          (f)->ops->hlv((f), (d), (x))
 134
 135 /*----- Helpful field operations ------------------------------------------*/
 136
 137 /* --- @field_id@ --- *
 138  *
 139  * Arguments:   @field *f@ = pointer to a field
 140  *              @mp *d@ = a destination element
 141  *              @mp *x@ = a source element
 142  *
 143  * Returns:     The result element.
 144  *
 145  * Use:         An identity operation which can be used if your field has no
 146  *              internal representation.
 147  */
 148
 149 extern mp *field_id(field */*f*/, mp */*d*/, mp */*x*/);
 150
 151 /*----- Creating fields ---------------------------------------------------*/
 152
 153 /* --- @field_prime@ --- *
 154  *
 155  * Arguments:   @mp *p@ = the characteristic of the field
 156  *
 157  * Returns:     A pointer to the field.
 158  *
 159  * Use:         Creates a field structure for a prime field of size %$p$%,
 160  *              using Montgomery reduction for arithmetic.
 161  */
 162
 163 extern field *field_prime(mp */*p*/);
 164
 165 /* --- @field_binpoly@ --- *
 166  *
 167  * Arguments:   @mp *p@ = an irreducible polynomial over %$\gf{2}$%
 168  *
 169  * Returns:     A pointer to the field.
 170  *
 171  * Use:         Creates a field structure for a binary field using naive
 172  *              arithmetic.
 173  */
 174
 175 extern field *field_binpoly(mp */*p*/);
 176
 177 /*----- That's all, folks -------------------------------------------------*/
 178
 179 #ifdef __cplusplus
 180   }
 181 #endif
 182
 183 #endif