3 * $Id: field.h,v 1.11 2004/04/08 01:36:15 mdw Exp $
5 * Definitions for field arithmetic
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 #ifndef CATACOMB_FIELD_H
31 #define CATACOMB_FIELD_H
37 /*----- Header files ------------------------------------------------------*/
39 #ifndef CATACOMB_GRAND_H
47 #ifndef CATACOMB_QDPARSE_H
51 /*----- Data structures ---------------------------------------------------*/
53 typedef struct field
{
54 const struct field_ops
*ops
; /* Field operations */
55 mp
*zero
, *one
; /* Identities in the field */
56 mp
*m
; /* Modulus (prime and binary) */
57 unsigned long nbits
; /* Length of field element in bits */
58 size_t noctets
; /* Length of element in octets */
66 typedef struct field_ops
{
68 /* --- General information --- */
70 unsigned ty
; /* What kind of field this is */
71 const char *name
; /* Human-readable name string */
73 /* --- Universal operations --- */
75 void (*destroy
)(field */
*f*/
);
76 mp
*(*rand
)(field */
*f*/
, mp */
*d*/
, grand */
*r*/
);
77 int (*samep
)(field */
*f*/
, field */
*g*/
);
79 mp
*(*in
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
80 mp
*(*out
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
82 int (*zerop
)(field */
*f*/
, mp */
*x*/
);
83 mp
*(*neg
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
84 mp
*(*add
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
, mp */
*y*/
);
85 mp
*(*sub
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
, mp */
*y*/
);
86 mp
*(*mul
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
, mp */
*y*/
);
87 mp
*(*sqr
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
88 mp
*(*inv
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
89 mp
*(*reduce
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
90 mp
*(*sqrt
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
92 /* --- Operations for binary fields only --- */
94 mp
*(*quadsolve
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
96 /* --- Operations for prime fields only --- */
98 mp
*(*dbl
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
99 mp
*(*tpl
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
100 mp
*(*qdl
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
101 mp
*(*hlv
)(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
105 #define F_TYPE(f) (f)->ops->ty
106 #define F_NAME(f) (f)->ops->name
108 #define F_DESTROY(f) (f)->ops->destroy((f))
109 #define F_RAND(f, d, r) (f)->ops->rand((f), (d), (r))
110 #define F_SAMEP(f, g) (f)->ops->samep((f), (g))
112 #define F_IN(f, d, x) (f)->ops->in((f), (d), (x))
113 #define F_OUT(f, d, x) (f)->ops->out((f), (d), (x))
115 #define F_ZEROP(f, x) (f)->ops->zerop((f), (x))
116 #define F_NEG(f, d, x) (f)->ops->neg((f), (d), (x))
117 #define F_ADD(f, d, x, y) (f)->ops->add((f), (d), (x), (y))
118 #define F_SUB(f, d, x, y) (f)->ops->sub((f), (d), (x), (y))
119 #define F_MUL(f, d, x, y) (f)->ops->mul((f), (d), (x), (y))
120 #define F_SQR(f, d, x) (f)->ops->sqr((f), (d), (x))
121 #define F_INV(f, d, x) (f)->ops->inv((f), (d), (x))
122 #define F_REDUCE(f, d, x) (f)->ops->reduce((f), (d), (x))
123 #define F_SQRT(f, d, x) (f)->ops->sqrt((f), (d), (x))
125 #define F_QUADSOLVE(f, d, x) (f)->ops->quadsolve((f), (d), (x))
127 #define F_DBL(f, d, x) (f)->ops->dbl((f), (d), (x))
128 #define F_TPL(f, d, x) (f)->ops->tpl((f), (d), (x))
129 #define F_QDL(f, d, x) (f)->ops->qdl((f), (d), (x))
130 #define F_HLV(f, d, x) (f)->ops->hlv((f), (d), (x))
132 /*----- Helpful field operations ------------------------------------------*/
134 /* --- @field_id@ --- *
136 * Arguments: @field *f@ = pointer to a field
137 * @mp *d@ = a destination element
138 * @mp *x@ = a source element
140 * Returns: The result element.
142 * Use: An identity operation which can be used if your field has no
143 * internal representation.
146 extern mp
*field_id(field */
*f*/
, mp */
*d*/
, mp */
*x*/
);
148 /* --- @field_samep@ --- *
150 * Arguments: @field *f, *g@ = two fields
152 * Returns: Nonzero if the fields are identical (not just isomorphic).
154 * Use: Checks for sameness of fields. This function does the full
155 * check, not just the field-type-specific check done by the
156 * @sampep@ field operation.
159 extern int field_samep(field */
*f*/
, field */
*g*/
);
161 /* --- @field_stdsamep@ --- *
163 * Arguments: @field *f, *g@ = two fields
165 * Returns: Nonzero if the fields are identical (not just isomorphic).
167 * Use: Standard sameness check, based on equality of the @m@
171 extern int field_stdsamep(field */
*f*/
, field */
*g*/
);
173 /*----- Creating fields ---------------------------------------------------*/
175 /* --- @field_prime@ --- *
177 * Arguments: @mp *p@ = the characteristic of the field
179 * Returns: A pointer to the field.
181 * Use: Creates a field structure for a prime field of size %$p$%,
182 * using Montgomery reduction for arithmetic.
185 extern field
*field_prime(mp */
*p*/
);
187 /* --- @field_niceprime@ --- *
189 * Arguments: @mp *p@ = the characteristic of the field
191 * Returns: A pointer to the field.
193 * Use: Creates a field structure for a prime field of size %$p$%,
194 * using efficient reduction for nice primes.
197 extern field
*field_niceprime(mp */
*p*/
);
199 /* --- @field_binpoly@ --- *
201 * Arguments: @mp *p@ = an irreducible polynomial over %$\gf{2}$%
203 * Returns: A pointer to the field.
205 * Use: Creates a field structure for a binary field using naive
209 extern field
*field_binpoly(mp */
*p*/
);
211 /* --- @field_binnorm@ --- *
213 * Arguments: @mp *p@ = the reduction polynomial
214 * @mp *beta@ = representation of normal point
216 * Returns: A pointer to the field.
218 * Use: Creates a field structure for a binary field mod @p@ which
219 * uses a normal basis representation externally. Computations
220 * are still done on a polynomial-basis representation.
223 extern field
*field_binnorm(mp */
*p*/
, mp */
*beta*/
);
225 /* --- @field_parse@ --- *
227 * Arguments: @qd_parse *qd@ = parser context
229 * Returns: Field pointer if OK, or null.
231 * Use: Parses a field description, which has the form
233 * * `prime', `niceprime', `binpoly', or `binnorm'
235 * * the field modulus
236 * * for `binnorm', an optional `,' and the beta value
239 extern field
*field_parse(qd_parse */
*qd*/
);
241 /*----- That's all, folks -------------------------------------------------*/