3 * $Id: field.h,v 1.3 2002/01/13 13:48:44 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 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 2002/01/13 13:48:44 mdw
36 * Revision 1.2 2001/05/07 17:30:13 mdw
37 * Add an internal-representation no-op function.
39 * Revision 1.1 2001/04/29 18:12:33 mdw
44 #ifndef CATACOMB_FIELD_H
45 #define CATACOMB_FIELD_H
51 /*----- Header files ------------------------------------------------------*/
57 /*----- Data structures ---------------------------------------------------*/
59 typedef struct field {
60 const struct field_ops *ops; /* Field operations */
61 mp *zero, *one; /* Identities in the field */
64 typedef struct field_ops {
66 /* --- Universal operations --- */
68 void (*destroy)(field */*f*/);
70 mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/);
71 mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/);
73 mp *(*neg)(field */*f*/, mp */*d*/, mp */*x*/);
74 mp *(*add)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
75 mp *(*sub)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
76 mp *(*mul)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
77 mp *(*sqr)(field */*f*/, mp */*d*/, mp */*x*/);
78 mp *(*inv)(field */*f*/, mp */*d*/, mp */*x*/);
79 mp *(*reduce)(field */*f*/, mp */*d*/, mp */*x*/);
81 /* --- Operations for prime fields only --- */
83 mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/);
84 mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/);
85 mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/);
89 #define F_DESTROY(f) (f)->ops->destroy((f))
91 #define F_IN(f, d, x) (f)->ops->in((f), (d), (x))
92 #define F_OUT(f, d, x) (f)->ops->out((f), (d), (x))
93 #define F_NEG(f, d, x) (f)->ops->neg((f), (d), (x))
94 #define F_ADD(f, d, x, y) (f)->ops->add((f), (d), (x), (y))
95 #define F_SUB(f, d, x, y) (f)->ops->sub((f), (d), (x), (y))
96 #define F_MUL(f, d, x, y) (f)->ops->mul((f), (d), (x), (y))
97 #define F_SQR(f, d, x) (f)->ops->sqr((f), (d), (x))
98 #define F_INV(f, d, x) (f)->ops->inv((f), (d), (x))
99 #define F_REDUCE(f, d, x) (f)->ops->reduce((f), (d), (x))
101 #define F_DBL(f, d, x) (f)->ops->dbl((f), (d), (x))
102 #define F_TPL(f, d, x) (f)->ops->tpl((f), (d), (x))
103 #define F_SQRT(f, d, x) (f)->ops->sqrt((f), (d), (x))
105 /*----- Helpful field operations ------------------------------------------*/
107 /* --- @field_id@ --- *
109 * Arguments: @field *f@ = pointer to a field
110 * @mp *d@ = a destination element
111 * @mp *x@ = a source element
113 * Returns: The result element.
115 * Use: An identity operation which can be used if your field has no
116 * internal representation.
119 extern mp *field_id(field */*f*/, mp */*d*/, mp */*x*/);
121 /*----- Creating fields ---------------------------------------------------*/
123 /* --- @field_prime@ --- *
125 * Arguments: @mp *p@ = the characteristic of the field
127 * Returns: A pointer to the field.
129 * Use: Creates a field structure for a prime field of size %$p$%,
130 * using Montgomery reduction for arithmetic.
133 extern field *field_prime(mp */*p*/);
135 /* --- @field_binpoly@ --- *
137 * Arguments: @mp *p@ = an irreducible polynomial over %$\gf{2}$%
139 * Returns: A pointer to the field.
141 * Use: Creates a field structure for a binary field using naive
145 extern field *field_binpoly(mp */*p*/);
147 /* --- @field_binsparsepoly@ --- *
149 * Arguments: @unsigned deg@ = the degree of the field polynomial
150 * @const unsigned *c@ = degrees of nonzero coefficients
152 * Returns: A pointer to the field.
154 * Use: Creates a field structure for a binary field taking advantage
155 * of the sparseness of the given polynomial to improve
156 * reduction performance.
159 extern field *field_binsparsepoly(unsigned /*deg*/, const unsigned */*c*/);
161 /*----- That's all, folks -------------------------------------------------*/