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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: field.h,v 1.3 2002/01/13 13:48:44 mdw Exp $ |
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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 $ |
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33 | * Revision 1.3 2002/01/13 13:48:44 mdw |
34 | * Further progress. |
35 | * |
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36 | * Revision 1.2 2001/05/07 17:30:13 mdw |
37 | * Add an internal-representation no-op function. |
38 | * |
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39 | * Revision 1.1 2001/04/29 18:12:33 mdw |
40 | * Prototype version. |
41 | * |
42 | */ |
43 | |
44 | #ifndef CATACOMB_FIELD_H |
45 | #define CATACOMB_FIELD_H |
46 | |
47 | #ifdef __cplusplus |
48 | extern "C" { |
49 | #endif |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
53 | #ifndef CATACOMB_MP_H |
54 | # include "mp.h" |
55 | #endif |
56 | |
57 | /*----- Data structures ---------------------------------------------------*/ |
58 | |
59 | typedef struct field { |
60 | const struct field_ops *ops; /* Field operations */ |
61 | mp *zero, *one; /* Identities in the field */ |
62 | } field; |
63 | |
64 | typedef struct field_ops { |
65 | |
66 | /* --- Universal operations --- */ |
67 | |
68 | void (*destroy)(field */*f*/); |
69 | |
70 | mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/); |
71 | mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/); |
72 | |
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73 | mp *(*neg)(field */*f*/, mp */*d*/, mp */*x*/); |
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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*/); |
80 | |
81 | /* --- Operations for prime fields only --- */ |
82 | |
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*/); |
86 | |
87 | } field_ops; |
88 | |
89 | #define F_DESTROY(f) (f)->ops->destroy((f)) |
90 | |
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)) |
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93 | #define F_NEG(f, d, x) (f)->ops->neg((f), (d), (x)) |
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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)) |
100 | |
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)) |
104 | |
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105 | /*----- Helpful field operations ------------------------------------------*/ |
106 | |
107 | /* --- @field_id@ --- * |
108 | * |
109 | * Arguments: @field *f@ = pointer to a field |
110 | * @mp *d@ = a destination element |
111 | * @mp *x@ = a source element |
112 | * |
113 | * Returns: The result element. |
114 | * |
115 | * Use: An identity operation which can be used if your field has no |
116 | * internal representation. |
117 | */ |
118 | |
119 | extern mp *field_id(field */*f*/, mp */*d*/, mp */*x*/); |
120 | |
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121 | /*----- Creating fields ---------------------------------------------------*/ |
122 | |
123 | /* --- @field_prime@ --- * |
124 | * |
125 | * Arguments: @mp *p@ = the characteristic of the field |
126 | * |
127 | * Returns: A pointer to the field. |
128 | * |
129 | * Use: Creates a field structure for a prime field of size %$p$%, |
130 | * using Montgomery reduction for arithmetic. |
131 | */ |
132 | |
133 | extern field *field_prime(mp */*p*/); |
134 | |
135 | /* --- @field_binpoly@ --- * |
136 | * |
137 | * Arguments: @mp *p@ = an irreducible polynomial over %$\gf{2}$% |
138 | * |
139 | * Returns: A pointer to the field. |
140 | * |
141 | * Use: Creates a field structure for a binary field using naive |
142 | * arithmetic. |
143 | */ |
144 | |
145 | extern field *field_binpoly(mp */*p*/); |
146 | |
147 | /* --- @field_binsparsepoly@ --- * |
148 | * |
149 | * Arguments: @unsigned deg@ = the degree of the field polynomial |
150 | * @const unsigned *c@ = degrees of nonzero coefficients |
151 | * |
152 | * Returns: A pointer to the field. |
153 | * |
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. |
157 | */ |
158 | |
159 | extern field *field_binsparsepoly(unsigned /*deg*/, const unsigned */*c*/); |
160 | |
161 | /*----- That's all, folks -------------------------------------------------*/ |
162 | |
163 | #ifdef __cplusplus |
164 | } |
165 | #endif |
166 | |
167 | #endif |