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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: field.h,v 1.11 2004/04/08 01:36:15 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 | |
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30 | #ifndef CATACOMB_FIELD_H |
31 | #define CATACOMB_FIELD_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
9b8b6877 |
39 | #ifndef CATACOMB_GRAND_H |
40 | # include "grand.h" |
41 | #endif |
42 | |
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43 | #ifndef CATACOMB_MP_H |
44 | # include "mp.h" |
45 | #endif |
46 | |
432c4e18 |
47 | #ifndef CATACOMB_QDPARSE_H |
48 | # include "qdparse.h" |
49 | #endif |
50 | |
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51 | /*----- Data structures ---------------------------------------------------*/ |
52 | |
53 | typedef struct field { |
54 | const struct field_ops *ops; /* Field operations */ |
55 | mp *zero, *one; /* Identities in the field */ |
432c4e18 |
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 */ |
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59 | } field; |
60 | |
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61 | enum { |
62 | FTY_PRIME, |
63 | FTY_BINARY |
64 | }; |
65 | |
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66 | typedef struct field_ops { |
67 | |
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68 | /* --- General information --- */ |
69 | |
70 | unsigned ty; /* What kind of field this is */ |
71 | const char *name; /* Human-readable name string */ |
72 | |
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73 | /* --- Universal operations --- */ |
74 | |
75 | void (*destroy)(field */*f*/); |
9b8b6877 |
76 | mp *(*rand)(field */*f*/, mp */*d*/, grand */*r*/); |
34e4f738 |
77 | int (*samep)(field */*f*/, field */*g*/); |
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78 | |
79 | mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/); |
80 | mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/); |
81 | |
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82 | int (*zerop)(field */*f*/, mp */*x*/); |
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83 | mp *(*neg)(field */*f*/, mp */*d*/, mp */*x*/); |
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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*/); |
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90 | mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/); |
91 | |
92 | /* --- Operations for binary fields only --- */ |
93 | |
94 | mp *(*quadsolve)(field */*f*/, mp */*d*/, mp */*x*/); |
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95 | |
96 | /* --- Operations for prime fields only --- */ |
97 | |
98 | mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/); |
99 | mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/); |
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100 | mp *(*qdl)(field */*f*/, mp */*d*/, mp */*x*/); |
101 | mp *(*hlv)(field */*f*/, mp */*d*/, mp */*x*/); |
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102 | |
103 | } field_ops; |
104 | |
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105 | #define F_TYPE(f) (f)->ops->ty |
106 | #define F_NAME(f) (f)->ops->name |
107 | |
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108 | #define F_DESTROY(f) (f)->ops->destroy((f)) |
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109 | #define F_RAND(f, d, r) (f)->ops->rand((f), (d), (r)) |
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110 | #define F_SAMEP(f, g) (f)->ops->samep((f), (g)) |
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111 | |
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)) |
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114 | |
115 | #define F_ZEROP(f, x) (f)->ops->zerop((f), (x)) |
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116 | #define F_NEG(f, d, x) (f)->ops->neg((f), (d), (x)) |
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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)) |
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123 | #define F_SQRT(f, d, x) (f)->ops->sqrt((f), (d), (x)) |
124 | |
125 | #define F_QUADSOLVE(f, d, x) (f)->ops->quadsolve((f), (d), (x)) |
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126 | |
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)) |
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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)) |
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131 | |
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132 | /*----- Helpful field operations ------------------------------------------*/ |
133 | |
134 | /* --- @field_id@ --- * |
135 | * |
136 | * Arguments: @field *f@ = pointer to a field |
137 | * @mp *d@ = a destination element |
138 | * @mp *x@ = a source element |
139 | * |
140 | * Returns: The result element. |
141 | * |
142 | * Use: An identity operation which can be used if your field has no |
143 | * internal representation. |
144 | */ |
145 | |
146 | extern mp *field_id(field */*f*/, mp */*d*/, mp */*x*/); |
147 | |
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148 | /* --- @field_samep@ --- * |
149 | * |
150 | * Arguments: @field *f, *g@ = two fields |
151 | * |
152 | * Returns: Nonzero if the fields are identical (not just isomorphic). |
153 | * |
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. |
157 | */ |
158 | |
159 | extern int field_samep(field */*f*/, field */*g*/); |
160 | |
161 | /* --- @field_stdsamep@ --- * |
162 | * |
163 | * Arguments: @field *f, *g@ = two fields |
164 | * |
165 | * Returns: Nonzero if the fields are identical (not just isomorphic). |
166 | * |
167 | * Use: Standard sameness check, based on equality of the @m@ |
168 | * member. |
169 | */ |
170 | |
171 | extern int field_stdsamep(field */*f*/, field */*g*/); |
172 | |
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173 | /*----- Creating fields ---------------------------------------------------*/ |
174 | |
175 | /* --- @field_prime@ --- * |
176 | * |
177 | * Arguments: @mp *p@ = the characteristic of the field |
178 | * |
179 | * Returns: A pointer to the field. |
180 | * |
181 | * Use: Creates a field structure for a prime field of size %$p$%, |
182 | * using Montgomery reduction for arithmetic. |
183 | */ |
184 | |
185 | extern field *field_prime(mp */*p*/); |
186 | |
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187 | /* --- @field_niceprime@ --- * |
188 | * |
189 | * Arguments: @mp *p@ = the characteristic of the field |
190 | * |
191 | * Returns: A pointer to the field. |
192 | * |
193 | * Use: Creates a field structure for a prime field of size %$p$%, |
194 | * using efficient reduction for nice primes. |
195 | */ |
196 | |
197 | extern field *field_niceprime(mp */*p*/); |
198 | |
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199 | /* --- @field_binpoly@ --- * |
200 | * |
201 | * Arguments: @mp *p@ = an irreducible polynomial over %$\gf{2}$% |
202 | * |
203 | * Returns: A pointer to the field. |
204 | * |
205 | * Use: Creates a field structure for a binary field using naive |
206 | * arithmetic. |
207 | */ |
208 | |
209 | extern field *field_binpoly(mp */*p*/); |
210 | |
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211 | /* --- @field_binnorm@ --- * |
212 | * |
213 | * Arguments: @mp *p@ = the reduction polynomial |
214 | * @mp *beta@ = representation of normal point |
215 | * |
216 | * Returns: A pointer to the field. |
217 | * |
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. |
221 | */ |
222 | |
223 | extern field *field_binnorm(mp */*p*/, mp */*beta*/); |
224 | |
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225 | /* --- @field_parse@ --- * |
226 | * |
227 | * Arguments: @qd_parse *qd@ = parser context |
228 | * |
229 | * Returns: Field pointer if OK, or null. |
230 | * |
231 | * Use: Parses a field description, which has the form |
232 | * |
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233 | * * `prime', `niceprime', `binpoly', or `binnorm' |
432c4e18 |
234 | * * an optional `:' |
235 | * * the field modulus |
4edc47b8 |
236 | * * for `binnorm', an optional `,' and the beta value |
432c4e18 |
237 | */ |
238 | |
239 | extern field *field_parse(qd_parse */*qd*/); |
240 | |
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241 | /*----- That's all, folks -------------------------------------------------*/ |
242 | |
243 | #ifdef __cplusplus |
244 | } |
245 | #endif |
246 | |
247 | #endif |