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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: f-binpoly.c,v 1.3 2004/03/23 12:08:26 mdw Exp $ |
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4 | * |
5 | * Binary fields with polynomial basis representation |
6 | * |
7 | * (c) 2004 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: f-binpoly.c,v $ |
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33 | * Revision 1.3 2004/03/23 12:08:26 mdw |
34 | * Random field-element selection. |
35 | * |
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36 | * Revision 1.2 2004/03/21 22:52:06 mdw |
37 | * Merge and close elliptic curve branch. |
38 | * |
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39 | * Revision 1.1.2.1 2004/03/21 22:39:46 mdw |
40 | * Elliptic curves on binary fields work. |
41 | * |
42 | */ |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include <mLib/sub.h> |
47 | |
48 | #include "field.h" |
49 | #include "gf.h" |
50 | #include "gfreduce.h" |
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51 | #include "mprand.h" |
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52 | |
53 | /*----- Data structures ---------------------------------------------------*/ |
54 | |
55 | typedef struct fctx { |
56 | field f; |
57 | gfreduce r; |
58 | } fctx; |
59 | |
60 | /*----- Main code ---------------------------------------------------------*/ |
61 | |
62 | /* --- Field operations --- */ |
63 | |
64 | static void fdestroy(field *ff) |
65 | { |
66 | fctx *f = (fctx *)ff; |
67 | gfreduce_destroy(&f->r); |
68 | DESTROY(f); |
69 | } |
70 | |
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71 | static mp *frand(field *ff, grand *r, mp *d) |
72 | { |
73 | fctx *f = (fctx *)ff; |
74 | return (mprand(d, mp_octets(f->r.p) - 1, r, 0)); |
75 | } |
76 | |
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77 | static int fzerop(field *ff, mp *x) |
78 | { |
79 | return (!MP_LEN(x)); |
80 | } |
81 | |
82 | static mp *fadd(field *ff, mp *d, mp *x, mp *y) |
83 | { |
84 | return (gf_add(d, x, y)); |
85 | } |
86 | |
87 | static mp *fmul(field *ff, mp *d, mp *x, mp *y) |
88 | { |
89 | fctx *f = (fctx *)ff; |
90 | d = gf_mul(d, x, y); |
91 | return (gfreduce_do(&f->r, d, d)); |
92 | } |
93 | |
94 | static mp *fsqr(field *ff, mp *d, mp *x) |
95 | { |
96 | fctx *f = (fctx *)ff; |
97 | d = gf_sqr(d, x); |
98 | return (gfreduce_do(&f->r, d, d)); |
99 | } |
100 | |
101 | static mp *finv(field *ff, mp *d, mp *x) |
102 | { |
103 | fctx *f = (fctx *)ff; |
104 | gf_gcd(0, 0, &d, f->r.p, x); |
105 | return (d); |
106 | } |
107 | |
108 | static mp *freduce(field *ff, mp *d, mp *x) |
109 | { |
110 | fctx *f = (fctx *)ff; |
111 | return (gfreduce_do(&f->r, d, x)); |
112 | } |
113 | |
114 | static mp *fsqrt(field *ff, mp *d, mp *x) |
115 | { |
116 | fctx *f = (fctx *)ff; |
117 | return (gfreduce_sqrt(&f->r, d, x)); |
118 | } |
119 | |
120 | static mp *fquadsolve(field *ff, mp *d, mp *x) |
121 | { |
122 | fctx *f = (fctx *)ff; |
123 | return (gfreduce_quadsolve(&f->r, d, x)); |
124 | } |
125 | |
126 | /* --- Field operations table --- */ |
127 | |
128 | static field_ops fops = { |
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129 | fdestroy, frand, |
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130 | freduce, field_id, |
131 | fzerop, field_id, fadd, fadd, fmul, fsqr, finv, freduce, fsqrt, |
132 | fquadsolve, |
133 | 0, 0, 0, 0 |
134 | }; |
135 | |
136 | /* --- @field_binpoly@ --- * |
137 | * |
138 | * Arguments: @mp *p@ = the reduction polynomial |
139 | * |
140 | * Returns: A pointer to the field. |
141 | * |
142 | * Use: Creates a field structure for a binary field mod @p@. |
143 | */ |
144 | |
145 | field *field_binpoly(mp *p) |
146 | { |
147 | fctx *f = CREATE(fctx); |
148 | f->f.ops = &fops; |
149 | f->f.zero = MP_ZERO; |
150 | f->f.one = MP_ONE; |
151 | gfreduce_create(&f->r, p); |
152 | return (&f->f); |
153 | } |
154 | |
155 | /*----- That's all, folks -------------------------------------------------*/ |