ceb3f0c0 |
1 | /* -*-c-*- |
2 | * |
a69a3efd |
3 | * $Id$ |
ceb3f0c0 |
4 | * |
5 | * Binary fields with polynomial basis representation |
6 | * |
7 | * (c) 2004 Straylight/Edgeware |
8 | */ |
9 | |
45c0fd36 |
10 | /*----- Licensing notice --------------------------------------------------* |
ceb3f0c0 |
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. |
45c0fd36 |
18 | * |
ceb3f0c0 |
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. |
45c0fd36 |
23 | * |
ceb3f0c0 |
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 | |
ceb3f0c0 |
30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <mLib/sub.h> |
33 | |
34 | #include "field.h" |
f94b972d |
35 | #include "field-guts.h" |
9b8b6877 |
36 | #include "mprand.h" |
ceb3f0c0 |
37 | |
4edc47b8 |
38 | /*----- Polynomial basis --------------------------------------------------*/ |
ceb3f0c0 |
39 | |
ceb3f0c0 |
40 | /* --- Field operations --- */ |
41 | |
f94b972d |
42 | static void fdestroy(field *ff) { |
43 | fctx_binpoly *f = (fctx_binpoly *)ff; |
1d7857e7 |
44 | gfreduce_destroy(&f->r); MP_DROP(f->f.q); |
f94b972d |
45 | DESTROY(f); |
46 | } |
ceb3f0c0 |
47 | |
f94b972d |
48 | static mp *frand(field *f, mp *d, grand *r) { |
49 | return (mprand(d, f->nbits, r, 0)); |
50 | } |
9b8b6877 |
51 | |
a69a3efd |
52 | static int fzerop(field *ff, mp *x) { return (MP_ZEROP(x)); } |
ceb3f0c0 |
53 | |
4edc47b8 |
54 | static mp *fadd(field *ff, mp *d, mp *x, mp *y) { return (gf_add(d, x, y)); } |
ceb3f0c0 |
55 | |
4edc47b8 |
56 | static mp *fmul(field *ff, mp *d, mp *x, mp *y) { |
f94b972d |
57 | fctx_binpoly *f = (fctx_binpoly *)ff; d = gf_mul(d, x, y); |
ceb3f0c0 |
58 | return (gfreduce_do(&f->r, d, d)); |
59 | } |
60 | |
4edc47b8 |
61 | static mp *fsqr(field *ff, mp *d, mp *x) { |
f94b972d |
62 | fctx_binpoly *f = (fctx_binpoly *)ff; d = gf_sqr(d, x); |
ceb3f0c0 |
63 | return (gfreduce_do(&f->r, d, d)); |
64 | } |
65 | |
f94b972d |
66 | static mp *finv(field *ff, mp *d, mp *x) { |
67 | fctx_binpoly *f = (fctx_binpoly *)ff; |
68 | d = gf_modinv(d, x, f->r.p); |
69 | return (d); |
70 | } |
ceb3f0c0 |
71 | |
f94b972d |
72 | static mp *freduce(field *ff, mp *d, mp *x) { |
73 | fctx_binpoly *f = (fctx_binpoly *)ff; |
74 | return (gfreduce_do(&f->r, d, x)); |
75 | } |
ceb3f0c0 |
76 | |
f94b972d |
77 | static mp *fsqrt(field *ff, mp *d, mp *x) { |
78 | fctx_binpoly *f = (fctx_binpoly *)ff; |
79 | return (gfreduce_sqrt(&f->r, d, x)); |
80 | } |
ceb3f0c0 |
81 | |
f94b972d |
82 | static mp *fquadsolve(field *ff, mp *d, mp *x) { |
83 | fctx_binpoly *f = (fctx_binpoly *)ff; |
84 | return (gfreduce_quadsolve(&f->r, d, x)); |
85 | } |
ceb3f0c0 |
86 | |
87 | /* --- Field operations table --- */ |
88 | |
4e66da02 |
89 | static const field_ops fops = { |
bc985cef |
90 | FTY_BINARY, "binpoly", |
34e4f738 |
91 | fdestroy, frand, field_stdsamep, |
ceb3f0c0 |
92 | freduce, field_id, |
93 | fzerop, field_id, fadd, fadd, fmul, fsqr, finv, freduce, fsqrt, |
94 | fquadsolve, |
95 | 0, 0, 0, 0 |
96 | }; |
97 | |
98 | /* --- @field_binpoly@ --- * |
99 | * |
100 | * Arguments: @mp *p@ = the reduction polynomial |
101 | * |
102 | * Returns: A pointer to the field. |
103 | * |
104 | * Use: Creates a field structure for a binary field mod @p@. |
105 | */ |
106 | |
107 | field *field_binpoly(mp *p) |
108 | { |
f94b972d |
109 | fctx_binpoly *f = CREATE(fctx_binpoly); |
ceb3f0c0 |
110 | f->f.ops = &fops; |
111 | f->f.zero = MP_ZERO; |
112 | f->f.one = MP_ONE; |
432c4e18 |
113 | f->f.nbits = mp_bits(p) - 1; |
114 | f->f.noctets = (f->f.nbits + 7) >> 3; |
ceb3f0c0 |
115 | gfreduce_create(&f->r, p); |
432c4e18 |
116 | f->f.m = f->r.p; |
1d7857e7 |
117 | f->f.q = mp_lsl(MP_NEW, MP_ONE, f->f.nbits); |
ceb3f0c0 |
118 | return (&f->f); |
119 | } |
120 | |
4edc47b8 |
121 | /*----- Normal basis ------------------------------------------------------*/ |
122 | |
4edc47b8 |
123 | /* --- Field operations --- */ |
124 | |
125 | static void fndestroy(field *ff) { |
f94b972d |
126 | fctx_binnorm *f = (fctx_binnorm *)ff; gfreduce_destroy(&f->f.r); |
1d7857e7 |
127 | gfn_destroy(&f->ntop); gfn_destroy(&f->pton); MP_DROP(f->f.f.q); |
4edc47b8 |
128 | DESTROY(f); |
129 | } |
130 | |
131 | static int fnsamep(field *ff, field *gg) { |
f94b972d |
132 | fctx_binnorm *f = (fctx_binnorm *)ff, *g = (fctx_binnorm *)gg; |
4edc47b8 |
133 | return (MP_EQ(f->ntop.r[0], g->ntop.r[0]) && field_stdsamep(ff, gg)); |
134 | } |
135 | |
f94b972d |
136 | static mp *fnin(field *ff, mp *d, mp *x) { |
137 | fctx_binnorm *f = (fctx_binnorm *)ff; |
138 | return (gfn_transform(&f->ntop, d, x)); |
139 | } |
4edc47b8 |
140 | |
f94b972d |
141 | static mp *fnout(field *ff, mp *d, mp *x) { |
142 | fctx_binnorm *f = (fctx_binnorm *)ff; |
143 | return (gfn_transform(&f->pton, d, x)); |
144 | } |
4edc47b8 |
145 | |
146 | /* --- Field operations table --- */ |
147 | |
4e66da02 |
148 | static const field_ops fnops = { |
4edc47b8 |
149 | FTY_BINARY, "binnorm", |
150 | fndestroy, frand, fnsamep, |
151 | fnin, fnout, |
152 | fzerop, field_id, fadd, fadd, fmul, fsqr, finv, freduce, fsqrt, |
153 | fquadsolve, |
154 | 0, 0, 0, 0 |
155 | }; |
156 | |
157 | /* --- @field_binnorm@ --- * |
158 | * |
159 | * Arguments: @mp *p@ = the reduction polynomial |
160 | * @mp *beta@ = representation of normal point |
161 | * |
162 | * Returns: A pointer to the field. |
163 | * |
164 | * Use: Creates a field structure for a binary field mod @p@ which |
165 | * uses a normal basis representation externally. Computations |
166 | * are still done on a polynomial-basis representation. |
167 | */ |
168 | |
169 | field *field_binnorm(mp *p, mp *beta) |
170 | { |
f94b972d |
171 | fctx_binnorm *f = CREATE(fctx_binnorm); |
4edc47b8 |
172 | f->f.f.ops = &fnops; |
173 | f->f.f.zero = MP_ZERO; |
174 | f->f.f.one = MP_ONE; |
175 | f->f.f.nbits = mp_bits(p) - 1; |
176 | f->f.f.noctets = (f->f.f.nbits + 7) >> 3; |
177 | gfreduce_create(&f->f.r, p); |
178 | f->f.f.m = f->f.r.p; |
1d7857e7 |
179 | f->f.f.q = mp_lsl(MP_NEW, MP_ONE, f->f.f.nbits); |
4edc47b8 |
180 | gfn_create(p, beta, &f->ntop, &f->pton); |
181 | return (&f->f.f); |
182 | } |
183 | |
ceb3f0c0 |
184 | /*----- That's all, folks -------------------------------------------------*/ |