Commit | Line | Data |
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3688eb75 | 1 | /* -*-c-*- |
3688eb75 | 2 | * |
3 | * Abstraction for prime groups | |
4 | * | |
5 | * (c) 2004 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
3688eb75 | 9 | * |
10 | * This file is part of Catacomb. | |
11 | * | |
12 | * Catacomb is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
45c0fd36 | 16 | * |
3688eb75 | 17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU Library General Public License for more details. | |
45c0fd36 | 21 | * |
3688eb75 | 22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
28 | /*----- Header files ------------------------------------------------------*/ | |
29 | ||
30 | #include <mLib/sub.h> | |
31 | ||
32 | #include "mpmont.h" | |
33 | #include "pgen.h" | |
34 | ||
b919de21 | 35 | #define ge ge_bin |
3688eb75 | 36 | #include "group-guts.h" |
37 | ||
38 | /*----- Main code ---------------------------------------------------------*/ | |
39 | ||
40 | /* --- Group operations --- */ | |
41 | ||
42 | static void gdestroygroup(group *gg) { | |
43 | gctx_bin *g = (gctx_bin *)gg; | |
b919de21 | 44 | mp_drop(g->gen.x); mp_drop(g->g.r); mp_drop(g->g.h); |
3688eb75 | 45 | gfreduce_destroy(&g->r); |
46 | DESTROY(g); | |
47 | } | |
48 | ||
b919de21 MW |
49 | static ge_bin *gcreate(group *gg) { |
50 | gctx_bin *g = (gctx_bin *)gg; ge_bin *x = CREATE(ge_bin); | |
51 | x->x = MP_COPY(g->one.x); return (x); | |
52 | } | |
3688eb75 | 53 | |
b919de21 MW |
54 | static void gcopy(group *gg, ge_bin *d, ge_bin *x) |
55 | { mp *t = MP_COPY(x->x); MP_DROP(d->x); d->x = t; } | |
3688eb75 | 56 | |
b919de21 | 57 | static void gburn(group *gg, ge_bin *x) { x->x->f |= MP_BURN; } |
3688eb75 | 58 | |
b919de21 | 59 | static void gdestroy(group *gg, ge_bin *x) { MP_DROP(x->x); DESTROY(x); } |
3688eb75 | 60 | |
61 | static int gsamep(group *gg, group *hh) { | |
62 | gctx_bin *g = (gctx_bin *)gg, *h = (gctx_bin *)hh; | |
63 | return (MP_EQ(g->r.p, h->r.p)); | |
64 | } | |
65 | ||
b919de21 MW |
66 | static int geq(group *gg, ge_bin *x, ge_bin *y) |
67 | { return (MP_EQ(x->x, y->x)); } | |
3688eb75 | 68 | |
69 | static const char *gcheck(group *gg, grand *gr) { | |
70 | gctx_bin *g = (gctx_bin *)gg; int rc; mp *t, *tt; | |
71 | if (!gf_irreduciblep(g->r.p)) return ("p is not irreducible"); | |
72 | t = mp_mul(MP_NEW, g->g.r, g->g.h); t = mp_add(t, t, MP_ONE); | |
73 | tt = mp_lsl(MP_NEW, MP_ONE, g->g.nbits); | |
74 | rc = MP_EQ(t, tt); MP_DROP(t); MP_DROP(tt); | |
75 | if (!rc) return ("not a subgroup"); | |
76 | return (group_stdcheck(gg, gr)); | |
77 | } | |
78 | ||
b919de21 MW |
79 | static void gmul(group *gg, ge_bin *d, ge_bin *x, ge_bin *y) { |
80 | gctx_bin *g = (gctx_bin *)gg; mp *r = gf_mul(d->x, x->x, y->x); | |
81 | d->x = gfreduce_do(&g->r, r, r); | |
3688eb75 | 82 | } |
83 | ||
b919de21 MW |
84 | static void gsqr(group *gg, ge_bin *d, ge_bin *x) { |
85 | gctx_bin *g = (gctx_bin *)gg; mp *r = gf_sqr(d->x, x->x); | |
86 | d->x = gfreduce_do(&g->r, r, r); | |
3688eb75 | 87 | } |
88 | ||
b919de21 MW |
89 | static void ginv(group *gg, ge_bin *d, ge_bin *x) |
90 | { gctx_bin *g = (gctx_bin *)gg; d->x = gf_modinv(d->x, x->x, g->r.p); } | |
3688eb75 | 91 | |
b919de21 MW |
92 | static void gexp(group *gg, ge_bin *d, ge_bin *x, mp *n) { |
93 | gctx_bin *g = (gctx_bin *)gg; | |
94 | d->x = gfreduce_exp(&g->r, d->x, x->x, n); | |
95 | } | |
3688eb75 | 96 | |
b919de21 | 97 | static int gread(group *gg, ge_bin *d, const mptext_ops *ops, void *p) { |
3688eb75 | 98 | mp *t; if ((t = mp_read(MP_NEW, 0, ops, p)) == 0) return (-1); |
b919de21 | 99 | mp_drop(d->x); d->x = t; return (0); |
3688eb75 | 100 | } |
101 | ||
b919de21 | 102 | static int gwrite(group *gg, ge_bin *x, const mptext_ops *ops, void *p) { |
3688eb75 | 103 | int rc = -1; |
b919de21 | 104 | if (!ops->put("0x", 2, p) && !mp_write(x->x, 16, ops, p)) rc = 0; |
3688eb75 | 105 | return (rc); |
106 | } | |
107 | ||
b919de21 | 108 | static mp *gtoint(group *gg, mp *d, ge_bin *x) { return MP_COPY(x->x); } |
3688eb75 | 109 | |
b919de21 MW |
110 | static int gfromint(group *gg, ge_bin *d, mp *x) |
111 | { d->x = MP_COPY(x); return 0; } | |
3688eb75 | 112 | |
b919de21 MW |
113 | static int gtobuf(group *gg, buf *b, ge_bin *x) |
114 | { int rc = buf_putmp(b, x->x); return (rc); } | |
3688eb75 | 115 | |
b919de21 | 116 | static int gfrombuf(group *gg, buf *b, ge_bin *d) { |
3688eb75 | 117 | gctx_bin *g = (gctx_bin *)gg; mp *x; |
118 | if ((x = buf_getmp(b)) == 0) return (-1); | |
b919de21 | 119 | MP_DROP(d->x); d->x = gfreduce_do(&g->r, x, x); |
3688eb75 | 120 | return (0); |
121 | } | |
122 | ||
b919de21 MW |
123 | static int gtoraw(group *gg, buf *b, ge_bin *x) { |
124 | gctx_bin *g = (gctx_bin *)gg; octet *q; | |
3688eb75 | 125 | if ((q = buf_get(b, g->g.noctets)) == 0) return (-1); |
b919de21 | 126 | mp_storeb(x->x, q, g->g.noctets); return (0); |
3688eb75 | 127 | } |
128 | ||
b919de21 MW |
129 | static int gfromraw(group *gg, buf *b, ge_bin *d) { |
130 | gctx_bin *g = (gctx_bin *)gg; mp *x; octet *q; | |
3688eb75 | 131 | if ((q = buf_get(b, g->g.noctets)) == 0) return (-1); |
132 | x = mp_loadb(MP_NEW, q, g->g.noctets); | |
b919de21 | 133 | MP_DROP(d->x); d->x = gfreduce_do(&g->r, x, x); |
3688eb75 | 134 | return (0); |
135 | } | |
136 | ||
137 | /* --- @group_binary@ --- * | |
138 | * | |
139 | * Arguments: @const gbin_param *gb@ = group parameters | |
140 | * | |
141 | * Returns: A pointer to the group, or null. | |
142 | * | |
143 | * Use: Constructs an abstract group interface for a subgroup of a | |
144 | * prime field. Group elements are @mp *@ pointers. | |
145 | */ | |
146 | ||
147 | static const group_ops gops = { | |
148 | GTY_BINARY, "bin", | |
149 | gdestroygroup, gcreate, gcopy, gburn, gdestroy, | |
150 | gsamep, geq, group_stdidentp, | |
151 | gcheck, | |
152 | gmul, gsqr, ginv, group_stddiv, gexp, group_stdmexp, | |
153 | gread, gwrite, | |
154 | gtoint, gfromint, group_stdtoec, group_stdfromec, gtobuf, gfrombuf, | |
155 | gtoraw, gfromraw | |
156 | }; | |
157 | ||
158 | group *group_binary(const gbin_param *gb) | |
159 | { | |
160 | gctx_bin *g; | |
161 | mp *t; | |
162 | ||
163 | if (!MP_POSP(gb->p)) | |
164 | return (0); | |
165 | g = CREATE(gctx_bin); | |
166 | g->g.ops = &gops; | |
167 | g->g.nbits = mp_bits(gb->p) - 1; | |
168 | g->g.noctets = (g->g.nbits + 7) >> 3; | |
169 | gfreduce_create(&g->r, gb->p); | |
b919de21 | 170 | g->one.x = MP_ONE; |
3688eb75 | 171 | g->g.i = &g->one; |
b919de21 | 172 | g->gen.x = MP_COPY(gb->g); |
3688eb75 | 173 | g->g.g = &g->gen; |
174 | g->g.r = MP_COPY(gb->q); | |
175 | t = mp_lsl(MP_NEW, MP_ONE, g->g.nbits); | |
176 | t = mp_sub(t, t, MP_ONE); | |
177 | g->g.h = MP_NEW; mp_div(&g->g.h, 0, t, gb->q); | |
178 | MP_DROP(t); | |
179 | return (&g->g); | |
180 | } | |
181 | ||
182 | /*----- That's all, folks -------------------------------------------------*/ |