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 | |
35 | #define ge mp * |
36 | #include "group.h" |
37 | #include "group-guts.h" |
38 | |
39 | /*----- Main code ---------------------------------------------------------*/ |
40 | |
41 | /* --- Group operations --- */ |
42 | |
43 | static void gdestroygroup(group *gg) { |
44 | gctx_bin *g = (gctx_bin *)gg; |
45 | mp_drop(g->gen); mp_drop(g->g.r); mp_drop(g->g.h); |
46 | gfreduce_destroy(&g->r); |
47 | DESTROY(g); |
48 | } |
49 | |
50 | static mp **gcreate(group *gg) |
51 | { mp **x = CREATE(mp *); *x = MP_COPY(*gg->i); return (x); } |
52 | |
53 | static void gcopy(group *gg, mp **d, mp **x) |
54 | { mp *t = MP_COPY(*x); MP_DROP(*d); *d = t; } |
55 | |
56 | static void gburn(group *gg, mp **x) { (*x)->f |= MP_BURN; } |
57 | |
58 | static void gdestroy(group *gg, mp **x) { MP_DROP(*x); DESTROY(x); } |
59 | |
60 | static int gsamep(group *gg, group *hh) { |
61 | gctx_bin *g = (gctx_bin *)gg, *h = (gctx_bin *)hh; |
62 | return (MP_EQ(g->r.p, h->r.p)); |
63 | } |
64 | |
65 | static int geq(group *gg, mp **x, mp **y) { return (MP_EQ(*x, *y)); } |
66 | |
67 | static const char *gcheck(group *gg, grand *gr) { |
68 | gctx_bin *g = (gctx_bin *)gg; int rc; mp *t, *tt; |
69 | if (!gf_irreduciblep(g->r.p)) return ("p is not irreducible"); |
70 | t = mp_mul(MP_NEW, g->g.r, g->g.h); t = mp_add(t, t, MP_ONE); |
71 | tt = mp_lsl(MP_NEW, MP_ONE, g->g.nbits); |
72 | rc = MP_EQ(t, tt); MP_DROP(t); MP_DROP(tt); |
73 | if (!rc) return ("not a subgroup"); |
74 | return (group_stdcheck(gg, gr)); |
75 | } |
76 | |
77 | static void gmul(group *gg, mp **d, mp **x, mp **y) { |
78 | gctx_bin *g = (gctx_bin *)gg; mp *r = gf_mul(*d, *x, *y); |
79 | *d = gfreduce_do(&g->r, r, r); |
80 | } |
81 | |
82 | static void gsqr(group *gg, mp **d, mp **x) { |
83 | gctx_bin *g = (gctx_bin *)gg; mp *r = gf_sqr(*d, *x); |
84 | *d = gfreduce_do(&g->r, r, r); |
85 | } |
86 | |
87 | static void ginv(group *gg, mp **d, mp **x) |
88 | { gctx_bin *g = (gctx_bin *)gg; *d = gf_modinv(*d, *x, g->r.p); } |
89 | |
90 | static void gexp(group *gg, mp **d, mp **x, mp *n) |
91 | { gctx_bin *g = (gctx_bin *)gg; *d = gfreduce_exp(&g->r, *d, *x, n); } |
92 | |
93 | static int gread(group *gg, mp **d, const mptext_ops *ops, void *p) { |
94 | mp *t; if ((t = mp_read(MP_NEW, 0, ops, p)) == 0) return (-1); |
95 | mp_drop(*d); *d = t; return (0); |
96 | } |
97 | |
98 | static int gwrite(group *gg, mp **x, const mptext_ops *ops, void *p) { |
99 | int rc = -1; |
100 | if (!ops->put("0x", 2, p) && !mp_write(*x, 16, ops, p)) rc = 0; |
101 | return (rc); |
102 | } |
103 | |
104 | static mp *gtoint(group *gg, mp *d, mp **x) { return MP_COPY(*x); } |
105 | |
106 | static int gfromint(group *gg, mp **d, mp *x) { *d = MP_COPY(x); return 0; } |
107 | |
108 | static int gtobuf(group *gg, buf *b, mp **x) |
109 | { int rc = buf_putmp(b, *x); return (rc); } |
110 | |
111 | static int gfrombuf(group *gg, buf *b, mp **d) { |
112 | gctx_bin *g = (gctx_bin *)gg; mp *x; |
113 | if ((x = buf_getmp(b)) == 0) return (-1); |
114 | MP_DROP(*d); *d = gfreduce_do(&g->r, x, x); |
115 | return (0); |
116 | } |
117 | |
118 | static int gtoraw(group *gg, buf *b, mp **x) { |
119 | gctx_bin * g = (gctx_bin *)gg; octet *q; |
120 | if ((q = buf_get(b, g->g.noctets)) == 0) return (-1); |
121 | mp_storeb(*x, q, g->g.noctets); return (0); |
122 | } |
123 | |
124 | static int gfromraw(group *gg, buf *b, mp **d) { |
125 | gctx_bin * g = (gctx_bin *)gg; mp *x; octet *q; |
126 | if ((q = buf_get(b, g->g.noctets)) == 0) return (-1); |
127 | x = mp_loadb(MP_NEW, q, g->g.noctets); |
128 | MP_DROP(*d); *d = gfreduce_do(&g->r, x, x); |
129 | return (0); |
130 | } |
131 | |
132 | /* --- @group_binary@ --- * |
133 | * |
134 | * Arguments: @const gbin_param *gb@ = group parameters |
135 | * |
136 | * Returns: A pointer to the group, or null. |
137 | * |
138 | * Use: Constructs an abstract group interface for a subgroup of a |
139 | * prime field. Group elements are @mp *@ pointers. |
140 | */ |
141 | |
142 | static const group_ops gops = { |
143 | GTY_BINARY, "bin", |
144 | gdestroygroup, gcreate, gcopy, gburn, gdestroy, |
145 | gsamep, geq, group_stdidentp, |
146 | gcheck, |
147 | gmul, gsqr, ginv, group_stddiv, gexp, group_stdmexp, |
148 | gread, gwrite, |
149 | gtoint, gfromint, group_stdtoec, group_stdfromec, gtobuf, gfrombuf, |
150 | gtoraw, gfromraw |
151 | }; |
152 | |
153 | group *group_binary(const gbin_param *gb) |
154 | { |
155 | gctx_bin *g; |
156 | mp *t; |
157 | |
158 | if (!MP_POSP(gb->p)) |
159 | return (0); |
160 | g = CREATE(gctx_bin); |
161 | g->g.ops = &gops; |
162 | g->g.nbits = mp_bits(gb->p) - 1; |
163 | g->g.noctets = (g->g.nbits + 7) >> 3; |
164 | gfreduce_create(&g->r, gb->p); |
165 | g->one = MP_ONE; |
166 | g->g.i = &g->one; |
167 | g->gen = MP_COPY(gb->g); |
168 | g->g.g = &g->gen; |
169 | g->g.r = MP_COPY(gb->q); |
170 | t = mp_lsl(MP_NEW, MP_ONE, g->g.nbits); |
171 | t = mp_sub(t, t, MP_ONE); |
172 | g->g.h = MP_NEW; mp_div(&g->g.h, 0, t, gb->q); |
173 | MP_DROP(t); |
174 | return (&g->g); |
175 | } |
176 | |
177 | /*----- That's all, folks -------------------------------------------------*/ |