Commit | Line | Data |
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34e4f738 | 1 | /* -*-c-*- |
2 | * | |
34e4f738 | 3 | * Abstraction for prime groups |
4 | * | |
5 | * (c) 2004 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
34e4f738 | 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 | * |
34e4f738 | 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 | * |
34e4f738 | 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 | ||
34e4f738 | 28 | /*----- Header files ------------------------------------------------------*/ |
29 | ||
30 | #include <mLib/sub.h> | |
31 | ||
32 | #include "mpmont.h" | |
33 | #include "pgen.h" | |
34 | ||
b919de21 | 35 | #define ge ge_prime |
f94b972d | 36 | #include "group-guts.h" |
34e4f738 | 37 | |
38 | /*----- Main code ---------------------------------------------------------*/ | |
39 | ||
40 | /* --- Group operations --- */ | |
41 | ||
42 | static void gdestroygroup(group *gg) { | |
f94b972d | 43 | gctx_prime *g = (gctx_prime *)gg; |
b919de21 | 44 | mp_drop(g->gen.x); mp_drop(g->g.r); mp_drop(g->g.h); |
34e4f738 | 45 | mpmont_destroy(&g->mm); |
46 | DESTROY(g); | |
47 | } | |
48 | ||
b919de21 MW |
49 | static ge_prime *gcreate(group *gg) { |
50 | gctx_prime *g = (gctx_prime *)gg; ge_prime *x = CREATE(ge_prime); | |
51 | x->x = MP_COPY(g->i.x); return (x); | |
52 | } | |
34e4f738 | 53 | |
b919de21 MW |
54 | static void gcopy(group *gg, ge_prime *d, ge_prime *x) |
55 | { mp *t = MP_COPY(x->x); MP_DROP(d->x); d->x = t; } | |
34e4f738 | 56 | |
b919de21 | 57 | static void gburn(group *gg, ge_prime *x) { x->x->f |= MP_BURN; } |
34e4f738 | 58 | |
b919de21 | 59 | static void gdestroy(group *gg, ge_prime *x) { MP_DROP(x->x); DESTROY(x); } |
34e4f738 | 60 | |
02d7884d | 61 | static int gsamep(group *gg, group *hh) { |
f94b972d | 62 | gctx_prime *g = (gctx_prime *)gg, *h = (gctx_prime *)hh; |
02d7884d | 63 | return (MP_EQ(g->mm.m, h->mm.m)); |
64 | } | |
34e4f738 | 65 | |
b919de21 MW |
66 | static int geq(group *gg, ge_prime *x, ge_prime *y) |
67 | { return (MP_EQ(x->x, y->x)); } | |
34e4f738 | 68 | |
69 | static const char *gcheck(group *gg, grand *gr) { | |
f94b972d | 70 | gctx_prime *g = (gctx_prime *)gg; int rc; mp *t; |
34e4f738 | 71 | if (!pgen_primep(g->mm.m, gr)) return ("p is not prime"); |
72 | t = mp_mul(MP_NEW, g->g.r, g->g.h); t = mp_add(t, t, MP_ONE); | |
73 | rc = MP_EQ(t, g->mm.m); MP_DROP(t); if (!rc) return ("not a subgroup"); | |
74 | return (group_stdcheck(gg, gr)); | |
75 | } | |
76 | ||
b919de21 MW |
77 | static void gmul(group *gg, ge_prime *d, ge_prime *x, ge_prime *y) { |
78 | gctx_prime *g = (gctx_prime *)gg; | |
79 | d->x = mpmont_mul(&g->mm, d->x, x->x, y->x); | |
80 | } | |
34e4f738 | 81 | |
b919de21 MW |
82 | static void gsqr(group *gg, ge_prime *d, ge_prime *x) { |
83 | gctx_prime *g = (gctx_prime *)gg; mp *r = mp_sqr(d->x, x->x); | |
84 | d->x = mpmont_reduce(&g->mm, r, r); | |
34e4f738 | 85 | } |
86 | ||
b919de21 MW |
87 | static void ginv(group *gg, ge_prime *d, ge_prime *x) { |
88 | gctx_prime *g = (gctx_prime *)gg; | |
89 | mp *r = mpmont_reduce(&g->mm, d->x, x->x); | |
90 | r = mp_modinv(r, r, g->mm.m); d->x = mpmont_mul(&g->mm, r, r, g->mm.r2); | |
34e4f738 | 91 | } |
92 | ||
b919de21 MW |
93 | static void gexp(group *gg, ge_prime *d, ge_prime *x, mp *n) |
94 | { | |
95 | gctx_prime *g = (gctx_prime *)gg; | |
96 | d->x = mpmont_expr(&g->mm, d->x, x->x, n); | |
97 | } | |
34e4f738 | 98 | |
b919de21 MW |
99 | static void gmexp(group *gg, ge_prime *d, const group_expfactor *f, size_t n) |
100 | { | |
f94b972d | 101 | gctx_prime *g = (gctx_prime *)gg; size_t i; |
34e4f738 | 102 | mp_expfactor *ff = xmalloc(n * sizeof(mp_expfactor)); |
b919de21 MW |
103 | for (i = 0; i < n; i++) |
104 | { ff[i].base = f[i].base->x; ff[i].exp = f[i].exp; } | |
105 | d->x = mpmont_mexpr(&g->mm, d->x, ff, n); xfree(ff); | |
34e4f738 | 106 | } |
107 | ||
b919de21 | 108 | static int gread(group *gg, ge_prime *d, const mptext_ops *ops, void *p) { |
f94b972d | 109 | gctx_prime *g = (gctx_prime *)gg; mp *t; |
34e4f738 | 110 | if ((t = mp_read(MP_NEW, 0, ops, p)) == 0) return (-1); |
b919de21 | 111 | mp_drop(d->x); d->x = mpmont_mul(&g->mm, t, t, g->mm.r2); return (0); |
34e4f738 | 112 | } |
113 | ||
b919de21 | 114 | static int gwrite(group *gg, ge_prime *x, const mptext_ops *ops, void *p) { |
f94b972d | 115 | gctx_prime *g = (gctx_prime *)gg; |
b919de21 | 116 | mp *t = mpmont_reduce(&g->mm, MP_NEW, x->x); |
34e4f738 | 117 | int rc = mp_write(t, 10, ops, p); MP_DROP(t); return (rc); |
118 | } | |
119 | ||
b919de21 | 120 | static mp *gtoint(group *gg, mp *d, ge_prime *x) { |
f94b972d | 121 | gctx_prime *g = (gctx_prime *)gg; |
b919de21 | 122 | return (mpmont_reduce(&g->mm, d, x->x)); |
f94b972d | 123 | } |
34e4f738 | 124 | |
b919de21 MW |
125 | static int gfromint(group *gg, ge_prime *d, mp *x) { |
126 | gctx_prime *g = (gctx_prime *)gg; mp_div(0, &d->x, x, g->mm.m); | |
127 | d->x = mpmont_mul(&g->mm, d->x, d->x, g->mm.r2); return (0); | |
34e4f738 | 128 | } |
129 | ||
b919de21 | 130 | static int gtobuf(group *gg, buf *b, ge_prime *x) { |
f94b972d | 131 | gctx_prime *g = (gctx_prime *)gg; |
b919de21 | 132 | mp *t = mpmont_reduce(&g->mm, MP_NEW, x->x); |
34e4f738 | 133 | int rc = buf_putmp(b, t); MP_DROP(t); return (rc); |
134 | } | |
135 | ||
b919de21 | 136 | static int gfrombuf(group *gg, buf *b, ge_prime *d) { |
f94b972d | 137 | gctx_prime * g = (gctx_prime *)gg; mp *x; |
138 | if ((x = buf_getmp(b)) == 0) return (-1); | |
b919de21 MW |
139 | mp_div(0, &x, x, g->mm.m); mp_drop(d->x); |
140 | d->x = mpmont_mul(&g->mm, x, x, g->mm.r2); return(0); | |
34e4f738 | 141 | } |
142 | ||
b919de21 | 143 | static int gtoraw(group *gg, buf *b, ge_prime *x) { |
f94b972d | 144 | gctx_prime *g = (gctx_prime *)gg; octet *q; |
b919de21 | 145 | mp *t = mpmont_reduce(&g->mm, MP_NEW, x->x); |
0f3faccd | 146 | if ((q = buf_get(b, g->g.noctets)) == 0) { MP_DROP(t); return (-1); } |
147 | mp_storeb(t, q, g->g.noctets); MP_DROP(t); return (0); | |
148 | } | |
149 | ||
b919de21 | 150 | static int gfromraw(group *gg, buf *b, ge_prime *d) { |
f94b972d | 151 | gctx_prime * g = (gctx_prime *)gg; mp *x; octet *q; |
0f3faccd | 152 | if ((q = buf_get(b, g->g.noctets)) == 0) return (-1); |
153 | x = mp_loadb(MP_NEW, q, g->g.noctets); | |
b919de21 MW |
154 | mp_div(0, &x, x, g->mm.m); mp_drop(d->x); |
155 | d->x = mpmont_mul(&g->mm, x, x, g->mm.r2); return(0); | |
0f3faccd | 156 | } |
157 | ||
34e4f738 | 158 | /* --- @group_prime@ --- * |
159 | * | |
160 | * Arguments: @const gprime_param *gp@ = group parameters | |
161 | * | |
02d7884d | 162 | * Returns: A pointer to the group, or null. |
34e4f738 | 163 | * |
164 | * Use: Constructs an abstract group interface for a subgroup of a | |
165 | * prime field. Group elements are @mp *@ pointers. | |
166 | */ | |
167 | ||
168 | static const group_ops gops = { | |
f94b972d | 169 | GTY_PRIME, "prime", |
34e4f738 | 170 | gdestroygroup, gcreate, gcopy, gburn, gdestroy, |
171 | gsamep, geq, group_stdidentp, | |
172 | gcheck, | |
173 | gmul, gsqr, ginv, group_stddiv, gexp, gmexp, | |
174 | gread, gwrite, | |
0f3faccd | 175 | gtoint, gfromint, group_stdtoec, group_stdfromec, gtobuf, gfrombuf, |
176 | gtoraw, gfromraw | |
34e4f738 | 177 | }; |
178 | ||
179 | group *group_prime(const gprime_param *gp) | |
180 | { | |
f94b972d | 181 | gctx_prime *g; |
34e4f738 | 182 | |
a69a3efd | 183 | if (!MP_POSP(gp->p) || !MP_ODDP(gp->p)) |
02d7884d | 184 | return (0); |
f94b972d | 185 | g = CREATE(gctx_prime); |
34e4f738 | 186 | g->g.ops = &gops; |
187 | g->g.nbits = mp_bits(gp->p); | |
188 | g->g.noctets = (g->g.nbits + 7) >> 3; | |
189 | mpmont_create(&g->mm, gp->p); | |
b919de21 MW |
190 | g->i.x = g->mm.r; g->g.i = &g->i; |
191 | g->gen.x = mpmont_mul(&g->mm, MP_NEW, gp->g, g->mm.r2); | |
34e4f738 | 192 | g->g.g = &g->gen; |
193 | g->g.r = MP_COPY(gp->q); | |
194 | g->g.h = MP_NEW; mp_div(&g->g.h, 0, gp->p, gp->q); | |
195 | return (&g->g); | |
196 | } | |
197 | ||
198 | /*----- That's all, folks -------------------------------------------------*/ |