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1 | /* -*-c-*- |
2 | * |
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3 | * Abstraction for elliptic curve groups |
4 | * |
5 | * (c) 2004 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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16 | * |
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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. |
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21 | * |
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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 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <ctype.h> |
31 | |
32 | #include <mLib/sub.h> |
33 | |
34 | #define ge ec |
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35 | #include "ec-raw.h" |
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36 | #include "group-guts.h" |
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37 | |
38 | /*----- Main code ---------------------------------------------------------*/ |
39 | |
40 | /* --- Group operations --- */ |
41 | |
42 | static void gdestroygroup(group *gg) { |
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43 | gctx_ec *g = (gctx_ec *)gg; |
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44 | EC_DESTROY(&g->gen); |
45 | ec_freeinfo(&g->ei); |
46 | DESTROY(g); |
47 | } |
48 | |
49 | static ec *gcreate(group *gg) |
50 | { ec *x = CREATE(ec); EC_CREATE(x); return (x); } |
51 | |
52 | static void gcopy(group *gg, ec *d, ec *x) { EC_COPY(d, x); } |
53 | |
54 | static void gburn(group *gg, ec *x) { if (x->x) (x->x)->f |= MP_BURN; } |
55 | |
56 | static void gdestroy(group *gg, ec *x) { EC_DESTROY(x); DESTROY(x); } |
57 | |
58 | static int gsamep(group *gg, group *hh) { |
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59 | gctx_ec *g = (gctx_ec *)gg, *h = (gctx_ec *)hh; |
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60 | return (ec_sameinfop(&g->ei, &h->ei)); |
61 | } |
62 | |
63 | static int geq(group *gg, ec *x, ec *y) { |
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64 | gctx_ec *g = (gctx_ec *)gg; EC_FIX(g->ei.c, x, x); EC_FIX(g->ei.c, y, y); |
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65 | return (EC_EQ(x, y)); |
66 | } |
67 | |
68 | static int gidentp(group *gg, ec *x) { return (EC_ATINF(x)); } |
69 | |
70 | static const char *gcheck(group *gg, grand *gr) |
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71 | { gctx_ec *g = (gctx_ec *)gg; return (ec_checkinfo(&g->ei, gr)); } |
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72 | |
73 | static void gmul(group *gg, ec *d, ec *x, ec *y) |
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74 | { gctx_ec *g = (gctx_ec *)gg; EC_ADD(g->ei.c, d, x, y); } |
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75 | |
76 | static void gsqr(group *gg, ec *d, ec *x) |
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77 | { gctx_ec *g = (gctx_ec *)gg; EC_DBL(g->ei.c, d, x); } |
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78 | |
79 | static void ginv(group *gg, ec *d, ec *x) |
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80 | { gctx_ec *g = (gctx_ec *)gg; EC_NEG(g->ei.c, d, x); } |
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81 | |
82 | static void gdiv(group *gg, ec *d, ec *x, ec *y) |
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83 | { gctx_ec *g = (gctx_ec *)gg; EC_SUB(g->ei.c, d, x, y); } |
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84 | |
85 | static void gexp(group *gg, ec *d, ec *x, mp *n) |
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86 | { gctx_ec *g = (gctx_ec *)gg; ec_imul(g->ei.c, d, x, n); } |
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87 | |
88 | static void gmexp(group *gg, ec *d, const group_expfactor *f, size_t n) { |
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89 | gctx_ec *g = (gctx_ec *)gg; size_t i; |
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90 | ec_mulfactor *ff = xmalloc(n * sizeof(ec_mulfactor)); |
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91 | for (i = 0; i < n; i++) { ff[i].base = *f[i].base; ff[i].exp = f[i].exp; } |
92 | ec_immul(g->ei.c, d, ff, n); xfree(ff); |
93 | } |
94 | |
95 | static int gread(group *gg, ec *d, const mptext_ops *ops, void *p) { |
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96 | gctx_ec *g = (gctx_ec *)gg; |
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97 | ec t = EC_INIT; |
98 | int rc = -1; |
99 | int ch; |
100 | |
101 | ch = ops->get(p); |
102 | if (tolower(ch) == 'i') { |
103 | if (tolower(ops->get(p)) != 'n' || tolower(ops->get(p)) != 'f') |
104 | return (-1); |
105 | EC_SETINF(d); |
106 | return (0); |
107 | } |
108 | ops->unget(ch, p); |
109 | if ((t.x = mp_read(MP_NEW, 0, ops, p)) == 0) goto done; |
110 | do ch = ops->get(p); while (ch == ',' || isspace(ch)); ops->unget(ch, p); |
111 | if ((t.y = mp_read(MP_NEW, 0, ops, p)) == 0) goto done; |
112 | EC_IN(g->ei.c, &t, &t); |
113 | if (EC_CHECK(g->ei.c, &t)) goto done; |
114 | EC_COPY(d, &t); rc = 0; |
115 | EC_DESTROY(&t); |
116 | done: |
117 | return (rc); |
118 | } |
119 | |
120 | static int gwrite(group *gg, ec *x, const mptext_ops *ops, void *p) { |
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121 | gctx_ec *g = (gctx_ec *)gg; int rc = -1; ec t = EC_INIT; |
122 | EC_OUT(g->ei.c, &t, x); if (EC_ATINF(&t)) rc = ops->put("inf", 3, p); |
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123 | else if (!ops->put("0x", 2, p) && !mp_write(t.x, 16, ops, p) && |
124 | !ops->put(", 0x", 4, p) && !mp_write(t.y, 16, ops, p)) rc = 0; |
125 | EC_DESTROY(&t); return (rc); |
126 | } |
127 | |
128 | static mp *gtoint(group *gg, mp *d, ec *x) { |
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129 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; mp *i; if (EC_ATINF(x)) i = 0; |
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130 | else { EC_OUT(g->ei.c, &t, x); i = MP_COPY(t.x); EC_DESTROY(&t); } |
131 | mp_drop(d); return (i); |
132 | } |
133 | |
134 | static int gfromint(group *gg, ec *d, mp *x) { |
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135 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; |
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136 | if (!ec_find(g->ei.c, &t, x)) return (-1); |
137 | EC_IN(g->ei.c, d, &t); EC_DESTROY(&t); return (0); |
138 | } |
139 | |
140 | static int gtoec(group *gg, ec *d, ec *x) |
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141 | { gctx_ec *g = (gctx_ec *)gg; EC_OUT(g->ei.c, d, x); return (0); } |
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142 | |
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143 | static int gfromec(group *gg, ec *d, const ec *x) { |
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144 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; EC_IN(g->ei.c, &t, x); |
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145 | rc = EC_CHECK(g->ei.c, &t); if (!rc) EC_COPY(d, &t); EC_DESTROY(&t); |
146 | return (rc); |
147 | } |
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148 | |
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149 | static int gtobuf(group *gg, buf *b, ec *x) { |
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150 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
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151 | EC_OUT(g->ei.c, &t, x); rc = buf_putec(b, &t); EC_DESTROY(&t); return (rc); |
152 | } |
153 | |
154 | static int gfrombuf(group *gg, buf *b, ec *d) { |
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155 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
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156 | if (buf_getec(b, &t)) return (-1); |
157 | EC_IN(g->ei.c, &t, &t); rc = EC_CHECK(g->ei.c, &t); |
158 | if (!rc) EC_COPY(d, &t); EC_DESTROY(&t); return (rc); |
159 | } |
160 | |
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161 | static int gtoraw(group *gg, buf *b, ec *x) { |
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162 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
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163 | EC_OUT(g->ei.c, &t, x); rc = ec_putraw(g->ei.c, b, &t); |
164 | EC_DESTROY(&t); return (rc); |
165 | } |
166 | |
167 | static int gfromraw(group *gg, buf *b, ec *d) { |
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168 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
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169 | if (ec_getraw(g->ei.c, b, &t)) return (-1); |
170 | EC_IN(g->ei.c, &t, &t); rc = EC_CHECK(g->ei.c, &t); |
171 | if (!rc) EC_COPY(d, &t); EC_DESTROY(&t); return (rc); |
172 | } |
173 | |
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174 | /* --- @group_ec@ --- * |
175 | * |
176 | * Arguments: @const ec_info *ei@ = elliptic curve parameters |
177 | * |
178 | * Returns: A pointer to the group. |
179 | * |
180 | * Use: Constructs an abstract group interface for an elliptic curve |
181 | * group. Group elements are @ec@ structures. The contents of |
182 | * the @ec_info@ structure becomes the property of the @group@ |
183 | * object; you can (and should) free the structure itself, but |
184 | * calling @ec_freeinfo@ on it is not allowed. |
185 | */ |
186 | |
187 | static const group_ops gops = { |
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188 | GTY_EC, "ec", |
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189 | gdestroygroup, gcreate, gcopy, gburn, gdestroy, |
190 | gsamep, geq, gidentp, |
191 | gcheck, |
192 | gmul, gsqr, ginv, gdiv, gexp, gmexp, |
193 | gread, gwrite, |
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194 | gtoint, gfromint, gtoec, gfromec, gtobuf, gfrombuf, gtoraw, gfromraw |
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195 | }; |
196 | |
197 | group *group_ec(const ec_info *ei) |
198 | { |
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199 | gctx_ec *g = CREATE(gctx_ec); |
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200 | |
201 | g->g.ops = &gops; |
202 | g->g.nbits = ei->c->f->nbits * 2; |
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203 | g->g.noctets = ei->c->f->noctets * 2 + 1; |
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204 | g->ei = *ei; |
205 | EC_CREATE(&g->id); |
206 | g->g.i = &g->id; |
207 | EC_CREATE(&g->gen); |
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208 | g->g.g = &g->gen; |
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209 | EC_IN(g->ei.c, &g->gen, &ei->g); |
210 | g->g.r = ei->r; |
211 | g->g.h = ei->h; |
212 | return (&g->g); |
213 | } |
214 | |
215 | /*----- That's all, folks -------------------------------------------------*/ |