| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Abstraction for elliptic curve groups |
| 4 | * |
| 5 | * (c) 2004 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 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. |
| 16 | * |
| 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. |
| 21 | * |
| 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 <ctype.h> |
| 31 | |
| 32 | #include <mLib/sub.h> |
| 33 | |
| 34 | #define ge ec |
| 35 | #include "group.h" |
| 36 | #include "ec-raw.h" |
| 37 | #include "group-guts.h" |
| 38 | |
| 39 | /*----- Main code ---------------------------------------------------------*/ |
| 40 | |
| 41 | /* --- Group operations --- */ |
| 42 | |
| 43 | static void gdestroygroup(group *gg) { |
| 44 | gctx_ec *g = (gctx_ec *)gg; |
| 45 | EC_DESTROY(&g->gen); |
| 46 | ec_freeinfo(&g->ei); |
| 47 | DESTROY(g); |
| 48 | } |
| 49 | |
| 50 | static ec *gcreate(group *gg) |
| 51 | { ec *x = CREATE(ec); EC_CREATE(x); return (x); } |
| 52 | |
| 53 | static void gcopy(group *gg, ec *d, ec *x) { EC_COPY(d, x); } |
| 54 | |
| 55 | static void gburn(group *gg, ec *x) { if (x->x) (x->x)->f |= MP_BURN; } |
| 56 | |
| 57 | static void gdestroy(group *gg, ec *x) { EC_DESTROY(x); DESTROY(x); } |
| 58 | |
| 59 | static int gsamep(group *gg, group *hh) { |
| 60 | gctx_ec *g = (gctx_ec *)gg, *h = (gctx_ec *)hh; |
| 61 | return (ec_sameinfop(&g->ei, &h->ei)); |
| 62 | } |
| 63 | |
| 64 | static int geq(group *gg, ec *x, ec *y) { |
| 65 | gctx_ec *g = (gctx_ec *)gg; EC_FIX(g->ei.c, x, x); EC_FIX(g->ei.c, y, y); |
| 66 | return (EC_EQ(x, y)); |
| 67 | } |
| 68 | |
| 69 | static int gidentp(group *gg, ec *x) { return (EC_ATINF(x)); } |
| 70 | |
| 71 | static const char *gcheck(group *gg, grand *gr) |
| 72 | { gctx_ec *g = (gctx_ec *)gg; return (ec_checkinfo(&g->ei, gr)); } |
| 73 | |
| 74 | static void gmul(group *gg, ec *d, ec *x, ec *y) |
| 75 | { gctx_ec *g = (gctx_ec *)gg; EC_ADD(g->ei.c, d, x, y); } |
| 76 | |
| 77 | static void gsqr(group *gg, ec *d, ec *x) |
| 78 | { gctx_ec *g = (gctx_ec *)gg; EC_DBL(g->ei.c, d, x); } |
| 79 | |
| 80 | static void ginv(group *gg, ec *d, ec *x) |
| 81 | { gctx_ec *g = (gctx_ec *)gg; EC_NEG(g->ei.c, d, x); } |
| 82 | |
| 83 | static void gdiv(group *gg, ec *d, ec *x, ec *y) |
| 84 | { gctx_ec *g = (gctx_ec *)gg; EC_SUB(g->ei.c, d, x, y); } |
| 85 | |
| 86 | static void gexp(group *gg, ec *d, ec *x, mp *n) |
| 87 | { gctx_ec *g = (gctx_ec *)gg; ec_imul(g->ei.c, d, x, n); } |
| 88 | |
| 89 | static void gmexp(group *gg, ec *d, const group_expfactor *f, size_t n) { |
| 90 | gctx_ec *g = (gctx_ec *)gg; size_t i; |
| 91 | ec_mulfactor *ff = xmalloc(n * sizeof(ec_mulfactor)); |
| 92 | for (i = 0; i < n; i++) { ff[i].base = *f[i].base; ff[i].exp = f[i].exp; } |
| 93 | ec_immul(g->ei.c, d, ff, n); xfree(ff); |
| 94 | } |
| 95 | |
| 96 | static int gread(group *gg, ec *d, const mptext_ops *ops, void *p) { |
| 97 | gctx_ec *g = (gctx_ec *)gg; |
| 98 | ec t = EC_INIT; |
| 99 | int rc = -1; |
| 100 | int ch; |
| 101 | |
| 102 | ch = ops->get(p); |
| 103 | if (tolower(ch) == 'i') { |
| 104 | if (tolower(ops->get(p)) != 'n' || tolower(ops->get(p)) != 'f') |
| 105 | return (-1); |
| 106 | EC_SETINF(d); |
| 107 | return (0); |
| 108 | } |
| 109 | ops->unget(ch, p); |
| 110 | if ((t.x = mp_read(MP_NEW, 0, ops, p)) == 0) goto done; |
| 111 | do ch = ops->get(p); while (ch == ',' || isspace(ch)); ops->unget(ch, p); |
| 112 | if ((t.y = mp_read(MP_NEW, 0, ops, p)) == 0) goto done; |
| 113 | EC_IN(g->ei.c, &t, &t); |
| 114 | if (EC_CHECK(g->ei.c, &t)) goto done; |
| 115 | EC_COPY(d, &t); rc = 0; |
| 116 | EC_DESTROY(&t); |
| 117 | done: |
| 118 | return (rc); |
| 119 | } |
| 120 | |
| 121 | static int gwrite(group *gg, ec *x, const mptext_ops *ops, void *p) { |
| 122 | gctx_ec *g = (gctx_ec *)gg; int rc = -1; ec t = EC_INIT; |
| 123 | EC_OUT(g->ei.c, &t, x); if (EC_ATINF(&t)) rc = ops->put("inf", 3, p); |
| 124 | else if (!ops->put("0x", 2, p) && !mp_write(t.x, 16, ops, p) && |
| 125 | !ops->put(", 0x", 4, p) && !mp_write(t.y, 16, ops, p)) rc = 0; |
| 126 | EC_DESTROY(&t); return (rc); |
| 127 | } |
| 128 | |
| 129 | static mp *gtoint(group *gg, mp *d, ec *x) { |
| 130 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; mp *i; if (EC_ATINF(x)) i = 0; |
| 131 | else { EC_OUT(g->ei.c, &t, x); i = MP_COPY(t.x); EC_DESTROY(&t); } |
| 132 | mp_drop(d); return (i); |
| 133 | } |
| 134 | |
| 135 | static int gfromint(group *gg, ec *d, mp *x) { |
| 136 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; |
| 137 | if (!ec_find(g->ei.c, &t, x)) return (-1); |
| 138 | EC_IN(g->ei.c, d, &t); EC_DESTROY(&t); return (0); |
| 139 | } |
| 140 | |
| 141 | static int gtoec(group *gg, ec *d, ec *x) |
| 142 | { gctx_ec *g = (gctx_ec *)gg; EC_OUT(g->ei.c, d, x); return (0); } |
| 143 | |
| 144 | static int gfromec(group *gg, ec *d, const ec *x) { |
| 145 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; EC_IN(g->ei.c, &t, x); |
| 146 | rc = EC_CHECK(g->ei.c, &t); if (!rc) EC_COPY(d, &t); EC_DESTROY(&t); |
| 147 | return (rc); |
| 148 | } |
| 149 | |
| 150 | static int gtobuf(group *gg, buf *b, ec *x) { |
| 151 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
| 152 | EC_OUT(g->ei.c, &t, x); rc = buf_putec(b, &t); EC_DESTROY(&t); return (rc); |
| 153 | } |
| 154 | |
| 155 | static int gfrombuf(group *gg, buf *b, ec *d) { |
| 156 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
| 157 | if (buf_getec(b, &t)) return (-1); |
| 158 | EC_IN(g->ei.c, &t, &t); rc = EC_CHECK(g->ei.c, &t); |
| 159 | if (!rc) EC_COPY(d, &t); EC_DESTROY(&t); return (rc); |
| 160 | } |
| 161 | |
| 162 | static int gtoraw(group *gg, buf *b, ec *x) { |
| 163 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
| 164 | EC_OUT(g->ei.c, &t, x); rc = ec_putraw(g->ei.c, b, &t); |
| 165 | EC_DESTROY(&t); return (rc); |
| 166 | } |
| 167 | |
| 168 | static int gfromraw(group *gg, buf *b, ec *d) { |
| 169 | gctx_ec *g = (gctx_ec *)gg; ec t = EC_INIT; int rc; |
| 170 | if (ec_getraw(g->ei.c, b, &t)) return (-1); |
| 171 | EC_IN(g->ei.c, &t, &t); rc = EC_CHECK(g->ei.c, &t); |
| 172 | if (!rc) EC_COPY(d, &t); EC_DESTROY(&t); return (rc); |
| 173 | } |
| 174 | |
| 175 | /* --- @group_ec@ --- * |
| 176 | * |
| 177 | * Arguments: @const ec_info *ei@ = elliptic curve parameters |
| 178 | * |
| 179 | * Returns: A pointer to the group. |
| 180 | * |
| 181 | * Use: Constructs an abstract group interface for an elliptic curve |
| 182 | * group. Group elements are @ec@ structures. The contents of |
| 183 | * the @ec_info@ structure becomes the property of the @group@ |
| 184 | * object; you can (and should) free the structure itself, but |
| 185 | * calling @ec_freeinfo@ on it is not allowed. |
| 186 | */ |
| 187 | |
| 188 | static const group_ops gops = { |
| 189 | GTY_EC, "ec", |
| 190 | gdestroygroup, gcreate, gcopy, gburn, gdestroy, |
| 191 | gsamep, geq, gidentp, |
| 192 | gcheck, |
| 193 | gmul, gsqr, ginv, gdiv, gexp, gmexp, |
| 194 | gread, gwrite, |
| 195 | gtoint, gfromint, gtoec, gfromec, gtobuf, gfrombuf, gtoraw, gfromraw |
| 196 | }; |
| 197 | |
| 198 | group *group_ec(const ec_info *ei) |
| 199 | { |
| 200 | gctx_ec *g = CREATE(gctx_ec); |
| 201 | |
| 202 | g->g.ops = &gops; |
| 203 | g->g.nbits = ei->c->f->nbits * 2; |
| 204 | g->g.noctets = ei->c->f->noctets * 2 + 1; |
| 205 | g->ei = *ei; |
| 206 | EC_CREATE(&g->id); |
| 207 | g->g.i = &g->id; |
| 208 | EC_CREATE(&g->gen); |
| 209 | g->g.g = &g->gen; |
| 210 | EC_IN(g->ei.c, &g->gen, &ei->g); |
| 211 | g->g.r = ei->r; |
| 212 | g->g.h = ei->h; |
| 213 | return (&g->g); |
| 214 | } |
| 215 | |
| 216 | /*----- That's all, folks -------------------------------------------------*/ |