b0ab12e6 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: ec-prime.c,v 1.1 2001/04/29 18:12:33 mdw Exp $ |
4 | * |
5 | * Elliptic curves over prime fields |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: ec-prime.c,v $ |
33 | * Revision 1.1 2001/04/29 18:12:33 mdw |
34 | * Prototype version. |
35 | * |
36 | */ |
37 | |
38 | /*----- Header files ------------------------------------------------------*/ |
39 | |
40 | #include "ec.h" |
41 | |
42 | /*----- Data structures ---------------------------------------------------*/ |
43 | |
44 | typedef struct ecctx { |
45 | ec_curve c; |
46 | mp *a, *b; |
47 | } ecctx; |
48 | |
49 | /*----- Main code ---------------------------------------------------------*/ |
50 | |
51 | static void ecadd(ec_curve *c, ec *d, const ec *a, const ec *b) |
52 | { |
53 | /* --- Deal with the simple cases --- */ |
54 | |
55 | if (a == b) |
56 | ecdbl(c, d, a); |
57 | else if (EC_ATINF(a)) |
58 | EC_COPY(d, b); |
59 | else if (EC_ATINF(b)) |
60 | EC_COPY(d, a); |
61 | else if (MP_EQ(a->x, b->x) && MP_EQ(a->z, b->z)) { |
62 | if ((a->y->f ^ b->y->f) & MP_NEG) |
63 | EC_SETINF(d); |
64 | else |
65 | ecdbl(c, d, a); |
66 | } else { |
67 | |
68 | /* --- |
69 | } |
70 | } |
71 | |
72 | /*----- That's all, folks -------------------------------------------------*/ |