3 * $Id: ec-raw.c,v 1.2 2004/04/08 01:36:15 mdw Exp $
5 * Raw formatting of elliptic curve points
7 * (c) 2004 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Header files ------------------------------------------------------*/
35 /*----- Main code ---------------------------------------------------------*/
37 /* --- @ec_putraw@ --- *
39 * Arguments: @ec_curve *c@ = elliptic curve
40 * @buf *b@ = pointer to a buffer
41 * @const ec *p@ = an elliptic curve point
43 * Returns: Zero on success, nonzero on failure.
45 * Use: Puts an elliptic curve point to the given buffer using the
46 * standard uncompressed format described in P1383 and SEC1.
47 * This requires at most @1 + 2 * c->f->noctets@ space in the
48 * buffer. We don't do point compression.
51 int ec_putraw(ec_curve
*c
, buf
*b
, const ec
*p
)
56 if (EC_ATINF(p
)) return (buf_putbyte(b
, 0));
59 if ((q
= buf_get(b
, n
* 2)) == 0) return (-1);
60 mp_storeb(p
->x
, q
, n
);
61 mp_storeb(p
->y
, q
+ n
, n
);
65 /* --- @ec_getraw@ --- *
67 * Arguments: @ec_curve *c@ = elliptic curve
68 * @buf *b@ = pointer to a buffer
69 * @ec *d@ = an elliptic curve point
71 * Returns: Zero on success, nonzero on failure.
73 * Use: Reads an elliptic curve point from the given buffer using the
74 * standard uncompressed format described in P1383 and SEC1.
75 * We don't do point compression.
78 int ec_getraw(ec_curve
*c
, buf
*b
, ec
*d
)
84 if ((u
= buf_getbyte(b
)) < 0) return (-1);
85 if (!u
) { EC_SETINF(d
); return (0); }
86 if (!(u
& 4)) return (-1);
88 if ((q
= buf_get(b
, n
* 2)) == 0) return (-1);
90 d
->x
= mp_loadb(MP_NEW
, q
, n
);
91 d
->y
= mp_loadb(MP_NEW
, q
+ n
, n
);
96 /*----- That's all, folks -------------------------------------------------*/