3 * $Id: ec-raw.c,v 1.1 2004/04/04 19:04:11 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 /*----- Revision history --------------------------------------------------*
33 * Revision 1.1 2004/04/04 19:04:11 mdw
34 * Raw I/O of elliptic curve points and group elements.
38 /*----- Header files ------------------------------------------------------*/
43 /*----- Main code ---------------------------------------------------------*/
45 /* --- @ec_putraw@ --- *
47 * Arguments: @ec_curve *c@ = elliptic curve
48 * @buf *b@ = pointer to a buffer
49 * @const ec *p@ = an elliptic curve point
51 * Returns: Zero on success, nonzero on failure.
53 * Use: Puts an elliptic curve point to the given buffer using the
54 * standard uncompressed format described in P1383 and SEC1.
55 * This requires at most @1 + 2 * c->f->noctets@ space in the
56 * buffer. We don't do point compression.
59 int ec_putraw(ec_curve
*c
, buf
*b
, const ec
*p
)
64 if (EC_ATINF(p
)) return (buf_putbyte(b
, 0));
67 if ((q
= buf_get(b
, n
* 2)) == 0) return (-1);
68 mp_storeb(p
->x
, q
, n
);
69 mp_storeb(p
->y
, q
+ n
, n
);
73 /* --- @ec_getraw@ --- *
75 * Arguments: @ec_curve *c@ = elliptic curve
76 * @buf *b@ = pointer to a buffer
77 * @ec *d@ = an elliptic curve point
79 * Returns: Zero on success, nonzero on failure.
81 * Use: Reads an elliptic curve point from the given buffer using the
82 * standard uncompressed format described in P1383 and SEC1.
83 * We don't do point compression.
86 int ec_getraw(ec_curve
*c
, buf
*b
, ec
*d
)
92 if ((u
= buf_getbyte(b
)) < 0) return (-1);
93 if (!u
) { EC_SETINF(d
); return (0); }
94 if (!(u
& 4)) return (-1);
96 if ((q
= buf_get(b
, n
* 2)) == 0) return (-1);
98 d
->x
= mp_loadb(MP_NEW
, q
, n
);
99 d
->y
= mp_loadb(MP_NEW
, q
+ n
, n
);
104 /*----- That's all, folks -------------------------------------------------*/