3 * Raw formatting of elliptic curve points
5 * (c) 2004 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
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.
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.
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,
28 /*----- Header files ------------------------------------------------------*/
33 /*----- Main code ---------------------------------------------------------*/
35 /* --- @ec_putraw@ --- *
37 * Arguments: @ec_curve *c@ = elliptic curve
38 * @buf *b@ = pointer to a buffer
39 * @const ec *p@ = an elliptic curve point
41 * Returns: Zero on success, nonzero on failure.
43 * Use: Puts an elliptic curve point to the given buffer using the
44 * standard uncompressed format described in P1383 and SEC1.
45 * This requires at most @1 + 2 * c->f->noctets@ space in the
46 * buffer. We don't do point compression.
49 int ec_putraw(ec_curve
*c
, buf
*b
, const ec
*p
)
54 if (EC_ATINF(p
)) return (buf_putbyte(b
, 0));
57 if ((q
= buf_get(b
, n
* 2)) == 0) return (-1);
58 mp_storeb(p
->x
, q
, n
);
59 mp_storeb(p
->y
, q
+ n
, n
);
63 /* --- @ec_getraw@ --- *
65 * Arguments: @ec_curve *c@ = elliptic curve
66 * @buf *b@ = pointer to a buffer
67 * @ec *d@ = an elliptic curve point
69 * Returns: Zero on success, nonzero on failure.
71 * Use: Reads an elliptic curve point from the given buffer using the
72 * standard uncompressed format described in P1383 and SEC1.
73 * We don't do point compression.
76 int ec_getraw(ec_curve
*c
, buf
*b
, ec
*d
)
82 if ((u
= buf_getbyte(b
)) < 0) return (-1);
83 if (!u
) { EC_SETINF(d
); return (0); }
84 if (!(u
& 4)) return (-1);
86 if ((q
= buf_get(b
, n
* 2)) == 0) return (-1);
88 d
->x
= mp_loadb(MP_NEW
, q
, n
);
89 d
->y
= mp_loadb(MP_NEW
, q
+ n
, n
);
94 /*----- That's all, folks -------------------------------------------------*/