[u/mdw/catacomb] / math / ec-raw.c

/* -*-c-*-
 *
 * Raw formatting of elliptic curve points
 *
 * (c) 2004 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include "ec.h"
#include "ec-raw.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @ec_putraw@ --- *
 *
 * Arguments:	@ec_curve *c@ = elliptic curve
 *		@buf *b@ = pointer to a buffer
 *		@const ec *p@ = an elliptic curve point
 *
 * Returns:	Zero on success, nonzero on failure.
 *
 * Use:		Puts an elliptic curve point to the given buffer using the
 *		standard uncompressed format described in P1383 and SEC1.
 *		This requires at most @1 + 2 * c->f->noctets@ space in the
 *		buffer.  We don't do point compression.
 */

int ec_putraw(ec_curve *c, buf *b, const ec *p)
{
  octet *q;
  size_t n;

  if (EC_ATINF(p)) return (buf_putbyte(b, 0));
  buf_putbyte(b, 4);
  n = c->f->noctets;
  if ((q = buf_get(b, n * 2)) == 0) return (-1);
  mp_storeb(p->x, q, n);
  mp_storeb(p->y, q + n, n);
  return (0);
}

/* --- @ec_getraw@ --- *
 *
 * Arguments:	@ec_curve *c@ = elliptic curve
 *		@buf *b@ = pointer to a buffer
 *		@ec *d@ = an elliptic curve point
 *
 * Returns:	Zero on success, nonzero on failure.
 *
 * Use:		Reads an elliptic curve point from the given buffer using the
 *		standard uncompressed format described in P1383 and SEC1.
 *		We don't do point compression.
 */

int ec_getraw(ec_curve *c, buf *b, ec *d)
{
  const octet *q;
  size_t n;
  int u;

  if ((u = buf_getbyte(b)) < 0) return (-1);
  if (!u) { EC_SETINF(d); return (0); }
  if (!(u & 4)) return (-1);
  n = c->f->noctets;
  if ((q = buf_get(b, n * 2)) == 0) return (-1);
  EC_DESTROY(d);
  d->x = mp_loadb(MP_NEW, q, n);
  d->y = mp_loadb(MP_NEW, q + n, n);
  d->z = 0;
  return (0);
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
0f3faccd	1	/* --c--
0f3faccd	2	*
0f3faccd	3	* Raw formatting of elliptic curve points
	4	*
	5	* (c) 2004 Straylight/Edgeware
	6	*/
	7
45c0fd36	8	/----- Licensing notice --------------------------------------------------
0f3faccd	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.
45c0fd36	16	*
0f3faccd	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.
45c0fd36	21	*
0f3faccd	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
0f3faccd	28	/----- Header files ------------------------------------------------------/
	29
	30	#include "ec.h"
	31	#include "ec-raw.h"
	32
	33	/----- Main code ---------------------------------------------------------/
	34
	35	/* --- @ec_putraw@ --- *
	36	*
	37	* Arguments: @ec_curve *c@ = elliptic curve
	38	* @buf *b@ = pointer to a buffer
	39	* @const ec *p@ = an elliptic curve point
	40	*
	41	* Returns: Zero on success, nonzero on failure.
	42	*
	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.
	47	*/
	48
	49	int ec_putraw(ec_curve c, buf b, const ec *p)
	50	{
	51	octet *q;
	52	size_t n;
	53
	54	if (EC_ATINF(p)) return (buf_putbyte(b, 0));
	55	buf_putbyte(b, 4);
	56	n = c->f->noctets;
	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);
	60	return (0);
	61	}
	62
	63	/* --- @ec_getraw@ --- *
	64	*
	65	* Arguments: @ec_curve *c@ = elliptic curve
	66	* @buf *b@ = pointer to a buffer
	67	* @ec *d@ = an elliptic curve point
	68	*
	69	* Returns: Zero on success, nonzero on failure.
	70	*
	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.
	74	*/
	75
	76	int ec_getraw(ec_curve c, buf b, ec *d)
	77	{
	78	const octet *q;
	79	size_t n;
	80	int u;
	81
	82	if ((u = buf_getbyte(b)) < 0) return (-1);
	83	if (!u) { EC_SETINF(d); return (0); }
	84	if (!(u & 4)) return (-1);
	85	n = c->f->noctets;
	86	if ((q = buf_get(b, n * 2)) == 0) return (-1);
	87	EC_DESTROY(d);
	88	d->x = mp_loadb(MP_NEW, q, n);
	89	d->y = mp_loadb(MP_NEW, q + n, n);
	90	d->z = 0;
	91	return (0);
92	}
93
94	/----- That's all, folks -------------------------------------------------/