[u/mdw/catacomb] / ec-prime.c

/* -*-c-*-
 *
 * $Id: ec-prime.c,v 1.1 2001/04/29 18:12:33 mdw Exp $
 *
 * Elliptic curves over prime fields
 *
 * (c) 2001 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.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: ec-prime.c,v $
 * Revision 1.1  2001/04/29 18:12:33  mdw
 * Prototype version.
 *
 */

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

#include "ec.h"

/*----- Data structures ---------------------------------------------------*/

typedef struct ecctx {
  ec_curve c;
  mp *a, *b;
} ecctx;

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

static void ecadd(ec_curve *c, ec *d, const ec *a, const ec *b)
{
  /* --- Deal with the simple cases --- */

  if (a == b)
    ecdbl(c, d, a);
  else if (EC_ATINF(a))
    EC_COPY(d, b);
  else if (EC_ATINF(b))
    EC_COPY(d, a);
  else if (MP_EQ(a->x, b->x) && MP_EQ(a->z, b->z)) {
    if ((a->y->f ^ b->y->f) & MP_NEG)
      EC_SETINF(d);
    else
      ecdbl(c, d, a);
  } else {

    /* --- 
  }
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
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 -------------------------------------------------/