/* -*-apcalc-*-
*
- * $Id: ecp.cal,v 1.1.4.1 2003/06/10 13:43:53 mdw Exp $
+ * $Id: ecp.cal,v 1.5 2004/04/08 01:36:15 mdw Exp $
*
* Testbed for elliptic curve arithmetic over prime fields
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: ecp.cal,v $
- * Revision 1.1.4.1 2003/06/10 13:43:53 mdw
- * Simple (non-projective) curves over prime fields now seem to work.
- *
- * Revision 1.1 2000/10/08 16:01:37 mdw
- * Prototypes of various bits of code.
- *
- */
-
/*----- Object types ------------------------------------------------------*/
obj ecp_curve { a, b, p };
{
local e, alpha;
local obj ecp_pt d;
+ if (istype(a, 1))
+ return (0);
e = a.e;
alpha = (3 * a.x^2 + e.a) * minv(2 * a.y, e.p) % e.p;
d.x = (alpha^2 - 2 * a.x) % e.p;
{
local obj ecp_pt d;
d.x = a.x;
- d.y = -a.y;
+ d.y = a.e.p - a.y;
d.e = a.e;
return (d);
}