/* -*-c-*-
*
- * $Id: g-prime.c,v 1.3 2004/04/04 19:04:11 mdw Exp $
+ * $Id: g-prime.c,v 1.4 2004/04/08 01:36:15 mdw Exp $
*
* Abstraction for prime groups
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: g-prime.c,v $
- * Revision 1.3 2004/04/04 19:04:11 mdw
- * Raw I/O of elliptic curve points and group elements.
- *
- * Revision 1.2 2004/04/03 03:32:05 mdw
- * General robustification.
- *
- * Revision 1.1 2004/04/01 12:50:09 mdw
- * Add cyclic group abstraction, with test code. Separate off exponentation
- * functions for better static linking. Fix a buttload of bugs on the way.
- * Generally ensure that negative exponents do inversion correctly. Add
- * table of standard prime-field subgroups. (Binary field subgroups are
- * currently unimplemented but easy to add if anyone ever finds a good one.)
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include <mLib/sub.h>
static void ginv(group *gg, mp **d, mp **x) {
gctx *g = (gctx *)gg; mp *r = mpmont_reduce(&g->mm, *d, *x);
- mp_gcd(0, 0, &r, g->mm.m, r); *d = mpmont_mul(&g->mm, r, r, g->mm.r2);
+ r = mp_modinv(r, r, g->mm.m); *d = mpmont_mul(&g->mm, r, r, g->mm.r2);
}
static void gexp(group *gg, mp **d, mp **x, mp *n)
{ gctx *g = (gctx *)gg; return (mpmont_reduce(&g->mm, d, *x)); }
static int gfromint(group *gg, mp **d, mp *x) {
- gctx *g = (gctx *)gg; mp_div(0, &x, x, g->mm.m); mp_drop(*d);
- *d = mpmont_mul(&g->mm, x, x, g->mm.r2); return (0);
+ gctx *g = (gctx *)gg; mp_div(0, d, x, g->mm.m);
+ *d = mpmont_mul(&g->mm, *d, *d, g->mm.r2); return (0);
}
static int gtobuf(group *gg, buf *b, mp **x) {