/* -*-c-*-
*
- * $Id: rabin.c,v 1.7 2002/01/13 13:42:53 mdw Exp $
+ * $Id$
*
* Miller-Rabin primality test
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: rabin.c,v $
- * Revision 1.7 2002/01/13 13:42:53 mdw
- * More efficient Rabin-Miller test: with random witnesses, skip redundant
- * Montgomerization. (Being bijective, it can't affect the distribution.)
- *
- * Revision 1.6 2001/06/16 12:56:38 mdw
- * Fixes for interface change to @mpmont_expr@ and @mpmont_mexpr@.
- *
- * Revision 1.5 2000/10/08 12:11:22 mdw
- * Use @MP_EQ@ instead of @MP_CMP@.
- *
- * Revision 1.4 2000/06/22 19:03:02 mdw
- * Use the new @mp_odd@ function.
- *
- * Revision 1.3 1999/12/22 15:50:29 mdw
- * Reworking for new prime-search system. Add function for working out how
- * many iterations to use for a particular number.
- *
- * Revision 1.2 1999/12/10 23:29:48 mdw
- * Change header file guard names.
- *
- * Revision 1.1 1999/11/19 13:17:57 mdw
- * Prime number generator and tester.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include "mp.h"
* Arguments: @rabin *r@ = pointer to Rabin-Miller context
* @mp *m@ = pointer to number to test
*
- * Returns: ---
+ * Returns: Zero on success, nonzero on failure.
*
* Use: Precomputes some useful values for performing the
* Miller-Rabin probabilistic primality test.
*/
-void rabin_create(rabin *r, mp *m)
+int rabin_create(rabin *r, mp *m)
{
mp *m1 = mp_sub(MP_NEW, m, MP_ONE);
- mpmont_create(&r->mm, m);
+ if (mpmont_create(&r->mm, m)) {
+ MP_DROP(m1);
+ return (-1);
+ }
r->r = mp_odd(MP_NEW, m1, &r->s);
r->m1 = mp_sub(MP_NEW, m, r->mm.r);
mp_drop(m1);
+ return (0);
}
/* --- @rabin_destroy@ --- *
int rabin_iters(unsigned len)
{
- static struct {
+ static const struct {
unsigned b;
int i;
} *p, *q, tab[] = {