/* -*-c-*-
*
- * $Id: pgen-safe.c,v 1.2 2000/02/12 18:21:03 mdw Exp $
+ * $Id: pgen-safe.c,v 1.3 2000/06/17 11:52:36 mdw Exp $
*
* Safe prime generation
*
/*----- Revision history --------------------------------------------------*
*
* $Log: pgen-safe.c,v $
+ * Revision 1.3 2000/06/17 11:52:36 mdw
+ * Signal a pgen abort if the jump and base share a common factor.
+ *
* Revision 1.2 2000/02/12 18:21:03 mdw
* Overhaul of key management (again).
*
*
* The jump in @j.q@ is congruent to 2 (mod 4); see @strongprime_setup@.
* If @p@ is initially 1 (mod 4) then add @j.q@. Then double @j.q@ to
- * ensure that the step is 0 (mod 4).
+ * ensure that the step is 0 (mod 4). Ensure that @jq@ and @q@ don't
+ * have any common factors.
*/
case PGEN_BEGIN: {
mp *p = ev->m;
mp *q;
+ mp *g = MP_NEW;
if ((p->v[0] & 3) != 3)
p = mp_add(p, p, j->jq.m);
+ q = mp_lsr(MP_NEW, p, 1);
+ mp_gcd(&g, 0, 0, q, j->jq.m);
+ if (MP_CMP(g, >, MP_ONE)) {
+ ev->m = p;
+ mp_drop(q);
+ mp_drop(g);
+ return (PGEN_ABORT);
+ }
+ mp_drop(g);
rc = pfilt_create(&j->p, p);
pfilt_muladd(&j->jp, &j->jq, 2, 0);
- q = mp_lsr(MP_NEW, p, 1);
qrc = pfilt_create(&j->q, q);
mp_drop(p);
mp_drop(q);
/* -*-c-*-
*
- * $Id: pgen.c,v 1.4 1999/12/22 16:01:11 mdw Exp $
+ * $Id: pgen.c,v 1.5 2000/06/17 11:52:36 mdw Exp $
*
* Prime generation glue
*
/*----- Revision history --------------------------------------------------*
*
* $Log: pgen.c,v $
+ * Revision 1.5 2000/06/17 11:52:36 mdw
+ * Signal a pgen abort if the jump and base share a common factor.
+ *
* Revision 1.4 1999/12/22 16:01:11 mdw
* Same file, completely different code. Main interface for new prime-
* search system.
int rc = PGEN_ABORT;
switch (rq) {
- case PGEN_BEGIN:
+ case PGEN_BEGIN: {
+ mp *g = MP_NEW;
+ mp_gcd(&g, 0, 0, ev->m, f->j->m);
+ if (MP_CMP(g, >, MP_ONE)) {
+ mp_drop(g);
+ return (PGEN_ABORT);
+ }
+ mp_drop(g);
rc = pfilt_create(&f->f, ev->m);
mp_drop(ev->m);
- break;
+ } break;
case PGEN_TRY:
mp_drop(ev->m);
rc = pfilt_jump(&f->f, f->j);