/* -*-c-*-
*
- * $Id: bbs-gen.c,v 1.2 1999/12/22 15:52:28 mdw Exp $
+ * $Id: bbs-gen.c,v 1.3 2000/02/12 18:21:02 mdw Exp $
*
* Generate Blum integers
*
/*----- Revision history --------------------------------------------------*
*
* $Log: bbs-gen.c,v $
+ * Revision 1.3 2000/02/12 18:21:02 mdw
+ * Overhaul of key management (again).
+ *
* Revision 1.2 1999/12/22 15:52:28 mdw
* Reworking for new prime-search system.
*
#include "mp.h"
#include "mprand.h"
#include "pgen.h"
+#include "strongprime.h"
/*----- Data structures ---------------------------------------------------*/
typedef struct gcdctx {
- mp *q;
+ mp *q, *jq;
+ pfilt p, jp;
mp *r;
- pfilt p;
} gcdctx;
/*----- Custom stepper ----------------------------------------------------*/
mp *z = MP_NEW;
switch (rq) {
+
+ /* --- Set everything up --- */
+
case PGEN_BEGIN: {
- mp *p = ev->m = mp_split(ev->m);
- p->v[0] |= 3;
- g->q = mp_lsr(MP_NEW, p, 1);
+ mp *p = ev->m;
+ if ((p->v[0] & 3) != 3)
+ p = mp_add(p, p, g->jp.m);
rc = pfilt_create(&g->p, p);
+ g->q = mp_lsr(MP_NEW, p, 1);
+ g->jq = MP_COPY(g->jp.m);
+ pfilt_muladd(&g->jp, &g->jp, 2, 0);
+ g->jq = mp_lsr(MP_NEW, p, 1);
+ mp_drop(p);
} break;
+
+ /* --- Grind through another iteration --- */
+
case PGEN_TRY:
- g->q = mp_add(g->q, g->q, MP_FOUR);
- rc = pfilt_step(&g->p, 4);
+ mp_drop(ev->m);
+ rc = pfilt_jump(&g->p, &g->jp);
+ g->q = mp_add(g->q, g->q, g->jq);
break;
+
+ /* --- Finished --- */
+
case PGEN_DONE:
pfilt_destroy(&g->p);
mp_drop(g->q);
+ mp_drop(g->jq);
return (PGEN_DONE);
}
+
+ /* --- Step on until everything is OK --- */
+
for (;;) {
if (rc != PGEN_FAIL) {
mp_gcd(&z, 0, 0, g->r, g->q);
}
if (rc != PGEN_FAIL)
break;
- g->q = mp_add(g->q, g->q, MP_FOUR);
- rc = pfilt_step(&g->p, 4);
+ rc = pfilt_jump(&g->p, &g->jp);
+ g->q = mp_add(g->q, g->q, g->jq);
}
mp_drop(z);
- mp_drop(ev->m);
ev->m = MP_COPY(g->p.m);
return (rc);
}
/* --- @bbs_gen@ --- *
*
* Arguments: @bbs_param *bp@ = pointer to parameter block
- * @mp *p, *q@ = initial numbers to search from
- * @size_t n@ = number of attempts to make
+ * @unsigned nbits@ = number of bits in the modulus
+ * @grand *r@ = pointer to random number source
+ * @unsigned n@ = number of attempts to make
* @pgen_proc *event@ = event handler function
* @void *ectx@ = argument for event handler
*
* Shub pseudorandom bit generator.
*/
-int bbs_gen(bbs_param *bp, mp *p, mp *q, size_t n,
+int bbs_gen(bbs_param *bp, unsigned nbits, grand *r, unsigned n,
pgen_proc *event, void *ectx)
{
- rabin r;
- pgen_safestepctx c;
+ rabin rb;
+ pgen_safejumpctx j;
gcdctx g;
+ unsigned nb = nbits/2;
+ mp *x = MP_NEW;
/* --- Generate @p@ --- */
- if ((bp->p = pgen("p", MP_NEW, p, event, ectx, n, pgen_safestep, &c,
- rabin_iters(mp_bits(p)), pgen_test, &r)) == 0)
+ if ((x = strongprime_setup("p", x, &j.jq, nb, r, n, event, ectx)) == 0)
+ goto fail_x;
+ bp->p = pgen("p", MP_NEW, x, event, ectx, n, pgen_safejump, &j,
+ rabin_iters(nb), pgen_test, &rb);
+ pfilt_destroy(&j.jq);
+ if (!bp->p)
goto fail_p;
/* --- Generate @q@ --- */
+ nb = nbits - nb;
+ if ((x = strongprime_setup("q", x, &g.jp, nb, r, n, event, ectx)) == 0)
+ goto fail_q;
g.r = mp_lsr(MP_NEW, bp->p, 1);
- if ((bp->q = pgen("q", MP_NEW, q, event, ectx, n, gcdstep, &g,
- rabin_iters(mp_bits(q)), pgen_test, &r)) == 0)
+ bp->q = pgen("q", MP_NEW, x, event, ectx, n, gcdstep, &g,
+ rabin_iters(nb), pgen_test, &rb);
+ pfilt_destroy(&g.jp);
+ mp_drop(g.r);
+ if (!bp->q)
goto fail_q;
/* --- Compute @n@ --- */
bp->n = mp_mul(MP_NEW, bp->p, bp->q);
- mp_drop(g.r);
+ mp_drop(x);
return (PGEN_DONE);
/* --- Tidy up if things went wrong --- */
fail_q:
- mp_drop(g.r);
mp_drop(bp->p);
fail_p:
+ mp_drop(x);
+fail_x:
return (PGEN_ABORT);
}