/* -*-c-*-
*
- * $Id: bbs-gen.c,v 1.2 1999/12/22 15:52:28 mdw Exp $
+ * $Id: bbs-gen.c,v 1.6 2004/04/08 01:36:15 mdw Exp $
*
* Generate Blum integers
*
* (c) 1999 Straylight/Edgeware
*/
-/*----- Licensing notice --------------------------------------------------*
+/*----- Licensing notice --------------------------------------------------*
*
* This file is part of Catacomb.
*
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
- *
+ *
* Catacomb is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
- *
+ *
* You should have received a copy of the GNU Library General Public
* License along with Catacomb; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: bbs-gen.c,v $
- * Revision 1.2 1999/12/22 15:52:28 mdw
- * Reworking for new prime-search system.
- *
- * Revision 1.1 1999/12/10 23:14:59 mdw
- * Blum-Blum-Shub generator, and Blum-Goldwasser encryption.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include <stdio.h>
#include "mp.h"
#include "mprand.h"
#include "pgen.h"
-
-/*----- Data structures ---------------------------------------------------*/
-
-typedef struct gcdctx {
- mp *q;
- mp *r;
- pfilt p;
-} gcdctx;
-
-/*----- Custom stepper ----------------------------------------------------*/
-
-static int gcdstep(int rq, pgen_event *ev, void *p)
-{
- gcdctx *g = p;
- int rc = PGEN_ABORT;
- mp *z = MP_NEW;
-
- switch (rq) {
- case PGEN_BEGIN: {
- mp *p = ev->m = mp_split(ev->m);
- p->v[0] |= 3;
- g->q = mp_lsr(MP_NEW, p, 1);
- rc = pfilt_create(&g->p, p);
- } break;
- case PGEN_TRY:
- g->q = mp_add(g->q, g->q, MP_FOUR);
- rc = pfilt_step(&g->p, 4);
- break;
- case PGEN_DONE:
- pfilt_destroy(&g->p);
- mp_drop(g->q);
- return (PGEN_DONE);
- }
- for (;;) {
- if (rc != PGEN_FAIL) {
- mp_gcd(&z, 0, 0, g->r, g->q);
- if (MP_CMP(z, !=, MP_ONE))
- rc = PGEN_FAIL;
- }
- if (rc != PGEN_FAIL)
- break;
- g->q = mp_add(g->q, g->q, MP_FOUR);
- rc = pfilt_step(&g->p, 4);
- }
-
- mp_drop(z);
- mp_drop(ev->m);
- ev->m = MP_COPY(g->p.m);
- return (rc);
-}
+#include "strongprime.h"
/*----- Main code ---------------------------------------------------------*/
/* --- @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
+ * Arguments: @bbs_priv *bp@ = pointer to parameter block
+ * @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
*
* Returns: If it worked OK, @PGEN_DONE@, otherwise @PGEN_ABORT@.
*
* Use: Finds two prime numbers %$p'$% and %$q'$% such that both are
- * congruent to %$3 \bmod 4$%, and $(p - 1)/2$% and
+ * congruent to %$3 \bmod 4$%, and $(p - 1)/2$% and
* %$(q - 1)/2$% have no common factors. The product %$n = pq$%
* is eminently suitable for use as a modulus in a Blum-Blum-
* Shub pseudorandom bit generator.
*/
-int bbs_gen(bbs_param *bp, mp *p, mp *q, size_t n,
+int bbs_gen(bbs_priv *bp, unsigned nbits, grand *r, unsigned n,
pgen_proc *event, void *ectx)
{
- rabin r;
- pgen_safestepctx c;
- gcdctx g;
+ rabin rb;
+ pfilt jp;
+ pgen_jumpctx j;
+ pgen_gcdstepctx 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)
- goto fail_p;
+again:
+ if ((x = strongprime_setup("p", x, &jp, nb, r, n, event, ectx)) == 0)
+ goto fail_x;
+ j.j = &jp;
+ bp->p = pgen("p", MP_NEW, x, event, ectx, n, pgen_jump, &j,
+ rabin_iters(nb), pgen_test, &rb);
+ pfilt_destroy(&jp);
+ if (!bp->p) {
+ if (n)
+ goto fail_p;
+ goto again;
+ }
/* --- Generate @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)
+ nb = nbits - nb;
+ if ((x = strongprime_setup("q", x, &g.jp, nb, r, n, event, ectx)) == 0)
goto fail_q;
+ if ((x->v[0] & 3) != 3)
+ x = mp_add(x, x, g.jp.m);
+ pfilt_muladd(&g.jp, &g.jp, 2, 0);
+ g.r = mp_lsr(MP_NEW, bp->p, 1);
+ g.g = MP_NEW;
+ g.max = MP_ONE;
+ bp->q = pgen("q", MP_NEW, x, event, ectx, n, pgen_gcdstep, &g,
+ rabin_iters(nb), pgen_test, &rb);
+ pfilt_destroy(&g.jp);
+ mp_drop(g.r);
+ mp_drop(g.g);
+ if (!bp->q) {
+ if (n)
+ goto fail_q;
+ mp_drop(bp->p);
+ goto again;
+ }
/* --- 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);
}
projects / u / mdw / catacomb / blobdiff