[u/mdw/catacomb] / pgen-safe.c

/* -*-c-*-
 *
 * $Id: pgen-safe.c,v 1.1 1999/12/22 16:01:34 mdw Exp $
 *
 * Safe prime generation
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * 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: pgen-safe.c,v $
 * Revision 1.1  1999/12/22 16:01:34  mdw
 * Find `safe' primes (i.e., %$p = 2q + 1$%).
 *
 */

/*----- Header files ------------------------------------------------------*/

#include "mp.h"
#include "mprand.h"
#include "pgen.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @pgen_safestep@ --- *
 *
 * Steps two numbers, %$q$% and %$p = 2q + 1$%, such that neither has any
 * small factors.  %$p$% is put in the event block.
 */

int pgen_safestep(int rq, pgen_event *ev, void *p)
{
  pgen_safestepctx *c = p;
  int prc = PGEN_ABORT, qrc;

  switch (rq) {
    case PGEN_BEGIN: {
      mp *p = mp_split(MP_COPY(ev->m));
      mp *q;
      p->v[0] |= 3;
      q = mp_lsr(MP_NEW, p, 1);
      qrc = pfilt_create(&c->q, q);
      prc = pfilt_create(&c->p, p);
      mp_drop(p);
      mp_drop(q);
    } goto step;
    case PGEN_TRY:
    again:
      qrc = pfilt_step(&c->q, 2);
      prc = pfilt_step(&c->p, 4);
    step:
      if (qrc == PGEN_FAIL || prc == PGEN_FAIL)
	goto again;
      mp_drop(ev->m);
      ev->m = MP_COPY(c->p.m);
      if (qrc == PGEN_TRY)
	prc = PGEN_TRY;
      break;
    case PGEN_DONE:
      pfilt_destroy(&c->q);
      pfilt_destroy(&c->p);
      break;
  }
  return (prc);
}

/* --- @pgen_safetest@ --- *
 *
 * Applies Rabin-Miller tests to %$p$% and %$q$%.
 */

int pgen_safetest(int rq, pgen_event *ev, void *p)
{
  pgen_safetestctx *c = p;
  int rc = PGEN_ABORT;

  switch (rq) {
    case PGEN_BEGIN:
      rabin_create(&c->q, c->c.q.m);
      rabin_create(&c->p, c->c.p.m);
      rc = PGEN_TRY;
      break;
    case PGEN_TRY: {
      mp *m = mprand_range(MP_NEW, c->c.q.m, ev->r, 0);
      rc = rabin_test(&c->p, m);
      if (rc == PGEN_PASS)
	rc = rabin_test(&c->q, m);
      mp_drop(m);
    } break;
    case PGEN_DONE:
      rabin_destroy(&c->q);
      rabin_destroy(&c->p);
      break;
  }
  return (rc);
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
1c42b462	1	/* --c--
	2	*
	3	* $Id: pgen-safe.c,v 1.1 1999/12/22 16:01:34 mdw Exp $
	4	*
	5	* Safe prime generation
	6	*
	7	* (c) 1999 Straylight/Edgeware
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of Catacomb.
	13	*
	14	* Catacomb is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU Library General Public License as
	16	* published by the Free Software Foundation; either version 2 of the
	17	* License, or (at your option) any later version.
	18	*
	19	* Catacomb is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU Library General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU Library General Public
	25	* License along with Catacomb; if not, write to the Free
	26	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	27	* MA 02111-1307, USA.
	28	*/
	29
	30	/----- Revision history --------------------------------------------------
	31	*
	32	* $Log: pgen-safe.c,v $
	33	* Revision 1.1 1999/12/22 16:01:34 mdw
	34	* Find `safe' primes (i.e., %$p = 2q + 1$%).
	35	*
	36	*/
	37
	38	/----- Header files ------------------------------------------------------/
	39
	40	#include "mp.h"
	41	#include "mprand.h"
	42	#include "pgen.h"
	43
	44	/----- Main code ---------------------------------------------------------/
	45
	46	/* --- @pgen_safestep@ --- *
	47	*
	48	* Steps two numbers, %$q$% and %$p = 2q + 1$%, such that neither has any
	49	* small factors. %$p$% is put in the event block.
	50	*/
	51
	52	int pgen_safestep(int rq, pgen_event ev, void p)
	53	{
	54	pgen_safestepctx *c = p;
	55	int prc = PGEN_ABORT, qrc;
	56
	57	switch (rq) {
	58	case PGEN_BEGIN: {
	59	mp *p = mp_split(MP_COPY(ev->m));
	60	mp *q;
	61	p->v[0] \|= 3;
	62	q = mp_lsr(MP_NEW, p, 1);
	63	qrc = pfilt_create(&c->q, q);
	64	prc = pfilt_create(&c->p, p);
65	mp_drop(p);
66	mp_drop(q);
67	} goto step;
68	case PGEN_TRY:
69	again:
70	qrc = pfilt_step(&c->q, 2);
71	prc = pfilt_step(&c->p, 4);
72	step:
73	if (qrc == PGEN_FAIL \|\| prc == PGEN_FAIL)
74	goto again;
75	mp_drop(ev->m);
76	ev->m = MP_COPY(c->p.m);
77	if (qrc == PGEN_TRY)
78	prc = PGEN_TRY;
79	break;
80	case PGEN_DONE:
81	pfilt_destroy(&c->q);
82	pfilt_destroy(&c->p);
83	break;
84	}
85	return (prc);
86	}
87
88	/* --- @pgen_safetest@ --- *
89	*
90	* Applies Rabin-Miller tests to %$p$% and %$q$%.
91	*/
92
93	int pgen_safetest(int rq, pgen_event ev, void p)
94	{
95	pgen_safetestctx *c = p;
96	int rc = PGEN_ABORT;
97
98	switch (rq) {
99	case PGEN_BEGIN:
100	rabin_create(&c->q, c->c.q.m);
101	rabin_create(&c->p, c->c.p.m);
102	rc = PGEN_TRY;
103	break;
104	case PGEN_TRY: {
105	mp *m = mprand_range(MP_NEW, c->c.q.m, ev->r, 0);
106	rc = rabin_test(&c->p, m);
107	if (rc == PGEN_PASS)
108	rc = rabin_test(&c->q, m);
109	mp_drop(m);
110	} break;
111	case PGEN_DONE:
112	rabin_destroy(&c->q);
113	rabin_destroy(&c->p);
114	break;
115	}
116	return (rc);
117	}
118
119	/----- That's all, folks -------------------------------------------------/