Implementation of the Digital Signature Algorithm.

[u/mdw/catacomb] / pgen.h

/* -*-c-*-
 *
 * $Id: pgen.h,v 1.1 1999/11/19 13:17:57 mdw Exp $
 *
 * Finding and testing prime numbers
 *
 * (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.h,v $
 * Revision 1.1  1999/11/19 13:17:57  mdw
 * Prime number generator and tester.
 *
 */

#ifndef PGEN_H
#define PGEN_H

#ifdef __cplusplus
  extern "C" {
#endif

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

#ifndef MP_H
#  include "mp.h"
#endif

#ifndef PTAB_H
#  include "ptab.h"
#endif

/*----- Constants ---------------------------------------------------------*/

#define PGEN_COMPOSITE (-1)		/* Number is definitely composite */
#define PGEN_MAYBE (0)			/* Number may be prime */
#define PGEN_PRIME (1)			/* Number is definitely prime */

/*----- Data structures ---------------------------------------------------*/

typedef struct pgen {
  mp *m;
  unsigned char r[NPRIME];
} pgen;

/*----- Functions provided ------------------------------------------------*/

/* --- @pgen_create@ --- *
 *
 * Arguments:	@pgen *p@ = pointer to prime generation context
 *		@mp *m@ = pointer to initial number to test
 *
 * Returns:	One of the @PGEN@ constants above.
 *
 * Use:		Tests an initial number for primality by computing its
 *		residue modulo various small prime numbers.  This is fairly
 *		quick, but not particularly certain.  If a @PGEN_MAYBE@
 *		result is returned, perform Rabin-Miller tests to confirm.
 */

extern int pgen_create(pgen */*p*/, mp */*m*/);

/* --- @pgen_destroy@ --- *
 *
 * Arguments:	@pgen *p@ = pointer to prime generation context
 *
 * Returns:	---
 *
 * Use:		Discards a context and all the resources it holds.
 */

extern void pgen_destroy(pgen */*p*/);

/* --- @pgen_step@ --- *
 *
 * Arguments:	@pgen *p@ = pointer to prime generation context
 *		@mpw step@ = how much to step the number
 *
 * Returns:	One of the @PGEN@ constants above.
 *
 * Use:		Steps a number by a small amount.  Stepping is much faster
 *		than initializing with a new number.  The test performed is
 *		the same simple one used by @ptab_create@, so @PGEN_MAYBE@
 *		results should be followed up by a Rabin-Miller test.
 */

extern int pgen_step(pgen */*p*/, mpw /*step*/);

/* --- @pgen_jump@ --- *
 *
 * Arguments:	@pgen *p@ = pointer to prime generation context
 *		@pgen *j@ = pointer to another generation context
 *
 * Returns:	One of the @PGEN@ constants above.
 *
 * Use:		Steps a number by a large amount.  Even so, jumping is much
 *		faster than initializing a new number.  The test peformed is
 *		the same simple one used by @ptab_create@, so @PGEN_MAYBE@
 *		results should be followed up by a Rabin-Miller test.
 *
 *		Note that the number stored in the @j@ context is probably
 *		better off being even than prime.  The important thing is
 *		that all of the residues for the number have already been
 *		computed.
 */

extern int pgen_jump(pgen */*p*/, pgen */*j*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif