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// -*-c++-*-
/* $Id: prime.h,v 1.6 1999/04/22 07:16:50 dm Exp $ */
/*
*
* Copyright (C) 1999 David Mazieres (dm@uun.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*/
#ifndef _SFSCRYPT_PRIME_H_
#define _SFSCRYPT_PRIME_H_ 1
#include "bigint.h"
extern const u_int small_primes[];
extern const int num_small_primes;
extern const u_int odd_sieve[2];
extern const u_int srpprime_sieve[];
class prime_finder {
public:
enum { nprimes = 2048 };
private:
bigint p;
const u_int *const sieve;
const u_int sievesize;
u_int sievepos;
int inc;
int maxinc;
bigint tmp;
int mods[nprimes];
public:
prime_finder (const bigint &p, const u_int *sv = odd_sieve, u_int svsz = 2);
~prime_finder ();
void calcmods ();
const bigint &getp () const { return p; }
u_int getinc () const { return inc; }
void setmax (int m) { assert (maxinc == -1 && m > 0); maxinc = m; }
bigint &next_weak ();
bigint &next_fermat ();
bigint &next_strong (u_int iter = 32);
};
bigint random_zn (const bigint &n);
bigint random_bigint (size_t bits);
bool prime_test (const bigint &n, u_int iter = 32);
bigint prime_search (const bigint &base, u_int range,
const u_int *sieve = odd_sieve,
const u_int sievesize = 2, u_int iter = 32);
bool srpprime_test (const bigint &n, u_int iter = 32);
bigint srpprime_search (const bigint &start, u_int iter = 32);
inline bigint
random_prime (u_int nbits, const u_int *sieve = odd_sieve,
const u_int sievesize = 2, u_int iter = 32)
{
bigint p;
while (!(p = prime_search (random_bigint (nbits), 4 * sievesize * nbits,
sieve, sievesize, iter)))
;
return p;
}
inline bigint
random_srpprime (u_int nbits)
{
return srpprime_search (random_bigint (nbits - 1));
}
#endif /* !_SFSCRYPT_PRIME_H_ */
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