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///////////////////////////////////////////////////////////////
// Copyright 2012 John Maddock. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_
//[safe_prime
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/miller_rabin.hpp>
#include <iostream>
#include <iomanip>
int main()
{
using namespace boost::random;
using namespace boost::multiprecision;
typedef cpp_int int_type;
mt11213b base_gen(clock());
independent_bits_engine<mt11213b, 256, int_type> gen(base_gen);
//
// We must use a different generator for the tests and number generation, otherwise
// we get false positives.
//
mt19937 gen2(clock());
for(unsigned i = 0; i < 100000; ++i)
{
int_type n = gen();
if(miller_rabin_test(n, 25, gen2))
{
// Value n is probably prime, see if (n-1)/2 is also prime:
std::cout << "We have a probable prime with value: " << std::hex << std::showbase << n << std::endl;
if(miller_rabin_test((n-1)/2, 25, gen2))
{
std::cout << "We have a safe prime with value: " << std::hex << std::showbase << n << std::endl;
return 0;
}
}
}
std::cout << "Ooops, no safe primes were found" << std::endl;
return 1;
}
//]
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