On Sun, Jan 03, 1999 at 07:48:11PM +0000, William Allen Simpson wrote:
> This generates "safe" primes, rather than "strong" primes.
>
> I meant to put this in a RFC someday, but it would be nice to know
> whether I'd done something wrong first.... Any problems/suggestions?
This code is kind of hard to understand. I couldn't figure out why you're
using three sieves (large, small, and tiny). Also, your sieve appears to
sieve candidates for p that are 3 mod 4, but you only need to sieve
integers that are 11 mod 12.
You might want to take a look at the safe prime generation code in
Crypto++ 3.0 (see the first constructor of PrimeAndGenerator in
nbtheory.cpp). The sieving code there is influenced by Colin Plumb's
bignum library.
// generate a safe prime with Crypto++
#include <iostream>
#include <rng.h>
#include <dh.h>
void main()
{
CryptoPP::LC_RNG rng(321);
CryptoPP::DH dh(rng, 1024);
std::cout << "p = " << dh.Prime() << std::endl;
std::cout << "g = " << dh.Generator() << std::endl;
}
