| public IsProbablePrime ( int certainty ) : bool | ||
| certainty | int | |
| return | bool | |
public bool IsProbablePrime(
int certainty)
{
if (certainty <= 0)
return true;
BigInteger n = Abs();
if (!n.TestBit(0))
return n.Equals(Two);
if (n.Equals(One))
return false;
return n.CheckProbablePrime(certainty, RandomSource);
}
/// <summary>Choose a random prime value for use with RSA</summary>
/// <param name="bitlength">the bit-length of the returned prime</param>
/// <param name="e">the RSA public exponent</param>
/// <returns>a prime p, with (p-1) relatively prime to e</returns>
protected virtual BigInteger ChooseRandomPrime(int bitlength, BigInteger e)
{
for (;;)
{
BigInteger p = new BigInteger(bitlength, 1, param.Random);
if (p.Mod(e).Equals(BigInteger.One))
continue;
if (!p.IsProbablePrime(param.Certainty))
continue;
if (!e.Gcd(p.Subtract(BigInteger.One)).Equals(BigInteger.One))
continue;
return p;
}
}