// initializes the private variables (throws CryptographicException)
private void Initialize(BigInteger p, BigInteger g, BigInteger x, int secretLen, bool checkInput)
{
if (!p.IsProbablePrime() || g <= 0 || g >= p || (x != null && (x <= 0 || x > p - 2)))
throw new CryptographicException();
// default is to generate a number as large as the prime this
// is usually overkill, but it's the most secure thing we can
// do if the user doesn't specify a desired secret length ...
if (secretLen == 0)
secretLen = p.BitCount();
m_P = p;
m_G = g;
if (x == null)
{
BigInteger pm1 = m_P - 1;
for (m_X = BigInteger.GenerateRandom(secretLen);
m_X >= pm1 || m_X == 0;
m_X = BigInteger.GenerateRandom(secretLen))
{
}
}
else
{
m_X = x;
}
}