public Pkcs5S2KeyGenerator(int keyBitSize = 256, int iterations = 1000)
{
if (iterations < 1000)
throw new ArgumentOutOfRangeException($"Minimum value of {nameof(iterations)} is 1000");
if (keyBitSize < 0)
throw new ArgumentOutOfRangeException($"{nameof(keyBitSize)} must be positive");
_keyBitSize = keyBitSize;
_iterations = iterations;
}