/// <summary>
/// Constructor with given starting prime number.
/// </summary>
/// <param name="startPrime">Starting prime number set to CurrentPrime property</param>
public PrimeNumberGenerator(uint startPrime)
{
if (!NumericUtilities.IsPrime(startPrime))
{
throw new ArgumentException("Given start value is not a prime number!");
}
CurrentPrime = startPrime;
}
/// <summary>
/// Generate next prime number and save it to CurrentPrime property.
/// </summary>
/// <returns>Next generated prime number</returns>
public uint GetNext()
{
if (CurrentPrime == 2)
{
// Optimalization
return(CurrentPrime = 3);
}
do
{
CurrentPrime += 2; // Skip even numbers
} while (!NumericUtilities.IsPrime(CurrentPrime));
return(CurrentPrime);
}
/// <summary>
/// Create instance of SimpleRSA class.
/// P and Q parameters must be prime numbers and P != Q.
/// Their product should be large enough to correctly compute encrypted/decrypted messages.
/// </summary>
/// <param name="p">Prime number P</param>
/// <param name="q">Primer number Q</param>
public SimpleRSA(ushort p, ushort q)
{
if (!NumericUtilities.IsPrime(p))
{
throw new ArgumentException("P is not prime");
}
if (!NumericUtilities.IsPrime(q))
{
throw new ArgumentException("Q is not prime");
}
var euler = (uint)((p - 1) * (q - 1));
Modulo = (uint)p * q;
PublicKey = CountPublicKey(euler);
PrivateKey = CountPrivateKey(euler, PublicKey);
}