// SimpleProgram.cs
//

using System;
using System.Collections.Generic;
#if (DEBUG)
using System.Diagnostics;
#endif // #if (DEBUG)
using System.Text;
using BroccoliProducts.Maths;

namespace SimpleProgram
{

	/////////////////////////////////////////////////////////////////
	// declaration of Program class

	class SimpleProgram
	{

		/////////////////////////////////////////////////////////////
		// main function

		static void Main(string[] args)
		{

			/////////////////////////////////////////////////////////
			// A - Choosing two prime numbers, p and q

			// declare p, a prime number
			JumboInteger p = new JumboInteger(17);
			Console.WriteLine("p = {0}", p);

			// declare q, a prime number
			JumboInteger q = new JumboInteger(11);
			Console.WriteLine("q = {0}", q);

			/////////////////////////////////////////////////////////
			// B - Combing p and q to produce another number N

			// calculate N = p x q
			JumboInteger N = p * q;
			Console.WriteLine("N = {0}", N);

			/////////////////////////////////////////////////////////
			// C - Choose e, between 1 and N

			// declare e
			JumboInteger e = new JumboInteger(7);

			/////////////////////////////////////////////////////////
			// D - Publishing the public key

			// show the public key
			Console.WriteLine( "Public Key [e,N] = [{0},{1}]", e, N );

			/////////////////////////////////////////////////////////
			// E - Message "X" is encrypted using the public key

			// declare message 'X'
			JumboInteger M = new JumboInteger(88);
			Console.WriteLine("M = {0}", M);

			// encrypt the message
			JumboInteger C = M.PowerMod(e, N);

			/////////////////////////////////////////////////////////
			// F - The encrypted message can now be sent to the receipient

			// display cypher text
			Console.WriteLine("C = {0}", C);

			/////////////////////////////////////////////////////////
			// G - Using p and q, create the private key, d

			// calculate d
			JumboInteger phi = (p - 1) * (q - 1);
			JumboInteger d = JumboInteger.ModularInverse(e, phi);

			// show the public key
			Console.WriteLine("Private Key [d] = [{0}]", d);

			/////////////////////////////////////////////////////////
			// H - Use the private key to decrypt the cypher-text C

			// decrypt the message
			JumboInteger M2 = C.PowerMod(d, N);
			Console.WriteLine("M2 = {0}", M2);

			/////////////////////////////////////////////////////////
			// application finished

			Console.WriteLine("\nSimpleProgram finished.");
			Console.WriteLine("Click any key to close...");
			while (!Console.KeyAvailable) { }

		}

	}

}