public static void Decryption(String bitStringForCipherText, String[] key)
{
var pmt = new Permutation();
var p = new Program();
var BitStringForCipherText = pmt.GenerateIP(bitStringForCipherText);
String L0 = BitStringForCipherText.Substring(0, 32);
String R0 = BitStringForCipherText.Substring(32, 32);
String L1 = "", R1 = "";
for (var i = 0; i < 16; i++)
{
L1 = R0;
var expansioned48BitString = p.expansionPermutation(R0);
var inputForSBox = p.XOR(expansioned48BitString, key[15 - i]);
var s = new SBox(inputForSBox);
var sBox32BitOutputString = s.getOutput();
var pBoxPermutation32BitOutput = pmt.pBox(sBox32BitOutputString);
R1 = p.XOR(L0, pBoxPermutation32BitOutput);
R0 = R1;
L0 = L1;
}
var BitStringForPlainText = R0 + L0;
BitStringForPlainText = pmt.GenerateIP_1(BitStringForPlainText);
Console.WriteLine("\n\nPlain Text For Given Cipher Text Bit : \t" + BitStringForPlainText);
Console.Read();
}
static void Main(string[] args)
{
var program = new Program();
var permutation = new Permutation();
Console.WriteLine(program.BitStringToString("0000000011111111100000000110011000000000111111110111100001010101"));
var K = new String[17];
var KeyOfFourtyEigntBit = new String[16];
//var M = "0000000100100011010001010110011110001001101010111100110111101111";
var M = program.StringToBitString("12345678");
Console.WriteLine("Given Plain Text \t\t\t" + M);
var IP = permutation.GenerateIP(M);
String L0 = IP.Substring(0, 32), R0 = IP.Substring(32, 32);
K[0] = program.generateKeyOf56Bit();
//Console.WriteLine("First Key "+K[0]);
String L1 = "", R1 = "";
for (int i = 0; i < 16; i++)
{
L1 = R0;
var expansioned48BitString = "";
expansioned48BitString = program.expansionPermutation(R0);
K[i + 1] = program.ShiftKey(K[i], program.KeyShiftAmount(i));
var inputForSBox = "";
KeyOfFourtyEigntBit[i] = program.PC2Permutation(K[i + 1]);
inputForSBox = program.XOR(expansioned48BitString, KeyOfFourtyEigntBit[i]);
var sBox32BitOutputString = "";
var s = new SBox(inputForSBox);
sBox32BitOutputString = s.getOutput();
var pBoxPermutation32BitOutput = "";
pBoxPermutation32BitOutput = permutation.pBox(sBox32BitOutputString);
R1 = program.XOR(L0, pBoxPermutation32BitOutput);
R0 = R1;
L0 = L1;
}
var BitStringOfCipherText = R0 + L0;
BitStringOfCipherText = permutation.GenerateIP_1(BitStringOfCipherText);
Console.WriteLine("\n\nCipher Text For Given Plain Text : \t" + BitStringOfCipherText);
//var CipherText = program.BitStringToString(BitStringOfCipherText);
//Console.WriteLine("\nThe Cipher Text : " + BitStringOfCipherText + "\n\n");
Decryption(BitStringOfCipherText, KeyOfFourtyEigntBit);
Console.WriteLine();
Console.Read();
}
