public BitArrayPair GenerateKeys(BitArray inputKey)
{
var keyPair = new BitArrayPair();
keyPair.firstItem = new BitArray(8);
keyPair.secondItem = new BitArray(8);
var workingKey = PermuteTen(inputKey);
var splitKey = SplitBitArray(workingKey);
splitKey.firstItem = Shift(splitKey.firstItem, -1);
splitKey.secondItem = Shift(splitKey.secondItem, -1);
workingKey = JoinBitArrays(splitKey);
workingKey = PermuteEight(workingKey); //Key 1
keyPair.firstItem = workingKey;
splitKey.firstItem = Shift(splitKey.firstItem, -2);
splitKey.secondItem = Shift(splitKey.secondItem, -2);
workingKey = JoinBitArrays(splitKey);
workingKey = PermuteEight(workingKey); //Key 2
keyPair.secondItem = workingKey;
return(keyPair);
}
// Same as Encrypt, just switch keys
public BitArray Decrypt(BitArray plainText, BitArray key)
{
BitArrayPair keyPair = GenerateKeys(key);
BitArrayPair splitBitArray = SplitBitArray(PermuteEightEncrypt(plainText)); //do not overwrite this
BitArray xorTemp = EncryptExpand(splitBitArray.secondItem).Xor(keyPair.secondItem);
BitArrayPair splitXoredArray = SplitBitArray(xorTemp);
BitArrayPair sBoxArrays = new BitArrayPair();
sBoxArrays.firstItem = SBoxes(splitXoredArray.firstItem, new char[, ] {
{ '1', '0', '3', '2' },
{ '3', '2', '1', '0' },
{ '0', '2', '1', '3' },
{ '3', '1', '3', '2' }
});
sBoxArrays.secondItem = SBoxes(splitXoredArray.secondItem, new char[, ] {
{ '0', '1', '2', '3' },
{ '2', '0', '1', '3' },
{ '3', '0', '1', '0' },
{ '2', '1', '0', '3' }
});
BitArray temp = new BitArray(splitBitArray.firstItem);
BitArray firstHalfOfDecrypt = temp.Xor(EncryptPermuteFour(JoinBitArrays(sBoxArrays)));
xorTemp = EncryptExpand(firstHalfOfDecrypt).Xor(keyPair.firstItem);
splitXoredArray = SplitBitArray(xorTemp);
sBoxArrays.firstItem = SBoxes(splitXoredArray.firstItem, new char[, ] {
{ '1', '0', '3', '2' },
{ '3', '2', '1', '0' },
{ '0', '2', '1', '3' },
{ '3', '1', '3', '2' }
});
sBoxArrays.secondItem = SBoxes(splitXoredArray.secondItem, new char[, ] {
{ '0', '1', '2', '3' },
{ '2', '0', '1', '3' },
{ '3', '0', '1', '0' },
{ '2', '1', '0', '3' }
});
BitArray secondHalfOfDecrypt = splitBitArray.secondItem.Xor(EncryptPermuteFour(JoinBitArrays(sBoxArrays)));
BitArrayPair bothHalves = new BitArrayPair();
bothHalves.firstItem = secondHalfOfDecrypt;
bothHalves.secondItem = firstHalfOfDecrypt;
BitArray DecryptedOutput = PermuteEightEncryptInverted(JoinBitArrays(bothHalves));
return(DecryptedOutput);
}
public BitArray JoinBitArrays(BitArrayPair input)
{
BitArray output = new BitArray(input.firstItem.Count + input.secondItem.Count);
for (int i = 0; i < input.firstItem.Count; i++)
{
output[i] = input.firstItem[i];
}
for (int i = 0; i < input.secondItem.Count; i++)
{
output[i + input.firstItem.Count] = input.secondItem[i];
}
return(output);
}
public BitArrayPair SplitBitArray(BitArray input)
{
BitArrayPair splitArrays = new BitArrayPair();
int midway = input.Count / 2;
splitArrays.firstItem = new BitArray(midway);
splitArrays.secondItem = new BitArray(midway);
for (int i = 0; i < midway; i++)
{
splitArrays.firstItem[i] = input[i];
}
for (int i = midway; i < input.Count; i++)
{
splitArrays.secondItem[i - midway] = input[i];
}
return(splitArrays);
}
static void Main(string[] args)
{
BitArray userKey = new BitArray(10);
BitArray key_1 = new BitArray(8);
BitArray key_2 = new BitArray(8);
BitArray userText = new BitArray(8);
Tools tools = new Tools();
BitArrayPair keys = new BitArrayPair();
BitArray outText = new BitArray(8);
string UserChoice = "";
bool exit = false;
bool validInput = false;
string validCharacters = "eEdDqQ";
// Loop to allow user to replay
while (!exit)
{
Console.WriteLine("Welcome!");
Console.WriteLine("Enter Q or q at anytime to quit");
// Encrypt or Decrypt
validInput = false;
while (!validInput)
{
Console.WriteLine("Would you like to encrypt or decrypt your 8 bit input?");
Console.WriteLine("E/D.......");
UserChoice = Console.ReadLine();
if (validCharacters.Contains(UserChoice[0]))
{
validInput = true;
if (UserChoice[0] == 'Q' || UserChoice[0] == 'q')
{
exit = true;
break;
}
}
else
{
Console.WriteLine("Please enter correct input...");
}
}
// Get user plain/ciphertext
validInput = false;
while (!validInput && !exit)
{
if (UserChoice[0] == 'e' || UserChoice[0] == 'E')
{
Console.WriteLine("Please enter your 8 bit plaintext for encryption:");
}
else
{
Console.WriteLine("Please enter your 8 bit ciphertext for decryption:");
}
string userTextString = Console.ReadLine();
userText = new BitArray(userTextString.Select(c => c == '1').ToArray());
if (userText.Length == 8)
{
validInput = true;
Console.WriteLine("Your eight bit text: " + tools.BitArrayToString(userText));
}
else
{
if (userTextString[0] == 'Q' || userTextString[0] == 'q')
{
exit = true;
break;
}
Console.WriteLine("Please enter exactly 8 bits (only 1 or 0) for the text...");
}
}
// Get 10 bit key
validInput = false;
while (!validInput && !exit)
{
Console.WriteLine("Please enter a 10 Bit Key");
string userKeyString = Console.ReadLine();
userKey = new BitArray(userKeyString.Select(c => c == '1').ToArray());
if (userKey.Length == 10)
{
validInput = true;
Console.WriteLine("Your ten bit key: " + tools.BitArrayToString(userKey));
}
else
{
if (userKeyString[0] == 'Q' || userKeyString[0] == 'q')
{
exit = true;
break;
}
Console.WriteLine("Please enter exactly 10 bits (only 1 or 0) for the key...");
}
}
// Output Keys and plain/ciphertext here
if (!exit)
{
// Generate Keys here
keys = tools.GenerateKeys(userKey);
if (UserChoice[0] == 'e' || UserChoice[0] == 'E')
{
outText = tools.Encrypt(userText, userKey);
Console.WriteLine("Your encrypted ciphertext: " + tools.BitArrayToString(outText));
}
else
{
outText = tools.Decrypt(userText, userKey);
Console.WriteLine("Your Decrypted plaintext: " + tools.BitArrayToString(outText));
}
Console.WriteLine("Your 8 bit keys are listed below...");
Console.WriteLine("Key 1: " + tools.BitArrayToString(keys.firstItem));
Console.WriteLine("Key 2: " + tools.BitArrayToString(keys.secondItem));
}
// Ask user if they want to quit
validInput = false;
while (!validInput && !exit)
{
Console.WriteLine("Would you like to exit?");
Console.WriteLine("Y/N.......");
UserChoice = Console.ReadLine();
if (UserChoice[0] == 'Y' || UserChoice[0] == 'y')
{
validInput = true;
exit = true;
break;
}
if (UserChoice[0] == 'N' || UserChoice[0] == 'n')
{
validInput = true;
}
else
{
Console.WriteLine("Please enter correct input...");
}
}
}
Console.WriteLine("Exiting!");
Console.ReadKey();
}
