private string ExtendBlockSize(string bitStr)
{
string[] formattedBitStr = Utills.BinaryFormat(bitStr, 4).Split(' ');
StringBuilder extendedBitStr;
StringBuilder result = new StringBuilder(48);
for (int i = 0; i < formattedBitStr.Length; i++)
{
extendedBitStr = new StringBuilder(6);
extendedBitStr.Append(formattedBitStr[(i - 1 + 8) % 8].ElementAt(3));
extendedBitStr.Append(formattedBitStr[i]);
extendedBitStr.Append(formattedBitStr[(i + 1 + 8) % 8].ElementAt(0));
result.Append(extendedBitStr);
}
return(result.ToString());
}
public Des(string message, string key)
{
Message = message;
Key = key;
LPart = message.Substring(0, message.Length / 2);
RPart = message.Substring(message.Length / 2, message.Length / 2);
BinaryMessage = Utills.StickedBinaryMsg(Message);
InitialPermutedMessage = PermuteElements(BinaryMessage, InitialPermutation);
LPart = InitialPermutedMessage.Substring(0, InitialPermutedMessage.Length / 2);
RPart = InitialPermutedMessage.Substring(InitialPermutedMessage.Length / 2, InitialPermutedMessage.Length / 2);
ExtendeRBlock = ExtendBlockSize(RPart);
BinaryKey = GenerateKey(Utills.StickedBinaryMsg(Key));
KeyWithExtendedR = Utills.Modulo2(ExtendeRBlock, BinaryKey, 48);
SBlockSubstituted = SBlockSubstitution(KeyWithExtendedR, SubstitutionBoxes);
SBlockSubstituted = PermuteElements(SBlockSubstituted, ExpansionFunction);
ConcatedRL = string.Concat(LPart + SBlockSubstituted);
FinalPermutedMessage = PermuteElements(ConcatedRL, FinalPermutation);
}
