public static string DecodeString(string input, int[] key)
{
string finalInput = input;
string finalOutput = "";
int howManyAdd = 0;
if (input.Length % 8 != 0)
{
howManyAdd = 8 - (input.Length % 8);
}
for (int i = 0; i < howManyAdd; i++)
{
finalInput = finalInput + " ";
}
int currentIndex = 0;
for (currentIndex = 0; currentIndex < finalInput.Length; currentIndex = currentIndex + 8)
{
byte[] currentSubString = StringToByteArray(finalInput.Substring(currentIndex, 8));
int[] textToEncrypt = new int[64];
int indxOfInput = 0;
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
int valueOfBit = ((currentSubString[i] & (1 << j)) == 0) ? 0 : 1;
textToEncrypt[indxOfInput] = valueOfBit;
indxOfInput++;
}
}
DES2 algorytmDes = new DES2();
algorytmDes.assignCipherTextAndKey(textToEncrypt, key);
algorytmDes.startDecryption();
int[] outputEncrypted = algorytmDes.getDecryption();
indxOfInput = 0;
for (int j = 0; j < 8; j++)
{
byte outByte = 0;
for (int i = 0; i < 8; i++)
{
if (outputEncrypted[indxOfInput] == 1)
{
outByte = (byte)(outByte | (1 << i));
}
indxOfInput++;
}
//bw.Write(outByte);
finalOutput = finalOutput + Convert.ToChar(outByte);
}
}
return(finalOutput);
}
public static void DecryptFromBinFileToBinFile(string inputFileName, string outputFileName, int[] _key, int howManyBytesToRemove = -1)
{
using (BinaryWriter bw = new BinaryWriter(File.Open(outputFileName, FileMode.Create)))
using (BinaryReader br = new BinaryReader(File.Open(inputFileName, FileMode.Open)))
{
int pos = 0, i, j;
int length = (int)br.BaseStream.Length;
int[] textToDecrypt = new int[64];
byte v;
bool areFullBlocks = true;
int numOfAdditionalBytes = 0;
while (pos < length)
{
int indxOfInput = 0;
for (j = 0; j < 8; j++) //8 bajtów bo 8 bajtów po 8 bitów to 8*8=64 bity
{
if (pos < length)
{
v = br.ReadByte();
for (i = 7; i >= 0; i--)
{
int valueOfBit = ((v & (1 << i)) == 0) ? 0 : 1;
textToDecrypt[indxOfInput] = valueOfBit;
indxOfInput++;
}
}
else //w przypadku gdy skoczyl sie plik ale mamy zaczety blok - dopelnij blok zerami
{
areFullBlocks = false;
for (i = 7; i >= 0; i--)
{
int valueOfBit = 0;
textToDecrypt[indxOfInput] = valueOfBit;
indxOfInput++;
}
numOfAdditionalBytes++;
}
pos += sizeof(byte);
}
if (!areFullBlocks)
{
Console.WriteLine("Twój plik wejściowy nie miał pełnych 64-bitowych bloków - dopełniono " + numOfAdditionalBytes + " bajtami");
}
DES2 algorytmDes = new DES2();
algorytmDes.assignCipherTextAndKey(textToDecrypt, _key);
algorytmDes.startDecryption();
int[] outputDecrypted = algorytmDes.getDecryption();
if (pos < length || howManyBytesToRemove <= 0)
{
indxOfInput = 0;
for (j = 0; j < 8; j++)
{
byte outByte = 0;
for (i = 7; i >= 0; i--)
{
if (outputDecrypted[indxOfInput] == 1)
{
outByte = (byte)(outByte | (1 << i));
}
indxOfInput++;
}
bw.Write(outByte);
}
}
else if (howManyBytesToRemove > 0)
{
indxOfInput = 0;
for (j = 0; j < 8 - howManyBytesToRemove; j++)
{
byte outByte = 0;
for (i = 7; i >= 0; i--)
{
if (outputDecrypted[indxOfInput] == 1)
{
outByte = (byte)(outByte | (1 << i));
}
indxOfInput++;
}
bw.Write(outByte);
}
}
}
}
Console.WriteLine("Zapisano wyniki w pliku \"{0}\".", outputFileName);
}
