public string Decrypt(string text)
{
string encrypted = null;
List <BitArray> blocks = DesHelper.BinaryStringToBitArrayBlocks(text);
List <BitArray> xoredBlocks = new List <BitArray>();
List <BitArray> permutatedBlocks = new List <BitArray>();
foreach (BitArray bitArray in blocks)
{
xoredBlocks.Add(bitArray.Xor(KeyXor1));
}
foreach (BitArray bitArray in xoredBlocks)
{
permutatedBlocks.Add(Permutations.Permute(Data.InitialPermutationTable1, bitArray));
}
foreach (BitArray permutatedBlock in permutatedBlocks)
{
DesHelper.DivideToTwoArrays(permutatedBlock, out BitArray leftArray, out BitArray rightArray);
for (int i = 15; i >= 0; i--)
{
BitArray temp = leftArray;
leftArray = rightArray;
rightArray = temp.Xor(FunctionF(rightArray, SubKeys[i]));
}
BitArray sum = leftArray.Add(rightArray);
BitArray final = Permutations.Permute(Data.InitialPermutationTable2, sum);
BitArray xoredFinal = final.Xor(KeyXor2);
encrypted += xoredFinal.TToString();
}
return(encrypted);
}
public void Get16SubKeysFromKey()
{
BitArray permutatedKey = Permutations.Permute(Data.Permutation56Table, Key);
DesHelper.DivideToTwoArrays(permutatedKey, out BitArray leftPermutatedKey, out BitArray rightPermutatedKey);
List <BitArray> leftShitedKeys = new List <BitArray>(16);
List <BitArray> rightShitedKeys = new List <BitArray>(16);
leftShitedKeys.Add(DesHelper.ShiftLeft(leftPermutatedKey));
rightShitedKeys.Add(DesHelper.ShiftLeft(rightPermutatedKey));
for (int i = 0; i < 15; i++)
{
leftShitedKeys.Add(DesHelper.ShiftLeft(leftShitedKeys[i]));
rightShitedKeys.Add(DesHelper.ShiftLeft(rightShitedKeys[i]));
}
List <BitArray> shiftedSubKeys = new List <BitArray>(16);
for (int i = 0; i < 16; i++)
{
DesHelper.ConnectTwoArraysIntoOne(leftShitedKeys[i], rightShitedKeys[i], out BitArray connected);
shiftedSubKeys.Add(connected);
SubKeys.Add(Permutations.Permute(Data.Permutation48Table, shiftedSubKeys[i]));
}
}
private BitArray FunctionSBox(BitArray array)
{
BitArray sBoxedArray = new BitArray(32);
for (int i = 0; i < 8; i++)
{
BitArray temp = array.GetRange(6 * i, 6);
sBoxedArray.Add(Permutations.Permute(Data.SBox[i], temp));
}
return(sBoxedArray);
}
private BitArray FunctionP(BitArray array)
{
return(Permutations.Permute(Data.PermutationPTable, array));
}
private BitArray FunctionE(BitArray rightArray)
{
return(Permutations.Permute(Data.PetmutationETable, rightArray));
}