/// <summary>
/// Converts a BitBlock into an array of bytes.
/// The number of items in the BitBlock must be divisible by 8.
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
public static byte[] ConvertToByteArray(BitBlock input)
{
int size = input.Length;
if (size % 8 != 0)
{
throw new Exception("Input lenght must be divisible and greater by/than 8");
}
byte[] byteArray = new byte[size / 8];
int b = 0;
BitBlock bb = new BitBlock(8);
for (int i = 0; i < size; i++)
{
bb[i % 8] = input[i];
if ((i + 1) % 8 == 0)
{
byte _byte = BitBlock.ConvertBinaryToDecimal(bb);
byteArray[b++] = _byte;
}
}
return(byteArray);
}
private BitBlock S(BitBlock input, int sreferenceTableNumber)
{
BitBlock outerBits = new BitBlock(2);
BitBlock middleBits = new BitBlock(4);
outerBits[0] = input[0];
outerBits[1] = input[5];
middleBits[0] = input[1];
middleBits[1] = input[2];
middleBits[2] = input[3];
middleBits[3] = input[4];
int middleNumber = BitBlock.ConvertBinaryToDecimal(middleBits);
int outerNumber = BitBlock.ConvertBinaryToDecimal(outerBits);
int tableValue = 0;
switch (sreferenceTableNumber)
{
case 1:
tableValue = tables.SBox1Table[outerNumber, middleNumber];
break;
case 2:
tableValue = tables.SBox2Table[outerNumber, middleNumber];
break;
case 3:
tableValue = tables.SBox3Table[outerNumber, middleNumber];
break;
case 4:
tableValue = tables.SBox4Table[outerNumber, middleNumber];
break;
case 5:
tableValue = tables.SBox5Table[outerNumber, middleNumber];
break;
case 6:
tableValue = tables.SBox6Table[outerNumber, middleNumber];
break;
case 7:
tableValue = tables.SBox7Table[outerNumber, middleNumber];
break;
case 8:
tableValue = tables.SBox8Table[outerNumber, middleNumber];
break;
}
BitBlock bitBlock = BitBlock.ConvertDecimalToBinary(tableValue, 4);
return(bitBlock);
}