public static Bitmap EncodeImage(Bitmap original, StegoType type, byte[] data)
{
Bitmap encodedImage = (Bitmap)original.Clone();
byte[] dataToWrite = new byte[data.Length + 4];
BitConverter.GetBytes(data.Length).CopyTo(dataToWrite, 0);
data.CopyTo(dataToWrite, 4);
int dataToWriteIndex = 0;
bool is_high_bits = true;
switch (type)
{
case StegoType.DylanLSB:
for (int x = 0; x < original.Width; x++)
{
for (int y = 0; y < original.Height; y++)
{
if (dataToWriteIndex < dataToWrite.Length)
{
Color c = encodedImage.GetPixel(x, y);
byte bit3 = 0;
byte bit2 = 0;
byte bit1 = 0;
byte bit0 = 0;
if (is_high_bits)
{
bit3 = (byte)((dataToWrite[dataToWriteIndex] & 0b10000000) >> 7);
bit2 = (byte)((dataToWrite[dataToWriteIndex] & 0b01000000) >> 6);
bit1 = (byte)((dataToWrite[dataToWriteIndex] & 0b00100000) >> 5);
bit0 = (byte)((dataToWrite[dataToWriteIndex] & 0b00010000) >> 4);
is_high_bits = !is_high_bits;
}
else
{
bit3 = (byte)((dataToWrite[dataToWriteIndex] & 0b00001000) >> 3);
bit2 = (byte)((dataToWrite[dataToWriteIndex] & 0b00000100) >> 2);
bit1 = (byte)((dataToWrite[dataToWriteIndex] & 0b00000010) >> 1);
bit0 = (byte)((dataToWrite[dataToWriteIndex] & 0b00000001));
is_high_bits = !is_high_bits;
dataToWriteIndex++;
}
byte r = 0;
byte g = 0;
byte b = 0;
byte a = 0;
byte setMask = 0b00000001;
byte resetMask = 0b11111110;
/*Console.Write($"{bit3}{bit2}{bit1}{bit0}");
*
* if (is_high_bits)
* Console.WriteLine();*/
//Console.WriteLine($"is_high_bits={!is_high_bits}");
r = (byte)(bit3 == 1 ? c.R | setMask : c.R & resetMask);
g = (byte)(bit2 == 1 ? c.G | setMask : c.G & resetMask);
b = (byte)(bit1 == 1 ? c.B | setMask : c.B & resetMask);
a = (byte)(bit0 == 1 ? c.A | setMask : c.A & resetMask);
//Console.WriteLine($"old: r={c.R}, g={c.G}, b={c.B}, a={c.A}");
//Console.WriteLine($"new: r={r}, g={g}, b={b}, a={a}");
Color newColor = Color.FromArgb(a, r, g, b);
encodedImage.SetPixel(x, y, newColor);
}
else
{
return(encodedImage);
}
}
}
break;
default:
return(original);
}
return(original);
}
public static byte[] DecodeImage(Bitmap image, StegoType type)
{
List <byte> dataBytes = new List <byte>();
byte buff = 0;
bool is_high_bits = true;
int data_length = 0;
switch (type)
{
case StegoType.DylanLSB:
for (int x = 0; x < image.Width; x++)
{
for (int y = 0; y < image.Height; y++)
{
Color c = image.GetPixel(x, y);
//Console.WriteLine($"r={c.R}, g={c.G}, b={c.B}, a={c.A}");
byte mask = 0b00000001;
byte bit3 = (byte)(c.R & mask);
byte bit2 = (byte)(c.G & mask);
byte bit1 = (byte)(c.B & mask);
byte bit0 = (byte)(c.A & mask);
/*Console.Write($"{bit3}{bit2}{bit1}{bit0}");
*
* if (!is_high_bits)
* Console.WriteLine();*/
if (is_high_bits)
{
buff = (byte)(bit3 << 7 | bit2 << 6 | bit1 << 5 | bit0 << 4);
is_high_bits = false;
}
else
{
buff = (byte)(buff | bit3 << 3 | bit2 << 2 | bit1 << 1 | bit0);
dataBytes.Add(buff);
// we finished reading the length bytes
if (data_length == 0 && dataBytes.Count == 4)
{
List <byte> len_bytes = dataBytes.GetRange(0, 4);
//len_bytes.Reverse();
data_length = BitConverter.ToInt32(len_bytes.ToArray(), 0);
if (data_length < 0)
{
Console.WriteLine($"Data length [{data_length}] < 0");
return(new byte[] { });
}
}
// we're done reading the data
else if (data_length != 0 && (dataBytes.Count - 4) == data_length)
{
Console.WriteLine($"Finished reading 4+{data_length} bytes");
return(dataBytes.GetRange(4, data_length).ToArray());
}
is_high_bits = true;
}
}
}
break;
default:
return(new byte[] { });
}
Console.WriteLine("Didn't do anything?");
return(new byte[] { });
}
