internal static string GetHiddenValue(StegoBitmap bitmap, Channel channel)
{
byte[] hidden = bitmap.GetChannel(channel);
bool[] headerBits = hidden.Take(16).SelectMany(x => GetNLastBit(x, 1)).ToArray();
byte E = BoolArrayToByte(headerBits.Take(8).ToArray());
byte lengthSize = BoolArrayToByte(headerBits.Skip(8).Take(8).ToArray());
bool[] lengthBits = hidden.Skip(16).Take(lengthSize * 8).SelectMany(x => GetNLastBit(x, 1)).ToArray();
List <byte> lengthBytes = new List <byte>();
for (int i = 0; i < lengthBits.Length; i += 8)
{
lengthBytes.Add(BoolArrayToByte(lengthBits.Skip(i).Take(8).ToArray()));
}
int length = GetIntFromBytes(lengthBytes);
bool[] bits = hidden.Skip(16 + lengthSize * 8).Take(length * 8).SelectMany(x => GetNLastBit(x, 1)).ToArray();
List <byte> bytes = new List <byte>();
for (int i = 0; i < bits.Length; i += 8)
{
bytes.Add(BoolArrayToByte(bits.Skip(i).Take(8).ToArray()));
}
return(ByteArrayToString(bytes.ToArray()));
}
public StegoBitmap(StegoBitmap stegoBitmap, byte[] changedChannel, Channel channel)
{
RedChannel = stegoBitmap.RedChannel;
GreenChannel = stegoBitmap.GreenChannel;
BlueChannel = stegoBitmap.BlueChannel;
if (channel == Channel.R)
{
RedChannel = changedChannel;
}
if (channel == Channel.G)
{
GreenChannel = changedChannel;
}
if (channel == Channel.B)
{
BlueChannel = changedChannel;
}
sourceFile = new Bitmap(stegoBitmap.sourceFile.Width, stegoBitmap.sourceFile.Height);
int counter = 0;
for (int i = 0; i < sourceFile.Width; i++)
{
for (int j = 0; j < sourceFile.Height; j++)
{
sourceFile.SetPixel(i, j, System.Drawing.Color.FromArgb(RedChannel[counter], GreenChannel[counter], BlueChannel[counter]));
counter++;
}
}
}
private void DrawHistogram(StegoBitmap sourceBitmap, StegoBitmap modifiedBitmap)
{
DrawToCanvas(imgRS, sourceBitmap.RedChannel, System.Windows.Media.Colors.PaleVioletRed);
DrawToCanvas(imgRM, modifiedBitmap.RedChannel, System.Windows.Media.Colors.DarkRed);
DrawToCanvas(imgGS, sourceBitmap.GreenChannel, System.Windows.Media.Colors.LightGreen);
DrawToCanvas(imgGM, modifiedBitmap.GreenChannel, System.Windows.Media.Colors.DarkGreen);
DrawToCanvas(imgBS, sourceBitmap.BlueChannel, System.Windows.Media.Colors.LightBlue);
DrawToCanvas(imgBM, modifiedBitmap.BlueChannel, System.Windows.Media.Colors.DarkBlue);
}
private void Ofd_FileOk(object sender, System.ComponentModel.CancelEventArgs e)
{
sourceBitmap = new StegoBitmap(ofd.FileName);
imgSource.Source = GetSource(sourceBitmap.GetImage());
Channel?result = Stego.HasHiddenValue(sourceBitmap);
if (result.HasValue)
{
tbInput.Text = Stego.GetHiddenValue(sourceBitmap, result.Value);
}
else
{
CalculateLabels();
}
}
internal static Channel?HasHiddenValue(StegoBitmap bitmapImage)
{
if (HasE(bitmapImage.RedChannel))
{
return(Channel.R);
}
else if (HasE(bitmapImage.GreenChannel))
{
return(Channel.G);
}
else if (HasE(bitmapImage.BlueChannel))
{
return(Channel.B);
}
else
{
return(null);
}
}
internal static Bitmap Hide(StegoBitmap bitmap, string text, Channel channel)
{
byte[] sourceChannel = bitmap.GetChannel(channel);
byte flag = Convert.ToByte('E');
byte size = GetSizeOfLength(text.Length);
byte[] length = GetLengthInBytes(text.Length, size);
byte[] stegoText = StringToByteArray(text);
byte[] stegoBytes = new byte[1 + 1 + length.Length + stegoText.Length];
stegoBytes[0] = flag;
stegoBytes[1] = size;
int counter = 0;
for (int i = 0; i < length.Length; i++)
{
stegoBytes[i + 2] = length[counter++];
}
counter = 0;
for (int i = 0; i < stegoText.Length; i++)
{
stegoBytes[i + 2 + length.Length] = stegoText[counter++];
}
bool[] stegoBits = stegoBytes.SelectMany(x => ByteToBoolArray(x)).ToArray();
for (int i = 0; i < stegoBits.Length; i++)
{
if ((sourceChannel[i] % 2 == 0) && stegoBits[i])
{
sourceChannel[i]++;
}
else if ((sourceChannel[i] % 2 == 1) && !stegoBits[i])
{
sourceChannel[i]--;
}
}
return(new StegoBitmap(bitmap, sourceChannel, channel).GetImage());
}
private void BtnHide_Click(object sender, RoutedEventArgs e)
{
Channel channel;
if (((ComboBoxItem)cmbChannel.SelectedItem).Content.ToString() == "Otomatik")
{
int changeInRed = Stego.CalculateChange(sourceBitmap.RedChannel, Stego.StringToByteArray(tbInput.Text));
int changeInGreen = Stego.CalculateChange(sourceBitmap.GreenChannel, Stego.StringToByteArray(tbInput.Text));
int changeInBlue = Stego.CalculateChange(sourceBitmap.BlueChannel, Stego.StringToByteArray(tbInput.Text));
int min = changeInRed;
if (changeInGreen < min)
{
min = changeInGreen;
}
if (changeInBlue < min)
{
min = changeInBlue;
}
if (min == changeInRed)
{
channel = Channel.R;
}
else if (min == changeInGreen)
{
channel = Channel.G;
}
else
{
channel = Channel.B;
}
}
else
{
channel = (Channel)(cmbChannel.SelectedIndex - 1);
}
modifiedBitmap = new StegoBitmap(Stego.Hide(sourceBitmap, tbInput.Text, channel));
imgModified.Source = GetSource(modifiedBitmap.GetImage());
DrawHistogram(sourceBitmap, modifiedBitmap);
}
