//decodes an steg image
static public void Decode(string InputImage, string outputTxt, bool encrypted = false)
{
//formating
Console.WriteLine("\n\n");
//decalare as null so we can check later for cleanup
Bitmap image = null;
FileStream output = null;
ShellProgressBar.ProgressBar bar = null;
string password = null;
int count = 0;
//get the password before we start to read the data
if (encrypted)
{
//Some Console.WroteLine() for formating
Console.WriteLine();
Console.Write("Please enter the password: "******"\n");
}
try
{
//Open file streams and read all neccessary data like the image and get the progress bar
output = new FileStream(outputTxt, FileMode.Create);
bar = Progress.GetProgressBar(100, InputImage, outputTxt, "decode");
bar.Tick("Reading Image...");
image = new Bitmap(InputImage);
bar.Tick("Decoding image");
//update the MaxTicks after reading the image
bar.MaxTicks = image.Height / 2;
List <byte> buffer = new List <byte>();
//loop through the image pixels
for (int y = 0; y < image.Height; y++)
{
bar.Tick(y);
for (int x = 0; x < image.Width; x++)
{
Color imagePixel = image.GetPixel(x, y);
for (int channel = 0; channel < 3; channel++)
{
LSB.bitCount++;
switch (channel)
{
case 0:
getLSB(imagePixel.R);
break;
case 1:
getLSB(imagePixel.G);
break;
case 2:
getLSB(imagePixel.B);
break;
}
//if we are done with the byte
if (AtEndOfByte())
{
LSB.byteCount++;
buffer.Add(currentByte);
//if the byte is all 0's aka null byte
if (LSB.currentByte == '\0')
{
//if we are at the end of the image with a count of 5
count++;
if (count == 5)
{
//mark that we reached the end and fufull exit conditions for the loop
LSB.atEnd = true;
x = image.Width - 1;
y = image.Height - 1;
break;
}
}
else
{
//if the byte is not null we write it to the output
count = 0;
output.Write(buffer.ToArray(), 0, buffer.ToArray().Length);
buffer.Clear();
}
//reset bit count and current byte
LSB.bitCount = 0;
LSB.currentByte = 0;
}
}
}
}
//if we never find the end points of the encoded data
if (LSB.atEnd == false)
{
Exception ex = new Exception("The image does not seem to be encoded or the image was altered after encoding");
throw ex;
}
//if the data was encrypted then we need to decrypt the data inorder to revert to original form
if (encrypted)
{
output.Close();
bar.Tick("Decypting the file...");
outputTxt = Encypt.GetDecryptedFile(outputTxt, password);
}
bar.Tick("Got " + LSB.byteCount + " bytes from " + InputImage + " and extracted to " + outputTxt);
bar.Tick(bar.MaxTicks);
}
catch (Exception ex)
{
Console.WriteLine("Error while decoding image: " + ex.Message);
}
finally
{
//cleanup
if (image != null)
{
image.Dispose();
}
if (output != null)
{
output.Dispose();
}
if (bar != null)
{
bar.Dispose();
}
}
}
//encodes and image with the given txt file
static public void Encode(string InputImage, string InputTxt, string OutputImage, bool encrypted = false)
{
//formating
Console.WriteLine("\n\n\n");
Bitmap image = null;
FileStream input = null;
ShellProgressBar.ProgressBar bar = null;
int count = 0;
//if the file is to be encrypted we encrypt the file and get the new encrypted one before moving on
if (encrypted)
{
//gets the new encrypted file
InputTxt = Encypt.GetEncryptedFile(InputTxt);
//formating
Console.WriteLine();
Console.WriteLine();
}
try
{
//gets the file that is to be places in the image
input = new FileStream(InputTxt, FileMode.Open);
//get the progress bar
bar = Progress.GetProgressBar((int)input.Length, InputTxt, InputImage, "encode");
//update the progress bar
bar.Tick("Reading image...");
//read the image
image = new Bitmap(InputImage);
//update progress bar
bar.Tick("Encoding image..");
//get the first byte from the file
int temp = input.ReadByte();
LSB.currentByte = (byte)temp;
//check if the file is empty
if (temp == -1)
{
Exception ex = new Exception("The file seems to be empty");
throw ex;
}
//loop through the whole image
for (int y = 0; y < image.Height; y++)
{
//update progress bar with the byte count
//one of the parameters in creating the progress bar is the size of the file
//so the bar knows the complete size and can calculate percent based on current count
bar.Tick(LSB.byteCount);
for (int x = 0; x < image.Width; x++)
{
//current pixel
Color imagePixel = image.GetPixel(x, y);
byte red = 0;
byte green = 0;
byte blue = 0;
//loop through the color channels RGB
for (int i = 0; i < 3; i++)
{
//check which channel we are on and encode based on that
//calls the setLSB methos which encodes the pixel channel to match that of the byte from the file
switch (i)
{
case 0:
red = setLSB(imagePixel.R);
break;
case 1:
green = setLSB(imagePixel.G);
break;
case 2:
blue = setLSB(imagePixel.B);
break;
}
//update our bit count so we know when we completed a whole byte
LSB.bitCount++;
//if we have complete a whole byte we need to get the next byte from the file
if (AtEndOfByte())
{
//update byte count
LSB.byteCount++;
//read the byte
temp = input.ReadByte();
//set current byte
LSB.currentByte = (byte)temp;
//if there was nothing left in the file
if (temp == -1)
{
//update count
count++;
//if we have put 6 null bytes at the end of the encoding
//this means we have completly encoded the txt file within the image
if (count == 6)
{
//break out and close the file and set the end bool to true as we have finished
if (input != null)
{
input.Close();
}
LSB.atEnd = true;
break;
}
//set current byte to a null byte so that we can encode it within the image
//6 null bytes are placed in the image to signify the end of the encoded message
//this is so when we decode we know that we have finshed reading the encoded data
LSB.currentByte = (byte)'\0';
}
//reset bit count as we got a new byte
LSB.bitCount = 0;
}
}
//once we have finished encoding one pixel we replace the old one with the new encoded one
image.SetPixel(x, y, Color.FromArgb(red, green, blue));
//if we are dont encoding exit the loops
if (LSB.atEnd && LSB.bitCount == 8)
{
x = image.Width - 1;
y = image.Height - 1;
}
}
}
//if we have finished looping through the image but did not finish encoding that means the txt file was too large for this image
if (LSB.bitCount != 8 || LSB.atEnd == false)
{
Exception ex = new Exception("The file you are trying to hide is too big try with a larger image or smaller message");
throw ex;
}
try
{
//save the new enocded image
bar.Tick("Saving Image...");
image.Save(OutputImage, System.Drawing.Imaging.ImageFormat.Png);
bar.Tick(bar.MaxTicks);
}
catch (Exception e)
{
//if we get an error while saving the image
Exception ex = new Exception("The image failed to save make sure the file does not already exist");
throw ex;
}
}
catch (Exception ex)
{
Console.WriteLine("Error while encoding the image: " + ex.Message);
}
finally
{
//cleanup
if (image != null)
{
image.Dispose();
}
if (input != null)
{
input.Dispose();
}
if (bar != null)
{
bar.Dispose();
}
}
}
