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| public partial class Steganography : Form
{
PasswordForm passwordForm = new PasswordForm();
Bitmap bmpOriginal;
Bitmap bmpModified;
byte[] exampleFile;
byte[] exFile;
byte[] file;
public Steganography()
{
InitializeComponent();
}
private void SteganographyAlgorithmForm_Paint(object sender, PaintEventArgs e)
{
OriginalPictureBox.Image = bmpOriginal;
if (bmpModified == null)
{
return;
}
ModifiedPictureBox.Image = bmpModified;
}
private byte[] PasswordSHA(string password)
{
return new SHA256Managed().ComputeHash(Encoding.ASCII.GetBytes(password));
}
private byte[] EncryptionSymmetricAlgorithm(byte[] file, byte[] password, SymmetricAlgorithm sa, CipherMode cm, PaddingMode pm)
{
byte[] buffer;
byte[] cipherbytes;
sa.Key = password;
sa.IV = new byte[] { 2, 3, 1, 86, 31, 76, 24, 46, 31, 76, 24, 46, 86, 31, 76, 24 };
sa.Mode = cm;
sa.Padding = pm;
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(
ms,
sa.CreateEncryptor(),
CryptoStreamMode.Write);
buffer = file;
cs.Write(buffer, 0, buffer.Length);
cs.Close();
cipherbytes = ms.ToArray();
ms.Close();
return cipherbytes;
}
private void SaveAImage(byte[] file)
{
try
{
this.Cursor = Cursors.WaitCursor;
bmpModified = new Bitmap(bmpOriginal, bmpOriginal.Width, bmpOriginal.Height);
int numberbytes = file.Length;
byte[] bytesOriginal = new byte[numberbytes + 1];
bytesOriginal[0] = (byte)numberbytes;
for (int i = 0; i < file.Length; i++)
{
bytesOriginal[i + 1] = file[i];
}
int byteCount = 0;
for (int i = 0; i < bmpOriginal.Width; i++)
{
for (int j = 0; j < bmpOriginal.Height; j++)
{
if (bytesOriginal.Length == byteCount)
return;
Color clrPixelOriginal = bmpOriginal.GetPixel(i, j);
byte r = (byte)((clrPixelOriginal.R & ~0x7) | (bytesOriginal[byteCount] >> 0) & 0x7);
byte g = (byte)((clrPixelOriginal.G & ~0x7) | (bytesOriginal[byteCount] >> 3) & 0x7);
byte b = (byte)((clrPixelOriginal.B & ~0x3) | (bytesOriginal[byteCount] >> 6) & 0x3);
byteCount++;
bmpModified.SetPixel(i, j, Color.FromArgb(r, g, b));
}
}
}
catch (Exception ex)
{
MessageBox.Show("Error hiding message." + ex.Message);
}
finally
{
this.Cursor = Cursors.Arrow;
Invalidate();
}
}
private void ExtractTheFile()
{
byte[] bytesExtracted = new byte[256 + 1];
try
{
this.Cursor = Cursors.WaitCursor;
int byteCount = 0;
for (int i = 0; i < bmpModified.Width; i++)
{
for (int j = 0; j < bmpModified.Height; j++)
{
if (bytesExtracted.Length == byteCount)
{
return;
}
Color clrPixelModified = bmpModified.GetPixel(i, j);
byte bits123 = (byte)((clrPixelModified.R & 0x7) << 0);
byte bits456 = (byte)((clrPixelModified.G & 0x7) << 3);
byte bits78 = (byte)((clrPixelModified.B & 0x3) << 6);
bytesExtracted[byteCount] = (byte)(bits78 | bits456 | bits123);
byteCount++;
}
}
}
catch (Exception ex)
{
MessageBox.Show("Error extracting message." + ex.Message);
}
finally
{
this.Cursor = Cursors.Arrow;
int numberbytes = bytesExtracted[0];
byte[] file = new byte[numberbytes];
for (int i = 0; i < numberbytes; i++)
{
file[i] = bytesExtracted[i + 1];
}
exFile = file;
}
}
private byte[] DecryptionSymmetricAlgorithm(byte[] cipherbytes, byte[] password, SymmetricAlgorithm sa, CipherMode cm, PaddingMode pm)
{
byte[] buffer;
sa.Key = password;
sa.IV = new byte[] { 2, 3, 1, 86, 31, 76, 24, 46, 31, 76, 24, 46, 86, 31, 76, 24 };
sa.Mode = cm;
sa.Padding = pm;
MemoryStream ms = new MemoryStream(cipherbytes);
CryptoStream cs = new CryptoStream(
ms,
sa.CreateDecryptor(),
CryptoStreamMode.Read);
buffer = new Byte[cipherbytes.Length];
cs.Read(buffer, 0, cipherbytes.Length);
cs.Close();
ms.Close();
return buffer;
}
private void openFileToolStripMenuItem_Click(object sender, EventArgs e)
{
if (openFileDialog.ShowDialog() == DialogResult.OK)
exampleFile = File.ReadAllBytes(openFileDialog.FileName);
}
private void originalImageToolStripMenuItem_Click(object sender, EventArgs e)
{
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
bmpOriginal = (Bitmap)Bitmap.FromFile(openFileDialog.FileName);
}
}
private void modifiedImageToolStripMenuItem_Click(object sender, EventArgs e)
{
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
bmpOriginal = (Bitmap)Bitmap.FromFile(openFileDialog.FileName);
bmpModified = (Bitmap)Bitmap.FromFile(openFileDialog.FileName);
}
}
private void saveFileToolStripMenuItem_Click(object sender, EventArgs e)
{
if (passwordForm.ShowDialog() == DialogResult.Cancel)
{
return;
}
ExtractTheFile();
try
{
file = DecryptionSymmetricAlgorithm(
exFile,
PasswordSHA(passwordForm.Password),
Rijndael.Create(),
CipherMode.ECB,
PaddingMode.Zeros
);
if (saveFileDialog.ShowDialog() == DialogResult.OK)
{
File.WriteAllText(saveFileDialog.FileName, Encoding.GetEncoding(1251).GetString(file));
}
}
catch (Exception ex)
{
MessageBox.Show("Wrong password. " + ex);
}
}
private void modifiedIToolStripMenuItem_Click(object sender, EventArgs e)
{
if (passwordForm.ShowDialog() == DialogResult.Cancel)
{
return;
}
SaveAImage(EncryptionSymmetricAlgorithm(
exampleFile,
PasswordSHA(passwordForm.Password),
Rijndael.Create(),
CipherMode.ECB,
PaddingMode.Zeros
));
saveFileDialog.Filter = "jpg files (*.jpg)|*.jpg|All files (*.*)|*.*";
if (saveFileDialog.ShowDialog() == DialogResult.OK)
{
long quality = 90L;
if (quality < 0 || quality > 100)
{
throw new ArgumentOutOfRangeException("quality must be between 0 and 100");
}
EncoderParameter qualityParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
EncoderParameters encoderParameters = new EncoderParameters(1);
encoderParameters.Param[0] = qualityParam;
ModifiedPictureBox.Image.Save(saveFileDialog.FileName, GetEncoder(ImageFormat.Jpeg), encoderParameters);
}
}
private void exitToolStripMenuItem_Click(object sender, EventArgs e)
{
this.Close();
}
public static ImageCodecInfo GetEncoder(ImageFormat format)
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
foreach (ImageCodecInfo codec in codecs)
{
if (codec.FormatID == format.Guid)
{
return codec;
}
}
return null;
}
public partial class PasswordForm : Form
{
public string Password { get; set; }
public PasswordForm()
{
InitializeComponent();
}
private void OKButton_Click(object sender, EventArgs e)
{
Password = PasswordTextBox.Text;
Close();
}
private void CancelButton_Click(object sender, EventArgs e)
{
Password = "";
Close();
}
} |
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