private void btnDecrypt_Click(object sender, EventArgs e)
{
if (tbInputKey.Text.Trim().Length < 8)
{
MessageBox.Show("Minimum secret passphrase length is 8 characters", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
try
{
lblStatus.Text = "Processing...";
var passphrase = tbInputKey.Text.Trim();
// Retrieve the Id block as string
var retrievedIdBlockString = Encoding.ASCII.GetString(ByteCipher.Decrypt(stegoFileBytes.Skip(stegoFileBytes.Length - 112).ToArray(), passphrase)).Split('|');
if (retrievedIdBlockString.Length != 3)
{
throw new Exception("File is corrupted or invalid");
}
var retrievedHash = retrievedIdBlockString[0];
var hiddenFileType = retrievedIdBlockString[1].ToLower();
var keyindex = Convert.ToInt32(retrievedIdBlockString[2]);
var retrievedCipherBytesWithIdBlock = stegoFileBytes.Skip(keyindex).ToArray();
var retrievedCipherBytes = retrievedCipherBytesWithIdBlock.Take(retrievedCipherBytesWithIdBlock.Length - 112).ToArray();
// Attempt to decrypt
var retrievedMessageBytes = ByteCipher.Decrypt(retrievedCipherBytes, passphrase);
if (retrievedHash != HashGenerator.GetHash(retrievedMessageBytes))
{
throw new Exception("File has been modified");
}
// Save the retrieved message file
saveExtractedFileDialog.Filter = String.Format("{0} file (*.{1})|*.{1}", hiddenFileType.ToUpper(), hiddenFileType);
DialogResult saveExtractedFileDialogResult = saveExtractedFileDialog.ShowDialog();
if (saveExtractedFileDialogResult == DialogResult.OK)
{
File.WriteAllBytes(saveExtractedFileDialog.FileName, retrievedMessageBytes);
DialogResult successDialog = MessageBox.Show("File extracted successfully", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
if (successDialog == DialogResult.OK && cbOpenRecoveredFile.Checked)
{
Process.Start(saveExtractedFileDialog.FileName);
}
}
}catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
// Reset the form visual
lblStatus.Text = "Ready";
lblFileNameStego.Text = "No file chosen";
lblStegoFileSize.Text = lblStegoFileType.Text = "-";
btnDecrypt.Enabled = false;
}
}
}
private void btnEncrypt_Click(object sender, EventArgs e)
{
if (tbGeneratedKey.Text.Trim().Length < 8)
{
MessageBox.Show("Minimum secret passphrase length is 8 characters", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
lblStatus.Text = "Processing...";
saveStegoFileDialog.Filter = String.Format("{1} file (*.{0})|*.{0}", coverFileType.ToLower(), coverFileType);
DialogResult saveStegoFileDialogResult = saveStegoFileDialog.ShowDialog();
if (saveStegoFileDialogResult == DialogResult.OK)
{
try
{
//Stopwatch sw = Stopwatch.StartNew(); // Stopwatch for benchmarking
var cipherBytes = ByteCipher.Encrypt(messageFileBytes, tbGeneratedKey.Text.Trim());
//sw.Stop(); // Stop the sw and write the elapsed time
//Debug.WriteLine("Total encryption time: "+ sw.ElapsedMilliseconds + " ms");
var cipherBytesWithIdBlock = cipherBytes.Concat(ByteCipher.Encrypt(generatedIdBlock, tbGeneratedKey.Text.Trim())).ToArray();
//sw.Restart(); // Restart the stopwatch
File.WriteAllBytes(saveStegoFileDialog.FileName, coverFileBytes.Concat(cipherBytesWithIdBlock).ToArray());
//sw.Stop();
//Debug.WriteLine("Total hiding time: " + sw.ElapsedMilliseconds + " ms");
DialogResult successDialog = MessageBox.Show("File encrypted and hid successfully", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
if (successDialog == DialogResult.OK && cbOpenStegoFile.Checked)
{
Process.Start(saveStegoFileDialog.FileName);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
// Reset form visual
lblStatus.Text = "Ready";
lblFileNameCover.Text = lblFileNameMessage.Text = "No file chosen";
lblCoverFileSize.Text = lblCoverFileType.Text = lblMessageFileSize.Text = lblMessageFileType.Text = "-";
coverFileExists = messageFileExists = false;
btnEncrypt.Enabled = false;
}
}
else
{
lblStatus.Text = "Ready";
}
}
}
