public void ExtractMessage(string keyFile, string inputFile)
{
FileStream sourceStream = null;
WaveStream audioStream = null;
//create an empty stream to receive the extracted message
MemoryStream messageStream = new MemoryStream();
//open the key file
Stream keyStream = new FileStream(keyFile, FileMode.Open);
try {
//open the carrier file
sourceStream = new FileStream(inputFile, FileMode.Open);
audioStream = new WaveStream(sourceStream);
WaveUtility utility = new WaveUtility(audioStream);
//exctract the message from the carrier wave
utility.Extract(messageStream, keyStream);
messageStream.Seek(0, SeekOrigin.Begin);
string extractedMessage = new StreamReader(messageStream).ReadToEnd();
Console.WriteLine("Message is.....");
Console.WriteLine(extractedMessage);
Console.ReadKey();
} catch (Exception ex) {
Console.WriteLine($"Error extracting message {ex.Message}");
} finally {
if (keyStream != null)
{
keyStream.Dispose();
}
if (messageStream != null)
{
messageStream.Dispose();
}
if (audioStream != null)
{
audioStream.Dispose();
}
if (sourceStream != null)
{
sourceStream.Dispose();
}
}
}
public void AddMessage(string message, string keyFile, string inputFile, string outputFile)
{
Stream sourceStream = null;
FileStream destinationStream = null;
WaveStream audioStream = null;
//create a stream that contains the message, preceeded by its length
Stream messageStream = GetMessageStream(message);
//open the key file
Stream keyStream = new FileStream(keyFile, FileMode.Open);
try {
//how man samples do we need?
long countSamplesRequired = WaveUtility.CheckKeyForMessage(keyStream, messageStream.Length);
if (countSamplesRequired > Int32.MaxValue)
{
throw new Exception("Message too long, or bad key! This message/key combination requires " + countSamplesRequired + " samples, only " + Int32.MaxValue + " samples are allowed.");
}
sourceStream = new FileStream(inputFile, FileMode.Open);
//create an empty file for the carrier wave
destinationStream = new FileStream(outputFile, FileMode.Create);
//copy the carrier file's header
audioStream = new WaveStream(sourceStream, destinationStream);
if (audioStream.Length <= 0)
{
throw new Exception("Invalid WAV file");
}
//are there enough samples in the carrier wave?
if (countSamplesRequired > audioStream.CountSamples)
{
String errorReport = "The carrier file is too small for this message and key!\r\n" +
"Samples available: " + audioStream.CountSamples + "\r\n" +
"Samples needed: " + countSamplesRequired;
throw new Exception(errorReport);
}
//hide the message
WaveUtility utility = new WaveUtility(audioStream, destinationStream);
utility.Hide(messageStream, keyStream);
} catch (Exception ex) {
Console.WriteLine($"Error: {ex.Message}");
} finally {
if (keyStream != null)
{
keyStream.Dispose();
}
if (messageStream != null)
{
messageStream.Dispose();
}
if (audioStream != null)
{
audioStream.Dispose();
}
if (sourceStream != null)
{
sourceStream.Dispose();
}
if (destinationStream != null)
{
destinationStream.Dispose();
}
}
}
