How to store and extract data from WIND (.wnd) file in Android

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I want that no one can copy the sound file of my app as it's copyrighted. For this I am thinking to store the sound file (.ogg) in the wind file and extract the sound file at runtime.

How can we do this?

Thank you

android
1 Answers

I am not 100% sure that a WIND file is a secure filetype for audio storage, so I base this on a theory: In my earlier days I used FFT (Fast Fourier Transform) to make a spectrum of audio-data and these functions was called "WIND" types.

An example is found here: https://github.com/bewantbe/audio-analyzer-for-android/blob/master/audioSpectrumAnalyzer/src/main/java/github/bewantbe/audio_analyzer_for_android/STFT.java

     (...line 74 ...)
     private void initWindowFunction(int fftlen, String wndName) {
         wnd = new double[fftlen];
         switch (wndName) {
             case "Bartlett":
                 for (int i=0; i<wnd.length; i++) {  // Bartlett
                     wnd[i] = asin(sin(PI*i/wnd.length))/PI*2;
                 }
                 break;
             case "Hanning":

If these data is store it could be a "wind-file" of some kind. Earlier versions of TM Soft "White noise" saved files as WND: https://www.tmsoft.com/white-noise/

Now for your problem to store files secure.
Google states that you should use file system encryption: https://developer.android.com/training/articles/security-tips

To provide additional protection for sensitive data, you can encrypt local files using a key that is not directly accessible to the application. For example, you can place a key in a KeyStore and protect it with a user password that is not stored on the device. While this does not protect data from a root compromise that can monitor the user inputting the password, it can provide protection for a lost device without file system encryption.

I would suggest that you encrypt and then decrypt within your app using this method: https://code.tutsplus.com/tutorials/storing-data-securely-on-android--cms-30558

By encrypting your files your files will be safe, even if the device is rooted.

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