How to protect the mp3 file from read or copy on Android?

Question

I have mp3 files in root folder of my app, but some users have root rights and they can play or copy.
I want to protect my files, use them just in my app.
How can I do this?
Archiving is not a option.

Answer 1

There is no way to prevent users from copying, modifying or deleting files on the filesystem if they have root access.

Archiving would be the only way, because converting your files back to mp3 would take some effort (reversing your android application in order to retrieve the packing algorithm).

Answer 2

You may encrypt your files to make extraction harder but that won't work against qualified person because you'll have to keep decryption key somewhere on device or inside app. You should accept the fact that any of your resource might be extracted and stop worrying.