If you have audio files that you would like to protect, then one way to do this is audio watermark them. In other words, add an extra piece of audio, like a voiceover or sound effect, to the audio file that repeats perhaps every ten seconds or so. If you have a lot of files, then to do this manually would take a lot of time.
AG Watermark Generator
Luckily there is a very good program to do all the work for you, and you can download a free demo and try it out.