How to apply DRM on a .mp3/.wav file

Question

Can anyone help me to apply DRM on .mp3 or .wav. I know about DRM, but i have no idea about it's implementation process. If anyone has any idea on DRM's implementation(for .mp3/.wav) pleae help me. It would be great if this is for C#. It would be nice if any of you give me some Source/link.

Thanks Pranab

Answer 1

To DRM any sort of file, all you are really doing is encrypting it in such a way that only authorized clients (programs) can retrieve the content from the file. Typically, this requires special client software. Depending on your requirements, it may also require a central server for these clients to call back to.

In general, you cannot simple "DRM an .mp3", because a generic MP3 player cannot read the data then. (if it could, it wouldn't be a DRMed file then, now would it?)

Answer 2

Possible, yes. Easy, not so much:

• The "easiest" way is to drop the MP3 or WAV requirement and go with WMA (Windows Media Audio). In that case, you could use the Microsoft PlayReady Server SDK (expensive - several tens of thousand $) to do Windows Media DRM-compatible encryption. The resulting encrypted WMA can then be played by Windows Media Player and by a very large number of portable devices, after having received a "license" (essentially, decryption key + usage rights).
• If you decide to go with WMA and you can't do large upfront investments, perhaps a hosted (SaaS) solution such as BuyDRM is for you.
• Another possibility, which requires an even larger investment, if you want to stick with MP3 or WAV, is to use PlayReady itself with the "Envelope" format, or OMA 2 DRM with the "DCF" format, or Marlin DRM, or several other ones, which in addition to investing on the server side would also require you to write a custom media player.