forward lock mp3 file in Android 2.x

I want add some drm protection (forward lock) to mp3 file to use it in android phone.

Can i encrypt my mp3 file with an application and push it in the android phone ?

OR

I need to implement the application to encrypt the f开发者_Python百科ile and after that push it in the andoird phone? (if i need to implement the encrypter - Wich library (API) i need to use ?)

Thank's a lot and excuz my english

OK! more exemples.

case 1: User get file from server (music file1.mp3) in android phone ! User use it like ringtones but can't share it or download it in computer.

case 2: User get file from server (picture file1.png) in android phone ! User use it like wallpapers but can't share it or download it in computer.

PROBLEM : how can i implement -> the user can't share the file or download it in computer ?

DRM is -> digital rights management.

MP3 does not support DRM.

Is DRM really what you want to accomplish? What exactly is your goal? You can encrypt a file and decrypt it again in your app (will take long time, it's a mobile cpu!), but then your application needs to have the decryption key inside. Basically anyone can read this key from your app. This is rather "security by obscurity". No win.

So, again: what you really want to do?