So far you can't close the "analog hole."
I've seen folk work hard on protecting the MP3 digital content and then I show them how I can tap into the headphone jack and get the content out unprotected again.
So there it is. There is no protection known for audio works.
I know almost nothing about mp3 players and I am having a hard time find the information I need for something I want to do with one. I want to buy a cheap mp3 player and load some music/audio books on it. I need to be able to make it so that someone else can not delete or add music/audio books/other files to it. Any recommendations on an mp3 player and way to accomplish this? Thanks