there are many application available to ensure security.but there is wall there is also one entrance to bypass security. you should read this site for DRM system. http://en.wikipedia.org/wiki/Digital_rights_management[^]

Pete O'Hanlon wrote: Ooh. Text speak. Guaranteed to really annoy. Man, forget helping the OP now, as far as I'm concerned. "The clue train passed his station without stopping." - John Simmons / outlaw programmer "Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon "Not only do you continue to babble nonsense, you can't even correctly remember the nonsense you babbled just minutes ago." - Rob Graham