DRM is surprisingly security oriented, if you think about it,the premise of DRM is not trusting the user, which is more extreme than most security models (allow the user root/admin access to the OS is anithetical to not trusting the user).
Much of the base terminology of DRM comes from the military, and it involves the generals "back home" being able to trust that a computer out in the field, containing sensitive data, will not allow non-authorized personnel, never mind the enemy, to access said data.
Because it works both ways. I can send my data to a server and have it do things to it without ever actually knowing it. You can't let me watch a video without letting me watch a video.
