Image Number 5 for United States Patent #7693280.
A sequence of content keys are shared between a receiver of pieces of digital content and a computing device upon which the content is to be rendered. The receiver encrypts each piece of content according to a corresponding content key in the sequence and forwards the encrypted content to the computing device and the computing device decrypts the encrypted content according to the corresponding content key. The receiver initially transmits to the computing device an initialization digital license with an initial content key (CK0) therein. Each of the receiver and the computing device derive a new content key (CKx) in the sequence from the initial content key (CK(0)) in the sequence on an as-needed basis and in a coordinated fashion. The initialization license is required only once for the sequence of content keys, and the receiver need not explicitly communicate (CKx) to the computing device for each piece of content.