Method for controlling access to encrypted content using multiple broadcast encryption based control blocks

Abstract

An apparatus and a method are provided for selectively accessing digital content carried on a distribution medium such as a physical medium or a broadcast medium. In one embodiment, a plurality of digital content items are encrypted under a plurality of different key management blocks, wherein each key management block is associated with a different set of device keys. The plurality of content items may be provided together on a single distribution medium to devices having assigned device keys, so that devices may selectively access content as determined by the different key management block used to encrypt the various content items and by the device keys assigned to the devices. Depending on the association between the device key and the key management blocks, the decoding device may decode all of the content items, some of the content items, or none of the content items. To provide greater security, each content item may be multiple encrypted using multiple key management blocks per content item.