Patent ID: 7756272
Filing Date: 2010-07-13
Classification: G11B,H04L,H04N

Abstract:
1. A non-transitory computer-readable medium comprising: encrypted digital content, the encrypted digital content including representations of a plurality of versions of a plurality of regions of the encrypted digital content, each version of the plurality of versions being encrypted with a unique cryptographic key; and program logic for processing by an interpreter in a playback device, including: program logic configured to query said playback device to obtain the results of cryptographic computations performed by said playback device, where said cryptographic operations use a plurality of cryptographic keys, each cryptographic key of the plurality of cryptographic kegs corresponding to a unique version of the plurality of versions, the plurality of cryptographic keys not being accessible by said program logic; program logic configured to determine whether playback is authorized to proceed on said playback device by using said obtained results; and program logic configured to derive values of the plurality of cryptographic keys for decrypting a particular version of the plurality of versions and thereby enable playback of the particular version, if it is it determined that playback is authorized.