On Tuesdays the USPTO issues new patents. Today's Spotlight Patents concern techniques for copy protection and for conditional access. Assigned to LG Electronics (KR), the first patent concerns a copy protection method for digital media. Assigned to Nagravision (CH), the second patent concerns a process for managing the handling of conditional access data by at least two decoders.
A method of digital media copy protection is disclosed. The method of the present invention is applicable to any type of digital media data and makes no assumptions on any specific media properties. The method includes a process of protecting digital media data with a public key using a hybrid cryptographic technique, a process of watermarking the media data, and an output device compliance testing process through an authenticated handshake protocol. Because of the media data protection with the hybrid cryptographic technique, a non-compliant playing device is not able to play or read a protected media data set. The output device compliance testing protocol is used to prevent the media signal from being copied to any non-compliant device. These features of the present invention are used to reduce the possibility of making any illegal copies on any nonstandard equipment. In addition, the data watermarking is used to modify the played and recorded media signals, to keep track of the identification information of the related devices for detecting any illegal copy maker, and to separate legal media data sets from the illegal data sets.
7,502,473, "Process for managing the handling of conditional access data by at least two decoders," assigned to Nagravision S.A. (CH).
One embodiment of the invention relates to a management method for conditional access data processing by at least three decoders associated to a subscriber. These decoders include activation/deactivation means for conditional access data processing and local communication means structured to allow communication between the subscribers' decoders. This method comprises a reception step, a determination step, and a comparison step. In addition conditional access data processing by said first decoder (STB) is deactivated if the latter has not received messages from the required number of different decoders. Another embodiment of the invention relates to a decoder that allows the implementation of the method according to the invention and characterized in that it includes local communication means (10) structured to transmit messages to other decoders and to receive messages originating from said other decoders, and processing means for messages received by said local communication means (10).