General Instrument Corporation

Annie On-yee Chen

Lawrence W Tang

Akiko Wakabayashi

Eric J Sprunk

Douglas M Petty

John I Okimoto

Bridget Diane Kimball

A system is described for uniquely mating components of a communication network such as a smartcard and a set-top box. When mated, the smartcard and set-top box are tied together and have a single identity. Further, the smartcard operates properly only when inserted into an authorized set-top box. Exchanges of information between both components are secured by encryption and authentication to guard against piracy of the exchanged information. The system provides the same authentication key to the set-top box and the smartcard. This key is used for authenticating communication between the set-top box and the smartcard. First, the authentication key is encrypted by a set-top box mating key. The set-top box employs this mating key to decrypt the authentication key. After it is derived, the authentication key is stored in the set-top box's memory. Further, the same authentication key is encrypted by a smartcard mating key. Thereafter, the smartcard employs the smartcard mating key to extract the authentication key. The clear authentication key is stored in the smartcard's memory as well. In this manner, the authentication key is used for securing all communication between the set-top box and the smart-card. For example, the set-top box may request control words from the smartcard. Only after authenticating the request, are the control words for decrypting digital content provided to the set-top box. If the smartcard authentication key is different from the set-top box key, the request for control words is denied.

Smart card mating protocol

A method for forwarding messages containing cryptographic keys from a conditional access system that controls a population of set-top boxes to an encryption renewal system. The method includes storing a fictitious address of a virtual set-top box; generating a message based on the fictitious address, the message containing a cryptographic key; and forwarding the message to the fictitious address of the virtual set-top box. The encryption renewal system has information regarding the virtual set-top box, and is the recipient of the message. In addition, the encryption renewal system is for controlling access to pre-encrypted content generated by an encryption device. The system includes software instructions for receiving a request to retrofit an entitlement control message that allows a home device to access pre-encrypted content; and software instructions for retrofitting the entitlement control message only after verifying that the pre-encrypted content was generated prior to or contemporaneous with an authorized timestamp.

System for denying access to content generated by a compromised off line encryption device and for conveying cryptographic keys from multiple conditional access systems

Growing community of inventors

Del Mar, CA, United States of America

Annie On-yee Chen