General Instrument Corporation

William A Frezza

Robert M Simons

Richard Westerfer

David Kaufman

Richard D Conover

Apparatus and a method are disclosed to enable on-line modification and upgrading of terminal software in a communication network while maintaining the integrity of communication between a service provider and a subscriber using the network. Software is downloaded on a booter channel on the communication network. A subscriber terminal, coupled to the network initiates a communication with the network to receive downloaded booter data. The downloaded data is stored, and a checksum is computed from at least a portion of the downloaded data. The checksum is tested for validity, and control of the subscriber terminal is released to the downloaded software only if the checksum is valid.

Bootstrap channel security arrangement for communication network

A method and apparatus prevent unauthorized programming viewing via a downloadable cable television converter. A booter checksum is computed from data contained in a downloaded booter image. A valid checksum is extracted from tag data associated with a scrambled program signal transmitted on the cable system. The booter checksum is compared to the extracted valid checksum. If the booter checksum and valid checksums match, a descrambler is enabled to descramble the scrambled program signal. If the checksums do not match, the descrambler is not enabled. In this manner, a pirate is prevented from downloading a false booter image to defeat the integrity of the converter.

Security arrangement for downloadable cable television converters

Apparatus restricts access to a communication network having at least one service node for providing services to subscribers. A subscriber terminal, coupled to the communication network, includes a secret node key. A succession of frame verifier (FV) codes, derived through the use of the secret node key, is generated and transmitted on the network. A network access controller (NAC), coupled to the network, includes a record of the secret node key and uses the key to encrypt a seed which is transmitted to the subscriber terminal for use in generating the FV codes. The NAC also independently computes the succession of FV codes which should be generated by the subscriber terminal. A distributed access controller (DAC), coupled to the communication network, includes a look-up table for storing the succession of FV codes computed by the NAC. The FV codes transmitted by the subscriber terminal are detected and compared to those stored in the look-up table. If proper correspondence between the detected and stored FV codes is not found to exist, the communication network is jammed.

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Warminster, PA, United States of America

William A Frezza