General Instrument Corporation

Other

Motorola Mobility LLC

Google Technology Holdings LLC

Steven E Anderson

Alexander Medvinsky

Paul Moroney

Eric J Sprunk

James N Esserman

Jonathan A Fellows

Roy A Griffin, Iii

Thomas J Kolze

Ron D Katznelson

Christopher John Bennett

Victor T Hou

Steven R Hart

Nancy S Lucore

Sasha Medvinsky

A secure Internet Protocol (IP) telephony system, apparatus, and methods are disclosed. Communications over an IP telephony system can be secured by securing communications to and from a Cable Telephony Adapter (CTA). The system can include one or more CTAs, network servers, servers configured as signaling controllers, key distribution centers (KDC), and can include gateways that couple the IP telephony system to a Public Switched Telephone Network (PSTN). Each CTA can be configured as secure hardware and can be configured with multiple encryption keys that are used to communicate signaling or bearer channel communications. The KDC can be configured to periodically distribute symmetric encryption keys to secure communications between devices that have been provisioned to operate in the system and signaling controllers. The secure devices, such as the CTA, can communicate with other secure devices by establishing signaling and bearer channels that are encrypted with session specific symmetric keys derived from a symmetric key distributed by a signaling controller.

Internet protocol telephony security architecture

Duplicate participants (e.g., cloned subscriber units) () are detected in a communication network, such as a hybrid fiber/coax (HFC) cable television network or the like, by monitoring the physical layer of the network to detect transmission differences between such units. The subscriber units () may be cable modems that transmit upstream signals with associated identifiers to a headend (), e.g., to access the Internet or for telephony. Measured characteristics of the upstream signals can include: (1) propagation time (), (2) frequency (), (3) power (), and (4) spectral characteristics (). For propagation time, the reception time of the upstream message can be compared to a headend clock () and also to other messages with the same modem ID. For spectral characteristics, adjustment coefficients can be provided to the units to normalize the spectrum of the upstream signal to a baseline spectrum. When discrepancies are detected for an upstream signal that indicate duplicate modems are operating in the network, the account of the corresponding unit can be terminated.

Detection of duplicate participants in a two-way modem environment

Roller assembly for lawnmower

Apparatus is provided for communicating data packets in variable length bursts over a physical layer in a multilayer data communication scheme. Each burst contains information data (,) and overhead (,). The overhead includes forward error control (FEC) data (,). Different burst modes (FIG.,) are provided to enable a trade-off to be made between bandwidth efficiency and data transmission robustness. The burst modes provide different combinations of modulation (such as QPSK and 16-QAM), symbol rates, FEC coding levels and frame and preamble structure. The apparatus is particularly suitable for use in upstream communications over hybrid fiber coax cable television plants.

Variable length burst transmission over the physical layer of a multilayer transmission format

Compromise of a predetermined secure data processing routine by a procedure known as a 'clock attack' is prevented by a method that inhibits synchronization with externally generated instructions by preventing determination of the time of execution predetermined data processing routine in relation to occurrence of an externally observable event that precedes the execution of the predetermined routine. The method includes the step of (a) randomly varying the duration between the occurrence of the externally observable event and the execution of the predetermined routine. Step (a) includes the steps of (b) executing one or more interim data processing routines between the occurrence of the externally observable event and the execution of the predetermined routine; and (c) randomly varying the duration of said interim routines. Steps (b) and (c) may include the step of (d) randomly assembling m said interim routines for said execution from a group of n stored routines having different durations, wherein m and n are integers, with n being greater than m. Step (d) may include either the step of (e) randomly accessing said m interim routines from a secure memory; or the steps of (f) randomly accessing pointers for said m interim routines from a secure memory; and (g) accessing said m interim routines from a memory in response to said pointers. Step (c) includes the step of (h) randomly varying the duration of the interim routines in response to dynamically processed data that does not repetitively recur each time said interim routines are accessed. The method further includes the steps of (i) monitoring said interim routines to detect whether said interim routines are being tampered with; and (j) preventing the execution of said predetermined routine in response to detecting that said interim routines are being tampered with.

Determination of time of execution of predetermined data processing

A remotely retunable receiver for use in a satellite video programming distribution system includes the capability to retune groups of subscribers to different satellite feeds during a blackout of a video programming event. To achieve flexible control over program blackouts, a receiver retune command message is selectively sent to desired groups of descramblers at CATV satellite downlinks. The retune command message identifies an alternate satellite feed and a time for which the satellite receiver is to tune to the alternate satellite feed. The receiver stores the retune command, and at the appropriate time retunes the satellite receiver to the identified alternate feed. By command messages received on the alternate feed, the group of blacked out satellite receivers are returned to the original programming channel at the end of the blacked out event. Also provided is a command message for local insertion of demographically targeted advertising which command message designates the start time and duration of the local insertion. Furthermore, a home channel command is provided to individual satellite receivers to return the receiver to a home satellite feed in the event of an unrecoverable error.

Satellite receiver retuning system

A descrambler for descrambling scrambled information signals through use of a predetermined decryption key. The processing means are adapted for processing data in accordance with a number of different data processing routines to descramble said scrambled information signals, including a routine for descrambling said scrambled information signals that utilizes said predetermined decryption key, and a routine for generating said predetermined decryption key. The processing means includes means for responding to an instruction for generating said predetermined decryption key by processing a first signal provided by the processing means with a second signal to generate said predetermined decryption key; and means for providing at least a portion of said second signal for processing with said first signal by retrieving a portion of said stored data from a portion of said memory means identified by a dynamic pointer contained in said instruction for generating said decryption key, with said retrieved data being data that is also used in a said data processing routine other than said routine for generating said predetermined decryption key.

Security enhancement in a data processor through use of dynamic

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La Jolla, CA, United States of America

Steven E Anderson