Cisco Technology, Inc.

Nds Corporation

Tandberg Television Asa

Martin Gold

Ian Bastable

David John White

Michal Irit Devir

Harel Cain

David Wachtfogel

Keith Millar

Nicholas Thexton

Max Berman

Brett Walzer

Yorai Feldman

Nigel Stephen Dallard

Paul Austin Merry

Anthony Mountifield

A Headend system including a encoder to encode input data yielding a plurality of data packets, each of the packets having a header and a payload, a post encoding processor to identify ones of the data packets having a payload with a suspected known plaintext, and modify at least some of the identified packets, and an encryption processor to encrypt at least some of the data packets yielding encrypted data packets. Related apparatus and methods are also described.

Known plaintext attack protection

A data modeling method for modeling data for an electronic program guide (EPG) at a broadcast headend is described. The method includes grouping receiver types according to a first set of characteristics associated with a receiver type, thereby producing a plurality of groups of receivers, assigning a bit-number to each group of receivers, providing EPG data, the EPG data including data for display at an EPG, the EPG data being included in a data fragment, evaluating the data fragment and the EPG data included therein according to at least one characteristic from a second set of characteristics, thereby producing a result, adding metadata to the data fragment, the metadata including a bit field including the assigned bit number, the bit number being determined in accordance with the result, the metadata being indicative of at least one characteristic from the first set of characteristics with which a data container and EPG data included therein are associated, and broadcasting the data fragment in the data container. Related methods and apparatus are also described.

Headend modeling of data

A data modeling method for modeling data for an electronic program guide (EPG) at a broadcast headend is described. The method includes grouping receiver types according to a first set of characteristics associated with a receiver type, thereby producing a plurality of groups of receivers, assigning a bit number to each group of receivers, providing EPG data, the EPG data including data for display at an EPG, the EPG data being included in a data fragment, evaluating the data fragment and the EPG data included therein according to at least one characteristic from a second set of characteristics, thereby producing a result, adding metadata to the data fragment, the metadata including a bit field including the assigned bit number, the bit number being determined in accordance with the result, the metadata being indicative of at least one characteristic from the first set of characteristics with which a data container and EPG data included therein are associated, and broadcasting the data fragment in the data container. Related methods and apparatus are also described.

Transmission synchronization and bandwidth adjustment in a broadcast system are described. At least one service tool in the broadcast system supplies service information useful for selecting, from a series of broadcast events, broadcast events to be viewed by subscribers of the broadcast system. A conditional access (CA) unit in the broadcast system applies conditional access attributes to the series of broadcast events. Transmission synchronizing apparatus in the broadcast system synchronizes the CA unit and the at least one service tool by instructing the CA unit to blackout a particular event from the series of broadcast events to subscribers that are refused access to the particular event and instructing the at least one service tool to provide a replacement service to the subscribers that are refused access to the particular event. Alternatively or additionally, the transmission synchronizing apparatus adjusts transmission bandwidth allocated to the series of broadcast events in response to instructing the CA unit to blackout the particular event to subscribers that are refused access to the particular event and instructing the at least one service tool to provide the replacement service to the subscribers that are refused access to the particular event. Related apparatus and method are also described.

Digital video broadcast system

In a method of receiving packets of data addressed to one or more receivers each having an individual identifier, wherein the data is included in a digital signal having destination addresses successively encrypted from a sequence of control words and receiver identifiers, and control messages containing the control words in encrypted form, address flags and control flags. The method processes the control messages to construct receiver addresses from the control words and the receiver identifier; directs the receiver addresses to update a receiver address register selected by the associated control flag in response to the transmitted control flags; directs each destination address to be compared with the receiver address to one of the address registers selected by the associated address flag in response to the address flags and; accepts each packet of data having a destination address matching the receiver address to which it was compared.

Secure data broadcasting

Growing community of inventors

Stockbridge, United Kingdom

Martin Gold