William Frezza, Robert Simons, Richard Westerfer: Security arrangement for downloadable cable television converters. General Instrument Corporation, Barry R Lipsitz Esq, December 8, 1987: US04712239 (168 worldwide citation)

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 cab ...

Richard Westerfer, Clyde Robbins, Anthony M Radice: Method and apparatus for enhancing the security of a scrambled television signal. General Instrument Corporation, Barry R Lipsitz, September 8, 1992: US05146496 (10 worldwide citation)

The scrambling security of a sync suppressed television signal is enhanced by eliminating the fixed time relationship between the normal color burst component and synchronization information in successive lines of the television signal. Transmission of a first plurality of television lines is delaye ...

Richard Westerfer, Henry S Landgraf: Method and apparatus for frustrating vertical interval detection in scrambled television signals. General Instrument Corporation, Barry R Lipsitz, February 15, 1994: US05287409 (2 worldwide citation)

In order to defeat pirate descramblers that detect the occurrence of a vertical blanking interval from a gap in timing data provided on the sound carrier of a scrambled television signal, diversionary pulse information is inserted into the sound carrier during the vertical blanking interval. A pirat ...