Information retrieval system for providing downstream loading of remote data and processing control thereof
Method and apparatus for scrambling and descrambling television programs
Address-programmable CATV converter Patent #: 4558464
ApplicationNo. 06/874845 filed on 06/16/1986
US Classes:380/242, Having command signal for receiver713/187, COMPUTER PROGRAM MODIFICATION DETECTION BY CRYPTOGRAPHY725/151, Receiver (e.g., set-top box)725/31With encryption or scrambling of video signal
ExaminersPrimary: Buczinski, Stephen C.
Attorney, Agent or Firm
International ClassesH04N 7/167 (20060101)
H04N 7/16 (20060101)
AbstractA 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.