Cryptography – Particular algorithmic function encoding – Nbs/des algorithm
Patent
1987-07-29
1990-06-26
Tarcza, Thomas H.
Cryptography
Particular algorithmic function encoding
Nbs/des algorithm
H04L 100
Patent
active
049378660
ABSTRACT:
In a pay television system, a program signal is transmitted scrambled to prevent its unauthorized reception, the scrambled signal being accompanied by authorization codes, one for each authorized subscriber, a subscription key and a pay-per-view key. At a receiver, if the appropriate authorization code is received, the receiver functions in the subscription mode in which mode the subscription key provides for the descrambling of the program signal. If the appropriate authorization code is not received, indicating that the subscriber is not pre-authorized to receive the program in an intelligible manner, the receiver is set to function in a pay-per-view mode in which mode, on request, the pay-per-view key provides for the descrambling of the program signal. If there is a delay receiving the appropriate authorization code, the receiver can be set into the pay-per-view mode for at least the period of the delay, so that the scrambled signal is immediately rendered intelligible.
REFERENCES:
patent: 4484217 (1984-11-01), Block et al.
patent: 4613901 (1986-09-01), Gilhousen et al.
patent: 4685131 (1987-08-01), Horne
patent: 4739510 (1988-04-01), Jeffers et al.
patent: 4759060 (1988-07-01), Hayashi et al.
Brennand Peter R.
Crowther Gerald O.
Cain David
Marion Michael E.
Tarcza Thomas H.
U.S. Philips Corporation
LandOfFree
System for decoding transmitted scrambled signals does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for decoding transmitted scrambled signals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for decoding transmitted scrambled signals will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1131402