Cryptography – Key management – Having particular key generator
Patent
1988-09-08
1989-09-05
Cangialosi, Salvatore
Cryptography
Key management
Having particular key generator
380 20, 380 21, H04L 900
Patent
active
048646148
ABSTRACT:
In a transmission system authorization codes are transmitted to authorize subscribers to receive scrambled signals in an intelligible manner, such a system being a television transmission system. If each subscriber were assigned a unique authorization code an extremely long period of time would be required to transmit these codes for a national broadcast system. With the present arrangement, the authorizing code includes a multi-bit binary code word (18,20) which is unique to a group of subscribers, this code word being followed by a train of binary pulses (19',19";21', 21",) the number of pulses in the train being not less than the number of subscribers in the group. Each subscriber is allocated a unique pulse position in the pulse train (19',19";21',21",) at which position the state of the pulse either authorizes or inhibits the subscriber from receiving the scrambled signal intelligibly.
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Cangialosi Salvatore
Marion Michael E.
U.S. Philips Corporation
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