Cryptography – Key management – Having particular key generator
Patent
1985-05-21
1989-03-28
Cangialosi, Salvatore
Cryptography
Key management
Having particular key generator
380 48, H04K 100
Patent
active
048171425
ABSTRACT:
A secure communications system requires special arrangements for the establishment and maintenance of framing and synchronization. A framing word is transmitted at a fixed frequency, and a key necessary to unscramble the transmission is transmitted in a fixed position in relation to the framing word. Synchronization information (reference clock bursts) is scrambled with the intelligence and may only be recovered once the key is available. When framing is being maintained, the receiver's phase-locked loop opens only during the short reference clock bursts in the incoming signal, and the framing signal generator is able to predict the occurrence of successive framing signals without reference to the incoming signal. When framing is lost, the receiver enters a "soft lock" condition in which its phase-locked loop is opened to receive the entire incoming signal and in which the framing signal generator refers solely to the incoming signal to generate framing signals.
REFERENCES:
patent: 3447085 (1969-05-01), De Haas et al.
patent: 3530232 (1970-09-01), Reiter et al.
patent: 3535451 (1970-10-01), Webb
patent: 3652799 (1972-03-01), Thomas
patent: 3757044 (1973-09-01), Verhoeckx et al.
patent: 3795763 (1974-03-01), Golding et al.
patent: 4002845 (1977-01-01), Kaul et al.
patent: 4005265 (1977-01-01), Verhoeckx et al.
patent: 4172963 (1979-10-01), Belcher et al.
patent: 4295155 (1981-10-01), Jarger et al.
patent: 4316284 (1982-02-01), Howson
patent: 4319273 (1982-03-01), Nossem
patent: 4333107 (1982-06-01), McGuire et al.
patent: 4383322 (1983-05-01), Halpern et al.
patent: 4424532 (1984-01-01), den Toonder et al.
patent: 4466017 (1984-08-01), Banker
patent: 4471380 (1984-09-01), Mobley
patent: 4523228 (1985-06-01), Banker
patent: 4594609 (1986-06-01), Romao et al.
patent: 4618888 (1986-10-01), Nohara et al.
patent: 4694491 (1987-09-01), Horne et al.
Cangialosi Salvatore
Scientific - Atlanta, Inc.
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