Cryptography – Key management – Having particular key generator
Patent
1994-07-25
1997-02-25
Gregory, Bernarr E.
Cryptography
Key management
Having particular key generator
380 10, 380 15, 380 20, 380 49, H04N 7167
Patent
active
056066120
ABSTRACT:
A method and apparatus for scrambling an original analog video signal samples predetermined portions of the original video signal at a first rate and stores the sampled portions of the original video signal within a memory device. The stored video signal is read out of the memory device at a second rate, which is less than the first rate, to produce a time expanded scrambled video signal. A predetermined code is inserted into the time expanded scrambled video signal which is then converted into an analog scrambled video signal and transmitted through a channel. A method and apparatus for descrambling the scrambled video signal to produce a reconstructed video signal samples the scrambled video signal at the second rate, stores the sampled scrambled video signal into a memory and reads the sampled scrambled video signal out of the memory at the first rate. Replicas of the eliminated portions of the original video signal are reinserted into the sampled video signal to produce a digital version of the original video signal which is then converted to analog to produce the reconstructed video signal. The code word within the scrambled video signal is used to align each frame of the reconstructed video signal with the frame of the incoming scrambled video signal to keep the reconstructed video signal synchronized with the scrambled video signal.
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Gregory Bernarr E.
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