Digital data cryptographic system
First Claim
Patent Images
1. A system comprising:
- a receiving means for receiving a transmitted signal, said transmitted signal including encrypted digital data and including commands for designating one of a plurality of decryption keys stored in said receiving means, said receiving means comprising;
decryption key storage means for storing a plurality of decryption keys;
decryption key selection means for selecting one of said plurality of decryption keys as an active key based upon said commands received by said receiving means;
decryption function storage means for storing one or more decryption functions; and
digital data decryption means for decrypting said encrypted digital data based upon one of said functions and said active key.
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Reexamination
Accused Products
Abstract
An audiovisual subscription system includes means for aperiodically inverting the lines of a transmitted video signal on a frame-by-frame basis and for decrypting encrypted PCM audio information which is transmitted along with the aperiodically inverted video information.
268 Citations
22 Claims
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1. A system comprising:
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a receiving means for receiving a transmitted signal, said transmitted signal including encrypted digital data and including commands for designating one of a plurality of decryption keys stored in said receiving means, said receiving means comprising; decryption key storage means for storing a plurality of decryption keys; decryption key selection means for selecting one of said plurality of decryption keys as an active key based upon said commands received by said receiving means; decryption function storage means for storing one or more decryption functions; and digital data decryption means for decrypting said encrypted digital data based upon one of said functions and said active key. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system, including a digital data decrypting system, comprising:
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a microprocessor; a programmable logic device (PLD), operatively coupled to said microprocessor, in which a digital data decryption circuit is defined; and a memory means for storing a plurality of decryption key values, wherein said microprocessor selects a specific one of said key values, based upon instructions transmitted to said system, as an active key to be used by said PLD for directly decrypting encrypted data inputted into said PLD, and wherein said PLD stores a plurality of decryption functions, and said instructions designate one of said decryption functions as well as an active key to be used by said PLD to decrypt said encrypted data. - View Dependent Claims (14, 15, 16, 17)
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18. A system, including a digital data decrypting system, comprising:
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a programmable logic device (PLD) in which a digital data decryption circuit is defined, said PLD storing a plurality of decryption functions; memory means for storing a plurality of decryption key values; and means for selecting a specific one of said key values as an active key, based upon instructions transmitted to said system, and for selecting a specific one of said decryption functions as an active function to be used by said PLD for directly decrypting encrypted data inputted into said PLD. - View Dependent Claims (19, 20, 21, 22)
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Specification