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Apparatus and method for upgrading terminals to maintain a secure communication network

  • US 5,144,664 A
  • Filed: 11/16/1990
  • Issued: 09/01/1992
  • Est. Priority Date: 11/16/1990
  • Status: Expired due to Term
First Claim
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1. A system for revising a set of terminals in a communication network to maintain signal security comprising:

  • a headend for transmitting signals;

    encryption means operatively associated with said headend for encrypting said signals according to a plurality of encryption algorithms, each algorithm associated with a different subset of terminals authorized to receive said signals;

    means for selectively terminating the transmission of said signals under a particular algorithm;

    means for providing a replacement algorithm in said encryption means for use instead of the terminated algorithm; and

    security means for providing a corresponding replacement algorithm to the subset of terminals associated with the terminated algorithm.

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