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Broadcast data access controller communication system

  • US 5,999,623 A
  • Filed: 11/05/1997
  • Issued: 12/07/1999
  • Est. Priority Date: 11/05/1997
  • Status: Expired due to Term
First Claim
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1. A method for enabling only authorized ones of a plurality of receiver stations to obtain access to first information transmitted by a transmitter station, the method comprising the steps of:

  • at the transmitter station, performing a first predefined algorithm to generate Subscription Key values for individual ones of the respective authorized receiver stations, wherein the first predefined algorithm is a function of a predetermined Decryption Key value;

    providing the Subscription Key values to the individual ones of the respective authorized receiver stations;

    at each of the authorized receiver stations, performing a second predefined algorithm using the Subscription Key value provided to the authorized receiver station, and generating a resultant value that equals the predetermined Decryption Key value;

    transmitting a first signal from the transmitter station, the first signal including an encrypted version of the first information;

    receiving the first signal at each of the receiver stations, and within each individual one of the authorized receiver stations, performing a third predefined algorithm using the resultant value to decrypt the encrypted version of the first information, thereby enabling the authorized receiver station to obtain access to the first information in decrypted form.

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