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Apparatus and method for access control

  • US 5,461,675 A
  • Filed: 09/14/1993
  • Issued: 10/24/1995
  • Est. Priority Date: 09/14/1992
  • Status: Expired due to Term
First Claim
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1. A method of controlling access to information included in a signal having an entitlement component including entitlement data indicating an access entitlement status of a user, said method comprising the steps of:

  • receiving said signal in a decoder for decoding a portion of said information in said signal other than said entitlement component in response to an access authorization signal, and for separating said entitlement component from said signal;

    transmitting said separated entitlement component front said decoder to a device for establishing access entitlement status of a user in response to said entitlement data;

    checking in said device to determine if said entitlement data evolves in a predetermined manner between two occurrences of said entitlement data, wherein said entitlement data includes a copy of a portion of scrambling data included in said signal for establishing said predetermined manner of evolution;

    generating in said device said access authorization signal to enable decoding of said portion of said signal only if said entitlement data evolves in said predetermined manner.

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