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Method for copy protecting a record carrier, copy protected record carrier and means for detecting access control information

  • US 6,353,890 B1
  • Filed: 05/29/1998
  • Issued: 03/05/2002
  • Est. Priority Date: 05/30/1997
  • Status: Expired due to Term
First Claim
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1. A method for controlling access to a record carrier, comprising the steps of:

  • creating an image file containing main information;

    generating access control information for controlling the access to the main information;

    producing a record carrier depending on the image file and the access control information, including the steps of;

    creating a correctable bit sequence by applying formatting and error correcting rules to the image file;

    modifying the correctable bit sequence according to the access control information with sufficient bit errors to provide uncorrectable errors which cannot be corrected by the error correcting rules and which constitute a predefined uncorrectable error pattern defined by uncorrectable error locations and error correctable locations; and

    translating the modified bit sequence into a physical pattern of marks on the record carrier.

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