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AssigneeC-Dilla Limited
InventorPeter A. Newman
Estimating the term…
A method for copy protecting a record carrier is disclosed, in which method the copy protected record carriers are provided with a pattern of logical errors which cannot be corrected by the error correcting rules predefined for said record carrier. The pattern of logical errors represents access control information. The logical errors are generated during decoding the bit sequence read from the record carrier. Bit errors may be positioned in the bit sequence so as to counteract de-interleaving which is part of an error decoding process in a reading device and accumulate in error words which are uncorrectable. Also a method for detecting access control information and a retrieval arrangement are disclosed, which retrieval arrangement serves to detect the access control information by selecting at least one error location, but not all error locations on the record carrier, and verifying the presence of an error by reading the selected error location via the reading means.
Method for copy protecting a record carrier having information stored thereon according to predetermined formatting and error correcting rules, comprising the steps of
Copy protected record carrier having a bit sequence stored thereon representing information according to predetermined formatting and error correcting rules, the information comprising main information and access control information for controlling the access to the main information, characterized in that the bit sequence comprises bit errors constituting logical errors which cannot be corrected by said error correcting rules and which constitute an error pattern representing at least part of the access control information.
Dependencies are inferred from the claim text.