Patent ID: 7173892
Filing Date: 2007-02-06
Classification: G11B

Abstract:
1. An optical disk drive for reading data from an optical disk, the optical disk storing the data and security information associated with the data, identical security information being stored at a plurality of locations on the optical disk, the optical disk drive comprising: a reading section for reading the data and the security information from the optical disk; and an access restricting section for restricting the reading of data, based on the security information associated with the data to be read, during when the data is read from the optical disk using the reading section, wherein a comparison is made among fragments of the security information read from the plurality of locations on the optical disk to be read, and the access restricting section restricts the reading of the data to be read based on a security information fragment with the highest frequency; wherein the security information is information represented by a string of consecutive bits, and the access restricting section compares, for each column of bits, bit values read as the security information from the plurality of locations, and selects a bit value with the highest frequency in each column of bits as a correct bit value in the column of bits.