| 摘要 |
PROBLEM TO BE SOLVED: To prevent the same area from being applied by the same physical action, when data is recorded, with which reliability for a recording medium is enhanced and confidentiality for user data is protected in addition. SOLUTION: A controller 1 generates a KK key, based on a value to which one is added to the number of times of writings on a sector to be recorded. A US key is generated, based on user key information set up by a user. An arithmetic section 71 calculates designated logical operation with the KK key and the US key, provided from the controller 1 as parameters. This enables providing of a different key to the arithmetic section 17 at each time of writing, and record the data with a different signal form on the sector, even if identical recorded user data with the identical content are recorded in the same sector. COPYRIGHT: (C)2004,JPO
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