| 摘要 |
PROBLEM TO BE SOLVED: To prevent a storage area from being wasted by efficiently leaving only an effective key for copyright management recorded in a secret area of a recording medium as to a managing method for a key effective in protecting the copyright of contents. SOLUTION: When key management information is not present in a normal area 20 and a title key 25 is present in the secret area 21 while the recording medium is inserted into a device managing a copyright key, the title key 25 in the secret area 21 and a key use flag indicating whether the title key 25 is used or not are all erased even if the key use flag indicates a use state. When key management information is present in the normal area 20 and the title key 25 is present in the secret area 21, the title key 25 in the secret area 21 that the key management information in the normal area 20 does not refer to is erased even if the key use flag indicates the use state. COPYRIGHT: (C)2006,JPO&NCIPI
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