Recording medium, recording-medium management method, and recording-medium management system

A recording-medium management method comprising:

• obtaining a first data line from an authentication region of a recording medium, the authentication region including a plurality of RAM bits and a plurality of ROM bits, the RAM bits and the ROM bits being intermingled in the authentication region, the first data line corresponding to an arrangement of the RAM bits and the ROM bits, the RAM bit being over-writable of data at least once by a first writing condition, and the ROM bit being not over-writable of data by the first writing condition;
• overwriting a predetermined data to the RAM bits;
• obtaining a second data line from the recording medium, the second data line corresponding to an arrangement of the over-written RAM bits and the ROM bits, and
• decrypting an encrypted data stored in a data storing region of the recording medium in reference to the first and second data lines.

A recording-medium management method comprising:

• obtaining a first data line from an authentication region of a recording medium, the authentication region including a plurality of RAM bits and a plurality of ROM bits, the RAM bits and the ROM bits being intermingled in the authentication region, the first data line corresponding to an arrangement of the RAM bits and the ROM bits, the RAM bit being over-writable of data at least once by a first writing condition, and the ROM bit being not over-writable of data by the first writing condition;
• overwriting a predetermined data to the RAM bits;
• obtaining a second data line from the recording medium, the second data line corresponding to an arrangement of the over-written RAM bit bits and the ROM bits, and
• judging propriety of an access to a data storing region of the recording-medium in reference to the first and second data lines.

A recording-medium management system comprising:

• a reproduction part;
• a recording part;
• and
• a control part performing
• a first control to obtain a first data line from an authentication region of a recording medium by making the reproduction part read the authentication region, the authentication region including a plurality of RAM bits and a plurality of ROM bits, the RAM bits and the ROM bits being intermingled in the authentication region, the first data line corresponding to an arrangement of the RAM bits and the ROM bits, the RAM bit being over-writable of data at least once by a first writing condition, and the ROM bit being not over-writable of data by the first writing condition;
• a second control to make the recording part overwrite predetermined data to the RAM bits;
• a third control to obtain a second data line from the recording-medium by making the reproduction part read the authentication region, the second data line corresponding to an arrangement of the over-written RAM bits and the ROM bits, and
• a fourth control to perform an authentication with regard to the recording medium in reference to the first and second data lines.