| 摘要 |
PROBLEM TO BE SOLVED: To securely and safely erase contents recorded on a recording medium by decoding an comparing data, used for overwriting on an opposite side, with overwriting data when the data are transferred and confirming that necessary information has been erased when recorded contents are deciphered. SOLUTION: Overwriting data for erasing information, needed to deciphere contents recorded on a recording medium (MC) 13, by overwriting are deciphered by using 1st common information generated by mutual authentication and then transferred to an opposite side. When data used for overwriting on the opposite side are transferred from the opposite side after being ciphered by using 2nd common information generated by performing mutual authentication again, the data are deciphered with the 2nd common information and then compared with the overwriting data to confirm that the information needed to deciphere the recorded contents has been erased. Where, the MC 13 processes an open area 13a, an identification information storage 13b, a secrecy 13c and an authentication part 13d, etc. |
