| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To much more accurately execute time management for the reproduction permission/inhibition of main data to be recorded in a recording medium. <P>SOLUTION: Predetermined standard time information from an NTP server connected through a network is received by a standard time reception processing part, and the current time information measured by a time measuring part 30 is corrected according to this. Thus, it is possible to perform accurate reproduction time management based on the predetermined standard time received from the predetermined NTP server. Also, the reproduction time data to be recorded in a disk 100 are encrypted by a secret key among encryption keys generated by an asymmetrical encryption system. In this case, the public key making a pair with the secret key is preliminarily assigned at the reproduction divice 10 side, and the reproduction time data reproduced from the disk 100 is decoded by using the public key at a reproduction device 10 side. Thus, it is possible only for a person who owns a legal secret key to decode the reproduction time data by a reproducing device 10 side. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
