Patent ID: 8467662

Claim:
A playback terminal which receives content from a content server and plays back the content, said playback terminal further receives usage expiration information corresponding to the content if the content has the usage expiration information, said playback terminal comprising: a content storage unit configured to store the content; a content expiration information storage unit configured to store the usage expiration information corresponding to the content if the content has the usage expiration information; a clock unit configured to manage time-of-day information; a clock setting instruction unit configured to receive an entry of a time of day to be set to said clock unit; and a control unit configured to (i) determine whether or not the usage expiration information corresponding to the content is stored in said content expiration information storage unit, and (ii) reject the entry from said clock setting instruction unit or to perform control not to update the time-of-day information of said clock unit to the time of day entered from said clock setting instruction unit when it is determined that the usage expiration information corresponding to the content is stored in said content expiration information storage unit.