| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an information validity period from being fraudulently extended without affecting resources of a terminal even when a terminal user fraudulently changes time. <P>SOLUTION: A time managing part 13 manages the current terminal time of a terminal 1 and a time difference between the current terminal time and the standard current time of a time server 3. An information managing part 12 manages information together with the information on time difference between an information distribution server time of an information distribution server 2 and the current terminal time. When a validity period is determined, the information managing part 12 determines whether an estimated current time calculated by using the information on time difference and the current terminal time is within the validity period. When the terminal user changes the current terminal time to an arbitrary time, the time managing part 13 updates a time error to a difference between the arbitrary time and the current terminal time, and a clock UI 14 uses the updated time difference and the current terminal time to recalculate and update a terminal display time. <P>COPYRIGHT: (C)2008,JPO&INPIT |
