Patent ID: 8041980

Claim:
A time certifying server comprising: a clock unit for outputting time information; time acquiring means for acquiring from the time information units of time equal to or larger than a predetermined unit; correction time acquiring means for acquiring a correction time from a correction time generating unit; time correcting means for correcting units of time from the time information smaller than the predetermined unit using the acquired correction time and without correcting the acquired units of time equal to or larger than the predetermined unit; reference time receiving means for receiving a reference time from a reference time distributing server that distributes reference time; verification means for verifying that the clock unit operates at a precision falling within a predetermined range by confirming that, in the time of the units equal to or larger than the predetermined unit, the time acquired by the time acquiring means and the received reference time coincide with each other; certification target information receiving means for receiving certification target information that serves as time certification target from a client terminal; time certification information generating means for generating time certification information of the received certification target information after verification of the operational precision of the clock unit and using the corrected units of time; and time certification information transmitting means for transmitting the generated time certification information to the client terminal.