| 摘要 |
PROBLEM TO BE SOLVED: To provide a false check system for a time stamp service capable of preventing system from being confused due to copy data out of malice, and discriminating and excluding the false data. SOLUTION: When a terminal device 20A on the side of a client 20 transmits a time stamp issue request 20T including hash value of object data and issue request creation date and time information to a time stamp issuing institution 10, the time stamp issuing institution 10 returns a time stamp. On the side of the time stamp issuing institution 10, it is checked whether date and time information included in the received time stamp issuing request 20T is within a permissible range. When it is outside the range, error processing is performed, while when within the range, matching is performed between the request and a past issuing request of the client 20 within the permissible range to check if there an identical one and it is checked whether identical data were received in the past. Thus, a false time stamp issuing request 20T is discriminated and excluded. COPYRIGHT: (C)2008,JPO&INPIT
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