| 摘要 |
PROBLEM TO BE SOLVED: To easily detect a change in recorded data without changing a recording format of log data or the like generated in time series. SOLUTION: A log data division storage part 102 stores a plurality of divided log data obtained by dividing log data stored in a log data time-series storage part 101 in time series. A hash value storage part 103 stores hash values of the divided log data. A hash value reading part 104 reads out a hash value and a divided log data reading part 105 reads the divided log data to be a calculation source of the hash value and a read hash value calculation part 106 calculates the hash value. When the read hash value coincides with the calculated hash value, whether the read divided log data is stored in the log data time-series storage part 101 or not is discriminated, and when the read divided log data is not stored, a log data alteration information output part 109 outputs information indicating the alteration of the log data. COPYRIGHT: (C)2009,JPO&INPIT |
