| 摘要 |
PROBLEM TO BE SOLVED: To ensure, for a long term, authenticity of log data generated at any time and in large quantities such as transaction data in a financial system and data on an access history related to utilization of medical information.SOLUTION: A log management server 101 receives first data; selects a plurality of pieces of second data at predetermined intervals in time series from second data held by a data holding unit; calculates a hash value of each of the plurality of pieces of second data; creates signature target data by combining the first data with the hash values of the plurality of pieces of second data; grants a digital signature to the signature target data to create second data; holds, in time series order, the second data in the data holding unit; accepts second data of a verification target; acquires second data capable of being independently verified from the data holding unit and verifies the acquired second data; sequentially compares a hash value obtained by performing calculation from the second data of the verification target to the second data capable of being independently verified with second data including the hash value; and performs verification by intermittently following a plurality of hash chains. |
