| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique which enables highly secured authentication by simple means.SOLUTION: In an authentication function unit 100 of a server 10, a registration information storage unit 102 stores registration information registering correlation of user identification information and location information. At authentication, a reception unit 103 receives user identification information and a data file transmitted from a user device 20. In an authentication execution unit 104, a location information acquisition unit 105 acquires location information corresponding to the received user identification information from the registration information. A location information extraction unit 106 extracts location information indicating a location where the data file was created, from meta information of the data file. A location authentication unit 107 authenticates a user on the condition that a location indicated by the location information extracted from the data file is within a predetermined range from a location indicated by the location information acquired from the registration information. |
