History information adding program, fraud determining program using history information, and fraud determining system using history information

摘要

A fraud determining system adds, to authorization data concerning a present use, history information, such as a difference in time of use or monetary value between the authorization data and authorization data concerning an immediately previous use. When a determination as to whether the present use involves a fraud is made on the basis of the authorization data concerning the present use, it is possible to determine whether or not the present use is irregular from the history information. The result of the determination is reflected in a score, and therefore, the score can be calculated with high reliability.