An IC module includes a storage unit, a communications unit, and a processing unit. The storage unit stores reference data. The communications unit receives check data. The processing unit detects a degree of similarity between the reference data and the check data. Furthermore, when the degree of similarity is equal to or larger than a first threshold value, the processing unit determines a verification success, and when the degree of similarity is smaller than the first threshold value, the processing unit determines a verification failure, and updates a verification failure history in a weighted manner according to the degree of similarity.