Biometric authentication system

A biometric authentication system, comprising:

• a client device that receives biometric information;
• an authenticating server that receives the biometric information from the client device and performs personal authentication;
• and
• a managing device that manages the personal authentication performed by the authenticating server, wherein
• the authenticating server includes
• a registration-biometric-information storage unit that stores therein registration biometric information that is biometric information of registered users previously registered as users, and is referred to at the personal authentication as comparison targets to the received biometric information, and personal authenticating methods;
• a biometric-information matching unit that matches the received biometric information with the registration biometric information stored in the registration-biometric-information storage unit;
• a similarity-determination matching-biometric-information storage unit that stores therein the received biometric information as similarity-determination matching biometric information to be Matched for similarity determination, to determine based on the matching whether the received biometric information is similar biometric information similar to any of the registration biometric information stored in the registration-biometric-information storage unit;
• a similar-biometric-information determining unit that determines whether the similar biometric information is included in the similarity-determination matching biometric information by comparing the similarity-determination matching biometric information stored in the similarity-determination matching-biometric-information storage unit and the registration biometric information stored in the registration-biometric-information storage unit with each other at a predetermined time;
• and
• a similarity-information output unit that outputs similarity information related to the similarity-determination matching biometric information determined to be the similar biometric information when the similarity-determination matching biometric information determined by the similar-biometric-information determining unit to be the similar biometric information is included in the similarity-determination matching biometric information stored in the similarity-determination matching-biometric-information storage unit.