Device and method for biometric authentication

A non-transitory computer-readable recording medium having stored therein a program for causing a biometric authentication device to execute a biometric authentication process based on biometric information input to a connected terminal device, the biometric authentication process comprising:

• receiving biometric information transmitted from the terminal device, a second enrolled template stored in the terminal device, and second attribute information including a parameter representing a type of a second input sensor to which the second enrolled template was input;
• performing authentication of a person who inputs the biometric information by matching the received biometric information and a first enrolled template stored in a storage unit of the biometric authentication device;
• calculating a judgement value φ according to a formula below in which Wc indicates a weighting value of the second enrolled template, Sc_c indicates a similarity between the received biometric information and the second enrolled template, Ws indicates a weighting value of the first enrolled template, Sc_s indicates a similarity between the received biometric information and the first enrolled template, and A indicates an adjustment parameter;
• φ=Wc×Sc_c−Ws×Sc_s+A
• selecting the first enrolled template or the second enrolled template based on the received second attribute information, first attribute information including a parameter representing a type of a first input sensor to which the first enrolled template was input, and the judgement value φ;
• and
• replacing the first enrolled template stored in the storage unit with the second enrolled template that is received from the terminal device, when the second enrolled template is selected, wherein
• when the received biometric information is accepted in the authentication, and when the type of the first input sensor and the type of the second input sensor are different from each other, and when the judgement value φ is larger than or equal to zero, the biometric authentication process selects the second enrolled template and replaces the first enrolled template stored in the storage unit with the second enrolled template.

A biometric authentication method used in a biometric authentication system including a terminal device and a biometric authentication device that performs biometric authentication based on biometric information input in the terminal device, the biometric authentication method comprising:

• transmitting, by the terminal device, input biometric information, a second enrolled template stored in the terminal device, and second attribute information including a parameter representing a type of a second input sensor to which the second enrolled template was input to the biometric authentication device;
• receiving, by the biometric authentication device, biometric information transmitted from the terminal device;
• performing authentication of a person who inputs the biometric information by matching the received biometric information and a first enrolled template stored in a storage unit of the biometric authentication device;
• calculating a judgement value φ according to a formula below in which Wc indicates a weighting value of the second enrolled template, Sc_c indicates a similarity between the received biometric information and the second enrolled template, Ws indicates a weighting value of the first enrolled template, Sc_s indicates a similarity between the received biometric information and the first enrolled template, and A indicates an adjustment parameter;
• φ=Wc×Sc_c−Ws×Sc_s+A
• selecting the first enrolled template or the second enrolled template based on the received second attribute information, first attribute information including a parameter representing a type of a first input sensor to which the first enrolled template was input, and the judgement value φ;
• and
• replacing the first enrolled template stored in the storage unit with the second enrolled template that is received from the terminal device, when the second enrolled template is selected, wherein
• when the received biometric information is accepted in the authentication, and when the type of the first input sensor and the type of the second input sensor are different from each other, and when the judgement value φ is larger than or equal to zero, the second enrolled template is selected and the first enrolled template stored in the storage unit is replaced with the second enrolled template.