Patent Publication Number: US-11379569-B2

Title: Biometric authentication device, biometric authentication method, and program

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2018-55942, filed on Mar. 23, 2018, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a biometric authentication device, a biometric authentication method, and a program. 
     BACKGROUND 
     To use a biometric authentication system for confirming a person using biometric information such as a fingerprint, biometric data is registered in advance. In a client-server type biometric authentication system, biometric data is registered in an authentication server. In biometric authentication, an authentication process is executed by generating biometric data for crosschecking from biometric information input from a client terminal, transmitting the generated biometric data to the authentication server, and causing the authentication server to crosscheck the biometric data with registered biometric data. 
     In a state in which biometric data is registered in the authentication server from a first terminal used by a user in the past, the same user may use the biometric authentication from a second terminal or, for example, a new terminal. In this case, when a biometric sensor of the second terminal is not compatible with the biometric data registered from the first terminal, it may not be possible to execute authentication by crosschecking biometric data for crosschecking that has been acquired from the biometric sensor of the second terminal with the biometric data registered from the first terminal. Thus, the biometric data is reregistered in the authentication server from the second terminal. The “biometric sensor of the second terminal” may be a biometric sensor included in the second terminal or may be a biometric sensor connected to the second terminal. 
     For the case where a biometric sensor of the first terminal used by the user is not compatible with the biometric sensor of the second terminal used by the same user, there is a method in which the user contacts a system administrator and has the system administrator issue a tentative password for reregistration in order to reregister the biometric data in the authentication server from the second terminal. When the user inputs the tentative password from the second terminal and the authentication of the password by the authentication server is successful, the registration of the biometric data acquired from the biometric sensor of the second terminal is permitted. In this method, however, it takes efforts to have the system administrator issue the tentative password. 
     To reduce the efforts to have the system administrator issue the tentative password, a method in which a conversion function (or a converter) is included in the authentication server has been proposed (refer to, for example, Japanese Laid-open Patent Publication No. 2005-259158). A requirement for collecting biometric data that has been registered in the authentication server and is fingerprint data or the like may be different from a requirement for collecting biometric data transmitted from a terminal to the authentication server upon authentication. In this case, the conversion function converts biometric data for crosschecking in accordance with, for example, the requirement for collecting the registered biometric data so as to enable the converted biometric data to be crosschecked with the registered biometric data. 
     The requirement for collecting biometric data by a biometric sensor of a terminal used upon authentication may be different from the requirement for collecting biometric data registered in the server. In this case, when a biometric sensor to be used for authentication is compatible with a biometric sensor to be used for registration, and biometric data acquired for the authentication is able to be crosschecked with converted registered biometric data, the method in which the conversion function is included in the authentication server is applicable. On the other hand, when the biometric sensor used for the authentication is not compatible with the biometric sensor used for the registration, biometric data for crosschecking is not converted in accordance with the requirement for collecting registered biometric data. When the biometric sensor used for the authentication is not compatible with the biometric sensor used for the registration, the method in which the conversion function is included in the authentication server is not applicable. Thus, when a biometric sensor of a terminal that tries to use the biometric authentication is not compatible with a biometric sensor of a terminal used for the registration of biometric data, biometric data is to be reregistered in the authentication server from the terminal that tries to use the biometric authentication. However, to reregister the biometric data in the authentication server, it takes efforts to have the system administrator issue a tentative password. 
     In the method in which the conversion function is included in the authentication server, biometric data may be registered in a database in the authentication server for each of the types of biometric sensors. For example, a certain user may register biometric data in the database for a first type biometric sensor and a second type biometric sensor. In this case, the authentication server may handle an authentication request from a first terminal having the first type biometric sensor and an authentication request from a second terminal having the second type biometric sensor. However, when biometric data acquired by the biometric sensors of the multiple types is registered, and the biometric authentication is used first by, for example, a terminal having a new type biometric sensor, the biometric data is reregistered in the authentication server. When the biometric authentication is used by a terminal having a biometric sensor of a certain type that is used first for the biometric authentication, it takes efforts to have the system administrator issue a tentative password in order to reregister the biometric sensor in the authentication server. 
     To reduce the efforts to have the system administrator issue the tentative password, a method for acquiring an electronic device holding an electronic certificate issued by, for example, the system administrator and connecting the electronic device to a terminal has been proposed (refer to, for example, Japanese Laid-open Patent Publication No. 2005-346120). The electronic device is a Universal Serial Bus (USB) token or the like. The terminal is a personal computer (PC) or the like. In the proposed method, the electronic certificate is used to execute mutual authentication between the terminal and the authentication server, and the authentication server automatically issues a tentative password when the authentication is successful. In the proposed method, however, it takes efforts to have the system administrator issue the electronic certificate in order to automatically issue the tentative password. In addition, it takes efforts for a user to acquire the electronic certificate, and the cost of the biometric authentication increases for the use of the electronic device holding the electronic certificate. 
     In related-art biometric authentication systems, since a user has a system administrator issue a tentative password or an electronic certificate in order to reregister biometric data in an authentication server from a terminal that tries to use biometric authentication, it is difficult to reduce the number of processes in the reregistration. Another example of related art is Japanese Laid-open Patent Publication No. 2006-227769. 
     In the related-art biometric authentication systems, it is difficult to reduce the number of processes in the case where biometric data is reregistered from a terminal that tries to use biometric authentication. 
     An aspect aims to provide a biometric authentication device, a biometric authentication method, and a program that may reduce the number of processes in the case where biometric data is reregistered from a terminal that tries to use biometric authentication. 
     SUMMARY 
     According to an aspect of the embodiments, a biometric authentication method causes a processor of a biometric authentication device to execute a process. The process may include: receiving user identification information and sensor type information from a terminal; confirming whether or not the received sensor type information has a predetermined relationship with a registered sensor type information corresponding to the received user identification that is among sensor type information of biometric sensors that have acquired biometric data registered for respective user identification information; and controlling, based on the confirmed sensor type information having the predetermined relationship, the issuance of a password to be used to re-register biometric data. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a functional block diagram illustrating an example of a biometric authentication system according to a first embodiment; 
         FIG. 2  is a block diagram illustrating an example of a computer; 
         FIG. 3  is a diagram illustrating an example of a user data management table; 
         FIG. 4  is a diagram illustrating an example of a compatibility management table; 
         FIG. 5  is a flowchart describing an example of a process according to the first embodiment; 
         FIG. 6  is a flowchart describing the example of the process according to the first embodiment; 
         FIG. 7  is a functional block diagram illustrating an example of a biometric authentication device according to a second embodiment; 
         FIG. 8  is a diagram describing an example of a session information management table; 
         FIG. 9  is a flowchart describing an example of a process according to the second embodiment; 
         FIG. 10  is a flowchart describing the example of the process according to the second embodiment; 
         FIG. 11  is a functional block diagram illustrating an example of a biometric authentication device according to a third embodiment; 
         FIG. 12  is a diagram describing an example of terminal management information; 
         FIG. 13  is a diagram describing an example of configuration management information; 
         FIG. 14  is a flowchart describing an example of a process according to the third embodiment; 
         FIG. 15  is a functional block diagram illustrating an example of a biometric authentication device according to a fourth embodiment; 
         FIG. 16  is a diagram describing an example of user data; 
         FIG. 17  is a flowchart describing an example of a process according to the fourth embodiment; 
         FIG. 18  is a functional block diagram illustrating an example of a biometric authentication device according to a fifth embodiment; 
         FIG. 19  is a functional block diagram illustrating an example of a biometric authentication device according to a sixth embodiment; 
         FIG. 20  is a functional block diagram illustrating an example of a biometric authentication device according to a seventh embodiment; and 
         FIG. 21  is a functional block diagram illustrating an example of a biometric authentication device according to an eighth embodiment; 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A biometric authentication device disclosed herein, a biometric authentication method disclosed herein, and a program disclosed herein confirm, in response to the reception of user identification information and sensor type information, whether or not sensor type information that is among sensor type information, registered for user identification information, of biometric sensors that have acquired biometric data and indicates a biometric sensor that has acquired biometric data corresponding to the received user identification information has a predetermined relationship with the received sensor type information, and control the issuance of a password to be used to reregister biometric data based on the confirmed sensor type information having the predetermined relationship. 
     Hereinafter, embodiments of the biometric authentication device disclosed herein, the biometric authentication method disclosed herein, and the program disclosed herein are described with reference to the accompanying drawings. 
     First Embodiment 
       FIG. 1  is a functional block diagram illustrating an example of a biometric authentication system according to a first embodiment. A client-server type biometric authentication system  1 - 1  illustrated in  FIG. 1  includes terminals  11 - 11  and  11 - 12  and an authentication server  12 - 1  that are connectable to each other via a network  13 . In the first embodiment, the authentication server  12 - 1  is an example of the biometric authentication device. The authentication server  12 - 1  may execute a program and execute processes in accordance with a biometric authentication method described below. 
     The terminals  11 - 11  and  11 - 12  are an example of multiple terminals included in the biometric authentication system  1 - 1 . The terminals  11 - 11  and  11 - 12  have the same configuration. Each of the terminals  11 - 11  and  11 - 12  includes a user ID acquirer  111 , a biometric information acquirer  112 , a sensor information acquirer  113 , and a biometric data generator  114 . The terminals  11 - 11  and  11 - 12  may be general-purpose computers such as PCs, smartphones, tablets, or the like. In this example, a biometric sensor  14 A of a sensor type A is connected to the terminal  11 - 11 , and a biometric sensor  14 B of a sensor type B different from the sensor type A is connected to the terminal  11 - 12 . The biometric sensor  14 A may be included in the terminal  11 - 11 , and the biometric sensor  14 B may be included in the terminal  11 - 12 . The sensor types indicate the types of the biometric sensors. The sensor types are an example of sensor type information indicating types such as models of the biometric sensors. In this example, fingerprint authentication that is an example of biometric authentication is executed using a fingerprint that is an example of a biometric body. In this case, the biometric sensors  14 A and  14 B may be fingerprint sensors having a known configuration. In each of the first embodiment, second to sixth embodiments described later, and an eighth embodiment described later, the number of terminals included in a biometric authentication system is not limited to 2 and may be 3 or more. 
     The type of the network  13  is not limited. The network  13  may be a wireless network, a wired network, or a combination of a wireless network and a wired network. For example, the network  13  may be the Internet, an intranet, or the like. 
     The authentication server  12 - 1  includes a sensor compatibility manager  121 , a user data manager  122 , a tentative password issuance determiner  123 , a biometric authenticator  124 , and a tentative password authenticator  125 . The authentication server  12 - 1  may be a general-purpose computer. The authentication server  12 - 1  may access a database  191  including biometric data and tentative password data. When a storage device storing the database  191  is accessible from the authentication server  12 - 1 , the storage device may be externally connected to the authentication server  12 - 1 , or connected to the network  13 , or included in the authentication server  12 - 1 . A tentative password may be referred to as one-time password and is an example of a password to be used to reregister biometric data in the authentication server  12 - 1 . 
     The sensor compatibility manager  121  and the user data manager  122  are an example of a confirming section. The confirming section confirms whether or not sensor type information that is among sensor type information, registered for user identification information, of biometric sensors that have acquired biometric data and indicates a biometric sensor that has acquired biometric data corresponding to received user identification information has a predetermined relationship with received sensor type information. The confirming section confirms, in response to the reception of user identification information and sensor type information, whether or not registered sensor type information of a biometric sensor that has acquired biometric data corresponding to the received user identification information has the predetermined relationship with the received sensor type information. The user data manager  122  is an example of a first manager configured to reference a user data management table in response to the reception of user identification information. The user data management table is an example of a first table. The user data management table stores, for user identification information, biometric data, sensor type information of biometric sensors that have acquired the biometric data, passwords, and password issuance flags indicating whether or not the passwords are to be issued. The sensor compatibility manager  121  is an example of a second manager configured to reference a compatibility management table in response to the reception of sensor type information. The compatibility management table is an example of a second table. The compatibility management table stores information indicating whether or not sensor type information has the predetermined relationship with other sensor type information. The tentative password issuance determiner  123 , the biometric authenticator  124 , and the tentative password authenticator  125  are an example of a controller configured to control the issuance of a password to be used to reregister biometric data based on confirmed sensor type information having the predetermined relationship. The tentative password issuance determiner  123  may be an example of a controller configured to control the enabling of a password issuance flag and control the issuance of a password. For example, when sensor type information of two biometric sensors has the predetermined relationship, the biometric sensors are compatible with each other. 
     Terminals including the terminals  11 - 11  and  11 - 12  and authentication servers including the authentication server  12 - 1  may be computers. 
       FIG. 2  is a block diagram illustrating an example of a computer. A computer  100  illustrated in  FIG. 2  has a configuration in which a central processing unit (CPU)  101 , a memory  102 , an input device  103 , a display device  104 , and an interface  105  are connected to each other via a bus  106 . The memory  102  is an example of a storage device. The computer  100 , however, is not limited to the configuration in which the CPU  101 , the memory  102 , the input device  103 , the display device  104 , and the interface  105  are connected to each other via the bus  106 . 
     The CPU  101  executes a program stored in the memory  102  and executes various processes including a biometric authentication process described later. The memory  102  stores the program, data, and the like. The memory  102  may be a computer-readable recording medium such as a portable recording medium, a semiconductor storage device, a magnetic recording medium, an optical recording medium, or a magneto-optical recording medium. The portable recording medium is a Universal Serial Bus (USB) memory or the like. The semiconductor storage device is a flash memory or the like. The optical recording medium is a compact disc-read only memory (CD-ROM), a digital versatile disc (DVD), or the like. When the magnetic recording medium, the optical recording medium, or the magneto-optical recording medium is used as the memory  102 , the recording medium is loaded into a drive such as a disk drive, the drive reads the program and the like from the recording medium and may write data or the like to the recording medium. 
     The input device  103  is operated by a user to input a command, data or the like to the computer  100  and may be a keyboard or the like. The display device  104  displays a message such as a biometric authentication result to the user. The input device  103  and the display device  104  may be unified into a single device such as a touch panel. The case where the touch panel is used as the input device  103  and the display device  104  is described later as an example. The interface  105  is an example of a transceiver that enables the computer  100  to be connected to the network  13 . 
     In the case where the computer  100  is the terminal  11 - 11 , the terminal  11 - 12 , or the like, the biometric sensors  14 A and  14 B and the like may be connected to the bus  106 , or connected directly to the CPU  101 , or included in the input device  103 , or connected to the interface  105 . In such a case, the CPU  101  may execute the program stored in the memory  102  and execute processes of the user ID acquirer  111 , biometric information acquirer  112 , sensor information acquirer  113 , and biometric data generator  114  of the terminal  11 - 11 , the terminal  11 - 12 , or the like. 
     In the case where the computer  100  is the authentication server  12 - 1  or the like, either or both of the input device  103  and the display device  104  may be omitted. In such a case, the CPU  101  may execute the program stored in the memory  102  and execute processes of the sections of the authentication server  12 - 1 . The processes of the sections of the authentication server  12 - 1  include processes of the sensor compatibility manager  121 , the user data manager  122 , the tentative password issuance determiner  123 , the biometric authenticator  124 , and the tentative password authenticator  125 . 
     In the following example, in a state in which biometric data of a user is already registered in the authentication server  12 - 1  from the terminal  11 - 11 , the same user uses biometric authentication from the terminal  11 - 12 . The state in which the biometric data is already registered in the authentication server  12 - 1  is a state in which the biometric data is already registered in the database  191  accessible by the authentication server  12 - 1 . For example, the terminal  11 - 11  may be an old terminal already used by the user, and the terminal  11 - 12  may be a new terminal to be newly used by the user. 
     An example in which the user uses a user ID “User0001” as a user identifier (ID) that is an example of user identification information is described below. In this example, user data is already registered in the database  191  of the authentication server  12 - 1 . The user data is associated with the user ID “User0001” and includes registered data of biometric data of the user, the sensor type A of the biometric sensor  14 A of the terminal  11 - 11  that has acquired the biometric data, and the like. 
       FIGS. 5 and 6  are flowcharts describing an example of a process according to the first embodiment. The process illustrated in  FIGS. 5 and 6  may be executed by causing CPUs  101  of computers  100  that are the terminals  11 - 11  and  11 - 12  and the authentication server  12 - 1  to execute the program stored in each of memories  102  of the computers  100 . The program causes the CPUs  101  of the computers  100  that are the terminals  11 - 11  and  11 - 12  and the authentication server  12 - 1  to execute the process illustrated in  FIGS. 5 and 6 . In the first embodiment, the authentication server  12 - 1  controls the issuance of a password while referencing the user data management table illustrated in  FIG. 3  and the compatibility management table illustrated in  FIG. 4 . 
       FIG. 3  illustrates an example of the user data management table. The user data management table stores, for user IDs, tentative password data including registered data, sensor types, tentative password issuance flags, tentative passwords, and tentative password expiration. The user IDs indicate data identifying users. The registered data indicate the names of files storing registered biometric data of the users. The sensor types indicate the types of the biometric sensors that have acquired the registered biometric data. When a tentative password issuance flag is enabled, a tentative password waits to be issued. The tentative passwords indicate issued tentative passwords. The tentative password expiration indicates the expiration of the issued tentative passwords. 
       FIG. 4  illustrates an example of the compatibility management table. The compatibility management table is a data table storing information indicating whether or not a biometric sensor that has acquired registered biometric data has a predetermined relationship with a biometric sensor able to acquire biometric data to be crosschecked with the registered biometric data. As an example, the compatibility management table stores sensor types that are information identifying biometric sensors that have acquired registered biometric data, and sensor types usable upon authentication among the types of biometric sensors able to acquire biometric data to be crosschecked with the registered biometric data so that the sensor types of the biometric sensors that have acquired the registered biometric data are associated with the sensor types usable upon the authentication. 
     For example, the user connects the terminal  11 - 12  that has yet to register biometric data to the authentication server  12 - 1 , and activates a biometric authentication application of the terminal  11 - 12  in order to use the biometric authentication. When the biometric authentication application is activated, an authentication screen is displayed on a touch panel of the terminal  11 - 12 , and the user enters the user ID “User0001” from the authentication screen. “The terminal that has yet to register biometric data” indicates the terminal that has yet to register biometric data in the authentication server  12 - 1 . In response to the entry of the user ID, the terminal  11 - 12  transmits the user ID to the authentication server  12 - 1  and transmits sensor type information of the biometric sensor  14 B of the terminal  11 - 12  to the authentication server  12 - 1  (in step S 1 ). For example, the user ID acquirer  111  of the terminal  11 - 12  acquires the entered user ID “User0001” and transmits the acquired user ID “User0001” to the authentication server  12 - 1  via the network  13 . In addition, the sensor information acquirer  113  of the terminal  11 - 12  acquires the sensor type B and transmits the acquired sensor type B to the authentication server  12 - 1  via the network  13 . The sensor type B is an example of the sensor type information of the biometric sensor  14 B of the terminal  11 - 12 . 
     The user data manager  122  of the authentication server  12 - 1  confirms a registration state of biometric data of the user ID “User0001” received from the terminal  11 - 12  in response to the reception of the user ID from the terminal  11 - 12  (in step S 2 ). For example, the user data manager  122  references the user data management table managed by the user data manager  122  and illustrated in  FIG. 3  and confirms the registration state of the biometric data of the user ID “User0001” received from the terminal  11 - 12 . In addition, the user data manager  122  determines whether or not registered data of the user ID “User0001” exists (in step S 3 ). In the example illustrated in  FIG. 3 , biometric data, acquired by the biometric sensor  14 A of the sensor type A, of the user of the user ID “User0001” is already registered (Yes in step S 3 ). Registered data “f/f9a9ana9ffa90g” stored for the user ID “User0001” in the user data management table is a file name, stored in the database  191 , of the biometric data of the user ID “User0001”. The format in which the registered data is stored, however, is not limited. When the result of the determination of step S 3  is No, the process proceeds to step S 6  described later. In this example, the user data management table and the compatibility management table are included in the database  191 . 
     The user data manager  122  confirms the compatibility of the sensor type B received from the terminal  11 - 12  with the sensor type A of the biometric sensor  14 A that has acquired the registered biometric data of the user ID in response to the reception of the sensor type information from the terminal  11 - 12  (in step S 4 ). The user data manager  122  references the compatibility management table managed by the sensor compatibility manager  121  and illustrated in  FIG. 4  and confirms the compatibility of the sensor type B with the sensor type A. For example, the user data manager  122  confirms the compatibility of the sensor type B that is the sensor type information received from the terminal  11 - 12  with the sensor type A of the biometric sensor  14 A that has acquired the biometric data, registered in the authentication server  12 - 1 , of the user ID “User0001”. The user data manager  122  determines whether or not the sensor type B and the sensor type A are compatible with each other (in step S 5 ). In this example, a sensor type usable upon authentication and compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the user ID “User0001” is only the sensor type A. Thus, the user data manager  122  determines that the sensor type B received from the terminal  11 - 12  is not compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the registered user ID “User0001” (No in step S 5 ). A “sensor type usable upon authentication” is a sensor type compatible with a sensor type used upon the registration of biometric data. 
     When the result of the determination of step S 5  is No, the tentative password issuance determiner  123  of the authentication server  12 - 1  determines whether or not a tentative password that is valid until tentative password expiration exists for the user ID “User0001” (in step S 6 ). For example, the tentative password issuance determiner  123  references user data of the user data management table illustrated in  FIG. 3  and determines whether or not the tentative password that is valid until the tentative password expiration exists for the user ID “User0001”. When the tentative password that is valid until the tentative password expiration exists (Yes in step S 7 ), the process proceeds to step S 10 . When the tentative password that is valid until the tentative password expiration exists (No in step S 7 ), the process proceeds to step S 8 . In the user data management table illustrated in  FIG. 3 , the tentative password does not exist for the user ID “User0001” (No in step S 7 ). Thus, the tentative password issuance determiner  123  enables a tentative password issuance flag for the user ID “User0001” (in step S 8 ). The tentative password issuance determiner  123  causes the terminal  11 - 12  to display a message, which notifies that the tentative password is to be acquired, on the authentication screen displayed on the touch panel of the terminal  11 - 12  (in step S 9 ). For example, the tentative password issuance determiner  123  causes the terminal  11 - 12  to display a message, which notifies that the authentication server  12 - 1  is to be accessed from the terminal  11 - 11  that has registered biometric data and that the tentative password is to be acquired by the terminal  11 - 11 , on the authentication screen of the terminal  11 - 12 . After step S 9 , the process returns to step S 1 . The “terminal that has registered the biometric data” indicates the terminal that has already registered the biometric data in the authentication server  12 - 1 . 
     Next, the user activates, in accordance with the message displayed in step S 9 , a biometric authentication application of the terminal  11 - 11  that has registered the biometric data in the authentication server  12 - 1 . When the biometric authentication application is activated, an authentication screen is displayed on a touch panel of the terminal  11 - 11 , and the user enters the user ID “User0001” from the authentication screen. In response to the entry of the user ID, the user ID acquirer  111  of the terminal  11 - 11  transmits the user ID “User0001” to the authentication server  12 - 1  and the sensor information acquirer  113  transmits the sensor type A of the biometric sensor  14 A of the terminal  11 - 11  to the authentication server  12 - 1  (in step S 1 ). For example, the user ID acquirer  111  of the terminal  11 - 11  acquires the user ID “User0001” and transmits the acquired user ID “User0001” to the authentication server  12 - 1  via the network  13 . The sensor information acquirer  113  of the terminal  11 - 11  acquires the sensor type A and transmits the acquired sensor type A to the authentication server  12 - 1  via the network  13 . The sensor type A is an example of sensor type information of the biometric sensor  14 A of the terminal  11 - 11 . 
     The user data manager  122  of the terminal  11 - 12  references the user data management table managed by the user data manager  122  and illustrated in  FIG. 3  and confirms a registration state of the biometric data of the user ID “User0001” received from the terminal  11 - 11  (in step S 2 ). In addition, the user data manager  122  determines whether or not registered data of the user ID “User0001” exists (in step S 3 ). In the example illustrated in  FIG. 3 , the biometric data, acquired by the biometric sensor  14 A of the sensor type A, of the user of the user ID “User0001” is already registered (Yes in step S 3 ). The user data manager  122  confirms the compatibility of the sensor type A that is the sensor type information received from the terminal  11 - 11  with the sensor type A of the biometric sensor  14 A that has acquired the biometric data, registered in the authentication server  12 - 1 , of the user ID “User0001” (in step S 4 ). For example, the user data manager  122  references the compatibility management table managed by the sensor compatibility manager  121  and illustrated in  FIG. 4  and confirms the aforementioned compatibility. The user data manager  122  determines whether or not the sensor type A received from the terminal  11 - 11  is compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data, registered in the authentication server  12 - 1 , of the user ID “User0001” (in step S 5 ). In this example, a sensor type usable upon authentication and compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the user ID “User0001” is the sensor type A. Thus, the user data manager  122  determines that the sensor type A received from the terminal  11 - 11  is compatible with the sensor type A of the biometric sensor  14 A that has acquired the registered biometric data of the user ID “User0001” (Yes in step S 5 ), and the process proceeds to step S 14  illustrated in  FIG. 6 . 
     When the result of the determination of step S 5  is Yes, the tentative password issuance determiner  123  causes the terminal  11 - 11  to display the authentication screen of the biometric authentication application on the touch panel of the terminal  11 - 11  via the network  13  (in step S 14 ). The user uses the biometric sensor  14 A to acquire biometric information of the user in accordance with a message displayed on the authentication screen and inputs the biometric information to the terminal  11 - 11 . In response to the input of the biometric information of the user, the biometric information acquirer  112  of the terminal  11 - 11  acquires the input biometric information, and the biometric data generator  114  generates biometric data and transmits the generated biometric data to the authentication server  12 - 1  (in step S 15 ). For example, the biometric data generator  114  of the terminal  11 - 11  generates the biometric data based on the biometric information acquired by the biometric information acquirer  112  and transmits the generated biometric data to the authentication server  12 - 1  via the network  13 . 
     Biometric information, acquired by the biometric sensors  14 A and  14 B, of the user is, for example, fingerprint images of the user or the like. Biometric data is generated from the biometric information such as the fingerprint images and is fingerprint data or the like and to be crosschecked with registered biometric data in the biometric authentication process. The biometric data is preferably in a format suitable to crosscheck the biometric data with the registered biometric data in the biometric authentication process. The format of the biometric data, however, is not limited. The biometric data such as the fingerprint data may be characteristic data extracted from the biometric information such as the fingerprint images. The biometric data such as the fingerprint data may be compressed, encrypted, or the like. 
     The biometric authenticator  124  of the authentication server  12 - 1  executes the biometric authentication process to crosscheck the biometric data received from the terminal  11 - 11  with the registered biometric data (in step S 16 ) and determines whether or not the biometric authentication has been successful (in step S 17 ). When the biometric authentication has been successful (Yes in step S 17 ), the tentative password issuance determiner  123  references the user data management table illustrated in  FIG. 3  and determines whether or not a tentative password issuance flag for the user ID “User0001” is enabled (in step S 18 ). When the tentative password issuance flag for the user ID “User0001” is enabled (Yes in step S 18 ), the process proceeds to step S 19 . The tentative password issuance determiner  123  issues a tentative password, causes the terminal  11 - 11  to display the issued tentative password on the authentication screen of the terminal  11 - 11 , disables the tentative password issuance flag for the user ID “User0001”, and records tentative password expiration (in step S 19 ). For example, the tentative password issuance determiner  123  issues the tentative password, transmits the issued tentative password to the terminal  11 - 11  via the network  13 , and causes the terminal  11 - 11  to display the tentative password on the authentication screen of the terminal  11 - 11 . In addition, the tentative password issuance determiner  123  disables the tentative password issuance flag for the user ID “User0001” included in the user data management table illustrated in  FIG. 3 , and records the tentative password expiration of the tentative password. 
     Next, the user activates the biometric authentication application of the terminal  11 - 12  and enters the user ID “User0001” from the authentication screen displayed on the touch panel in the same manner as described above. In response to the entry of the user ID, the user ID acquirer  111  of the terminal  11 - 12  transmits the user ID “User0001” to the authentication server  12 - 1  and the sensor information acquirer  113  transmits the sensor type B of the biometric sensor  14 B of the terminal  11 - 12  to the authentication server  12 - 1  (in step S 1 ). For example, the user ID acquirer  111  of the terminal  11 - 12  acquires the entered user ID and transmits the acquired user ID to the authentication server  12 - 1  via the network  13 . The sensor information acquirer  113  of the terminal  11 - 12  acquires the sensor type B and transmits the acquired sensor type B to the authentication server  12 - 1  via the network  13 . The sensor type B is an example of the sensor type information of the biometric sensor  14 B of the terminal  11 - 12 . 
     The user data manager  122  of the authentication server  12 - 1  references the user data management table managed by the user data manager  122  and illustrated in  FIG. 3  and confirms a registration state of biometric data of the user ID “User0001” received from the terminal  11 - 12  (in step S 2 ). In addition, the user data manager  122  determines whether or not registered data of the user ID “User0001” exists (in step S 3 ). In the example illustrated in  FIG. 3 , the biometric data, acquired by the biometric sensor  14 A of the sensor type A, of the user of the user ID “User0001” is already registered (Yes in step S 3 ). The user data manager  122  confirms, in response to the reception of the sensor type information from the terminal  11 - 12 , the compatibility of the sensor type B received from the terminal  11 - 12  with the sensor type A of the biometric sensor  14 A that has acquired the registered biometric data of the user ID (in step S 4 ). The user data manager  122  references the compatibility management table managed by the sensor compatibility manager  121  and illustrated in  FIG. 4  and confirms the compatibility of the sensor type B with the sensor type A. For example, the user data manager  122  confirms the compatibility of the sensor type B that is the sensor type information received from the terminal  11 - 12  with the sensor type A of the biometric sensor  14 A that has acquired the biometric data, registered in the authentication server  12 - 1 , of the user ID “User0001”. In addition, the user data manager  122  determines whether or not the sensor type B and the sensor type A are compatible with each other (in step S 5 ). In this example, a sensor type usable upon the authentication and compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the user ID “User0001” is only the sensor type A. Thus, the user data manager  122  determines that the sensor type B received from the terminal  11 - 12  is not compatible with the sensor type A of the biometric sensor  14 A that has acquired the registered biometric data of the user ID “User0001” (No in step S 5 ). When the result of the determination of step S 5  is No, the process proceeds to step S 6  illustrated in  FIG. 5 . 
     Next, the tentative password issuance determiner  123  of the authentication server  12 - 1  references the user data management table illustrated in  FIG. 3  and determines whether or not a tentative password that is valid until tentative password expiration exists for the user ID “User0001” (in step S 6 ). When the tentative password that is valid until the tentative password expiration exists (Yes in step S 7 ), the process proceeds to step S 10 . When the tentative password that is valid until the tentative password expiration does not exist (No in step S 7 ), the process proceeds to step S 8 . Since the tentative password for the user ID “User0001” exists in the user data management table illustrated in  FIG. 3  (Yes in step S 7 ), the process proceeds to step S 10 . The tentative password authenticator  125  controls the biometric authentication application of the terminal  11 - 12  via the network  13  so that the authentication screen for entering a tentative password is displayed on the touch panel of the terminal  11 - 12  (in step S 10 ). The user enters the user ID and the tentative password from the authentication screen displayed on the touch panel of the terminal  11 - 12 . The user ID acquirer  111  of the terminal  11 - 12  transmits the tentative password to the authentication server  12 - 1  via the network  13  in response to the entry of the user ID and the tentative password from the authentication screen (in step S 11 ). When the authentication of the tentative password by the tentative password authenticator  125  of the authentication server  12 - 1  is successful, the tentative password issuance determiner  123  controls the biometric authentication application of the terminal  11 - 12 . For example, the tentative password issuance determiner  123  controls the biometric authentication application of the terminal  11 - 12  via the network  13  so that the authentication screen for entering biometric information is displayed on the touch panel of the terminal  11 - 12 . The user uses the biometric sensor  14 B to acquire biometric information of the user and inputs the acquired biometric information to the terminal  11 - 12  in accordance with a message displayed on the authentication screen of the terminal  11 - 12 . In response to the input of the biometric information of the user, the biometric information acquirer  112  of the terminal  11 - 12  acquires the input biometric information and the biometric data generator  114  generates biometric data and transmits the generated biometric data to the authentication server  12 - 1  (in step S 12 ). For example, the biometric data generator  114  of the terminal  11 - 12  generates the biometric data based on the biometric information acquired by the biometric information acquirer  112  and transmits the generated biometric data to the authentication server  12 - 1  via the network  13  (in step S 12 ). The tentative password authenticator  125  of the authentication server  12 - 1  acquires the biometric data received from the terminal  11 - 12  and deletes the tentative password after the registration (in step S 13 ). For example, the tentative password authenticator  125  registers the acquired biometric data for registered data of the user ID “User0001” in the user data management table illustrated in  FIG. 3  and deletes the tentative password recorded for the user ID “User0001” after the registration of the biometric data for the registered data. 
     In the first embodiment, a user ID acquirer of a second terminal that has yet to register biometric data in the authentication server and is different from a first terminal that has registered biometric data in the authentication server acquires the user ID and transmits the acquired user ID to the authentication server in accordance with the process illustrated in  FIGS. 5 and 6 . In addition, a sensor information acquirer of the second terminal acquires sensor type information and transmits the acquired sensor type information to the authentication server. The tentative password issuance determiner of the authentication server executes the control on the user ID received from the second terminal based on whether or not registered data compatible with the sensor type information exists and whether or not a tentative password exists in the user data management table. When the tentative password does not exist in the user data management table, the tentative password issuance determiner enables a tentative password issuance flag in the user data management table via the user data manager. When the tentative password exists in the user data management table, the tentative password issuance determiner controls the second terminal so that an authentication screen for entering the tentative password is displayed in the second terminal. When the authentication server receives the tentative password entered by the user from the second terminal, the tentative password authenticator executes the authentication process and controls the second terminal so that biometric data is registerable from the second terminal upon the success of the authentication. 
     The biometric authenticator of the authentication server executes the biometric authentication process. When the biometric authentication is successful, the tentative password issuance determiner references a tentative password issuance flag via the user data manager. When the tentative password issuance determiner of the authentication server references the tentative password issuance flag and the tentative password issuance flag is enabled, the tentative password issuance determiner issues a tentative password and causes the issued tentative password to be stored in the user data management table via the user data manager. In addition, the tentative password issuance determiner transmits the tentative password to the first terminal and disables the tentative password issuance flag. 
     In the first embodiment, the authentication server may control the enabling of a tentative password issuance flag based on the user ID received from a terminal and sensor type information received from the terminal and determine whether or not a tentative password is to be issued. In addition, when the biometric authentication executed using a biometric sensor compatible with a biometric sensor that has acquired registered biometric data is successful, the authentication server issues a tentative password to be used to reregister biometric data in the authentication server. Thus, it may be possible to avoid the issuance of a tentative password to a person other than the user without a system administrator. Thus, it does not take efforts to have the system administrator issue a tentative password in order to reregister biometric data in the authentication server. Thus, in the first embodiment, it may be possible to reduce the number of processes in the case where biometric data is reregistered in the authentication server from a terminal that tries to use biometric authentication. 
     In each of the second and sixth embodiments described below, a seventh embodiment described below, and the eighth embodiment described below, it may be possible to reduce the number of processes in the case where biometric data is reregistered in an authentication server from a terminal that tries to use biometric authentication. 
     Second Embodiment 
       FIG. 7  is a functional block diagram illustrating an example of a biometric authentication device according to the second embodiment. Sections that are illustrated in  FIG. 7  and are the same as those illustrated in  FIG. 1  are indicated by the same reference symbols as those illustrated in  FIG. 1 , and a description thereof is omitted. In the second embodiment, an authentication server  12 - 2  of a biometric authentication system  1 - 2  is an example of the biometric authentication device. The authentication server  12 - 2  may execute a program and execute processes in accordance with a biometric authentication method described later. As illustrated in  FIG. 7 , in the second embodiment, each of terminals  11 - 21  and  11 - 22  further includes a terminal information acquirer  115 , and the authentication server  12 - 2  further includes a session information manager  126 . The terminal information acquirers  115  of the terminals  11 - 21  and  11 - 22  acquire terminal information of the terminals  11 - 21  and  11 - 22  and transmit the acquired terminal information to the authentication server  12 - 2 . When a tentative password for the user ID is not stored in the user data management table, the session information manager  126  of the authentication server  12 - 2  associates information with a session ID and sets and manages the information associated with the session ID in a session information management table illustrated in  FIG. 8 . The session ID is an example of session information. The information associated with the session ID includes the user ID, terminal information, authentication results of the biometric authentication process, and session expiration. In this example, a timestamp is set in the session information management table. Terminal information set in the session information management table is not limited as long as the terminal information set in the session information management table is information identifying a terminal connected to the authentication server  12 - 2  and is, for example, a Media Access Control (MAC) Internet Protocol (IP) address or the like. 
     The session information manager  126  is an example of a third manager configured to associate information with session information and set and manage the information associated with the session information in the session information management table when a password for user identification information is not stored in the user management table. The user management table is an example of the first table. The session information management table is an example of a third table. The information associated with the session information and set and managed in the session information management table includes user identification information, terminal information, an authentication result of the biometric authentication process, and session expiration. 
     An example in which the user uses the user ID “User0001” as a user identifier (ID) that is an example of the user identification information is described below. In a database  191  of the authentication server  12 - 2 , user data that includes registered data of biometric data of the user and the sensor type A of the biometric sensor  14 A of the terminal  11 - 21  that has acquired the biometric data are already registered. 
       FIGS. 9 and 10  are flowcharts describing an example of a process according to the second embodiment. The process illustrated in  FIGS. 9 and 10  may be executed by CPUs  101  of computers  100  that are the terminals  11 - 21  and  11 - 22  and the authentication server  12 - 2  to execute a program stored in each of memories  102  of the computers  100 . In the second embodiment, the authentication server  12 - 2  controls the issuance of a tentative password while referencing the user data management table illustrated in  FIG. 3 , the compatibility management table illustrated in  FIG. 4 , and the session information management table illustrated in  FIG. 8 . 
       FIG. 8  illustrates an example of the session information management table. The session information management table stores, for session IDs identifying sessions, timestamps, user IDs, terminal information, authentication results, and session expiration as information on the sessions. The timestamps indicate time when the sessions are established. The user IDs indicate IDs of users that have performed the establishment of the sessions. The terminal information indicates information identifying connected terminals and are MAC IP addresses or the like. The authentication results indicate whether or not the sessions have been successfully established. In the second embodiment, the biometric authentication is executed on the user in order to establish a session. The session expiration indicates the expiration of the sessions and may be specific time in each day or may be time when predetermined time elapses after the time indicated by the timestamps. 
     The user enters the user ID “User0001” from the terminal  11 - 21  that has registered biometric data and is illustrated in  FIG. 7 , as in the case of the process illustrated in  FIGS. 5 and 6 . In response to the entry of the user ID, the user ID acquirer  111  of the terminal  11 - 21  acquires the user ID and the sensor information acquirer  113  of the terminal  11 - 21  acquires the sensor type information of the biometric sensor  14 A. In the example illustrated in  FIG. 7 , the terminal  11 - 21  that has registered the biometric data has the biometric sensor  14 A of the sensor type A. Thus, the sensor information acquirer  113  of the terminal  11 - 21  acquires the sensor type A as the sensor type information. The user ID acquirer  111  transmits the acquired user ID “User0001” to the authentication server  12 - 2  via the network  13 . The sensor information acquirer  113  transmits the acquired sensor type A to the authentication server  12 - 2  via the network  13 . 
     The user data manager  122  of the authentication server  12 - 2  references the user data management table illustrated in  FIG. 3  and determines whether or not registered data of the user ID “User0001” exists. In the example illustrated in  FIG. 3 , the biometric data acquired by the biometric sensor  14 A of the sensor type A is already registered for the user ID “User0001”. The user data manager  122  of the authentication server  12 - 2  references the compatibility management table illustrated in  FIG. 4  and determines the compatibility. In this example, the user data manager  122  determines that the sensor type A received from the terminal  11 - 21  is compatible with the sensor type A registered in the authentication server  12 - 2 . The user data manager  122  causes the terminal  11 - 21  to display an authentication screen of a biometric authentication application on a touch panel of the terminal  11 - 21 . The sensor type A received from the terminal  11 - 21  is usable upon authentication. The biometric authentication acquirer  112  of the terminal  11 - 21  acquires biometric information input by the user from the biometric sensor  14 A. The biometric data generator  114  of the terminal  11 - 21  generates biometric data based on the biometric information acquired by the biometric authentication acquirer  112  and transmits the generated biometric data to the authentication server  12 - 2  via the network  13 . 
     When the biometric authenticator  124  of the authentication server  12 - 2  executes the biometric authentication process, and the biometric authentication is successful, the tentative password issuance determiner  123  references details associated with the user ID “User0001” in the user data management table (in step S 21 ). The tentative password issuance determiner  123  determines whether or not a tentative password that is associated with the user ID “User0001” and valid until tentative password expiration exists (in step S 22 ). When the tentative password issuance determiner  123  confirms that the tentative password that is associated with the user ID “User0001” and valid until the tentative password expiration exists in the user data management table (Yes in step S 22 ), a tentative password is not issued. When the result of the determination of step S 22  is Yes, the authentication server  12 - 2  waits for the next access from a terminal. On the other hand, when the tentative password issuance determiner  123  of the authentication server  12 - 2  determines that the tentative password that is associated with the user ID “User0001” and valid until the tentative password expiration does not exist (No in step S 22 ), the process proceeds to step S 23 . The session information manager  126  sets the session information management table illustrated in  FIG. 8  (in step S 23 ) and the authentication server  12 - 2  waits for the next access from a terminal. 
     For example, the terminal  11 - 22  that has the biometric sensor  14 B of the sensor type B and has yet to register biometric data in the authentication server  12 - 2  is connected to the authentication server  12 - 2  via the network  13 . For example, the user activates a biometric authentication application of the terminal  11 - 22  and enters the user ID “User0001” from an authentication screen of the terminal  11 - 22 . The user ID acquirer  111  of the terminal  11 - 22  acquires the entered user ID and transmits the acquired user ID to the authentication server  12 - 2  via the network  13 . The sensor information acquirer  113  of the terminal  11 - 22  acquires the sensor type information (sensor type B) of the biometric sensor  14 B of the terminal  11 - 22  and transmits the sensor type information to the authentication server  12 - 2  via the network  13 . The user data manager  122  of the authentication server  12 - 2  confirms whether or not biometric data associated with the received user ID exists in the authentication server  12 - 2  in response to the connection of the terminal  11 - 22  (in step S 24 ). For example, when the user data manager  122  detects the connection of the terminal  11 - 22 , the user data manager  122  references the user data management table and confirms whether or not registered data of the user ID received from the terminal  11 - 22  exists. In this example, the biometric data acquired by the biometric sensor  14 A of the sensor type A is already registered for the user ID “User0001” and the registered data exists. When the registered data associated with the received user ID does not exist (No in step S 25 ), the authentication server  12 - 2  executes a process of issuing a tentative password in the same manner as the process described with reference to  FIGS. 5 and 6 . When the registered data associated with the received user ID exists (Yes in step S 25 ), the process proceeds to step S 26 . The user data manager  122  references the compatibility management table illustrated in  FIG. 4  and confirms the compatibility of the sensor type received from the terminal with the sensor type registered in the authentication server  12 - 2  (in step S 26 ). In this example, the authentication server  12 - 2  receives the sensor type B from the terminal  11 - 22 , and the received sensor type B is not compatible with the sensor type A registered in the authentication server  12 - 2 . When the sensor type received from the terminal is compatible with the sensor type registered in the authentication server  12 - 2  (Yes in step S 27 ), the authentication server  12 - 2  executes the biometric authentication process in the same manner as the process described with reference to  FIGS. 5 and 6 . When the sensor type received from the terminal is not compatible with the sensor type registered in the authentication server  12 - 2  (No in step S 27 ), the authentication server  12 - 2  references the session information management table illustrated in  FIG. 8  and determines whether or not a tentative password is to be issued (in step S 28 ). 
     The tentative password issuance determiner  123  determines whether or not a session including the same user ID “User0001” exists in the session information management table (in step S 29 ). When the session including the same user ID “User0001” exists in the session information management table (Yes in step S 29 ), the tentative password issuance determiner  123  determines whether or not that the session is valid until session expiration (in step S 30 ). When the session is valid until the session expiration (Yes in step S 30 ), the tentative password issuance determiner  123  determines whether or not authentication executed in the biometric authentication process by the biometric authenticator  124  has been successful (in step S 31 ). When the authentication has been successful in the biometric authentication process (Yes in step S 31 ), the process proceeds to step S 32  illustrated in  FIG. 10 . 
     The tentative password issuance determiner  123  acquires terminal information associated with the corresponding session from the session information management table (in step S 32 ). In addition, the tentative password issuance determiner  123  controls the biometric authentication application of the terminal  11 - 21  to cause the terminal  11 - 21  indicated by the acquired terminal information to display the authentication screen, transmits a tentative password to the terminal  11 - 21 , and causes the terminal  11 - 21  to display the tentative password on the authentication screen of the terminal  11 - 21  (in step S 33 ). For example, the tentative password issuance determiner  123  controls the biometric authentication application of the terminal  11 - 21  via the network  13  so that the authentication screen is displayed on the touch panel of the terminal  11 - 21  indicated by the acquired terminal information. The tentative password issuance determiner  123  transmits the tentative password to the terminal  11 - 21  via the network  13  and causes the terminal  11 - 21  to display the tentative password on the authentication screen of the terminal  11 - 21 . 
     In the example illustrated in  FIG. 8 , a session including the user ID “User0001” exists and the user ID “User0001” for which a connection request has been provided from the terminal  11 - 22  that has yet to register biometric data in the authentication server  12 - 2  is associated with a session ID “0000000000000001”. The session including the user ID “User0001” is valid until session expiration. Thus, when the biometric authenticator  124  of the authentication server  12 - 2  determines that the authentication has been successful in the biometric authentication process by the biometric authenticator  124 , the tentative password issuance determiner  123  issues a tentative password. For example, the tentative password issuance determiner  123  issues the tentative password to the biometric authentication application of the terminal  11 - 21  having an IP address “wwww.xxxx.yyyy.0001” recorded in the terminal information of the terminal  11 - 21 . The tentative password issuance determiner  123  causes the terminal  11 - 21  to display the issued tentative password on the authentication screen of the biometric authentication application on the touch panel of the terminal  11 - 21 . 
     In the second embodiment, when the authentication is successful in the biometric authentication process in accordance with the process illustrated in  FIGS. 9 and 10 , the authentication server references the user data management table, and a tentative password for the user ID exists, the authentication server issues a tentative password in the same manner as the process described with reference to  FIGS. 5 and 6 . When the tentative password for the user ID does not exist, the authentication server associates the user ID, terminal information, the result of the biometric authentication process, and session expiration with a session ID and sets and manages the user ID, the terminal information, the result of the biometric authentication process, and the session expiration in the session information management table. Next, when a second terminal that has yet to register biometric data in the authentication server is connected to the authentication server, the user ID acquirer of the second terminal acquires the user ID and transmits the acquired user ID to the authentication server, and the sensor information acquirer acquires sensor type information and transmits the acquired sensor type information to the authentication server. 
     The authentication server determines whether or not a tentative password is to be issued in the same manner as the process described with reference to  FIGS. 5 and 6 . When the authentication server determines that the tentative password is to be issued, a session that includes the user ID and is valid until session expiration may exist. In this case, the authentication server acquires terminal information associated with the corresponding session. When a session that includes the same user ID as that received by the session information manager from the second terminal and is valid until session expiration exists, the authentication server acquires terminal information associated with the corresponding session. The tentative password issuance determiner generates a tentative password and transmits the generated tentative password to a first terminal indicated by the acquired terminal information. 
     In the second embodiment, the authentication server associates the management of the issuance of a tentative password with the session management. Thus, when a terminal having a biometric sensor incompatible with a biometric sensor that has acquired biometric data registered in the authentication server is connected to the authentication server, the authentication server issues a tentative password and transmits the issued tentative password to a terminal that holds a valid session and has already registered biometric data in the authentication server. After the terminal having the biometric sensor incompatible with the biometric sensor that has acquired the biometric data registered in the authentication server is connected to the authentication server, the biometric authentication is not executed again on the terminal having the biometric sensor that has acquired the registered biometric data. Thus, a procedure for issuing a tentative password may be simplified. 
     Third Embodiment 
       FIG. 11  is a functional block diagram illustrating an example of a biometric authentication device according to the third embodiment. Sections that are illustrated in  FIG. 11  and are the same as those illustrated in  FIG. 1  are indicated by the same reference symbols as those illustrated in  FIG. 1 , and a description thereof is omitted. In the third embodiment, an authentication server  12 - 3  of a biometric authentication system  1 - 3  is an example of the biometric authentication device. The authentication server  12 - 3  may execute a program and execute processes in accordance with a biometric authentication method described later. As illustrated in  FIG. 11 , in the third embodiment, each of terminals  11 - 31  and  11 - 32  does not include a terminal information acquirer  115 . The authentication server  12 - 3  further includes a terminal manager  127  and a configuration management information acquirer  128 . The terminal manager  127  manages terminal management information stored in a database  192  and illustrated in  FIG. 12 . The configuration management information acquirer  128  acquires configuration management information stored in a database  193  and illustrated in  FIG. 13 . The authentication server  12 - 3  may access the databases  191 ,  192 , and  193 . Two or more of the databases  191 ,  192 , and  193  may be included in a single database. 
     The terminal manager  127  is an example of a third manager. The terminal manager  127  acquires, from terminal configuration management information including terminal model names and sensor type information, sensor type information associated with a received terminal model name. In addition, the terminal manager  127  extracts, from the user data management table, sensor type information of a biometric sensor that has acquired biometric data of corresponding user identification information. The user data management table is an example of the first table. The tentative password issuance determiner  123  is an example of a controller configured to enable a password issuance flag. The tentative password issuance determiner  123  crosschecks the extracted sensor type information with the compatibility management table and determines whether or not a password is to be issued. The compatibility management table is an example of the second table. In addition, the tentative password issuance determiner  123  enables a password issuance flag when sensor type information compatible with the sensor type information associated with the terminal model name does not exist in the user data management table that is an example of the first table. 
     An example in which the user uses the user ID “User0001” as a user identifier (ID) that is an example of the user identification information is described below. In addition, user data that includes registered data of biometric data of the user and the sensor type A of the biometric sensor  14 A of the terminal  11 - 31  that has acquired the biometric data is associated with the user ID “User0001” and already registered in the database  191  of the authentication server  12 - 3 . 
       FIG. 14  is a flowchart describing an example of a process according to the third embodiment. The process illustrated in  FIG. 14  may be executed by CPUs  101  of computers  100  that are the terminals  11 - 31  and  11 - 32  and the authentication server  12 - 3  to execute a program stored in each of memories  102  of the computers  100 . 
     When the user activates a client application included in the terminal  11 - 32  and designed to manage the terminal  11 - 32  that has yet to register biometric data in the authentication server  12 - 3 , an input screen is displayed on a touch panel of the terminal  11 - 32 . When the user enters terminal management information from the input screen, the terminal management information is transmitted to the authentication server  12 - 3  via the network  13 , and the terminal manager  127  of the authentication server  12 - 3  registers the received terminal management information in the database  192  (in step S 34 ). The terminal management information entered by the user from the input screen includes the user ID “User0001”, a terminal name T2 of the terminal  11 - 32 , a terminal model name M2 of the terminal  11 - 32 . In an example of the terminal management information that is illustrated in  FIG. 12 , a terminal name T1 “Term1-1” of the terminal  11 - 31 , a terminal model name M1 “XXXXXXX1.” of the terminal  11 - 31 , a terminal name T2 “Term1-2” of the terminal  11 - 32 , and a terminal model name M2 “XXXXXXX2” of the terminal  11 - 32  are stored for the user “User0001” in the database  192 . The tentative password issuance determiner  123  of the authentication server  12 - 3  acquires a sensor type associated with a registered terminal model name in response to the registration of the terminal management information of the terminal  11 - 32  in the database  192  (in step S 35 ). For example, the tentative password issuance determiner  123  acquires the sensor type associated with the registered terminal model name from the configuration management information stored in the database  193  and illustrated in  FIG. 13  via the configuration management information acquirer  128 . In the example of the configuration management information that is illustrated in  FIG. 13 , the sensor type A of the biometric sensor  14 A is stored for the terminal model name “XXXXXXX1”, and the sensor type B of the biometric sensor  14 B is stored for the terminal model name “XXXXXXX2”. In this example, the tentative password issuance determiner  123  acquires the sensor type B stored for the terminal model name “XXXXXXX2” from the database  193  in response to the registration of the terminal  11 - 32  with the terminal model name “XXXXXXX2” in the database  192 . 
     Next, the tentative password issuance determiner  123  of the authentication server  12 - 3  extracts a sensor type that is sensor type information of registered data associated with the user ID “User0001” from the user data management table illustrated in  FIG. 3  (in step S 36 ). In this example, the extracted sensor type information is the sensor type A of the biometric sensor  14 A. The tentative password issuance determiner  123  crosschecks the extracted sensor type A with the compatibility management table illustrated in  FIG. 4  and determines whether or not a tentative password is to be issued (in step S 36 ). The tentative password issuance determiner  123  determines whether or not the sensor type of the newly registered terminal is compatible with a sensor type of sensor data of registered data (in step S 37 ). For example, the tentative password issuance determiner  123  determines whether or not the sensor type B of the terminal  11 - 32  whose terminal management information has been registered in the database  192  is compatible with the sensor type A of the biometric sensor  14 A that has acquired biometric data, registered in the database  191 , of the user ID “User0001”. Thus, the tentative password issuance determiner  123  determines whether or not the sensor type B associated with the terminal model name “XXXXXXX2” newly registered as described above is included in sensor types usable upon authentication. 
     In this example, since the sensor type B associated with the terminal  11 - 32  is not compatible with the sensor type A used upon the registration and is not included in the sensor types usable upon the authentication (No in step S 37 ), the process proceeds to step S 39 . The tentative password issuance determiner  123  enables a tentative password issuance flag for the user ID “User0001” in the user data management table and executes the processes after the enabling of the tentative password issuance flag in the same manner as the process described with reference to  FIGS. 5 and 6  (in step S 39 ). For example, the biometric authenticator  124  of the authentication server  12 - 3  executes the biometric authentication process to crosscheck biometric data received from the terminal  11 - 31  that has registered biometric data in the authentication server  12 - 3  with the registered biometric data and the tentative password issuance determiner  123  issues a tentative password. When the sensor type B associated with the terminal  11 - 32  is compatible with the sensor type A used upon the registration and is included in the sensor types usable upon the authentication (Yes in step S 37 ), the process proceeds to step S 38 . The tentative password issuance determiner  123  determines that a tentative password to be used to reregister biometric data in the authentication server  12 - 3  from the terminal  11 - 32  is not to be issued (in step S 38 ), and the process is terminated. 
     In the third embodiment, the user newly registers terminal management information including a terminal name and a terminal model name in the authentication server from a terminal in accordance with the process illustrated in  FIG. 14 . The authentication server acquires, from the terminal configuration management information including the terminal model name and the sensor type, the sensor type associated with the newly registered terminal model name. In addition, the authentication server extracts a sensor type of registered data of the corresponding user ID from the user data management information. The tentative password issuance determiner crosschecks the extracted sensor type with the compatibility management table and determines whether or not a tentative password is to be issued. When the registered data compatible with the sensor type associated with the newly registered terminal model name does not exist, the tentative password issuance determiner enables a tentative password issuance flag, executes the biometric authentication process to crosscheck biometric data received from a terminal that has registered biometric data in the authentication server with registered biometric data, and the tentative password issuance determiner issues a tentative password. 
     In the third embodiment, even when each terminal does not include a terminal information acquirer or the like that is configured to acquire a sensor type, the user may use the terminal manager of the authentication server and determine compatibility based on a registered terminal model name in the aforementioned manner. For example, the compatibility of a sensor type of a terminal model name registered in the configuration management information of the authentication server with a sensor type of registered data associated with the corresponding user ID in the user data management table is determined based on the compatibility management table. When the authentication server determines that the sensor types are not compatible with each other, the authentication server enables a tentative password issuance flag, issues a tentative password, and transmits the issued tentative password to a terminal that has registered biometric data in the authentication server. 
     Fourth Embodiment 
       FIG. 15  is a functional block diagram illustrating an example of a biometric authentication device according to the fourth embodiment. Sections that are illustrated in  FIG. 15  and are the same as those illustrated in  FIG. 11  are indicated by the same reference symbols as those illustrated in  FIG. 11 , and a description thereof is omitted. In the fourth embodiment, an authentication server  12 - 4  of a biometric authentication system  1 - 4  is an example of the biometric authentication device. The authentication server  12 - 4  may execute a program and execute processes in accordance with a biometric authentication method described later. As illustrated in  FIG. 15 , in the fourth embodiment, the authentication server  12 - 4  further includes a mail transmitter  129 . The authentication server  12 - 4  may access a database  194 . The user data manager  122  of the authentication server  12 - 4  manages a user data management table illustrated in  FIG. 16 . The user data management table illustrated in  FIG. 16  stores the user data illustrated in  FIG. 3  and mail addresses of user IDs. The mail transmitter  129  is an example of a transmitter configured to transmit a password to an acquired mail address. 
     An example in which the user uses the user ID “User0001” as a user identifier (ID) that is an example of the user identification information is described below. In a database  194  of the authentication server  12 - 4 , user data of the user is associated with the user ID “User0001” and already registered. The user data includes registered data of biometric data of the user, the sensor type A of the biometric sensor  14 A of the terminal  11 - 41  that has acquired the biometric data, a mail address “user0001@xxx.com” of the user. 
       FIG. 17  is a flowchart describing an example of a process according to the fourth embodiment. The process illustrated in  FIG. 17  may be executed by causing CPUs  101  of computers  100  that are the terminals  11 - 41  and  11 - 42  and the authentication server  12 - 4  to execute a program stored in each of memories  102  of the computers  100 . 
     For example, the user connects the terminal  11 - 42  that has yet to register biometric data in the authentication server  12 - 4  to the authentication server  12 - 4 . Then, the user activates a biometric authentication application of the terminal  11 - 42  to use biometric authentication. When the biometric authentication application is activated, an authentication screen is displayed on a touch panel of the terminal  11 - 42 , and the user enters the user ID “User0001” from the authentication screen. In response to the entry of the user ID, the user ID acquirer  111  of the terminal  11 - 42  transmits the user ID “User0001” to the authentication server  12 - 4  and the sensor information acquirer  113  transmits the sensor type B of the biometric sensor  14 B to the authentication server  12 - 4  (in step S 41 ). For example, the user ID acquirer  111  acquires the user ID “User0001” and transmits the acquired user ID “User0001” to the authentication server  12 - 4  via the network  13 . In addition, the sensor information acquirer  113  of the terminal  11 - 42  acquires the sensor type B and transmits the sensor type B to the authentication server  12 - 4  via the network  13 . The sensor type B is an example of the sensor type information of the biometric sensor  14 B of the terminal  11 - 42 . 
     The user data manager  122  of the authentication server  12 - 4  references the user data management table managed by the user data manager  122  and illustrated in  FIG. 16  and confirms a registration state of biometric data of the user ID “User0001” received from the terminal  11 - 42  (in step S 42 ). In addition, the user data manager  122  of the authentication server  12 - 4  determines whether or not registered data of the user ID “User0001” exists (in step S 43 ). In the example illustrated in  FIG. 16 , biometric data, acquired by the biometric sensor  14 A of the sensor type A, of the user of the user ID “User0001” is already registered (Yes in step S 43 ). In this example, registered data “f/f9a9ana9ffa90g” stored for the user ID “User0001” in the user data management table is stored in the database  194  and is a file name of biometric data of the user ID “User0001”. The format in which the registered data is stored, however, is not limited. When the result of the determination of step S 43  is No, the process proceeds to step S 44  described later. In this example, the user data management table and the compatibility management table are stored in the database  194 . 
     The user data manager  122  confirms the compatibility of the sensor type B that is the sensor type information received from the  11 - 42  with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the registered user ID “User0001” (in step S 46 ). For example, the user data manager  122  references the compatibility management table managed by the sensor compatibility manager  121  and illustrated in  FIG. 4  and confirms the aforementioned compatibility. The user data manager  122  determines whether or not the sensor type B received from the terminal  11 - 42  is compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the user ID “User0001” registered in the authentication server  12 - 4  (in step S 47 ). In this example, a sensor type usable upon authentication and compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the user ID “User0001” is only the sensor type A. Thus, the user data manager  122  determines that the sensor type B received from the terminal  11 - 42  is not compatible with the sensor type A of the biometric sensor  14 A that has acquired the biometric data of the user ID “User0001” registered in the authentication server  12 - 4  (No in step S 47 ). 
     When the result of the determination of step S 47  is No, the user data manager  122  of the authentication server  12 - 4  references user data of the user data management table illustrated in  FIG. 16  and acquires the mail address “user0001@xxx.com” of the user ID “User0001” (in step S 44 ). In addition, the mail transmitter  129  transmits a tentative password issued by the tentative password issuance determiner  123  to the acquired mail address “user0001@xxx.com” of the user ID “User0001”. In this case, the tentative password issuance determiner  123  may issue the tentative password in the same manner as the process described with reference to  FIGS. 5 and 6 . 
     When the result of the determination of step S 47  is Yes, the tentative password issuance determiner  123  causes the terminal  11 - 41  to display an authentication screen of a biometric authentication application on a touch panel of the terminal  11 - 41  in the same manner as the process described with reference to  FIGS. 5 and 6  (in step S 48 ). The user uses the biometric sensor  14 A to acquire biometric information of the user and inputs the acquired biometric information to the terminal  11 - 41  in accordance with a message displayed on the authentication screen. The biometric information acquirer  112  of the terminal  11 - 41  acquires the input biometric information, and the biometric data generator  114  of the terminal  11 - 41  generates biometric data and transmits the generated biometric data to the authentication server  12 - 4  (in step S 49 ). For example, the biometric data generator  114  of the terminal  11 - 41  generates the biometric data based on the biometric information acquired by the biometric information acquirer  112  and transmits the generated biometric data to the authentication server  12 - 4  via the network  13 . 
     In the fourth embodiment, when the user data manager determines that registered data compatible with the user ID does not exist, the user data manager acquires a mail address of the user ID from the user data management table in accordance with the process illustrated in  FIG. 17 . In addition, the tentative password issuance determiner generates a tentative password and transmits the generated tentative password to the acquired mail address. 
     In the fourth embodiment, the authentication server may use the user ID received from a terminal and sensor type information received from the terminal to control the issuance of a tentative password and may cause the control of the issuance of a tentative password to coordinate with a registered mail address associated with the user ID. 
     Fifth Embodiment 
       FIG. 18  is a functional block diagram illustrating an example of a biometric authentication device according to the fifth embodiment. Sections that are illustrated in  FIG. 18  and are the same as those illustrated in  FIG. 1  are indicated by the same reference symbols as those illustrated in  FIG. 1 , and a description thereof is omitted. In the fifth embodiment, an authentication server  12 - 5  of a biometric authentication system  1 - 5  is an example of the biometric authentication device. The authentication server  12 - 5  may execute a program and execute processes in accordance with a biometric authentication method described later. As illustrated in  FIG. 18 , in the fifth embodiment, a database  195  of tentatively registered data is used. The user data manager  122  and the biometric authenticator  124  are an example of a manager. The manager generates data to be registered and temporarily stores the generated data when the tentative password issuance determiner  123  that is an example of the controller determines that sensor type information compatible with received user identification information does not exist in the user data management that is an example of the first table. When biometric authentication executed on biometric data received from a terminal that has registered the biometric data is successful, the manager registers registered data of corresponding user identification information in the first table. 
     In the fifth embodiment, a process that is the same as or similar to the process described with reference to  FIGS. 5 and 6  is executed. When a terminal  11 - 52  that has yet to register biometric data in the authentication server  12 - 5  is connected to the authentication server  12 - 5  via the network  13 , and the user data manager  122  of the authentication server  12 - 5  determines that compatible registered data does not exist, the user data manager  122  generates data to be registered (in step st 1 ). For example, the generated data to be registered is temporarily stored as tentatively registered data in the database  195  of the authentication server  12 - 5 . In addition, when biometric authentication is successfully executed by the biometric authenticator  124  of the authentication server  12 - 5  on the biometric data received from the terminal  11 - 51  that has already registered the biometric data in the authentication server  12 - 5 , tentatively registered data of the corresponding user ID is reflected and registered in the database  191  (in step st 2 ). For example, the user data manager  122  treats the tentatively registered data of the corresponding user ID as data to be registered and reflects and registers the tentatively registered data in the database  191  of the authentication server  12 - 5  and deletes the tentatively registered data from the database  195 . 
     In the fifth embodiment, since tentatively registered data is temporarily stored, a process of reregistering biometric data from a terminal that has yet to register biometric data in the authentication server may be simplified. 
     Sixth Embodiment 
       FIG. 19  is a functional block diagram illustrating an example of a biometric authentication device according to the sixth embodiment. Sections that are illustrated in  FIG. 19  and are the same as those illustrated in  FIG. 1  are indicated by the same reference symbols as those illustrated in  FIG. 1 , and a description thereof is omitted. In the sixth embodiment, an authentication server  12 - 6  of a biometric authentication system  1 - 6  is an example of the biometric authentication device. The authentication server  12 - 6  may execute a program and execute processes in accordance with a biometric authentication method described later. As illustrated in  FIG. 19 , in the sixth embodiment, each of terminals  11 - 61  and  11 - 62  further includes a pairing section  116 . The tentative password issuance determiner  123  is an example of a controller configured to notify the permission of the registration of biometric data to a terminal that has yet to register biometric data and has been paired with a terminal that has already registered biometric data. 
     In the sixth embodiment, a process that is the same as or similar to the process described with reference to  FIGS. 5 and 6  is executed. As illustrated in  FIG. 19 , the terminal  11 - 62  that has yet to register biometric data in the authentication server  12 - 6  and the terminal  11 - 61  that has already registered biometric data in the authentication server  12 - 6  are paired with each other via a wireless connection, and the terminal  11 - 62  wirelessly transmits terminal information of the terminal  11 - 62  and sensor type information of the terminal  11 - 62  (in step ST 1 ). For example, the pairing section  116  of the terminal  11 - 62  wirelessly transmits the terminal information of the terminal  11 - 62  and the sensor type information of the terminal  11 - 62  to the pairing section  116  of the terminal  11 - 61  during the pairing. The pairing sections  116  of the terminals  11 - 61  and  11 - 62  may cause information indicating that the terminals  11 - 61  and  11 - 62  are paired with each other to be stored in memories  102  of the terminals  11 - 61  and  11 - 62 , for example. When the terminal  11 - 61  is connected to the authentication server  12 - 6  via the network  13  and transmits an authentication request to the authentication server  12 - 6 , the terminal  11 - 61  transmits various types of data of the terminal  11 - 61  to the authentication server  12 - 6  (in step ST 2 ). The user ID acquirer  111 , sensor information acquirer  113 , terminal information acquirer  115 , and biometric data generator  114  of the terminal  11 - 61  transmit the various types of data to the authentication server  12 - 6 . In this case, the terminal information acquirer  115  of the terminal  11 - 61  transmits data received via the pairing section  116  of the terminal  11 - 61  to the authentication server  12 - 6 . The various types of data include the user ID, sensor type information, biometric data, and terminal information and sensor type information of the paired terminal  11 - 62  that has yet to register biometric data in the authentication server  12 - 6 . 
     The biometric authenticator  124  of the authentication server  12 - 6  executes biometric authentication on the terminal  11 - 61  (in step ST 3 ). The biometric authentication is executed on the terminal  11 - 61  by crosschecking the biometric data received from the terminal  11 - 61  with registered biometric data. When the biometric authentication executed on the terminal  11 - 61  is successful, the tentative password issuance determiner  123  of the authentication server  12 - 6  determines that the registration of biometric data of the corresponding user ID from the paired terminal  11 - 62  is permitted (in step ST 4 ). For example, when the biometric authentication is successful, and registered data compatible with the corresponding user ID of the terminal  11 - 61  does not exist, the tentative password issuance determiner  123  determines that the registration of the biometric data of the corresponding user ID from the paired terminal  11 - 62  is permitted within a certain time period. The tentative password issuance determiner  123  of the authentication server  12 - 6  transmits, to the terminal  11 - 61 , a notification indicating the permission of the registration of biometric data from the paired terminal  11 - 62  (in step ST 5 ). The permission of the registration of the biometric data is notified to the pairing section  116  of the paired terminal  11 - 62  from the pairing section  116  of the terminal  11 - 61  via wireless communication. 
     When the terminal  11 - 62  is connected to the authentication server  12 - 6  via the network  13  and transmits a connection request to the authentication server  12 - 6 , the terminal  11 - 62  transmits the user ID, the sensor type information, and terminal information of the paired terminal  11 - 61  to the authentication server  12 - 6  (in step ST 6 ). For example, the user ID acquirer  111 , sensor information acquirer  113 , and terminal information acquirer  115  of the terminal  11 - 62  transmit the user ID, the sensor type information, and the terminal information of the paired terminal  11 - 61  to the authentication server  12 - 6 . In this case, the terminal information acquirer  115  of the terminal  11 - 62  transmits the terminal information, received via the pairing section  116  of the terminal  11 - 62 , of the paired terminal  11 - 61  to the authentication server  12 - 6 . 
     The tentative password issuance determiner  123  of the authentication server  12 - 6  checks whether or not the registration of biometric data by the terminal  11 - 62  is permitted in response to the connection request from the terminal  11 - 62  (in step ST 7 ). In this example, since the registration of biometric data of the user ID from the terminal  11 - 62  is permitted, the tentative password issuance determiner  123  of the authentication server  12 - 6  causes the terminal  11 - 62  to display an authentication screen of a biometric authentication application on a touch panel of the terminal  11 - 62  (in step ST 8 ). 
     When the user enters a registration request from the authentication screen displayed on the touch panel of the terminal  11 - 62 , the terminal  11 - 62  transmits the registration request to the authentication server  12 - 6  via the network  13  (in step ST 9 ). For example, the user ID acquirer  111 , sensor information acquirer  113 , and biometric data generator  114  of the terminal  11 - 62  transmit the user ID, the sensor type information, and biometric data to the authentication server  12 - 6 . When the user uses the biometric sensor  14 B to acquire biometric information of the user and inputs the acquired biometric information to the terminal  11 - 62  in accordance with a message displayed on the authentication screen of the terminal  11 - 62 , the biometric information acquirer  112  of the terminal  11 - 62  acquires the input biometric information. The biometric data generator  114  of the terminal  11 - 62  generates biometric data from the biometric information acquired by the biometric information acquirer  112  of the terminal  11 - 62  and transmits the generated biometric data to the authentication server  12 - 6 . 
     In the sixth embodiment, since the permission of the registration of biometric data is notified to a terminal that has yet to register biometric data in the authentication server and has been paired with a terminal that has already registered biometric data in the authentication server, a process of reregistering biometric data from a terminal that has yet to register biometric data in the authentication server may be simplified. 
     Seventh Embodiment 
       FIG. 20  is a functional block diagram illustrating an example of a biometric authentication device according to the seventh embodiment. Sections that are illustrated in  FIG. 20  and are the same as those illustrated in  FIG. 1  are indicated by the same reference symbols as those illustrated in  FIG. 1 , and a description thereof is omitted. In the seventh embodiment, a terminal  11 - 7  is an example of the biometric authentication device. The terminal  11 - 7  may execute a program and execute processes in accordance with a biometric authentication method described later and may form a standalone biometric authentication system. As illustrated in  FIG. 20 , in the seventh embodiment, the terminal  11 - 7  may execute the processes of the authentication servers described in the embodiments in an environment in which the biometric sensors  14 A and  14 B connectable to the terminal  11 - 7  via USB connections or the like are switched to each other and used. The USB connections between the sensors and the terminal are connections between the sensors and the terminal using USB. 
     As illustrated in  FIG. 20 , the terminal  11 - 7  includes a sensor compatibility manager  1210 , a user data manager  1220 , a tentative password issuance determiner  1230 , a biometric authenticator  1240 , and a tentative password authenticator  1250 . The sensor compatibility manager  1210 , the user data manager  1220 , the tentative password issuance determiner  1230 , the biometric authenticator  1240 , and the tentative password authenticator  1250  have the same functions as the corresponding sections described in the embodiments. For example, the corresponding sections described in the embodiments are the sensor compatibility manager  121 , the user data manager  122 , the tentative password issuance determiner  123 , the biometric authenticator  124 , and the tentative password authenticator  125  that are included in each of the authentication servers  12 - 1  to  12 - 6 . The terminal  11 - 7  may access a database  1910 . For example, processes of the sections of the terminal  11 - 7  may be executed by the CPU  101  of the computer  100  illustrated in  FIG. 2 . The database  1910  may be stored in the memory  102  of the computer  100 . Thus, the processes of the biometric authentication systems described in the embodiments may be executed in the terminal  11 - 7 . 
     In the seventh embodiment, a process that is the same as or similar to the process described with reference to  FIGS. 5 and 6  is executed in the terminal  11 - 7 . As illustrated in  FIG. 20 , the user connects the biometric sensor  14 B to the terminal  11 - 7  via a USB connection. When the tentative password issuance determiner  1230  determines that registered data compatible with the sensor type B of the biometric sensor  14 B does not exist in the database  1910 , the tentative password issuance determiner  1230  enables a tentative password issuance flag (in step ST 11 ). For example, the tentative password issuance determiner  1230  enables the tentative password issuance flag based on processes of the user data manager  1220  and the sensor compatibility manager  1210 . 
     The case where the user connects the biometric sensor  14 A to the terminal  11 - 7  via a USB connection after disconnecting the biometric sensor  14 B from the terminal  11 - 7  is described below. In this case, when biometric authentication by the biometric authenticator  1240  is successful, the tentative password issuance determiner  1230  generates and displays a tentative password (in step ST 12 ). For example, when the user connects the biometric sensor  14 A to the terminal  11 - 7 , the tentative password issuance determiner  1230  determines that registered data compatible with the sensor type A of the biometric sensor  14 A exists in the database  1910 . When the biometric authentication by the biometric authenticator  1240  is successful, the tentative password issuance determiner  1230  generates a tentative password and displays the tentative password on a touch panel of the terminal  11 - 7 . 
     The case where the user connects the biometric sensor  14 B to the terminal  11 - 7  via a USB connection after disconnecting the biometric sensor  14 A from the terminal  11 - 7  in accordance with, for example, a message displayed on an authentication screen is described. In this case, when the authentication of a tentative password by the tentative password authenticator  1250  is successful, the biometric data generator  114  generates biometric data based on biometric information, and the user data manager  1220  registers the biometric data in a user management table of the database  1910  (in step ST 13 ). For example, when the authentication of the tentative password by the tentative password authenticator  1250  is successful, the biometric information acquirer  112  acquires the user&#39;s biometric information input from the biometric sensor  14 B. In addition, the biometric data generator  114  generates the biometric data from the biometric information acquired by the biometric information acquirer  112 . Furthermore, the user data manager  1220  registers the biometric data generated by the biometric data generator  114  in the user management table of the database  1910 . 
     In the seventh embodiment, in the environment in which the biometric sensors of the terminal are switched to each other and used, the functions, provided by the authentication server according to the first embodiment, of managing the compatibility of the sensors, managing user data, issuing a tentative password, and the like are included in the terminal. When a biometric sensor of a compatible sensor type is connected to the terminal that has yet to register biometric data, the terminal determines whether or not a tentative password is to be issued, and enables a tentative password issuance flag in the same manner as the process described with reference to  FIGS. 5  and  6 . On the other hand, when a biometric sensor of a compatible sensor type is connected to the terminal that has registered biometric data, and biometric authentication is successful, the terminal issues a tentative password in the same manner as the process described with reference to  FIGS. 5 and 6 . In the seventh embodiment, however, the terminal connected to a biometric sensor to be used to newly use the biometric authentication is the same as the terminal to which a tentative password is notified. 
     For example, in the case where the terminal has multiple USB ports, the terminal may switch one of the USB ports to the other USB port and use the other USB port in a state in which the two biometric sensors of the different sensor types are connected to the USB ports, respectively. 
     In the seventh embodiment, in the environment in which the biometric sensors of the terminal are switched to each other and used, the functions, provided by the authentication servers according to the aforementioned embodiments, of managing the compatibility of the sensors, managing user data, issuing a tentative password, and the like may be enabled in the terminal. 
     In the seventh embodiment, the terminal may execute processes of any of the biometric authentication systems according to the first to sixth embodiments. In addition, the terminal may execute processes of a biometric authentication system corresponding to a combination of two or more of the first to sixth embodiments. 
     Eighth Embodiment 
       FIG. 21  is a functional block diagram illustrating an example of a biometric authentication device according to the eighth embodiment. Sections that are illustrated in  FIG. 21  and the same as those illustrated in  FIG. 1  are indicated by the same reference symbols as those illustrated in  FIG. 1 , and a description thereof is omitted. In the eighth embodiment, an authentication server  12 - 8  and an intermediate server  15  that are included in a biometric authentication system  1 - 8  form an example of the biometric authentication device. The intermediate server  15  forms a portion of the biometric authentication device. The authentication server  12 - 8  and the intermediate server  15  may execute a program and execute processes in accordance with a biometric authentication method described later. As illustrated in  FIG. 21 , in the eighth embodiment, the intermediate server  15  is installed. The intermediate server  15  may be connected to terminals  11 - 81  and  11 - 82  via a network  13 A such as an intranet and may be connected to the authentication server  12 - 8  via the network  13 A and a network  13 B such as the Internet. The terminals  11 - 81  and  11 - 82  may be connected to the authentication server  12 - 8  via the networks  13 A and  13 B. The intermediate server  15  may execute one or more of the processes of the authentication servers described in the first to seventh embodiments. 
     The intermediate server  15  may access a database  154  of user data. The intermediate server  15  includes a tentative password issuance determiner  151 , a sensor compatibility manager  152 , and a user data manager  153 . A storage device storing the database  154  is a cache memory storing the user data. The authentication server  12 - 8  may access a database  196  of user data. The user data and the like stored in the database  196  are the same as or similar to the user data stored in the database  191  described in the first embodiment, but are stored via the cache memory storing the database  154 . The user data manager  122  of the authentication server  12 - 8  manages the user data stored in the database  196  of the authentication server  12 - 8 . The user data manager  153  of the intermediate server  15  manages the user data cached in the database  154  of the intermediate server  15 . 
     In the eighth embodiment, the authentication server  12 - 8  and the intermediate server  15  execute a process, which is the same as or similar to the process described with reference to  FIGS. 5 and 6 , in a distributed manner. For example, when the terminal  11 - 82  that has yet to register biometric data in the authentication server  12 - 8  is connected to the authentication server  12 - 8 , and a biometric authentication application of the terminal  11 - 82  is activated to use biometric authentication, an authentication screen is displayed on a touch panel of the terminal  11 - 82 . When the user enters the user ID from the authentication screen, the user ID acquirer  111  of the terminal  11 - 82  acquires the user ID and transmits the acquired user ID to the intermediate server  15  via the network  13 A in response to the entry of the user ID. In addition, the sensor information acquirer  113  of the terminal  11 - 82  acquires the sensor type B and transmits the acquired sensor type B to the intermediate server  15  via the network  13 A. The sensor type B is an example of the sensor type information of the biometric sensor  14 B of the terminal  11 - 82 . The intermediate server  15  is connected to the authentication server  12 - 8  via the networks  13 A and  13 B and caches, in the database  154  of the intermediate server  15 , user data stored in the database  196  of the authentication server  12 - 8 . The tentative password issuance determiner  151 , sensor compatibility manager  152 , and user data manager  153  of the intermediate server  15  execute the same control as described in the first embodiment based on the user data cached in the database  154 . For example, the tentative password issuance determiner  151 , the sensor compatibility manager  152 , and the user data manager  153  control the enabling of a tentative password issuance flag and the issuance of a tentative password. Thus, the intermediate server  15  may issue a tentative password to be used to reregister biometric data in the authentication server  12 - 8  and transmit the issued tentative password to the terminal  11 - 81  that has already registered biometric data. 
     The intermediate server  15  may not be connected to the authentication server  12 - 8  via the network  13 A and may be connected to the authentication server  12 - 8  via the network  13 B. 
     In the eighth embodiment, a reduction in a processing speed due to the difference between a processing speed of the storage device storing the database and a processing speed of the authentication server may be reduced by using the intermediate server and the cache memory storing the database. 
     In the eighth embodiment, the intermediate server and the authentication server may execute processes of any of the authentication servers according to the first to sixth embodiments. In addition, the intermediate server and the authentication server may execute processes of a biometric authentication server corresponding to a combination of two or more of the first to sixth embodiments. 
     The sequential numbers of the first to eighth embodiments do not indicate priorities of the preferable embodiments. 
     Although the aforementioned embodiments describe the examples in which the fingerprint authentication that is an example of the biometric authentication is executed using a fingerprint that is an example of the biometric body, the biometric body is not limited to a fingerprint and may be an iris, a vein, a palmar print, palmar lines, or the like. 
     All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.