Abstract:
An in-vehicle device includes a storage unit storing a PIN code and an in-vehicle device ID kept confidential for a user and registered one for each vehicle; a first authentication unit determining whether the in-vehicle device is allowed to be connected to a mobile terminal on the basis of a comparison of the PIN code; a second authentication unit requesting an in-vehicle device ID from the mobile terminal that has been connected through authentication performed by the first authentication unit and authenticating the mobile terminal by comparing the in-vehicle device ID transmitted from the mobile terminal in response to the request with the in-vehicle device ID registered in the in-vehicle device; and a data transmission unit transmitting predetermined vehicle data, obtained from a vehicle equipped with the in-vehicle device and indicating a vehicle state, to the mobile terminal that has been authenticated by the second authentication unit.

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 2010-234702 filed on Oct. 19, 2010 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an in-vehicle device, a vehicle authentication system and a data communication method. 
     2. Description of Related Art 
     In a related art, there is known an authentication system that allows communication with a mobile terminal of which authentication based on first authentication information is successful and that performs authentication based on second authentication information after communication is allowed (for example, see Japanese Patent Application Publication No. 2009-123059 (JP-A-2009-123059)). A MAC address, a personal identification number (PIN) code or a fixed name corresponding to a mobile terminal (the name of a mobile terminal, which may be set by a user) is used as the first authentication information. In addition, mobile terminal fixed information (authentication key) that is generated by the authentication system and that is acquired by a mobile terminal through registration process and stored in a storage unit is used as the second authentication information. 
     When an application that uses vehicle data indicating a vehicle state, obtained from a vehicle equipped with an in-vehicle device, is caused to run on a mobile terminal, the vehicle data needs to be transmitted from the in-vehicle device to the mobile terminal; however, it is important for transmission of vehicle data having a high level of security to a mobile terminal to undergo authentication procedure having an appropriate high level of security. 
     SUMMARY OF THE INVENTION 
     The invention provides an in-vehicle device, vehicle authentication system and data communication method that are able to achieve a high level of security. 
     A first aspect of the invention provides an in-vehicle device. The in-vehicle device that relays wireless data communication between an in-vehicle electronic device and a mobile terminal includes: a storage unit that stores a PIN code and an in-vehicle device ID that is kept confidential for a user and that is registered one for each vehicle; a first authentication unit that determines whether the in-vehicle device is allowed to be connected to a mobile terminal on the basis of a comparison of the PIN code; a second authentication unit that requests an in-vehicle device ID from the mobile terminal that has been connected through authentication performed by the first authentication unit and that authenticates the mobile terminal by comparing the in-vehicle device ID transmitted from the mobile terminal in response to the request with the in-vehicle device ID registered in the in-vehicle device; and a data transmission unit that transmits predetermined vehicle data, which is obtained from the in-vehicle electronic device and which indicates a vehicle state, to the mobile terminal that has been authenticated by the second authentication unit. 
     A second aspect of the invention provides a vehicle authentication system. The vehicle authentication system includes: the in-vehicle device according to the first aspect; the mobile terminal; and a data management device that manages the in-vehicle device ID and that is managed at a vehicle maker or a facility under management of the vehicle maker, wherein the data management device is communicable with the mobile terminal and transmits the in-vehicle device ID to the mobile terminal. 
     A third aspect of the invention provides a data communication method between an in-vehicle device and a mobile terminal, wherein the in-vehicle device stores a PIN code and an in-vehicle device ID that is kept confidential for a user and that is registered one for each vehicle. The method includes: in the in-vehicle device, determining whether the in-vehicle device is allowed to be connected to the mobile terminal on the basis of a comparison of the PIN code; in the in-vehicle device, requesting an in-vehicle device ID from the mobile terminal that has been connected through authentication based on a comparison of the PIN code; in the in-vehicle device, authenticating the mobile terminal by comparing the in-vehicle device ID transmitted from the mobile terminal in response to the request for the in-vehicle device ID with the in-vehicle device ID registered in the in-vehicle device; and, in the in-vehicle device, transmitting predetermined vehicle data, which is obtained from the vehicle equipped with the in-vehicle device and which indicates a vehicle state, to the mobile terminal that has been authenticated by a comparison of the in-vehicle device ID. 
     According to the above aspects of the invention, it is possible to provide an in-vehicle device, vehicle authentication system and data communication method that are able to achieve a high level of security. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is a configuration diagram that shows the schematic configuration of a vehicle authentication system according to an embodiment of the invention; 
         FIG. 2  is a perspective view that shows the appearance of an example of a discrete in-vehicle device; 
         FIG. 3  is a view that shows major functional units of a control unit; 
         FIG. 4  is a view that shows major functional units of a mobile terminal; 
         FIG. 5  is a view that shows an example of a method of constructing a vehicle authentication system according to the embodiment of the invention and an example of the operation of the vehicle authentication system; 
         FIG. 6  is a view that shows the example of the method of constructing the vehicle authentication system according to the embodiment of the invention and the example of the operation of the vehicle authentication system; and 
         FIG. 7  is a view that shows an example of a method of constructing a vehicle authentication system according to another embodiment of the invention and an example of the operation of the vehicle authentication system. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. 
       FIG. 1  is a configuration diagram that shows the schematic configuration of a vehicle authentication system  1  according to the embodiment of the invention.  FIG. 2  is a perspective view that shows an example of the appearance of an in-vehicle device  10 .  FIG. 3  is a view that shows major functional units of a control unit  12 .  FIG. 4  is a view that shows major functional units of a mobile terminal  50 . 
     As shown in  FIG. 1 , the vehicle authentication system  1  includes the in-vehicle device  10 , the mobile terminal  50  and a data center (server)  60 . The in-vehicle device  10  and the mobile terminal  50  are able to carry out wireless communication with each other using a wireless technology such as Bluetooth (trademark). In addition, the mobile terminal  50  and the data center  60  are able to carry out communication with each other via a network such as the Internet. 
     As shown in  FIG. 1 , the in-vehicle device  10  includes the control unit  12 , a wireless device  14  having an antenna  14   a , a storage unit  16 , a button  17   a , an indicator  17   b , a LAN communication unit  18  and a power supply unit  19 . As will be described later, the in-vehicle device  10  functions as a gateway of communication between the mobile terminal  50  and various in-vehicle electronic devices (ECU, and the like)  30 . 
     The control unit  12  is a microcomputer formed of a CPU, a ROM, a RAM, and the like, that are connected to one another via a bus (not shown). The ROM stores various programs to be executed by the CPU. The storage unit  16  is connected to the control unit  12 . The storage unit  16  is typically formed of a recordable memory and may be formed of a rewritable memory, such as an EEPROM and a hard disk drive (HDD). The storage unit  16  stores a PIN code and an in-vehicle device ID (described later). 
     The control unit  12  includes a first authentication unit  12 A and a second authentication unit  12 B as major functional units. The functions of these units  12 A and  12 B may be implemented in such a manner that the CPU executes programs stored in the ROM. The functions of these units  12 A and  12 B will be described later with reference to  FIG. 5  and  FIG. 6 . 
     The in-vehicle device  10  carries out wireless communication with the mobile terminal  50  via the wireless device  14 . A wireless technology, such as Bluetooth (trademark), may be utilized for the wireless communication. In this embodiment, the description will be continued on the assumption that Bluetooth (trademark) is utilized. Various pieces of data required for authentication are exchanged between the in-vehicle device  10  and the mobile terminal  50 . In addition, vehicle data (vehicle data that indicates a vehicle state), and the like, obtained from a vehicle equipped with the in-vehicle device  10  is transmitted from the in-vehicle device  10  to the mobile terminal  50 . 
     The in-vehicle device  10  is connected to an in-vehicle battery via the power supply unit  19  and is supplied with electric power. In addition, the in-vehicle device  10  is connected to an in-vehicle LAN  22  via the LAN communication unit  18 . The in-vehicle device  10  is able to carry out data communication with the various in-vehicle electronic devices (ECU, and the like)  30  connected to the in-vehicle LAN  22 . The in-vehicle LAN  22  may be based on a controller area network (CAN), a local interconnect network (LIN), or the like. In addition, the in-vehicle LAN  22  may be formed of a plurality of in-vehicle LANs (for example, a LAN for power train system control and a LAN for body system control). 
     The button  17   a  is arranged at a position at which a user is able to operate the button  17   a . The indicator  17   b  is arranged at a position at which the user is able to visually recognize the indicator  17   b . For example, as shown in  FIG. 2 , the button  17   a  and the indicator  17   b  may be provided outside the housing of the in-vehicle device  10 . In this case, the in-vehicle device  10  may be provided at an appropriate location in a vehicle cabin (for example, an instrument panel, a console box, or the like) in a state where the button  17   a  and the indicator  17   b  are exposed to the vehicle cabin. The control unit  12  receives an operation signal (on signal) that is generated when the button  17   a  is operated by the user. In addition, the control unit  12  controls the state of illumination of the indicator  17   b.    
     The mobile terminal  50  is a terminal (for example, a smartphone) that is carried onto and used in the vehicle cabin, and has a wireless communication function. In this embodiment, the mobile terminal  50  has a wireless communication function according to Bluetooth (trademark). In addition, the mobile terminal  50  is able to access the Internet, and is able to exchange various pieces of data with the data center  60 . As shown in  FIG. 4 , the mobile terminal  50  includes a control and communication unit  52 , a display unit  54  and a storage unit  56  as major components. 
     The data center  60  includes a server that is installed at a place remote from the vehicle. The data center  60  is outsourced for management by a vehicle maker, and handles various pieces of information. The data center  60  includes a data base  62  that stores and manages various pieces of data required for authentication. 
       FIG. 5  and  FIG. 6  are views that show an example of a method of constructing the vehicle authentication system  1  according to the embodiment of the invention and an example of the operation of the vehicle authentication system  1 . 
     Here, the example of the method of constructing the vehicle authentication system  1  according to the embodiment of the invention and the example of the operation of the vehicle authentication system  1  will be described with reference to  FIG. 5  and  FIG. 6 . 
     In step  1 , as shown in  FIG. 5  and  FIG. 6 , at a supplier factory of the in-vehicle devices  10  (a maker of the in-vehicle devices  10 ), a PIN code and an in-vehicle device ID are allocated to each in-vehicle device  10 , and the PIN code and in-vehicle device ID that are allocated to each in-vehicle device  10  are transmitted to the data center  60 . The data center  60  stores the PIN codes and in-vehicle device IDs, transmitted from the supplier factory, in the data base  62 . In addition, the PIN code and in-vehicle device ID that are generated at the supplier factory are stored in the storage unit  16  of each in-vehicle device  10 . Note that the supplier factory is an example of a facility under management of the vehicle maker. 
     In step  2 , as shown in  FIG. 5 , the in-vehicle device  10  is delivered from the supplier factory to a vehicle assembly factory (vehicle maker). Note that the vehicle assembly factory may be a factory that is outsourced by the vehicle maker. In addition, the supplier factory may be a factory that may be identified as the vehicle assembly factory. That is, the in-vehicle device  10  may be a product manufactured by the vehicle maker in-house. 
     In step  3 , as shown in  FIG. 5  and  FIG. 6 , when the in-vehicle device  10  is assembled to a vehicle, a worker of the vehicle assembly factory, for example, uses a computer in the vehicle assembly factory to transmit the in-vehicle device ID of the in-vehicle device  10  and the frame number (VIN) of the vehicle, to which the in-vehicle device  10  is assembled, to the data center  60 . The data center  60  associates the VIN and the in-vehicle device ID, transmitted from the vehicle assembly factory, with each other, and stores the PIN code, the in-vehicle device ID and the VIN in the data base  62 . 
     In step  4 , as shown in  FIG. 5 , the completed vehicle to which the in-vehicle device  10  is assembled is delivered to a user. 
     In step  5 , as shown in  FIG. 6 , the user (owner) who receives the vehicle reads the VIN of the vehicle and inputs (registers) the VIN in the own mobile terminal  50 . The control and communication unit  52  of the mobile terminal  50  stores the input VIN in the storage unit  56 . 
     In step  6 , as shown in  FIG. 5  and  FIG. 6 , the user uses the own mobile terminal  50  to access the data center  60  and then conducts user registration. Specifically, first, as shown in  FIG. 6 , private information (for example, date of birth, and the like) is registered into the data center  60  together with the VIN registered in step  5 . In response to this, the data center  60  transmits a user ID and a temporary password to the mobile terminal  50  of the user by e-mail. In response to this, the user uses the user ID and the temporary password to register a regular password in the data center  60 . Note that the user keeps the user ID obtained in user registration and the regular password in mind. 
     In step  7 , as shown in  FIG. 5  and  FIG. 6 , the data center  60  extracts the PIN code, corresponding to the VIN transmitted through the user registration, from the data base  62 , and transmits the extracted PIN code to the mobile terminal  50  of the user. The control and communication unit  52  of the mobile terminal  50  stores the PIN code, transmitted from the data center  60 , in the storage unit  56  (see  FIG. 4 ). 
     In step  8 - 1 , as shown in  FIG. 6 , the user depresses the button  17   a  (see  FIG. 2 ). As the button  17   a  is depressed, the in-vehicle device  10  is placed in a standby state for a predetermined period of time. Note that, as the button  17   a  is depressed, the control unit  12  may maintain the indicator  17   b  in an illuminated state for a predetermined period of time in order to inform the user that the in-vehicle device  10  is in a standby state. 
     In step  8 - 2 , as shown in  FIG. 5  and  FIG. 6 , when the in-vehicle device  10  is in a standby state and the mobile terminal  50  of the user is located within a range in which the mobile terminal  50  is able to wirelessly communicate with the in-vehicle device  10 , for example, in the vehicle cabin, the in-vehicle device  10  and the mobile terminal  50  are paired. Specifically, as shown in  FIG. 6 , the mobile terminal  50  makes a search for the in-vehicle device  10 . In response to this, the in-vehicle device  10  in a standby state requests the PIN code from the mobile terminal  50 . In response to this, the control and communication unit  52  of the mobile terminal  50  transmits the PIN code obtained in step  7  to the in-vehicle device  10 . Note that an exchange of these pieces of information for pairing is achieved by wireless communication based on Bluetooth (trademark). Subsequently, the first authentication unit  12 A of the control unit  12  of the in-vehicle device  10  authenticates the mobile terminal  50  using the PIN code transmitted from the mobile terminal  50 . Specifically, the first authentication unit  12 A compares the PIN code transmitted from the mobile terminal  50  with the PIN code stored in the storage unit  16 . When both the PIN codes coincide with each other, the first authentication unit  12 A completes pairing. 
     Note that, even after the pairing is once completed, the first authentication unit  12 A may similarly authenticate the mobile terminal  50  using the PIN code transmitted from the mobile terminal  50 . In this case, authentication performed by the first authentication unit  12 A may be started triggering depression of the button  17   a  in step  8 - 1  as in the case of the pairing; instead, authentication may be automatically started without depression of the button  17   a.    
     In step  9 , as shown in  FIG. 6 , the in-vehicle device  10  receives first vehicle data from the various in-vehicle electronic devices  30  via the in-vehicle LAN  22 . The first vehicle data is data transmitted from the various in-vehicle electronic devices  30  to the in-vehicle LAN  22  by broadcasting, and may be data having a relatively low level of security. For example, the first vehicle data may be data that indicates a vehicle speed (data detected by a wheel speed sensor) or data that indicates a steering angle (data detected by a steering angle sensor). More specifically, the first vehicle data may be, for example, data required to indicate the fuel consumption (calculate the fuel consumption) of the vehicle. In this case, although it depends on a method of calculating the fuel consumption, the first vehicle data may be data relevant to a travel distance (the integral value of a vehicle speed) or a fuel injection amount. 
     In step  10 , as shown in  FIG. 6 , the wireless device  14  of the in-vehicle device  10  transmits the first vehicle data, obtained from the various in-vehicle electronic devices  30 , to the mobile terminal  50  by wireless communication based on Bluetooth (trademark). 
     In step  11 , as shown in  FIG. 6 , the control and communication unit  52  of the mobile terminal  50  displays the first vehicle data on the display unit  54 . The control and communication unit  52  of the mobile terminal  50  may display the first vehicle data as-is or may display another pieces of information converted from the first vehicle data. 
     In step  12 , as shown in  FIG. 6 , the control and communication unit  52  of the mobile terminal  50  accesses the data center  60  and requests a specific application from the data center  60 . The specific application may be an application that runs using second vehicle data (described later) or may be an application for loading the second vehicle data (described later). The second vehicle data, as well as the first vehicle data, is data that indicates a vehicle state; however, the second vehicle data is data having a higher level of security and confidentiality (data that requires a higher level of attention to be paid for management) than the first vehicle data. For example, the second vehicle data may be data (including diagnosis data) that indicates a failed/abnormal state of the vehicle. Note that a request for a specific application may be automatically executed by the control and communication unit  52  of the mobile terminal  50  in the stage in which connection to the in-vehicle device  10  is complete or may be executed after receiving user&#39;s approval or instructions. Note that a plurality of specific applications may be prepared in the data center  60 . In this case, the user may operate the mobile terminal  50 , select a desired specific application and then request the desired specific application. 
     In step  13 , as shown in  FIG. 5  and  FIG. 6 , the data center  60  transmits the requested specific application to the mobile terminal  50  (the mobile terminal  50  downloads the requested specific application from the data center  60 ). At this time, the data center  60  transmits the in-vehicle device ID stored in the data base  62  to the mobile terminal  50  together with the specific application. The in-vehicle device ID may be included in the specific application (that is, may be embedded in the specific application as a cipher key). The in-vehicle device ID is utilized as a cipher key for using the specific application on the mobile terminal  50 . On the basis of information that determines the connected mobile terminal  50  (for example, at least any one of the registered VIN, the registered PIN code, the user ID, the password, and the like), the data center  60  may extract the in-vehicle device ID associated with the information (the mobile terminal  50 ) from the data base  62 . In addition, transmission of the specific application and the in-vehicle device ID may require authentication, and, in this case, may utilize an authentication method and encryption method of secure sockets layer (SSL) or transport layer security (TLS). 
     Note that, in step  13 , when the connected state between the data center  60  and the mobile terminal  50  via the Internet is maintained from step  6  or when the approved state of the user ID and password is maintained in the data center  60 , the data center  60  may extract the associated in-vehicle device ID corresponding to the user ID and the password from the data base  62 . 
     In step  14 , as shown in  FIG. 5  and  FIG. 6 , in response to depression of the button of the mobile terminal  50  (for example, depression of a vehicle data loading button) made by the user, the control and communication unit  52  of the mobile terminal  50  transmits a request to load the second vehicle data to the in-vehicle device  10  by wireless communication based on Bluetooth (trademark). Note that the request to load the second vehicle data may be executed by launching a specific application. That is, the request to load the second vehicle data may be executed by the function of the downloaded specific application (step  13 ). In addition, the request to load the second vehicle data may be automatically executed subsequently to downloading of the specific application (step  13 ). In addition, the request to load the second vehicle data may accompany writing of data to the in-vehicle electronic devices  30  (ECU, and the like). 
     In step  15 , as shown in  FIG. 6 , as the in-vehicle device  10  receives the request to load the second vehicle data, the in-vehicle device  10  transmits an acknowledgement signal ACK to the mobile terminal  50  by wireless communication based on Bluetooth (trademark). The acknowledgement signal ACK includes a request for the in-vehicle device ID. 
     In step  16 , as shown in  FIG. 5  and  FIG. 6 , in response to the request for the in-vehicle device ID from the in-vehicle device  10 , the control and communication unit  52  of the mobile terminal  50  transmits the in-vehicle device ID obtained in step  13  to the in-vehicle device  10  by wireless communication based on Bluetooth (trademark). Note that the in-vehicle device ID may be included in the request to load the second vehicle data in step  14  and, in this case, step  15  and step  16  may be omitted. In addition, the request to load the second vehicle data including the in-vehicle device ID may be executed by the function of the downloaded specific application (step  13 ). 
     In step  17 , as shown in  FIG. 6 , the second authentication unit  12 B of the control unit  12  of the in-vehicle device  10  authenticates the mobile terminal  50  using the in-vehicle device ID transmitted from the mobile terminal  50  in step  16 . Specifically, the second authentication unit  12 B compares the in-vehicle device ID transmitted from the mobile terminal  50  with the in-vehicle device ID stored in the storage unit  16 . When both the in-vehicle device IDs coincide with each other, the second authentication unit  12 B allows the mobile terminal  50  to load the second vehicle data. 
     In step  18 , as shown in  FIG. 6 , the in-vehicle device  10  loads the second vehicle data. Specifically, the in-vehicle device  10  requests the second vehicle data from the in-vehicle electronic devices  30  via the in-vehicle LAN  22 . Note that the in-vehicle device  10  may directly transmit the request to load the second vehicle data from the mobile terminal  50  (step  14 ) to the in-vehicle LAN  22 . As described above, the second vehicle data is data having a higher level of security (confidentiality) than the first vehicle data, and may be, for example, various pieces of data (including various pieces of diagnosis data) that indicate a failed/abnormal state of the vehicle. The diagnosis data may be data detected by a sensor or data generated by the ECU on the basis of sensor information. The in-vehicle electronic devices  30  may load the required second vehicle data from its own memory and then transmit the second vehicle data to the in-vehicle LAN  22 . Note that the in-vehicle device  10  may determine a requested one of the in-vehicle electronic devices  30  in response to the type of the required second vehicle data and then request the second vehicle data from the requested one of the in-vehicle electronic devices  30 . 
     In step  19 , as shown in  FIG. 6 , the in-vehicle device  10  receives the second vehicle data, transmitted from the in-vehicle electronic devices  30 , via the in-vehicle LAN  22 . The second vehicle data is desirably transmitted to the in-vehicle device  10  as individual data that specifies a destination. 
     In step  20 , as shown in  FIG. 6 , the second vehicle data is individually loaded by the mobile terminal  50 . Specifically, the wireless device  14  of the in-vehicle device  10  transmits the second vehicle data obtained in step  19  to the mobile terminal  50  by wireless communication based on Bluetooth (trademark). Note that the second vehicle data may be time-series data and, in this case, the second vehicle data may be transmitted to the mobile terminal  50  in real time or may be transmitted to the mobile terminal  50  collectively at an interval of a predetermined period of time. 
     In step  21 , as shown in  FIG. 6 , the control and communication unit  52  of the mobile terminal  50  displays the second vehicle data on the display unit  54 . The control and communication unit  52  of the mobile terminal  50  may use a specific application to directly display the second vehicle data or may display another information that is converted from the second vehicle data. By way of example of the latter case, the second vehicle data may be utilized by the specific application to be executed on the mobile terminal  50 . That is, the specific application is operated by the second vehicle data. 
       FIG. 7  is a view that shows an example of a method of constructing the vehicle authentication system  1  according to another embodiment of the invention and an example of the vehicle authentication system  1 . 
     The example shown in  FIG. 7  mainly differs from the example shown in  FIG. 6  in that the processes of step  22  and step  23  are executed instead of the process of step  21 . Hereinafter, the difference will be specifically described. 
     In the example shown in  FIG. 7 , the specific application may be an application for loading the second vehicle data or may be an application for loading the second vehicle data and then transferring the loaded second vehicle data to the data center  60 . 
     In step  22 , as shown in  FIG. 7 , the control and communication unit  52  of the mobile terminal  50  uses the specific application to transmit (upload) the second vehicle data to the data center  60 . Note that the second vehicle data may be time-series data and, in this case, the second vehicle data may be transmitted to the data center  60  in real time or may be transmitted to the data center  60  collectively at an interval of a predetermined period of time. 
     Step  23  may be executed selectively. In step  23 , as shown in  FIG. 7 , the data center  60  transmits point information about a point for a transfer of the second vehicle data to the mobile terminal  50 . The point may be a point that may be reduced to any interest of the user on the basis of its value (the number of points). The data center  60  may manage the point information for each mobile terminal  50  and may increase the number of points in the data base  62  by a predetermined number of points each time the second vehicle data is transferred. In addition, the point information transmitted to the mobile terminal  50  in step  23  may be information about the number of points given because of a current transfer of the second vehicle data, the number of points at the present moment, or the like. At this time, the control and communication unit  52  of the mobile terminal  50  may display the point information on the display unit  54 . 
     With the above described vehicle authentication system  1  according to the present embodiment, particularly, the following advantageous effects are obtained. 
     With the vehicle authentication system  1  according to the present embodiment, as described above, when the mobile terminal  50  is wirelessly connected to the in-vehicle device  10  (and the various in-vehicle electronic devices  30  accordingly), authentication based on the PIN code is required. Then, when the second vehicle data having a high level of security is transmitted from the in-vehicle device  10  to the wirelessly connected mobile terminal  50 , authentication based on the in-vehicle device ID is required. By so doing, in the configuration that allows the mobile terminal  50  to load vehicle data from the in-vehicle device  10  (and the various in-vehicle electronic devices  30  accordingly), it is possible to ensure a high level of security for the loading. Particularly, the in-vehicle device ID is kept confidential for the user (information that the user cannot know, and is generated at the vehicle maker or a facility under management of the vehicle maker, so, for example, in comparison with a cipher key that is randomly generated by the in-vehicle device  10 , confidentiality (secrecy) is high and the level of security may be effectively increased. 
     In addition, with the vehicle authentication system  1  according to the present embodiment, for the first vehicle data having a relatively low level of security, transmission of the first vehicle data from the in-vehicle device  10  to the mobile terminal  50  is allowed when authentication based on the PIN code having a relatively low confidentiality is passed; whereas, for the second vehicle data having a relatively high level of security, transmission of the second vehicle data from the in-vehicle device  10  to the mobile terminal  50  is not allowed until authentication based on the in-vehicle device ID having a relatively high confidentiality is passed. By so doing, according to the present embodiment, the authentication method is varied depending on the level of security of vehicle data to thereby make it possible to effectively achieve both convenience and security. 
     The embodiments of the invention are described above; however, the aspect of the invention is not limited to the above described embodiments. Various modifications and/or replacements may be added to the above described embodiments without departing from the scope of the invention. 
     For example, in the above described embodiments, the specific application may be downloaded in step  12  and step  13  (see  FIG. 6  and  FIG. 7 ) for each usage or may be downloaded only for the first time. In the former case, the downloaded specific application may be cleared from the storage unit  56  of the mobile terminal  50  together with the in-vehicle device ID after the end of usage. On the other hand, in the latter case, the downloaded specific application may be held in the storage unit  56  of the mobile terminal  50  together with the in-vehicle device ID after the end of usage. In this case, in step  16 , in response to the request for the in-vehicle device ID from the in-vehicle device  10 , the control and communication unit  52  of the mobile terminal  50  may transmit the in-vehicle device ID held in the storage unit  56  to the in-vehicle device  10 . 
     In addition, in the above described embodiments, both the PIN codes may be compared with each other in a selected manner. For example, the PIN code used for comparison in the first authentication unit  12 A (PIN code stored in the storage unit  16 ) may be generated in the in-vehicle device  10  or may be generated in the mobile terminal  50 . In addition, another piece of authentication information, such as a MAC address, may be utilized in addition to the PIN code.