Key System

Abstract

This key system comprises: a first storage unit which is provided in a vehicle and in which identification information that makes it possible to identify the vehicle is stored; and a second storage unit which is provided in a key medium and in which unique information related to the identification information is stored. The vehicle comprises a first determination unit, a second determination unit, and a common key information transmission unit. The first determination unit determines whether or not the identification information stored in the first storage unit and the unique information stored in the second storage unit are related. If the identification information and the unique information are determined to be related by the first determination unit, the second determination unit determines whether or not unique information related to the identification information acquired from the key medium by a portable terminal and the identification information stored in the first storage unit are related. If the unique information and the identification information are determined to be related by the second determination unit, the common key information transmission unit transmits common key information that makes it possible to control the vehicle to the portable terminal.

Description

[Technical Field]

[0001] The present invention relates to a key system that communicates between a vehicle, a key unit, and a mobile terminal. [Background technology]

[0002] In recent years, technology has been used to control (start, etc.) a vehicle using an electronic key (also called an electronic lock) via a mobile terminal, etc. Examples of technology related to such electronic keys include those described in Patent Documents 1 and 2.

[0003] Patent Document 1 describes a car sharing system. In this car sharing system, key information is authenticated between a mobile terminal, on which key information is pre-registered as a vehicle key (corresponding to the above-mentioned "electronic key"), and a car sharing device installed in the vehicle, and the vehicle becomes available for use based on the authentication result. When a reconnection is made between the mobile terminal and the car sharing device, an encryption key different from the encryption key used during the previous connection is used between the mobile terminal and the car sharing device.

[0004] Patent Document 2 describes a vehicle communication system. In this vehicle communication system, different encryption keys (corresponding to the above-mentioned "electronic keys") are used in communication between a master unit and a slave unit. The encryption keys are configured to be updated as needed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-71559 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-85007 Summary of the Invention [Problem to be solved by the invention]

[0006] In the car sharing system described in Patent Document 1, a different encryption key is generated each time a connection is made between a mobile terminal and a car sharing device, which makes it difficult to manage the encryption keys in the mobile terminal and the car sharing device. Also, in the vehicle communication system described in Patent Document 2, if communication between the parent device and the child device is intercepted when sharing an encryption key, the vehicle may be used illegally.

[0007] Therefore, there is a demand for a key system that allows for easy delivery of electronic keys and has improved security. [Means for solving the problem]

[0008] The key system according to the present invention is characterized in that it comprises a first memory unit provided in a vehicle and storing identification information capable of identifying the vehicle, and a second memory unit provided in a key medium and storing unique information associated with the identification information, the vehicle comprising a first judgment unit, a second judgment unit, and a common key information transmission unit, the first judgment unit determining whether the identification information stored in the first memory unit is associated with the unique information stored in the second memory unit, the second judgment unit determining whether the unique information associated with the identification information acquired by a mobile terminal from the key medium is associated with the identification information stored in the first memory unit if the first judgment unit determines that they are associated, and the common key information transmission unit transmitting common key information to the mobile terminal that enables control of the vehicle if the second judgment unit determines that they are associated.

[0009] This characteristic configuration improves security by transmitting common key information when the identification information stored in the first storage unit of the vehicle and the unique information acquired by the mobile terminal are related to each other. Furthermore, because of the high security, there is no need to change the common key information each time the mobile terminal communicates with the vehicle, simplifying electronic key management. Furthermore, the key system improves convenience by transmitting an electronic key (a software key) via communication in response to a determination result of whether the identification information stored in the first storage unit of the vehicle and the unique information acquired by the mobile terminal are related to each other, rather than transmitting a physical key. In this way, security is improved by exchanging common key information using three different objects: the vehicle, the key medium, and the mobile terminal. The common key information is transmitted to the mobile terminal by the second determination unit and the common key information transmission unit, simplifying electronic key transmission.

[0010] Another characteristic configuration of the key system of the present invention is that it comprises a first memory unit provided in a vehicle and storing identification information capable of identifying the vehicle, and a second memory unit provided in a key medium and storing unique information related to the identification information, the vehicle comprising a first judgment unit, a second judgment unit, and a common key information transmission unit, the first judgment unit determining whether the identification information stored in the first memory unit is related to the unique information stored in the second memory unit, the second judgment unit determining whether the identification information capable of identifying the vehicle, obtained by a mobile terminal from the vehicle, is related to the identification information stored in the first memory unit, if the second judgment unit determines that they are related, the common key information transmission unit transmitting common key information that enables control of the vehicle to the mobile terminal.

[0011] This characteristic configuration improves security by transmitting common key information when the identification information stored in the vehicle's first storage unit and the identification information acquired by the mobile terminal that can identify the vehicle are related to each other. Furthermore, this characteristic configuration also provides high security, eliminating the need to change the common key information each time the mobile terminal communicates with the vehicle, simplifying electronic key management. Furthermore, this key system also improves convenience by transmitting an electronic key (a software key) via communication in response to a determination result of whether the identification information stored in the vehicle's first storage unit and the identification information acquired by the mobile terminal that can identify the vehicle are related to each other, rather than transmitting a physical key. In this way, security is improved by exchanging common key information using three different objects: the vehicle, the key medium, and the mobile terminal. The common key information is transmitted to the mobile terminal by the second determination unit and the common key information transmission unit, simplifying electronic key transmission. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing the configuration of a key system. [Figure 2] FIG. 10 is an explanatory diagram of the transfer of unique information from a key medium to a mobile terminal. [Figure 3] FIG. 2 is an explanatory diagram illustrating key exchange between a vehicle and a mobile terminal. [Figure 4] FIG. 2 is an explanatory diagram illustrating key exchange between a vehicle and a mobile terminal. [Figure 5] FIG. 10 is an explanatory diagram of key exchange between a mobile terminal and another mobile terminal. DETAILED DESCRIPTION OF THE INVENTION

[0013] The key system according to the present invention is configured to enable an electronic key that enables control of the vehicle to be exchanged between the vehicle and a mobile terminal. The key system 1 of this embodiment will now be described.

[0014] FIG. 1 is a block diagram showing a schematic configuration of a key system 1. As shown in FIG. 1, in this embodiment, the key system 1 communicates between a vehicle 2, a key medium 3, and a portable terminal 4 to exchange electronic keys. In this embodiment, the vehicle 2 includes a first storage unit 21, a determination unit 22, and a common key information transmission unit 23, and the key medium 3 includes a second storage unit 31. The portable terminal 4 includes a unique information acquisition unit 41, a third storage unit 42, a common key information storage unit 43, and a portable terminal transmission unit 44. In this embodiment, the portable terminal 4 is configured to be able to communicate with another portable terminal 5 (corresponding to "another portable terminal"), and the portable terminal 5 includes a common key information storage unit 51. Each functional unit is implemented using hardware, software, or both, with a CPU as its core component to perform processes related to the exchange of electronic keys.

[0015] The first storage unit 21 stores identification information that can identify the vehicle 2. Identification information that can identify the vehicle 2 is information that can identify (specify) one vehicle 2, for example, from among multiple vehicles 2. Such identification information can be configured, for example, by combining multiple alphanumeric characters and symbols (hereinafter referred to as "alphanumeric characters, etc."). In this case, the identification information is configured from multiple digits of alphanumeric characters, etc. Such identification information is registered in advance at the production factory or dealer (hereinafter referred to as "production factory, etc.") of the vehicle 2 (#0). In other words, registration can be performed at the production factory when the vehicle 2 is produced, and at the dealer after the vehicle 2 is shipped, and the identification information can be updated each time the vehicle 2 and the key medium 3 communicate with each other.

[0016] As described above, the second storage unit 31 is provided in the key medium 3, and the key medium 3 is associated with the vehicle 2. Being associated with the vehicle 2 means that the vehicle 2 and the key medium 3 are linked in a one-to-one correspondence. In this embodiment, the second storage unit 31 stores unique information associated with the identification information stored in the first storage unit 21. This unique information may be the same alphanumeric characters as the identification information, or may be the identification information combined with at least one additional alphanumeric character. In this embodiment, the unique information will be described as the same alphanumeric characters as the identification information. Therefore, hereinafter, the unique information will also be referred to as the identification information, and the identification information will also be referred to as the unique information. The unique information stored in the second storage unit 31 is registered in advance at a production plant or the like for the vehicle 2, similar to the storage of the identification information in the first storage unit 21 of the vehicle 2 (#1). The key medium 3 is configured as an IC card that enables the mobile terminal 4 to acquire the unique information stored in the second storage unit 31, for example, via short-range wireless communication. Therefore, the size of the key medium 3 is not limited to that shown in FIG. 1, and may be, for example, a size based on the international standard "ID-1."

[0017] The unique information acquisition unit 41 acquires the unique information from the second storage unit 31 (#2). In this embodiment, as described above, the key medium 3 is an IC card, and the unique information stored in the second storage unit 31 can be acquired by the mobile terminal 4 via short-range wireless communication. Therefore, the unique information acquisition unit 41 acquires the unique information from the second storage unit 31 via short-range wireless communication.

[0018] In this embodiment, the unique information includes first unique information and second unique information. The first unique information is information that the mobile terminal 4 can acquire via communication. Acquiring the first unique information via communication means that the mobile terminal 4 can acquire the first unique information via short-range wireless communication. On the other hand, the second unique information is information recorded on the key medium 3. In this embodiment, the key medium 3 is an IC card. Therefore, the second unique information is recorded on the IC card. In the example of FIG. 1, the first unique information is stored in the second storage unit 31, and the second unique information "123" is recorded on the IC card. Of course, the second card information may be alphanumeric characters other than "123." The number of digits may be four or more, or two or less. The second unique information may be recorded on a medium other than the key medium 3.

[0019] In such a case, the unique information acquisition unit 41 acquires the unique information based on the acquisition of the first unique information via communication and the input of the second unique information to the mobile terminal 4. That is, when the unique information acquisition unit 41 acquires the unique information, it may start an application related to the key system 1 on the mobile terminal 4, for example, and display a message on the mobile terminal 4 prompting the user to read the first unique information from the IC card, as shown in (A) of Fig. 2. Once the mobile terminal 4 reads the first unique information, it may display a message on the mobile terminal 4 prompting the user to input the second unique information written on the IC card, as shown in (B) of Fig. 2. When the unique information acquisition unit 41 receives input of second unique information and properly acquires unique information by combining the read first unique information with the second unique information, it displays a message indicating that the unique information has been acquired, as shown in (C) of Figure 2. If the second unique information is not received properly, or if combining the read first unique information with the second unique information does not result in proper unique information, it displays a message indicating that the unique information has not been acquired, as shown in (D) of Figure 2.

[0020] Returning to Fig. 1, the third storage unit 42 stores the unique information acquired by the unique information acquisition unit 41 (#3). As described above, when the unique information is made up of first unique information and second unique information, the third storage unit 42 may be configured to store the first unique information and the second unique information separately. Alternatively, the third storage unit 42 may be configured to store unique information that is a combination of the first unique information and the second unique information.

[0021] The determination unit 22 includes a first determination unit 221 and a second determination unit 222. The first determination unit 221 determines whether the identification information stored in the first storage unit 21 is related to the unique information stored in the second storage unit 31. In this embodiment, the first storage unit 21 is provided in the vehicle 2, and the second storage unit 31 is provided in the key medium 3. The determination by the first determination unit 221 is performed by reading the unique information stored in the key medium 3 at the vehicle 2 (#3A). In this embodiment, the identification information and the unique information are the same. Therefore, the first determination unit 221 determines whether the unique information acquired from the key medium 3 matches the identification information stored in the first storage unit 21. Here, as described above, if the unique information is composed of a combination of multiple alphanumeric characters and symbols, it is determined whether not only the alphanumeric characters and symbols match, but also their order. The determination result by the first determination unit 221 is transmitted to the second determination unit 222.

[0022] When the first determination unit 221 determines that the identification information and the unique information are related to each other, the second determination unit 222 determines whether the unique information acquired by the mobile terminal 4 from the second storage unit 31 is related to the identification information stored in the first storage unit 21. In this embodiment, as described above, the unique information acquired by the unique information acquisition unit 41 is stored in the third storage unit 42. Therefore, the second determination unit 222 acquires the unique information from the third storage unit 42 (#4) and determines whether the acquired unique information is related to the identification information stored in the first storage unit 21 (#5). In this embodiment, the identification information and the unique information are the same. Therefore, the second determination unit 222 determines whether the unique information acquired from the third storage unit 42 matches the identification information stored in the first storage unit 21. Here, too, as described above, when the unique information is composed of a combination of multiple alphanumeric characters and symbols, it is determined whether not only the alphanumeric characters and symbols match, but also their order. The determination result by the second determination unit 222 is transmitted to the common key information transmission unit 23. Based on the determination result by the second determination unit 222, the portable terminal 4 to which the common key information of the vehicle 2 can be transmitted is authenticated.

[0023] As described above, when the unique information is composed of first unique information and second unique information, the second determination unit 222 may determine whether or not the unique information is associated with the identification information based on the first unique information and the second unique information.

[0024] When the second determination unit 222 determines that the unique information is associated with the identification information, the common key information transmission unit 23 transmits to the mobile terminal 4 the common key information that enables control of the vehicle 2 (#6). In this embodiment, the identification information stored in the first storage unit 21 and the unique information stored in the second storage unit 31 are the same. Therefore, when the common key information transmission unit 23 determines that the unique information acquired from the third storage unit 42 matches the identification information stored in the first storage unit 21, the common key information transmission unit 23 transmits to the mobile terminal 4 the common key information that enables control of the vehicle 2. The common key information transmission unit 23 determines whether the second determination unit 222 has determined that the unique information acquired from the third storage unit 42 matches the identification information stored in the first storage unit 21, based on the determination result transmitted from the second determination unit 222. Being able to control the vehicle 2 means that it is possible to energize the electrical components of the vehicle 2 and / or that it is possible to start combustion in the engine (or to start running the vehicle 2 using the battery). Therefore, being able to control the vehicle 2 means that it is possible to start the electrical components and the engine of the vehicle 2 (or to drive the traction motor using the battery). When the second determination unit 222 transmits a determination result indicating that the unique information acquired from the third storage unit 42 matches the identification information stored in the first storage unit 21, the common key information transmission unit 23 transmits to the mobile terminal 4 the common key information that enables starting the electrical components and the engine of the vehicle 2 (or to drive the traction motor using the battery). Communication between the common key information transmission unit 23 and the mobile terminal 4 related to the transmission of this common key information may be performed via a network or short-range wireless communication.

[0025] The shared key information storage unit 43 stores the shared key information transmitted from the shared key information transmission unit 23. The user of the mobile terminal 4 can use the vehicle 2 by using a shared key corresponding to the shared key information stored in the shared key information storage unit 43.

[0026] Furthermore, in this embodiment, the inter-portable communication unit 44 of the portable terminal 4 is configured to be able to communicate the communicated common key information to another portable terminal 5 different from the portable terminal 4. When communicating the common key information to another portable terminal 5, the common key information transmission unit 24 transmits the common key information to the other portable terminal 5, for example, via email or a network (#7). Of course, it is also possible to transmit the common key information via short-range wireless communication.

[0027] In the mobile terminal 5, the shared key information storage unit 51 stores the shared key information transmitted from the shared key information transmission unit 24. This allows not only the user of the mobile terminal 4 but also the user of the mobile terminal 5 to use the vehicle 2. Note that, for example, if the users of the mobile terminals 4 and 5 are family members or if no particular restrictions on the use of the key information are set, the shared key information stored in the third storage unit 42 does not need to be deleted even when the shared key information is transmitted from the mobile terminal 4 to the mobile terminal 5. On the other hand, if restrictions on the use of the key information are set, such as when the vehicle 2 is used for car sharing, the shared key information stored in the third storage unit 42 may be deleted when the shared key information is transmitted from the mobile terminal 4 to the mobile terminal 5. It is also possible to set an expiration date for the shared key information stored in the shared key information storage unit 51 of the mobile terminal 5, and to invalidate the shared key information stored in the shared key information storage unit 51 of the mobile terminal 5 when the expiration date is reached. This improves security.

[0028] Here, the common key information is transmitted between the vehicle 2 and the mobile terminal 4 after being encrypted. Transmission of such encrypted common key information will be described with reference to Fig. 3. Note that a description of authentication of the mobile terminal 4 by the vehicle 2 based on the unique information, which is performed before transmitting the common key information, will be omitted here.

[0029] In the example of FIG. 3, five common keys (common key information) are stored in vehicle 2. Specifically, five common keys, "CK_A," "CK_B," "CK_C," "CK_D," and "CK_E," are stored in vehicle 2. "CK_A" and "CK_B" are common keys with no expiration date set for vehicle 2, "CK_C" and "CK_D" are common keys with an expiration date set for vehicle 2 (e.g., valid for only 24 hours), and "CK_E" is a common key that is only permitted to enter the passenger compartment of vehicle 2 (only permitted to unlock the doors). In addition, "PK_O" is stored in mobile terminal 4 as a public key, and "SK_O" is stored as a private key.

[0030] When the portable terminal 4 obtains the common key from the vehicle 2, first, the public key "PK_O" is registered from the portable terminal 4 to the vehicle 2. Then, in order to transition the vehicle 2 (the state of the vehicle 2) to a registration mode in which the public key "PK_O" can be registered, a predetermined command ("0" in the example of FIG. 3) for transitioning the vehicle 2 to the registration mode is sent from the portable terminal 4 to the vehicle 2 (#10). This causes the vehicle 2 to enter the registration mode.

[0031] With vehicle 2 in registration mode, mobile terminal 4 also transmits "PK_O", which is stored as a public key (#11). When vehicle 2 receives public key "PK_O", it encrypts common key "CK_A" with this public key "PK_O" (#12). Here, the encrypted common key "CK_A" is referred to as "*CK_A". "*CK_A" is transmitted from vehicle 2 to mobile terminal 4 (#13).

[0032] When the portable terminal 4 receives "*CK_A", it decrypts "*CK_A" with the private key "SK_O", and the decrypted "CK_A" is stored in the portable terminal 4 (#14). Next, in the vehicle 2, the four common keys "CK_B", "CK_C", "CK_D", and "CK_E" are encrypted with the common key "CK_A" (#15). The encrypted common keys are "*CK_B", "*CK_C", "*CK_D", and "*CK_E", respectively. "*CK_B", "*CK_C", "*CK_D", and "*CK_E" are transmitted in bulk from the vehicle 2 to the portable terminal 4 (#16).

[0033] When the mobile terminal 4 receives "*CK_B", "*CK_C", "*CK_D", and "*CK_E", it decrypts "*CK_B", "*CK_C", "*CK_D", and "*CK_E" using the common key "CK_A" that it previously obtained, and the decrypted "CK_B", "CK_C", "CK_D", and "CK_E" are stored in the mobile terminal 4 (#17).

[0034] In this way, the common key information transmission unit 23 encrypts the common key information (in this example, "CK_B," "CK_C," "CK_D," and "CK_E") using a common encryption key (in this example, "CK_A") previously set between the vehicle 2 and the portable terminal 4, transmits the encrypted common key information to the portable terminal 4, and decrypts the encrypted common key using the common key previously transmitted in the portable terminal 4. This enables the portable terminal 4 to obtain the common key stored in the vehicle 2.

[0035] In the example of Fig. 3, the common key is configured to be encrypted with common key information, but it is also possible to configure the common key to be encrypted with a public key (public key information) and transmitted. Such transmission of common key information encrypted with a public key will be described with reference to Fig. 4. Note that here too, a description of the authentication of the mobile terminal 4 by the vehicle 2 based on the unique information (determination by the first determination unit 221 and the second determination unit 222), which is performed before transmitting the common key information, will be omitted.

[0036] In the example of FIG. 4, five common keys (common key information) are stored in vehicle 2. Specifically, five common keys, "CK_A," "CK_B," "CK_C," "CK_D," and "CK_E," are stored in vehicle 2. "CK_A" and "CK_B" are common keys with no expiration date set for vehicle 2, "CK_C" and "CK_D" are common keys with an expiration date set for vehicle 2 (e.g., valid for only 24 hours), and "CK_E" is a common key that is only permitted to enter the passenger compartment of vehicle 2 (only permitted to unlock the doors). In addition, "PK_O" is stored in mobile terminal 4 as a public key, and "SK_O" is stored as a private key.

[0037] When the portable terminal 4 obtains the common key from the vehicle 2, first, the public key "PK_O" is registered from the portable terminal 4 to the vehicle 2. Then, in order to transition the vehicle 2 (the state of the vehicle 2) to a registration mode in which the public key "PK_O" can be registered, a predetermined command ("0" in the example of FIG. 4) for transitioning the vehicle 2 to the registration mode is sent from the portable terminal 4 to the vehicle 2 (#20). This causes the vehicle 2 to enter the registration mode.

[0038] With vehicle 2 in registration mode, mobile terminal 4 also transmits "PK_O", which is stored as a public key (#21). When vehicle 2 receives public key "PK_O", it encrypts common key "CK_A" with this public key "PK_O" (#22). Here, the encrypted common key "CK_A" is referred to as "*CK_A". "*CK_A" is transmitted from vehicle 2 to mobile terminal 4 (#23).

[0039] When the portable terminal 4 receives "*CK_A", it decrypts "*CK_A" using the private key "SK_O", and the decrypted "CK_A" is stored in the portable terminal 4 (#24). Next, in the vehicle 2, the four common keys "CK_B", "CK_C", "CK_D", and "CK_E" are encrypted using the public key "PK_O" (#25). The encrypted common keys are "*CK_B", "*CK_C", "*CK_D", and "*CK_E", respectively. "*CK_B", "*CK_C", "*CK_D", and "*CK_E" are transmitted in bulk from the vehicle 2 to the portable terminal 4 (#26).

[0040] When the mobile terminal 4 receives "*CK_B", "*CK_C", "*CK_D", and "*CK_E", it decrypts "*CK_B", "*CK_C", "*CK_D", and "*CK_E" using the private key "SK_O", and the decrypted "CK_B", "CK_C", "CK_D", and "CK_E" are stored in the mobile terminal 4 (#27).

[0041] In this way, the common key information transmission unit 23 encrypts the common key information (in this example, "CK_B", "CK_C", "CK_D", and "CK_E") with a public key (in this example, "PK_O") that has been set in advance between the vehicle 2 and the portable terminal 4, and decrypts the encrypted common key with a private key that has already been stored in the portable terminal 4. This allows the portable terminal 4 to obtain the common key stored in the vehicle 2 with high security.

[0042] Next, transmission of a common key (common key information) from the mobile terminal 4 to another mobile terminal 5 will be described with reference to FIG.

[0043] In the example of FIG. 5, the mobile terminal 4 stores a public key (public key information) "PK_O," a private key (private key information) "SK_O," and five common keys (common key information). Specifically, five common keys, "CK_A," "CK_B," "CK_C," "CK_D," and "CK_E," are stored in the vehicle 2. "CK_A" and "CK_B" are common keys with no expiration date set for the vehicle 2, "CK_C" and "CK_D" are common keys with an expiration date set for the vehicle 2 (e.g., valid for only 24 hours), and "CK_E" is a common key that is only permitted to enter the vehicle interior of the vehicle 2 (only permitted to unlock the doors). The example of FIG. 5 illustrates an example in which only "CK_E" is transmitted to the mobile terminal 5. In addition, the mobile terminal 5 stores "PK_F" as a public key and "SK_F" as a private key.

[0044] When the mobile terminal 4 registers the common key "CK_E" to the mobile terminal 5, it is first necessary to put the mobile terminal 5 (the state of the mobile terminal 5) into a registration mode in which the common key "CK_E" can be registered. Therefore, in order to transition the mobile terminal 5 (the state of the mobile terminal 5) into the registration mode, the mobile terminal 4 transmits to the mobile terminal 5 a predetermined command ("0" in the example of FIG. 5) that transitions the mobile terminal 5 into the registration mode (#30). This causes the mobile terminal 5 to enter the registration mode.

[0045] When the portable terminal 5 enters registration mode, it transmits "PK_F", which it has stored as a public key, to the portable terminal 4 (#31). When the portable terminal 4 receives the public key "PK_F", it encrypts the common key "CK_E" with this public key "PK_F" (#32). Here, the encrypted common key "CK_E" is referred to as "*CK_E". "*CK_E" is transmitted from the portable terminal 4 to the portable terminal 5 (#33).

[0046] When the portable terminal 5 receives "*CK_E", it decrypts "*CK_E" with the private key "SK_F", and the decrypted "CK_E" is stored in the portable terminal 5 (#34).

[0047] In this way, when transmitting a common key from mobile terminal 4 to mobile terminal 5, the public key (in this example, "PK_F") is transmitted from mobile terminal 5 to mobile terminal 4, the common key "CK_E" is encrypted with this public key "PK_F", and the encrypted common key is decrypted with the private key "SK_F" already stored in mobile terminal 5. This enables mobile terminal 4 to properly transmit the common key to mobile terminal 5.

[0048] Other Embodiments In the above embodiment, it has been described that the vehicle 2 and the portable terminal 4 transmit the common key information via short-range wireless communication, and that the portable terminals 4 and 5 transmit the common key information via email or a network. For example, if the vehicle 2 is equipped with a communication device capable of communicating via a network, it is also possible to configure the communication between the vehicle 2 and the portable terminal 4 to be performed via a server that the vehicle 2 and the portable terminal 4 can each access, instead of or in addition to short-range wireless communication. In this case, the communication between the portable terminals 4 and 5 can also be performed via the server.

[0049] In addition, if vehicle 2 does not have a communication device capable of communicating via a network, it is also possible to configure communication between vehicle 2 and mobile terminal 4 to be performed via short-range wireless communication as in the above embodiment, and communication between mobile terminal 4 and mobile terminal 5 to be performed via a server.

[0050] In the above embodiment, it has been described that the identification information stored in the first storage unit 21 and the unique information stored in the second storage unit 31 are the same, but the identification information stored in the first storage unit 21 and the unique information stored in the second storage unit 31 may be different from each other. In this case, for example, the identification information and the unique information may be configured to have a portion in common with each other. Also, for example, the unique information may be generated based on the identification information.

[0051] In the above embodiment, the key medium 3 is described as an IC card, but the key medium 3 may be a smart key that locks and unlocks the doors of the vehicle 2.

[0052] In the above embodiment, it has been described that the portable terminal 4 can transmit the common key information to the portable terminal 5, but it is also possible to configure the portable terminal 4 so that it cannot transmit the common key information to the portable terminal 5. In this case, the portable terminal 4 does not need to be provided with the inter-portable transmission unit 44.

[0053] In the above embodiment, it has been described that the common key information transmission unit 23 encrypts the common key information with an encryption key that is common between the vehicle 2 and the mobile terminal 4 in advance and transmits the encrypted common key information to the mobile terminal 4. The common key information transmission unit 23 can also be configured to transmit a plurality of pieces of common key information to the mobile terminal 4, and to encrypt the common key information that is first transmitted to the mobile terminal 4 among the plurality of pieces of common key information with an encryption key that is common between the vehicle 2 and the mobile terminal 4 in advance, and to encrypt the common key information transmitted thereafter based on the common key information transmitted immediately before.

[0054] 3, when multiple common keys "CK_A," "CK_B," "CK_C," "CK_D," and "CK_E" are transmitted from vehicle 2 to mobile terminal 4, the first common key "CK_A" to be transmitted is encrypted with a preset common encryption key "PK_O" and transmitted from vehicle 2 to mobile terminal 4, the next common key "CK_B" is encrypted with the most recently transmitted "CK_A," the next common key "CK_C" is encrypted with the most recently transmitted "CK_B," the next common key "CK_D" is encrypted with the most recently transmitted "CK_C," and the next common key "CK_E" is encrypted with the most recently transmitted "CK_D." Even with this configuration, common keys can be transmitted appropriately from vehicle 2 to mobile terminal 4.

[0055] In such a case, the next common key information can be acquired only if the first common key information has been properly acquired. Also, since multiple common key information are encrypted using different unique common key information, security can be further improved. Furthermore, since the previously transmitted common key information serves as the decryption key for decryption on the mobile terminal 4 side, there is no need to store the decryption key in advance. Therefore, the risk of the decryption key being stolen can be reduced, and security can be improved in this respect as well.

[0056] In the above embodiment, the unique information is described as including first unique information and second unique information, but the unique information may be composed of only a single piece of unique information. Furthermore, the unique information may be composed of third unique information in addition to the first unique information and the second unique information. In this case, the third unique information may be obtained from the vehicle 2, for example, or may be information written on the vehicle 2 (for example, a registration number, etc.).

[0057] In the above embodiment, it has been explained that "CK_A" and "CK_B" are common keys with no expiration date set for vehicle 2, "CK_C" and "CK_D" are common keys with an expiration date set for vehicle 2 (for example, valid for only 24 hours), and "CK_E" is a common key that is only permitted to enter the interior of vehicle 2 (only permitted to unlock the door locks). However, for example, by setting a common key with a function that allows a delivery company to only unlock the trunk of vehicle 2, it becomes possible for the delivery company to have the vehicle 2 store parcels when the delivery person is not at home and receive them. Furthermore, for example, when giving common key information to a user who is unfamiliar with driving operations, it may be configured to transmit common key information with a speed limit imposed.

[0058] In the above embodiment, the key system 1 is configured to communicate between the vehicle 2, the key medium 3, and the mobile terminal 4. The first determination unit 221 determines whether the identification information stored in the first storage unit 21 is related to the unique information stored in the second storage unit 31. If the first determination unit 221 determines that the identification information is related, the second determination unit 222 determines whether the unique information related to the identification information acquired by the mobile terminal 4 is related to the identification information stored in the first storage unit 21. In this case, the vehicle 2 is configured to read the unique information stored in the key medium 3, and the mobile terminal 4 is configured to read the unique information stored in the key medium 3. However, it is also possible to read the unique information stored in the key medium 3 in the vehicle 2, and hold the mobile terminal 4 over the vehicle 2 to read the unique information stored in the mobile terminal 4.

[0059] In this case, the key system 1 is configured to communicate between the key medium 3 and the mobile terminal 4 and the vehicle 2, and the key medium 3 is an IC card or the like that can communicate with the vehicle 2, and the key medium 3 and the vehicle 2 are linked together.

[0060] Such a key system 1 is configured to include: a first memory unit 21 provided in the vehicle 2 and storing identification information capable of identifying the vehicle 2; a second memory unit 31 provided in the key medium 3 and storing unique information associated with the identification information; a first judgment unit 221 that determines whether the identification information stored in the first memory unit 21 is associated with the unique information stored in the second memory unit 31; a second judgment unit 222 that, when the first judgment unit 221 determines that they are associated, determines whether the identification information capable of identifying the vehicle 2 acquired by the mobile terminal 4 is associated with the identification information stored in the first memory unit 21; and a common key information transmission unit 23 that transmits common key information that enables control of the vehicle 2 to the mobile terminal 4 when the second judgment unit 222 determines that they are associated.

[0061] In such a key system 1, the first storage unit 21, the second storage unit 31, and the first determination unit 221 are configured in the same manner as in the above embodiment, and communication between the key medium 3 and the vehicle 2 triggers a transition to a registration mode in which a user can be registered, and the vehicle 2 and the mobile terminal 4 are linked via short-range wireless communication. This linking may be achieved, for example, by transmitting one-time key information from the vehicle 2 to the mobile terminal 4 via short-range wireless communication, and the common key information transfer unit 23 may transfer the common key information to the mobile terminal 4 based on the one-time key information transferred to the mobile terminal 4. Note that this common key information may be transferred using a public key cryptosystem.

[0062] In addition to the configuration in the above embodiment, the key system 1 can also be configured as follows. (1) When communication is performed between the vehicle 2 and the mobile terminal 4, the communication may be linked to personal information of the user of the mobile terminal 4. (2) When communicating between the vehicle 2 and the portable terminal 4, the portable terminal 4 may be registered together with a device having other functions or uses (for example, a car navigation system). This allows operation via the car navigation system, improving visibility and operability, and improving convenience. (3) When the mobile terminal 4 acquires the common key information from the vehicle 2, the unique information acquired by the mobile terminal 4 may be deleted. (4) Before the vehicle 2 and the mobile terminal 4 communicate with each other, the common key information may be exchanged after operating the screen of the car navigation system installed in the vehicle 2. (5) When the shared key information is assigned a function restriction or an expiration date, the vehicle 2 may be configured to automatically invalidate the shared key information when the expiration date has passed. In addition, the mobile terminal 4 may be configured to invalidate the shared key information. (6) A specified number of times of common key information may be set, and a unique common key may be generated within the specified number of times. (7) The vehicle 2 and the mobile terminal 4 may be configured to communicate with each other after two-step authentication, thereby improving security.

[0063] [Summary of the above embodiment] The key system 1 described above will now be outlined.

[0064] (1) The key system 1 comprises a first memory unit 21 provided in the vehicle 2 and storing identification information capable of identifying the vehicle 2, and a second memory unit 31 provided in the key medium 3 and storing unique information associated with the identification information, the vehicle 2 comprising a first judgment unit 221, a second judgment unit 222, and a common key information transmission unit 23, the first judgment unit 221 determining whether the identification information stored in the first memory unit 21 is associated with the unique information stored in the second memory unit 31, the second judgment unit 222 determining whether the unique information associated with the identification information acquired by the mobile terminal 4 from the key medium 3 is associated with the identification information stored in the first memory unit 21 when the first judgment unit 221 determines that they are associated, and the common key information transmission unit 23 transmitting common key information enabling control of the vehicle 2 to the mobile terminal 4 when the second judgment unit 222 determines that they are associated.

[0065] According to this configuration, the common key information is transmitted when the identification information stored in the first storage unit 21 of the vehicle 2 and the unique information acquired by the mobile terminal 4 are correlated with each other, thereby improving security. Furthermore, due to the high security, it is not necessary to change the common key information each time the mobile terminal 4 communicates with the vehicle 2, simplifying management of the electronic key. Furthermore, according to the key system 1, instead of transferring a physical key, the electronic key (a software key) is transferred via communication in response to a determination result of whether the identification information stored in the first storage unit 21 of the vehicle 2 and the unique information acquired by the mobile terminal 4 are correlated with each other, thereby improving convenience. In this way, security is improved by exchanging the common key information using three different objects: the vehicle 2, the key medium 3, and the mobile terminal 4. The common key information is transferred to the mobile terminal 4 by the second determination unit 222 and the common key information transfer unit 23, simplifying the transfer of the electronic key.

[0066] (2) The key system 1 comprises a first memory unit 21 provided in the vehicle 2 and storing identification information capable of identifying the vehicle 2, and a second memory unit 31 provided in the key medium 3 and storing unique information associated with the identification information, the vehicle 2 comprising a first judgment unit 221, a second judgment unit 222, and a common key information transmission unit 23, the first judgment unit 221 determining whether the identification information stored in the first memory unit 21 is associated with the unique information stored in the second memory unit 31, the second judgment unit 222 determining whether the identification information capable of identifying the vehicle 2 obtained by the mobile terminal 4 from the vehicle 2 is associated with the identification information stored in the first memory unit 21 when the first judgment unit 221 determines that they are associated, and the common key information transmission unit 23 transmitting common key information enabling control of the vehicle 2 to the mobile terminal 4 when the second judgment unit 222 determines that they are associated.

[0067] According to this configuration, the common key information is transmitted when the identification information stored in the first storage unit 21 of the vehicle 2 and the identification information acquired by the mobile terminal 4 that can identify the vehicle 2 are related to each other, thereby improving security. Furthermore, with this characteristic configuration, the high security eliminates the need to change the common key information each time the mobile terminal 4 communicates with the vehicle 2, simplifying electronic key management. Furthermore, with the key system 1 of this characteristic configuration, instead of transferring a physical key, the electronic key (a software key) is transferred via communication in response to a determination result of whether the identification information stored in the first storage unit 21 of the vehicle 2 and the identification information acquired by the mobile terminal 4 that can identify the vehicle 2 are related to each other, improving convenience. In this way, security is improved by exchanging the common key information using three different objects: the vehicle 2, the key medium 3, and the mobile terminal 4. The common key information is transferred to the mobile terminal 4 by the second determination unit 222 and the common key information transfer unit 23, simplifying electronic key transfer.

[0068] (3) The key system 1 described in (2) is preferably configured to communicate between the key medium 3 and the vehicle 2, and to read the unique information stored in the key medium 3 at the vehicle 2.

[0069] According to this configuration, the unique information stored in the key medium 3 can be easily transferred between the vehicle 2 and the key medium 3.

[0070] (4) It is preferable that the key system 1 described in (1) to (3) further includes an inter-mobile communication unit 44 that transmits the common key information transmitted to the mobile terminal 4 to another mobile terminal 5 different from the mobile terminal 4.

[0071] This configuration allows multiple users to easily share common key information. Furthermore, the common key information can be shared between the mobile terminal 4 and another mobile terminal 5 using, for example, short-range wireless communication without going through a server, eliminating the need for server maintenance and management costs, thereby reducing the cost of the key system 1.

[0072] (5) In the key system 1 described in (1) to (3), it is preferable that the common key information transmission unit 23 encrypts the common key information using a common encryption key previously set between the vehicle 2 and the mobile terminal 4 and transmits it to the mobile terminal 4.

[0073] According to this configuration, for example, by setting a complex encryption key, it is possible to further improve security. Also, since the common encryption key is known only to a limited number of users, there is no need to change the encryption key every time, as in the case of encryption using a conventional public encryption key.

[0074] (6) In the key system 1 described in (1) to (3), the common key information transmission unit 23 transmits multiple pieces of common key information to the mobile terminal 4, and it is preferable that the common key information that is first transmitted to the mobile terminal 4 among the multiple pieces of common key information is encrypted with a common encryption key that has been set in advance between the vehicle 2 and the mobile terminal 4, and that the common key information transmitted thereafter is encrypted based on the common key information transmitted immediately before.

[0075] According to this configuration, the mobile terminal 4 can acquire the next shared key information only if it has properly acquired the first shared key information. Furthermore, since each of the multiple shared key information is encrypted using a different unique shared key information, security can be further improved. Furthermore, the previously transmitted shared key information serves as the decryption key for decrypting the next transmitted shared key information, eliminating the need for the mobile terminal 4 to store the decryption key in advance. This reduces the risk of the decryption key being stolen, further improving security.

[0076] (7) In the key system 1 described in (1) to (3), the unique information is composed of first unique information that the mobile terminal 4 can acquire via communication and second unique information written on the key medium 3, and it is preferable that the second judgment unit 222 judges whether or not the first unique information is associated with the identification information based on the first unique information and the second unique information input to the mobile terminal 4.

[0077] According to this configuration, it is possible to further improve security by determining whether or not the identification information is related to the unique information based on both the first unique information acquired through communication and the second unique information input by the user of the mobile terminal 4. Furthermore, since the second unique information is recorded on the key medium 3, the user sees and inputs it, thereby preventing fraudulent activity through remote control. [Industrial Applicability]

[0078] The present invention can be used in a key system that performs communication between a vehicle, a key unit, and a mobile terminal. [Explanation of symbols]

[0079] 1: key system, 2: vehicle, 3: key medium, 4: mobile terminal, 5: mobile terminal, 21: first storage unit, 23: common key information transmission unit, 31: second storage unit, 44: inter-mobile transmission unit, 221: first judgment unit, 222: second judgment unit

Claims

1. a first storage unit provided in a vehicle and storing identification information capable of identifying the vehicle; a second storage unit provided in the key medium and storing unique information related to the identification information; the vehicle includes a first determination unit, a second determination unit, and a common key information transmission unit; the first determination unit determines whether or not the identification information stored in the first storage unit and the unique information stored in the second storage unit are related to each other; the second determination unit determines whether or not unique information associated with the identification information acquired by the mobile terminal from the key medium is associated with the identification information stored in the first storage unit when the first determination unit determines that the identification information is associated; The common key information transmission unit transmits common key information that enables control of the vehicle to the mobile terminal when the second determination unit determines that they are related.

2. a first storage unit provided in a vehicle and storing identification information capable of identifying the vehicle; a second storage unit provided in the key medium and storing unique information related to the identification information; the vehicle includes a first determination unit, a second determination unit, and a common key information transmission unit; the first determination unit determines whether or not the identification information stored in the first storage unit and the unique information stored in the second storage unit are related to each other; the second determination unit determines whether or not identification information capable of identifying the vehicle, acquired by the mobile terminal from the vehicle, is associated with the identification information stored in the first storage unit when the first determination unit determines that the vehicle is associated; The common key information transmission unit transmits common key information that enables control of the vehicle to the mobile terminal when the second determination unit determines that they are related.

3. configured to communicate between the key medium and the vehicle; The key system according to claim 2 , configured to read the unique information stored in the key medium in the vehicle.

4. 4. A key system according to claim 1, further comprising an inter-mobile communication unit that transmits the common key information transmitted to the mobile terminal to another mobile terminal different from the mobile terminal.

5. A key system as described in any one of claims 1 to 3, wherein the common key information transmission unit encrypts the common key information using a common encryption key previously set between the vehicle and the mobile terminal and transmits the encrypted common key information to the mobile terminal.

6. 4. The key system according to claim 1, wherein the common key information transmission unit transmits a plurality of pieces of common key information to the mobile terminal, and the common key information that is first transmitted to the mobile terminal among the plurality of pieces of common key information is encrypted with a common encryption key that has been preset between the vehicle and the mobile terminal, and the common key information that is transmitted thereafter is encrypted based on the common key information that was transmitted immediately before.

7. the unique information includes first unique information that can be acquired by the mobile terminal via communication and second unique information that is written on the key medium; A key system described in any one of claims 1 to 3, wherein the second determination unit determines whether the first unique information is associated with the identification information based on the first unique information and the second unique information input into the mobile terminal.

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