Digital key issuance method and program

Abstract

To provide a digital key issuing method capable of sharing a digital key among multiple electronic information storage media separated from a communication device such as an electronic device, and a program.SOLUTION: An electronic device 3 performs a series of first authentication processing with a parent card 4a storing a digital key and performs a series of second authentication processing with a child card 4b storing no digital key. A digital key first certificate is acquired from the authenticated parent card 4a, a piece of data for digital key generation is extracted from the digital key first certificate, and the data for digital key generation is transmitted to the authenticated child card 4b. When the digital key second certificate of the digital key generated by the child card 4b based on the data for digital key generation is received from the child card 4b, a public key included in the digital key second certificate is transmitted to the parent card 4a. When a digital key third certificate generated by the parent card 4a is received from the parent card 4a, the digital key third certificate is transmitted to a vehicle 2.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to the technical field of systems for issuing digital keys necessary for controlling a control object such as a vehicle.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1 for example, an in-vehicle communication system capable of locking and unlocking a vehicle door and starting an engine using a digital key stored in an electronic device such as a smartphone is known. Such a method for issuing a digital key is defined in, for example, a technical standard (Car Connectivity Consortium Digital Key Release 2) published by the Car Connectivity Consortium (registered trademark). In such a technical standard, it targets an electronic device in which a digital key framework that communicates with a server to generate a digital key and a secure element that stores the generated digital key are integrally mounted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-mentioned technical standard does not stipulate a processing procedure when only the secure element part is independently separated from the electronic device as an electronic information storage medium such as an IC (Integrated Circuit) card that can be carried by the user. For example, a method for sharing a digital key from a card that can already operate a vehicle to a card that can newly operate the vehicle is not stipulated.

[0005] Therefore, the present invention has been made in view of the above points and the like, and an object thereof is to provide a digital key issuance method and a program capable of sharing a digital key among a plurality of electronic information storage media separated as a separate body from a communication device such as an electronic device.

Means for Solving the Problems

[0006] In order to solve the above problems, the invention according to claim 1 is a digital key issuance method executed by a control object, a communication device separated from the control object and capable of communicating with the control object, and a plurality of electronic information storage media separated from the control object and the communication device, capable of communicating with the communication device and portable by a user, comprising: performing a first authentication process between a first electronic information storage medium that stores a digital key necessary for controlling the control object among the plurality of electronic information storage media and the communication device; performing a second authentication process between a second electronic information storage medium that does not store the digital key among the plurality of electronic information storage media and the communication device; the communication device obtaining a first certificate of the digital key from the first electronic information storage medium authenticated by the first authentication process, extracting data for generating the digital key from the first certificate, and transmitting the data to the second electronic information storage medium authenticated by the second authentication process; the second electronic information storage medium receiving the data from the communication device, generating and storing the digital key based on the data, and transmitting a second certificate of the digital key to the communication device; the communication device receiving the second certificate of the digital key from the second electronic information storage medium, and transmitting the public key included in the second certificate to the first electronic information storage medium; the first electronic information storage medium receiving the public key included in the second certificate from the communication device, and generating a third certificate by signing the public key included in the second certificate with a first private key pre-stored in the first electronic information storage medium or a private key paired with the public key included in the digital key of the first electronic information storage medium, and transmitting the third certificate to the communication device; and the communication device transmitting the third certificate to the control object.

[0007] The invention according to claim 2 is a communication device separated from a control object and capable of communicating with the control object, and a computer included in a communication device separated from a plurality of electronically storable information media portable by a user and capable of communicating with the plurality of electronically storable information media. A first authentication means for performing a first authentication process between the first electronically storable information medium storing a digital key necessary for controlling the control object among the plurality of electronically storable information media; a second authentication means for performing a second authentication process between the second electronically storable information medium not storing the digital key among the plurality of electronically storable information media; a first receiving means for receiving a first certificate of the digital key from the first electronically storable information medium authenticated by the first authentication process; an extraction means for extracting data for generating the digital key from the first certificate of the digital key received by the first receiving means; a first transmitting means for transmitting the data extracted by the extraction means to the second electronically storable information medium authenticated by the second authentication process; a second receiving means for receiving a second certificate of the digital key generated based on the data and stored in the second electronically storable information medium from the second electronically storable information medium; a second transmitting means for transmitting the public key included in the second certificate received by the second receiving means to the first electronically storable information medium; a third receiving means for receiving a third certificate generated by signing the public key included in the second certificate with a first secret key stored in advance in the first electronically storable information medium or a secret key paired with the public key included in the digital key of the first electronically storable information medium from the first electronically storable information medium; and a third transmitting means for transmitting the third certificate received by the third receiving means to the control object.

[0008] The invention according to claim 3 is the program according to claim 2, wherein the second receiving means receives, from the second electronic information storage medium, a second certificate signed with a second private key pre-stored in the second electronic information storage medium and a fourth certificate including a public key paired with the second private key, and the program further functions to cause the computer to function as verification means for verifying the signature of the second certificate with the public key included in the fourth certificate received by the second receiving means, and when the verification by the verification means is successful, the second transmitting means transmits the public key included in the second certificate to the first electronic information storage medium.

[0009] The invention according to claim 4 is the program according to claim 2 or 3, wherein the program further functions to cause the computer to function as acquisition means for acquiring authentication information of an operator who operates the communication device, and as third authentication means for performing an authentication process on the operator based on the authentication information, and when the operator is authenticated by the third authentication means, the first authentication process and the second authentication process are performed.

Advantages of the Invention

[0010] According to the present invention, a digital key can be shared among a plurality of electronic information storage media separated as a separate body from the communication device.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below are embodiments when the present invention is applied to a digital key issuance system including a vehicle (an example of a control object), an electronic device (an example of a communication device) capable of communicating with the vehicle, and a plurality of IC cards (an example of an electronic information storage medium) capable of communicating with the electronic device and portable by a user. However, the present invention can also be applied to control objects other than vehicles, for example, a control device or its mechanism for locking and unlocking a residential door, a control device or its mechanism for locking and unlocking a locker door for storing articles, a control device or its mechanism for restricting the destination floor of an elevator with a key, and the like. In the following description, among the plurality of IC cards, the IC card that first stores the digital key is referred to as the parent card, and the IC card that shares the digital key from the parent card is referred to as the sub-card.

[0013] [1. Outline Configuration of Digital Key Issuance System S] First, with reference to FIG. 1 and the like, the outline configuration of the digital key issuance system S according to the present embodiment will be described. FIG. 1 is a diagram showing an example of the outline configuration of the digital key issuance system S. The digital key issuance system S includes a management server 1, a vehicle 2, an electronic device 3, a parent card 4a, and a sub-card 4b, and a digital key is issued through the processing procedures among these components. At this time, the electronic device 3 plays a role of determining the combination of the vehicle 2 and the parent card 4a and determining the combination of the vehicle 2 and the sub-card 4b. Note that the issuance of the digital key means that the digital key becomes available for controlling the vehicle 2. The electronic device 3 is separated independently as a separate body from the vehicle 2. Also, the parent card 4a and the sub-card 4b are each separated independently as separate bodies from the vehicle 2 and the electronic device 3.

[0014] The management server 1, the vehicle 2, and the management server 1 and the electronic device 3 are each capable of communicating via the network NW. The network NW is composed of, for example, the Internet, a mobile communication network, and its radio base stations. Also, the vehicle 2 and the electronic device 3 are capable of communicating via a dedicated line such as OBD2 (On Board Diagnosis second generation) or CAN (Controller Area Network). The dedicated line can be either wired or wireless (the same applies hereinafter). Also, the electronic device 3 and the parent card 4a can perform wireless communication (non-contact communication), and the electronic device 3 and the child card 4b can perform wireless communication. For wireless communication, technologies such as NFC (Near field communication), Bluetooth (registered trademark), ZigBee, LoRa, or UWB (Ultra Wide Band) are used. As an example of the management server 1, a vehicle manufacturer server can be mentioned.

[0015] FIG. 2 is a diagram showing an outline configuration example of an ECU (Electronic Control Unit) mounted on the vehicle 2. The ECU is mounted, for example, inside the center console of the vehicle 2. As shown in FIG. 2, the ECU includes a first communication unit 21, a second communication unit 22, a storage unit 23, a control unit 24, and the like. The first communication unit 21 is a communication device connected to the network NW for communicating with the management server 1. The second communication unit 22 is connected to a dedicated line such as OBD2 or CAN and is responsible for the communication function for communicating with the electronic device 3. Note that the second communication unit 22 may perform wireless communication (non-contact communication) with the electronic device 3.

[0016] The storage unit 23 stores an operating system (OS), applications, etc. The storage unit 23 also stores in advance a vehicle certificate and a private key (i.e., the private key of the vehicle) that forms a pair with the public key included in the vehicle certificate (i.e., the public key of the vehicle). The control unit 24 is configured to include a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The control unit 37 executes processing for issuing a digital key according to an application.

[0017] FIG. 3 is a diagram showing a schematic configuration example of the electronic device 3. In the present embodiment, it is assumed that the electronic device 3 is a personal computer (issuing PC) used for issuing a digital key in a factory, for example, but it may be a mobile terminal such as a smartphone. As shown in FIG. 3, the electronic device 3 includes a first communication unit 31, a second communication unit 32, a third communication unit 33, a storage unit 34, an operation unit 35, a display unit 36, a control unit 37, and the like. Note that the electronic device 3 has a clock function. The first communication unit 31 is a communication device connected to the network NW and configured to communicate with the management server 1. The second communication unit 32 is connected to a dedicated line such as OBD2 or CAN and is responsible for a communication function for communicating with the vehicle 2 (ECU).

[0018] The third communication unit 33 is a communication device for performing wireless communication with each of the parent card 4a and the child card 4b. Note that the parent card 4a and the child card 4b may be attached (e.g., inserted into a slot) to the electronic device 3 only in the factory, and in this case, the third communication unit 33 is electrically connected to each of the parent card 4a and the child card 4b via an interface. Examples of such an interface include SPI (Serial Peripheral Interface), I 2Examples include C (Inter-Integrated Circuit) and the interface of ISO / IEC 7816. The storage unit 34 stores an operating system and applications (including the program of the present invention). Note that a public key of the vehicle manufacturer may be stored in the storage unit 34 in advance.

[0019] The operation unit 35 receives operation instructions from the operator. The display unit 36 displays various information on the display. The control unit 37 includes a CPU, a RAM, a ROM, etc. The control unit 37 executes processing for issuing a digital key according to the application. Note that the program of the present invention causes a computer (CPU) included in the control unit 37 to function as the first authentication means, the second authentication means, the third authentication means, the extraction means, the first reception means, the second reception means, the third reception means, the first transmission means, the second transmission means, the third transmission means, the verification means, and the acquisition means in the present invention.

[0020] FIG. 4 is a diagram showing a schematic configuration example of a parent card 4a and a child card 4b. As shown in FIG. 4, the parent card 4a and the child card 4b are each configured to include a communication unit 41, a RAM 42, a NVM (Nonvolatile Memory) 43, a CPU 44, and the like. The communication unit 41 is a communication device for performing wireless communication with the electronic device 3. Note that the communication unit 41 may be electrically connected to each of the parent card 4a and the child card 4b via an interface. An operating system and an application are stored in the NVM 43. In addition, an intermediate CA (Certification Authority) certificate, and a private key that forms a pair with the public key (that is, the public key of the intermediate CA) included in the intermediate CA certificate are stored in advance in the NVM 43. That is, the parent card 4a and the child card 4b themselves function as an institution that issues digital certificates. Note that the private key stored in advance in the NVM 43 of the parent card 4a is an example of a first private key, the private key stored in advance in the NVM 43 of the child card 4b is an example of a second private key, and the intermediate CA certificate stored in advance in the NVM 43 of the child card 4b is an example of a fourth certificate. Further, a public key of the vehicle manufacturer may be stored in advance in the NVM 43. The CPU 44 executes a process for issuing a digital key according to the application.

[0021] In the above configuration, first, the digital key used by the parent card 4a is issued as follows. The electronic device 3 performs a first authentication process with the parent card 4a. Here, in the first authentication process, for example, a common key shared by the electronic device 3 and the parent card 4a is used, and a process of determining whether encrypted data obtained by encrypting a random number with a common key of one of the electronic device 3 and the parent card 4a can be decrypted with the common key of the other is performed. In this case, for example, the encrypted data generated by the parent card 4a is transmitted to the electronic device 3 by wireless communication. Note that the authentication method in the first authentication process is not particularly limited, and various known authentication methods such as a common key authentication method may be adopted. Further, the authentication in the first authentication process may be one-way authentication (authentication of the parent card 4a) or mutual authentication (authentication of the electronic device 3 and authentication of the parent card 4a).

[0022] When the electronic device 3 receives, via a dedicated line, data (hereinafter referred to as "data for generating a digital key") for generating a digital key necessary for controlling, for example, the mutually authenticated vehicle 2 (for example, controlling the locking and unlocking of vehicle doors, starting the engine, etc.), the received data for generating a digital key is transmitted wirelessly to the authenticated parent card 4a. Here, the data for generating a digital key includes, for example, a vehicle ID unique to the vehicle 2. When the parent card 4a receives the data for generating a digital key from the electronic device 3, based on the received data for generating a digital key, a digital key necessary for controlling the vehicle 2 is generated and stored in the NVM 43. Here, the digital key consists of a key pair of a public key and a private key of the vehicle. Further, the parent card 4a generates a first certificate of the stored digital key (hereinafter referred to as "the first digital key certificate"). Such a first digital key certificate includes the public key in the digital key and is signed with the private key of the intermediate CA pre-stored in the parent card 4a. Then, the parent card 4a transmits the first digital key certificate and the intermediate CA certificate of the parent card 4a wirelessly to the electronic device 3.

[0023] When the electronic device 3 receives the first digital key certificate and the intermediate CA certificate of the parent card 4a from the parent card 4a, the received first digital key certificate and the intermediate CA certificate of the parent card 4a are transmitted to the vehicle 2 via a dedicated line. When the vehicle 2 receives the first digital key certificate and the intermediate CA certificate of the parent card 4a via a dedicated line from the electronic device 3, the signature of the first digital key certificate is verified with the public key of the intermediate CA included in the intermediate CA certificate of the parent card 4a, and when the verification is successful, at least the public key in the digital key included in the first digital key certificate is stored in the storage unit 23. In this way, the digital key of the parent card 4a is issued, and the public key in the digital key of the parent card 4a is registered in the vehicle 2. As a result, the parent card 4a can control the vehicle 2 in a non-contact manner using the digital key.

[0024] Next, the digital key used by the child card 4b is issued as follows. The electronic device 3 performs a first authentication process with the parent card 4a that stores the digital key issued as described above, and performs a second authentication process with the child card 4b that does not store the digital key. Here, in the second authentication process, for example, a common key shared by the electronic device 3 and the child card 4b is used, and a process of determining whether encrypted data obtained by encrypting a random number with a common key of one of the electronic device 3 and the child card 4b can be decrypted with the common key of the other is performed. In this case, for example, the encrypted data generated by the child card 4b is transmitted to the electronic device 3 by wireless communication. Note that the authentication method in the second authentication process is not particularly limited, and various known authentication methods such as a common key authentication method may be adopted in the same manner as the second authentication process described above. Also, the authentication in the second authentication process may be one-sided authentication (authentication of the child card 4b) or mutual authentication (authentication of the electronic device 3 and authentication of the child card 4b).

[0025] The electronic device 3 acquires a digital key first certificate from the authenticated parent card 4a by wireless communication, extracts digital key generation data from the digital key first certificate, and transmits the digital key generation data to the authenticated child card 4b by wireless communication. When the child card 4b receives the digital key generation data from the electronic device 3, it generates a digital key necessary for controlling the vehicle 2 based on the digital key generation data and stores it in the NVM 43. Here, the digital key includes the same public key of the vehicle as that included in the digital key stored in the parent card 4a. That is, the digital key is shared from the parent card 4a to the child card 4b. Also, the child card 4b generates a second certificate of the stored digital key (hereinafter referred to as "digital key second certificate"). The digital key second certificate includes the public key in the digital key and is signed with the secret key of the intermediate CA pre-stored in the child card 4b. Then, the child card 4b transmits the signed digital key second certificate and the intermediate CA certificate of the child card 4b to the electronic device 3 by wireless communication.

[0026] When the electronic device 3 receives the signed digital key second certificate and the intermediate CA certificate of the child card 4b from the child card 4b, it verifies the signature of the digital key second certificate with the public key of the intermediate CA included in the intermediate CA certificate. When the verification of the signature is successful, the electronic device 3 transmits the public key included in the digital key second certificate to the parent card 4a by wireless communication. Then, the parent card 4a generates a third certificate (hereinafter referred to as the "digital key third certificate") by signing the public key included in the digital key second certificate with the private key of the intermediate CA pre-stored in the parent card 4a or the private key paired with the public key included in the digital key of the parent card 4a, and transmits the digital key third certificate to the electronic device 3 by wireless communication.

[0027] The electronic device 3 transmits the digital key third certificate received from the parent card 4a to the vehicle 2 by wireless communication. When the vehicle 2 receives the digital key third certificate from the electronic device 3, it verifies the signature of the key certificate with the public key of the intermediate CA included in the intermediate CA certificate of the parent card 4a or the public key included in the digital key of the parent card 4a. When the verification is successful, it stores at least the public key in the digital key included in the digital key third certificate in the storage unit 23. In this way, the digital key of the child card 4b is issued, and the public key in the digital key of the child card 4b is registered in the vehicle 2. As a result, the child card 4b can control the vehicle 2 in a non-contact manner using the digital key.

[0028] [2. Operation of the Digital Key Issuing System S] Next, the digital key issuance operation of the digital key issuance system S will be described. As a prerequisite for the issuance operation described below, at the card manufacturing factory, the intermediate CA certificate and the private key of the intermediate CA are written and stored in each of the parent card 4a and the child card 4b. In this way, the key pairs written in the parent card 4a (that is, the public key and private key of the intermediate CA) are different from the key pairs written in the child card 4b. Further, at the card manufacturing factory, individual common keys are written and stored in each of the parent card 4a and the child card 4b, and the USB (Universal Serial Bus) key inserted into the electronic device 3 stores the key from which the individual common keys written in each of the parent card 4a and the child card 4b are derived. Here, the USB key serves as a key for enabling the use of the electronic device 3 when inserted into the electronic device 3.

[0029] Then, from the card manufacturing factory, the USB key storing the common key with the parent card 4a, the common key with the electronic device 3, the intermediate CA certificate, and the parent card 4a storing the private key of the intermediate CA are shipped and received at the automobile factory. Further, the USB key storing the common key with the child card 4b, the common key with the electronic device 3, the intermediate CA certificate, and the child card 4b storing the private key of the intermediate CA are shipped and received at the automobile factory. Note that the parent card 4a and the child card 4b may be received at the automobile factory simultaneously, or the child card 4b may be received at the automobile factory after the parent card 4a is received at the automobile factory.

[0030] (2.1. Digital key issuance operation related to the parent card 4a) First, with reference to FIG. 5, the digital key issuance operation related to the parent card 4a will be described. FIG. 5 is a sequence diagram showing an example of the processing procedure implemented in the digital key issuance operation related to the parent card 4a. In the automobile factory, the electronic device 3 is prepared as the issuing PC, and a USB key is inserted into the electronic device 3. Also, in the automobile factory, the vehicle 2 to be combined with the parent card 4a is prepared. Then, in the automobile factory, the management server 1, the vehicle 2, and the electronic device 3 are connected to be communicable with each other, and the electronic device 3 and the parent card 4a are connected to be communicable with each other.

[0031] In the digital key issuance operation related to the parent card 4a, first, the electronic device 3 acquires the authentication information (for example, user ID and password) input by the operator (worker) who operates the electronic device 3 from the operation unit 35, and performs an authentication process for the operator based on the authentication information (step S1). In such an authentication process, for example, when the acquired authentication information matches the pre-registered authentication information, the operator is authenticated. When the operator is authenticated, the electronic device 3 can receive an operation instruction from the operator. That is, when the operator is authenticated, the electronic device 3 will perform the first authentication process with the parent card 4a. Note that when the operator cannot be authenticated, the electronic device 3 cannot receive an operation instruction from the operator and does not proceed to the first authentication process.

[0032] Then, when the authenticated operator gives an issuance instruction from the operation unit 35, the electronic device 3 transmits an authentication command to the parent card 4a in response to the issuance instruction, and performs the first authentication process described above with the parent card 4a (step S2). Note that when the authentication in the first authentication process is successful, a secure session is established between the electronic device 3 and the parent card 4a, and in the communication via such a secure session, encryption and message authentication using the session key generated in the first authentication process may be performed.

[0033] When the authentication (e.g., mutual authentication) between the electronic device 3 and the parent card 4a is successful, for example, authentication success information is transmitted from the electronic device 3 to the management server 1 via the network NW. When the management server 1 receives the authentication success information, it transmits an authentication request including parameters to the vehicle 2 via the network NW (step S3). Next, the management server 1 transmits an authentication request including a password to the electronic device 3 via the network NW (step S4).

[0034] When the vehicle 2 (ECU) receives an authentication request including parameters from the management server 1, it transmits a SELECT command (including the Application ID) indicating a selection command for an application for performing authentication processing with the vehicle 2 to the electronic device 3 via a dedicated line (step S5). Next, when the electronic device 3 receives the authentication request including the password from the management server 1 and also receives the SELECT command from the vehicle 2, it selects an application for performing authentication processing with the vehicle 2 and transmits a response to the SELECT command to the vehicle 2 via the dedicated line (step S6).

[0035] Next, when the vehicle 2 receives the response from the electronic device 3, it performs authentication processing with the electronic device 3 by transmitting an authentication command to the electronic device 3 (step S7). In such authentication processing, for example, parameters issued by the management server 1 and transmitted to the vehicle 2 and a password issued by the management server 1 and transmitted to the electronic device 3 (a value different from the parameters) are used, and a process of determining whether the value from which the parameters are derived and the value from which the password is derived match is performed. In this case, for example, the value from which the parameters are derived is calculated by the vehicle 2 and transmitted to the electronic device 3 via the dedicated line.

[0036] Note that the authentication method in such authentication processing is not particularly limited, and various known authentication methods such as challenge / response authentication method and password authentication method may be adopted. Also, the authentication in such authentication processing may be one-sided authentication (authentication of vehicle 2) or mutual authentication (authentication of vehicle 2 and electronic device 3). Note that when the authentication in such authentication processing is successful, a secure session is established between vehicle 2 and electronic device 3, and in the communication via such secure session, encryption and message authentication using the session key generated in the authentication processing may be performed.

[0037] When the authentication (for example, mutual authentication) between vehicle 2 and electronic device 3 is successful, vehicle 2 transmits a command (for example, including STORE DATA command) indicating a write & verification command for digital key generation data to electronic device 3 via a dedicated line (step S8). The data part of such command includes digital key generation data having a vehicle certificate in which, for example, a vehicle ID and an expiration date are described. Also, the vehicle certificate is signed with the private key of the vehicle manufacturer stored in the vehicle manufacturer server.

[0038] Next, when electronic device 3 receives a command including digital key generation data from vehicle 2, it writes the digital key generation data into storage unit 34 and verifies the signature of the vehicle certificate included in the digital key generation data with the public key of the vehicle manufacturer (step S9). Here, when the data length of the digital key generation data exceeds the data length that can be transmitted at one time, the transmission and reception of the command indicating the write & verification command and its response are performed multiple times, and the above verification is performed after all the writing of the digital key generation data is completed. Note that the verification may include verification as to whether the expiration date of the vehicle certificate has passed based on the time information (year / month / day / hour) acquired by the clock function of electronic device 3.

[0039] When the verification of the signature of the vehicle certificate and the verification of the expiration date of the vehicle certificate are successful, the electronic device 3 sends a response indicating normal completion to the vehicle 2 via a dedicated line (step S10). On the other hand, when the above verification fails, a response indicating an error is sent to the vehicle 2. Next, when the vehicle 2 receives a response indicating normal completion from the electronic device 3, it sends a command indicating a digital key generation command (for example, including a GET DATA command) to the electronic device 3 via a dedicated line (step S11). Next, when the electronic device 3 receives a command indicating a digital key generation command from the vehicle 2, it sends a command indicating a transmission command for the intermediate CA certificate to the parent card 4a by wireless communication (step S12).

[0040] Next, when the parent card 4a receives a command indicating a transmission command for the intermediate CA certificate from the electronic device 3, it reads the intermediate CA certificate from the NVM 43 and sends a response including the intermediate CA certificate (the intermediate CA certificate of the parent card 4a) to the electronic device 3 by wireless communication (step S13). Next, when the electronic device 3 receives a response including the intermediate CA certificate from the parent card 4a, it writes the CA certificate to the storage unit 34 and sends a command indicating a digital key generation command to the parent card 4a by wireless communication (step S14). The data part of such a command includes the digital key generation data verified in step S9 above.

[0041] Next, when the parent card 4a receives a command including digital key generation data from the electronic device 3, it generates a digital key of the parent card 4a based on the digital key generation data (step S15) and stores it in the NVM 43. Next, the parent card 4a generates a digital key first certificate based on the public key in the digital key generated in step S15 and the intermediate CA certificate of the parent card 4a (step S16), and signs the digital key first certificate with the private key of the intermediate CA pre-stored in the parent card 4a. For example, signature data is generated by encrypting the hash value of the digital key first certificate with the private key of the intermediate CA, and the signature is made on the digital key first certificate by adding the signature data to the digital key first certificate.

[0042] Next, the parent card 4a wirelessly transmits a response including the digital key first certificate generated and signed in step S16 to the electronic device 3 (step S17). Here, when the data length of the digital key first certificate exceeds the data length that can be transmitted at one time, the parent card 4a transmits a response indicating the data length of the digital key first certificate to the electronic device 3. Then, when the electronic device 3 receives the response, it transmits a read command to the parent card 4a, and the parent card 4a divides the digital key first certificate and transmits it to the electronic device 3. That is, the transmission and reception of the read command and its response are performed multiple times.

[0043] Note that the parent card 4a may transmit the public key in the digital key generated in step S15 to the electronic device 3, so that the electronic device 3 generates a digital key first certificate based on the public key and the intermediate CA certificate of the parent card 4a. In this case, the electronic device 3 transmits the generated digital key first certificate to the parent card 4a, and the parent card 4a signs the digital key first certificate with the private key of the intermediate CA and transmits it to the electronic device 3.

[0044] Next, when the electronic device 3 receives a response including the digital key first certificate from the parent card 4a, it transmits a response (response to the command indicating the digital key generation instruction) including the digital key first certificate and the intermediate CA certificate of the parent card 4a to the vehicle 2 via a dedicated line (step S18). Next, when the vehicle 2 receives a response including the digital key first certificate and the intermediate CA certificate of the parent card 4a from the electronic device 3, it verifies the signature of the digital key first certificate with the public key of the intermediate CA included in the intermediate CA certificate, and stores the digital key first certificate in the storage unit 23 when the verification is successful (step S19).

[0045] Next, the electronic device 3 records a log (operation history data) including the number of issued digital keys, the issue date and time, the identifier of the electronic device 3, and the operator's authentication information, and transmits the log to the management server 1 via the network NW (step S20). Next, when the management server 1 receives the log from the electronic device 3, it records the log (step S21). Thus, the operator and the electronic device 3 involved in the issuance of the digital key can be accurately identified later based on the logs recorded in the electronic device 3 and the management server 1.

[0046] (2.2. Digital key issuance operation related to the sub-card 4b) Next, with reference to FIG. 6, the digital key issuance operation related to the sub-card 4b will be described. FIG. 6 is a sequence diagram showing an example of the processing procedure implemented in the digital key issuance operation related to the sub-card 4b. The digital key issuance operation related to the sub-card 4b is assumed to be implemented following the digital key issuance operation related to the parent card 4a in an automobile factory, and the electronic device 3 and the sub-card 4b are communicably connected to each other.

[0047] In the digital key issuance operation related to the sub-card 4b, first, the electronic device 3 acquires the authentication information input by the operator operating the electronic device 3 from the operation unit 35, and performs authentication processing on the operator based on the authentication information (step S31). Such authentication processing is the same as step S1 described above. When the operator is authenticated, the electronic device 3 can receive operation instructions from the operator. That is, when the operator is authenticated, the electronic device 3 performs the first authentication process with the parent card 4a and the second authentication process with the sub-card 4b. Note that when the operator cannot be authenticated, the electronic device 3 cannot receive operation instructions from the operator and does not proceed to the first authentication process and the second authentication process.

[0048] Then, when the authenticated operator issues an instruction from the operation unit 35, the electronic device 3 transmits an authentication command to the parent card 4a in response to the issuance instruction, thereby performing the first authentication process described above with the parent card 4a (step S32). Note that when the authentication in the first authentication process is successful, a secure session is established between the electronic device 3 and the parent card 4a. In the communication via such a secure session, encryption and message authentication may be performed using the session key generated in the first authentication process.

[0049] When the authentication (for example, mutual authentication) between the electronic device 3 and the parent card 4a is successful, the electronic device 3 transmits an authentication command to the sub-card 4b, thereby performing the second authentication process described above with the sub-card 4b (step S33). Note that when the authentication in the second authentication process is successful, a secure session is established between the electronic device 3 and the sub-card 4b. In the communication via such a secure session, encryption and message authentication may be performed using the session key generated in the second authentication process.

[0050] Next, when the authentication (e.g., mutual authentication) between the electronic device 3 and the child card 4b is successful, the electronic device 3 wirelessly transmits a command (e.g., GET DATA command) indicating a transmission instruction for the key ID list to the parent card 4a (step S34). The key ID list is a list indicating key IDs corresponding to the number of digital keys that can be issued for the vehicle 2. For example, when the number of digital keys that can be issued is eight, eight different key IDs are described in the key ID list. Next, when the parent card 4a receives the command from the electronic device 3, it wirelessly transmits a response including the key ID list to the electronic device 3 (step S35).

[0051] Next, when the electronic device 3 receives the response including the key ID list from the parent card 4a, it selects one key ID from the key ID list (step S36). For example, the electronic device 3 causes the key ID list to be selectably displayed on the display unit 36, and selects the key ID specified by the operator via the operation unit 35 from among the plurality of key IDs described in the key ID list. Alternatively, the electronic device 3 may select, for example, the key ID in the order of appearance from among the plurality of key IDs described in the key ID list. If there is only one selectable key ID in the key ID list, the electronic device 3 may simply select the key ID. The key ID thus selected is stored in the NVM 43.

[0052] Next, the electronic device 3 wirelessly transmits a command indicating a transmission instruction for the first digital key certificate to the parent card 4a (step S37). Next, when the parent card 4a receives a command indicating a transmission instruction for the first digital key certificate from the electronic device 3, it reads out the first digital key certificate from the NVM 43 and wirelessly transmits a response including the first digital key certificate to the electronic device 3 (step S38). Next, when the electronic device 3 receives a response including the first digital key certificate from the parent card 4a, it extracts data for generating a digital key from the first digital key certificate (step S39), and wirelessly transmits a command indicating a generation instruction for the digital key, which includes the data for generating the digital key and the key ID selected in step S36, to the child card 4b (step S40).

[0053] Next, when the child card 4b receives a command indicating a generation instruction for the digital key from the electronic device 3, it generates a digital key of the child card 4b based on the data for generating the digital key included in the command (step S41), associates the digital key with the key ID included in the command, and stores the result in the NVM 43. Next, the child card 4b generates a second digital key certificate for the digital key generated in step S41 based on the public key in the digital key generated in step S41 and the intermediate CA certificate pre-stored in the NVM 43 of the child card 4b (step S42), and signs the public key in the digital key with the private key of the intermediate CA pre-stored in the child card 4b. Note that the method for generating the second digital key certificate is the same as the method for generating the first digital key certificate.

[0054] Next, the child card 4b wirelessly transmits a response including the signed digital key second certificate and the key ID associated with the digital key of the child card 4b to the electronic device 3 (step S43). Here, if the data length of the digital key second certificate exceeds the data length that can be transmitted at one time, the child card 4b transmits a response indicating the data length of the digital key second certificate to the electronic device 3. Then, when the electronic device 3 receives the response, it transmits a read command to the child card 4b, and the child card 4b divides the digital key second certificate and transmits it to the electronic device 3. That is, the transmission and reception of the read command and its response are performed multiple times.

[0055] Note that the child card 4b may transmit the public key in the digital key generated in step S41 to the electronic device 3, so that the electronic device 3 generates a digital key second certificate based on the public key and the intermediate CA certificate of the child card 4b. In this case, the electronic device 3 transmits the generated digital key second certificate to the child card 4b, and the child card 4b signs the digital key second certificate with the private key of the intermediate CA and transmits it to the electronic device 3.

[0056] Next, when the electronic device 3 receives a response including the digital key second certificate and the key ID from the child card 4b, it writes the digital key second certificate and the key ID into the storage unit 34, and wirelessly transmits a command indicating a transmission command for the intermediate CA certificate to the child card 4b (step S44). Next, when the child card 4b receives a command indicating a transmission command for the intermediate CA certificate from the electronic device 3, it reads the intermediate CA certificate from the NVM 43 and wirelessly transmits a response including the intermediate CA certificate (the intermediate CA certificate of the child card 4b) to the electronic device 3 (step S45).

[0057] Next, when the electronic device 3 receives a response including the intermediate CA certificate from the child card 4b, the electronic device 3 writes the intermediate CA certificate to the storage unit 34 and verifies the signature of the digital key second certificate with the public key of the intermediate CA included in the intermediate CA certificate (step S46). Next, when the verification of the signature is successful, the electronic device 3 transmits a command indicating a digital key certification command for the child card 4b to the parent card 4a by wireless communication (step S47). The data part of such a command includes the public key included in the digital key second certificate, the key ID associated with the digital key of the child card 4b, and the intermediate CA certificate of the child card 4b.

[0058] Next, when the parent card 4a receives a command including the public key included in the digital key second certificate from the electronic device 3, the key ID associated with the digital key of the child card 4b, and the intermediate CA certificate of the child card 4b, the parent card 4a generates a digital key third certificate by signing the public key included in the digital key second certificate with the private key of the intermediate CA pre-stored in the parent card 4a or the private key paired with the public key included in the digital key of the parent card 4a (step S48). At this time, the parent card 4a describes a registered flag for the key ID associated with the digital key of the child card 4b in the key ID list. Next, the parent card 4a transmits a response including the digital key third certificate generated in step S48 to the electronic device 3 by wireless communication (step S49).

[0059] Next, when the electronic device 3 receives a response including the digital key third certificate from the parent card 4a, the electronic device 3 transmits the digital key third certificate to the vehicle 2 by wireless communication (step S50).

[0060] Next, when the vehicle 2 receives the digital key third key certificate from the electronic device 3, the vehicle 2 verifies the signature of the digital key third certificate with the public key of the intermediate CA included in the intermediate CA certificate of the parent card 4a or the public key included in the digital key of the parent card 4a, and when the verification of the signature is successful, stores the key certificate in the storage unit 23 (step S51).

[0061] Next, the electronic device 3 records a log (operation history data) including the number of issued digital keys, the issue date and time, the identifier of the electronic device 3, and the operator's authentication information, and transmits the log to the management server 1 via the network NW (step S52). Next, when the management server 1 receives the log from the electronic device 3, it records the log. Thus, the operator and the electronic device 3 involved in the issuance of the digital key can be accurately identified later based on the logs recorded in the electronic device 3 and the management server 1.

[0062] As described above, according to the above embodiment, the electronic device 3 performs the first authentication process with the parent card 4a storing the digital key and the second authentication process with the child card 4b not storing the digital key, obtains the digital key first certificate from the authenticated parent card 4a, extracts the digital key generation data from the digital key first certificate, transmits the digital key generation data to the authenticated child card 4b, and when receiving the digital key second certificate of the digital key generated based on the digital key generation data from the child card 4b, transmits the public key included in the digital key second certificate to the parent card 4a, and when receiving the digital key third certificate generated by the parent card 4a from the parent card 4a, transmits the digital key third certificate to the vehicle 2. Therefore, the digital key can be shared between the parent card 4a and the child card 4b separated as a separate body from the electronic device 3.

[0063] In the above-described embodiment, the parent card 4a has been described as an example of the first electronic information storage medium of the present invention. However, as the first electronic information storage medium, a portable terminal such as a smartphone carried by a user (hereinafter referred to as a "parent device") may be used. Such a parent device is an integrated device of the electronic device 3 and the parent card 4a. In this case, after the digital key is stored in the parent device in the same manner as the "digital key issuance operation related to the parent card 4a" described above, for example, in the customer service floor of an authorized dealership that sells the vehicle 2, when the user (corresponding to the operator described above) activates the application of the parent device, the same operation as the "digital key issuance operation related to the child card 4b" described above is performed, and the digital key is shared from the parent device to the child card 4b.

Explanation of Reference Numerals

[0064] 1 Management Server 2 Vehicle 3 Electronic Device 4a Parent Card 4b Child Card 21 First Communication Unit 22 Second Communication Unit 23 Storage Unit 24 Control Unit 31 First Communication Unit 32 Second Communication Unit 33 Third Communication Unit 34 Storage Unit 35 Operation Unit 36 Display Unit 37 Control Unit 41 Communication Unit 42 RAM 43 NVM 44 CPU NW Network S Digital Key Issuance System

Claims

1. A digital key issuance method executed by a control object, a communication device separated from the control object and capable of communicating with the control object, and a plurality of electronic information storage media separated from the control object and the communication device and capable of communicating with the communication device and portable by a user, comprising: performing a first authentication process between a first electronic information storage medium that stores a digital key necessary for controlling the control object among the plurality of electronic information storage media and the communication device; performing a second authentication process between a second electronic information storage medium that does not store the digital key among the plurality of electronic information storage media and the communication device; the communication device obtains a first certificate of the digital key from the first electronic information storage medium authenticated by the first authentication process, extracts data for generating the digital key from the first certificate, and transmits the data to the second electronic information storage medium authenticated by the second authentication process; the second electronic information storage medium receives the data from the communication device, generates and stores the digital key based on the data, and transmits a second certificate of the digital key to the communication device; the communication device receives the second certificate of the digital key from the second electronic information storage medium and transmits the public key included in the second certificate to the first electronic information storage medium; the first electronic information storage medium receives the public key included in the second certificate from the communication device, generates a third certificate by signing the public key included in the second certificate with a first private key pre-stored in the first electronic information storage medium or a private key paired with the public key included in the digital key of the first electronic information storage medium, and transmits the third certificate to the communication device; the communication device transmits the third certificate to the control object; A digital key issuance method characterized by including the above steps.

2. A computer included in a communication device that is separated from a control object and capable of communicating with the control object, and is separated from a plurality of electronic information storage media portable by a user and capable of communicating with the plurality of electronic information storage media First authentication means for performing first authentication processing with a first electronic information storage medium that stores digital keys necessary for controlling the controlled object among the plurality of electronic information storage media; Second authentication means for performing second authentication processing with a second electronic information storage medium that does not store the digital keys among the plurality of electronic information storage media; First receiving means for receiving a first certificate of the digital key from the first electronic information storage medium authenticated by the first authentication processing; Extracting means for extracting data for generating the digital key from the first certificate of the digital key received by the first receiving means; First transmitting means for transmitting the data extracted by the extracting means to the second electronic information storage medium authenticated by the second authentication processing; Second receiving means for receiving, from the second electronic information storage medium, a second certificate of the digital key generated based on the data and stored in the second electronic information storage medium; Second transmitting means for transmitting the public key included in the second certificate received by the second receiving means to the first electronic information storage medium; Third receiving means for receiving, from the first electronic information storage medium, a third certificate generated by signing the public key included in the second certificate with a first secret key stored in the first electronic information storage medium in advance or a secret key that forms a pair with the public key included in the digital key of the first electronic information storage medium; A program characterized by causing the third transmitting means to function as third transmitting means for transmitting the third certificate received by the third receiving means to the controlled object.

3. The second receiving means receives, from the second electronic information storage medium, the second certificate signed with a second secret key stored in the second electronic information storage medium in advance and a fourth certificate including a public key that forms a pair with the second secret key, The program further causes the computer to function as verification means for verifying the signature of the second certificate with the public key included in the fourth certificate received by the second receiving means, The program according to claim 2, wherein the second transmitting means transmits the public key included in the second certificate to the first electronic information storage medium when the verification by the verification means is successful.

4. The computer is Acquisition means for acquiring authentication information of an operator who operates the communication device; Further function as third authentication means for performing authentication processing for the operator based on the authentication information, The program according to claim 2 or 3, characterized in that the first authentication process and the second authentication process are performed when the operator is authenticated by the third authentication means.

Images