KEY GENERATION MANAGEMENT DEVICE AND SIGNATURE VERIFICATION SYSTEM

Abstract

One task is to enable the specification of an in-vehicle electronic device, which is a signer, from a digital signature in a case where the authenticity of the digital signature cannot be verified, while simultaneously protecting privacy. To this end, a key generation and management device 11 generates and manages a signature key that is used to generate a signature to be added to vehicle data transmitted by an in-vehicle electronic device 21.The key generation management device 11 comprises a key generation unit 102, which generates a plurality of signature keys with different values ​​and a verification key corresponding to the plurality of signature keys using a group signature scheme; a communication unit 101, which receives the signature generated by the vehicle's in-vehicle electronic device 21 using the signature key and subjects it to processing to verify the authenticity of the signature using the verification key; and a signer verification processing unit 103, which performs signer verification processing to specify that the vehicle's in-vehicle electronic device 21 corresponds to the signer that generated the signature on the signature received by the communication unit 101.

Description

Technical field

[0001] The present invention relates to a key generation management device and a signature verification system. State of the art

[0002] A vehicle, such as a motor vehicle, contains a multitude of in-vehicle electronic devices known as Electrical Control Units (ECUs) that perform functions such as engine control, brake control, and safety control. These functions are implemented by in-vehicle software installed on the ECUs. In recent years, to implement features such as automated driving and driver assistance systems, these in-vehicle electronic devices have been interconnected via an in-vehicle network, allowing them to cooperate with each other and also connecting to a server outside the vehicle.A vehicle equipped with such a network connectivity function is referred to as a connected vehicle and transmits vehicle data, such as location information, driving history, and vehicle behavior data, from an in-vehicle electronic device to a server outside the vehicle. The server that receives the vehicle data then analyzes it and transmits the analysis result, in the form of a driving suggestion, back to the in-vehicle electronic device. It is expected that such services, such as automated driving or driver assistance systems, will become increasingly widespread in the future via such a network.

[0003] Since vehicles are also used as a means of transport across regions or countries, it is desirable that the aforementioned service can be used continuously even after crossing borders. To implement the service over such a network, it is crucial to ensure that the vehicle data corresponds to authentic data transmitted by an authorized vehicle; that is, that the vehicle data has not been falsified. To guarantee the authenticity of the vehicle data, it is typically augmented with a digital signature and transmitted to a server of a service provider who provides and manages the service. The service provider then verifies the digital signature added to the vehicle data.

[0004] PTL 1 is known as a technique for adding a digital signature to vehicle data and verifying the signature. PTL 1 describes a method in which a signature key used to add a digital signature is identical in all vehicles, and a method in which a vehicle identifier is used in combination with the method. List of literature on patent literature

[0005] PTL 1: JP 2020-201807 A Summary of the invention: Technical problem

[0006] Because a generic digital signature is uniquely associated with a signer, who is the entity that created the digital signature, a service provider performing signature verification collects information that can identify the signer. Therefore, a generic digital signature presents such a privacy issue that it allows a service provider to identify an individual who is a source of vehicle data transmission.

[0007] Furthermore, the method described in PTL 1 for using the same signature key in all vehicles makes it difficult to specify an in-vehicle electronic device based on the digital signature if the authenticity of the digital signature cannot be verified. Consequently, the method described in PTL 1 for using the same signature key in all vehicles is difficult to manage in the event of anomalies where the authenticity of the digital signature cannot be verified. Moreover, the method described in PTL 1 for using the vehicle identifier also presents the privacy issue described above, requiring the service provider to take separate measures to comply with laws and regulations regarding the handling of personal information.

[0008] The present invention was made accordingly with regard to the above description, and an object of the present invention is to enable the specification of an in-vehicle electronic device, which is a signer, based on a digital signature in a case where the authenticity of the digital signature cannot be verified, while simultaneously protecting privacy. Solution to the problem

[0009] To solve the problem described above, a key generation management device of the present invention is provided as a key generation management device that generates and manages a signature key which is used to generate a signature to be added to vehicle data that is transmitted from an in-vehicle electronic device to the outside of a vehicle, wherein the key generation management device comprises: a key generation unit that generates a plurality of signature keys with different values ​​and a verification key corresponding to the plurality of signature keys using a group signature scheme;a communication unit that receives the signature generated by the vehicle's electronic device using the signature key and has been subjected to signature verification processing to verify the authenticity of the signature using the verification key; and a signer verification processing unit that performs signer verification processing to specify that the vehicle's electronic device corresponds to a signer that generated the signature on the signature received from the communication unit. Advantageous effects of the invention

[0010] According to the present invention, it is possible to specify an in-vehicle electronic device, which is a signer, based on a digital signature in a case where the authenticity of the digital signature cannot be verified, while simultaneously protecting privacy.

[0011] Problems, configurations and effects other than those described above are further clarified by the following description of the embodiment. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a diagram illustrating a configuration of a signature verification system of the present embodiment. [ Fig. 2] Fig. 2 is a diagram showing a hardware configuration of each in Fig. 1 illustrated vehicle. [ Fig. 3] Fig. 3 is a diagram showing a hardware configuration of a system in Fig. 1 illustrated vehicle-internal electronic device illustrated. [ Fig. 4] Fig. Figure 4 is a diagram showing the hardware configuration of each of a key generation management device and one in Fig. 1 illustrated signature verification device illustrated. [ Fig. 5] Fig. 5 is a flowchart that represents one of the ones in Fig. 1. Processing performed by the signature verification system is illustrated. [ Fig. 6] Fig. 6 is a flowchart that details the key generation processing from the one in Fig. Step 5 illustrated S501. [ Fig. 7] Fig. 7 is a flowchart that details the key distribution processing from the one in Fig. Step 5 illustrated S502. [ Fig. 8] Fig. 8 is a flowchart that details the signature generation processing of the section in Fig. Step 5 illustrated in S503. [ Fig. 9] Fig. 9 is a flowchart that details the signature verification processing from the one in Fig. Step 5 is illustrated in S504. [ Fig. 10] Fig. 10 is a flowchart that details the signature verification processing from the one in Fig. Step 5 illustrated in S505. [ Fig. 11] Fig. Figure 11 is a diagram illustrating an example of a user screen that would be displayed to a user by the in Fig. 1 illustrated key generation management device is shown. [ Fig. 12] Fig. Figure 12 is a diagram for describing vehicle information and key generation-related information contained in the Fig. 1 illustrated key generation management device are stored. [ Fig. 13] Fig. Figure 13 is a diagram describing a determination processing in the key generation management device based on a relationship between a result of the signature verification processing and a result of the signer verification processing. Description of the embodiments

[0012] Embodiments of the present invention are described below with reference to the drawings. Configurations or functions designated by the same reference numerals in the respective embodiments represent similar configurations or functions in the respective embodiments, and a description of the latter is usually omitted unless otherwise stated.

[0013] Fig. Figure 1 is a diagram illustrating a configuration of a signature verification system 1 of the present embodiment.

[0014] The signature verification system 1 includes a key generation management center 10, vehicles 201 to 20 N , a signature verification center 30 and a network 40.

[0015] The key generation management center 10 comprises a key generation management device 11, which is a computer that generates and distributes a signature key and a verification key and verifies a signer.

[0016] The number of vehicles is 201 to 20 Nis not limited to a specific number. In the present embodiment, in cases where it is not necessary to distinguish each of the vehicles 201 to 20N separately, indices of the vehicles 201 to 20N are omitted, and the vehicles 201 to 20N are simply referred to as vehicle 20. Vehicle 20 further comprises an in-vehicle electronic device 21 that generates a digital signature (hereinafter also referred to as the "signature") and adds the digital signature to vehicle data.

[0017] The signature verification center 30 also represents part of a service provider that provides a service, such as automated driving or driver assistance, to the vehicle 20 via the network 40. For this purpose, the signature verification center 30 includes a signature verification device 31, which is a computer that performs signature verification and requests signer verification.

[0018] The key generation management device 11 also generates and manages the signature key used to create the signature to be added to the vehicle data transmitted from the vehicle's internal electronic device 21 to the vehicle's exterior 20. The key generation management device 11 transmits each of a plurality of generated signature keys to the vehicle's internal electronic device 21 and the generated verification key to the signature verification device 31. Furthermore, the key generation management device 11 performs signer verification processing on the signature transmitted by the signature verification device 31 to specify that the vehicle's internal electronic device 21 corresponds to the signer that created the signature.

[0019] The key generation management device 11 further comprises a communication unit 101, which communicates with the network 40; a key generation unit 102, which generates the signature key and the verification key; a signer verification processing unit 103, which performs the signer verification processing; and a notification unit 104, which notifies a user of a result of the signer verification processing. The key generation management device 11 further comprises a parameter storage unit 105, which stores a parameter used to generate the signature key and the verification key by the key generation unit 102; and a key storage unit 106, which stores the verification key generated by the key generation unit 102.Furthermore, the key generation management device 11 includes a signature storage unit 107, which stores the signature transmitted by the signature verification device 31, and a vehicle information storage unit 108, which stores vehicle information including the signature key generated by the key generation unit 102 and identification information of the vehicle's internal electronic device 21, and which specifies a transmission destination for the signature key.

[0020] The key generation unit 102 generates a multitude of signature keys, each with a different value, and a verification key corresponding to the multitude of signature keys, using a group signature scheme. Furthermore, the key generation unit 102 generates the multitude of signature keys using a multitude of different parameters.

[0021] The communication unit 101 receives from the signature verification device 31 the signature that was generated by the vehicle's internal electronic device 21 using the signature key and has been subjected to signature verification processing to verify the signature's authenticity using the verification key. For example, the communication unit 101 receives from the signature verification device 31 a signature whose authenticity has not been verified by the signature verification processing in the signature verification device 31.

[0022] The signer verification processing unit 103 performs signer verification processing on the signature received from the communication unit 101 to specify that the vehicle's internal electronic device 21 corresponds to the signer who generated the signature. In this signer verification processing, the signer verification processing unit 103 specifies which of the numerous parameters is used to generate the signature key that was used to create the signature received from the communication unit 101, thereby specifying that the vehicle's internal electronic device 21 corresponds to the signer.

[0023] In a case where the vehicle's internal electronic device 21 corresponding to the signer could not be specified by the signer verification processing, the signer verification processing unit 103 determines that there is a possibility that the vehicle data to which the signature received from the communication unit 101 was added has been falsified by a cyberattack. Furthermore, in a case where the vehicle's internal electronic device 21 corresponding to the signer has been specified by the signer verification processing, the signer verification processing unit 103 determines that there is a possibility that the vehicle data to which the signature received from the communication unit 101 was added contains a communication error.

[0024] Notification Unit 104 also displays the result of the signer verification processing on a screen to inform the user of the outcome. Furthermore, if it is determined that the vehicle data to which the signature received from Communication Unit 101 has been added may have been falsified by a cyberattack, Notification Unit 104 sends a notification of the determination result to an external field of Key Generation Management Device 11. For example, Notification Unit 104 notifies Key Generation Management Center 10, a security management department of the service provider, or the like of the determination result.Furthermore, if it is determined that the vehicle data to which the signature received from the communication unit 101 has been added may contain a communication error, the notification unit 104 sends a notification of the determination result to an external field of the key generation management device 11. For example, the notification unit 104 notifies a department responsible for the service provider that manages a communication status of vehicle 20, the corresponding vehicle 20, or the like, of the determination result.

[0025] The communication unit 101 can also receive the signature from the signature verification device 31, the authenticity of which has been verified by the signature verification processing in the signature verification device 31. In this case, the signer verification processing unit 103 can specify the vehicle-internal electronic device 21 corresponding to the signer through the signer verification processing.

[0026] The vehicle-internal electronic device 21 generates the signature using the signature key transmitted by the key generation management device 11, adds the signature to the vehicle data and transmits the signature added to the vehicle data to the signature verification device 31.

[0027] The vehicle-internal electronic device 21 further comprises a communication unit 201, which communicates with the network 40; a signature unit 202, which generates the signature using the signature key stored in a vehicle-internal storage unit 204 and adds the signature to the vehicle data; and a vehicle data generation unit 203, which generates the vehicle data. The vehicle-internal electronic device 21 also comprises the vehicle-internal storage unit 204, which stores the signature key transmitted by the key generation management device 11, and a vehicle data storage unit 205, which stores the vehicle data generated by the vehicle data generation unit 203.

[0028] The signature verification device 31 is further connected to the vehicle's internal electronic device 21 and the key generation and management device 11 via the network 40 and performs the signature verification processing to verify the authenticity of the signature. In particular, the signature verification device 31 performs the signature verification processing on the signature transmitted by the vehicle's internal electronic device 21 using the verification key transmitted by the key generation and management device 11. The signature verification device 31 also determines whether or not the execution of the signer verification processing is necessary.For this purpose, the signature verification device 31 transmits the signature for which it is to be determined that the execution of the signer verification processing is necessary to the key generation management device 11 and requests the key generation management device 11 to perform a signer verification.

[0029] The signature verification device 31 also includes a communication unit 301, which communicates with the network 40; a signature verification unit 302, which performs signature verification processing on the signature transmitted by the vehicle's internal electronic device 21; and a signer verification request unit 303, which requests the key generation management device 11 to perform signer verification. Furthermore, the signature verification device 31 includes a verification key storage unit 304, which stores the verification key transmitted by the key generation management device 11; a signature storage unit 305, which stores the signature transmitted by the vehicle's internal electronic device 21; and a verification result storage unit 306, which stores a result of the signature verification processing.

[0030] Fig. 2 is a diagram showing a hardware configuration of each of the in Fig. 1 illustrated vehicles 201 to 20 N illustrated.

[0031] In the vehicle 20, one or more vehicle-internal electronic devices 211 to 21 are included. M interconnected by an in-vehicle network 22. The number of in-vehicle electronic devices 211 to 21 M This number can be any number and is not limited to a specific number. Among the vehicle's internal electronic devices 211 to 21 M It can also be a master device that controls other in-vehicle electronic devices under in-vehicle electronic devices 211 to 21. M controls a slave device that receives an instruction from other in-vehicle electronic devices under in-vehicle electronic devices 211 to 21 Mreceives, a proxy device or a gateway device that enables communication between two or more other in-vehicle electronic devices, including in-vehicle electronic devices 211 to 21 M interposed and converted, and the like. In the present embodiment, in a case where it is not necessary to have each of the vehicle's internal electronic devices 211 to 21 M to be distinguished in particular, indices of the vehicle's internal electronic devices 211 to 21 M omitted, and the vehicle's internal electronic devices 211 to 21 Mreferred to simply as the vehicle's internal electronic device 21. The vehicle's internal network 22 is, for example, a Control Area Network (CAN) or an Ethernet network, but is not limited to these. Furthermore, a multitude of vehicle's internal networks 22 may be present in the vehicle 20.

[0032] Fig. 3 is a diagram showing a hardware configuration of the Fig. 1 illustrated vehicle-internal electronic device 21 illustrated.

[0033] The vehicle-internal electronic device 21 has a configuration in which a communication device 23, an input / output device 24, a central processing unit (CPU) 25, a memory 26, a storage device 27, and a secure device 28 are interconnected by an internal signal line 29, such as a bus. The secure device 28 can, for example, be a device that includes a memory area that is physically non-rewritable, a memory area that can only be rewritten once, or a memory area in which access control, such as authentication of a user or a process, is configured.For example, the secure device 28 may be a device that stores a key for encryption or decryption, a digital signature for verifying software or the like, an electronic certificate, a setting value, a verification value, identification information or the like, and performs encryption / decryption processing, verification processing, signature addition processing or the like, such as a hardware security module (HSM). The communication device 23 is also connected to the network 40 and transmits and receives data.

[0034] Fig. Figure 4 is a diagram showing a hardware configuration of each of the key generation management device 11 and the one in Fig. 1 illustrated signature verification device 31 illustrated.

[0035] The hardware configurations of the key generation management device 11 and the hardware configuration of the signature verification device 31 can be the same. Furthermore, the key generation management device 11 and the signature verification device 31 have a configuration in which a communication device 12, an input / output device 13, a CPU 14, a memory 15, and a storage device 16 are interconnected via an internal signal line 17. The input / output device 13 is, for example, a keyboard, a mouse, a touchscreen, a numeric keypad, a scanner, a microphone, a sensor, a display, a printer, or a speaker. The communication device 12 is also connected to the network 40 and transmits and receives data.

[0036] Fig. 5 is a flowchart that represents one of the ones in Fig. 1. Illustrated signature verification system 1. Illustrated processing.

[0037] The in Fig. The flowchart illustrated in Figure 5 is executed by loading programs stored in the respective memory devices 16 and 27 of the key generation management device 11, the signature verification device 31, and the vehicle's internal electronic device 21 into memory locations 15 and 26, and executing them by the CPUs 14 and 25. The programs stored in the respective memory devices 16 and 27 can be introduced into these memory devices at suitable times via an external recording medium or a communication medium (a network or a transmission wave propagating through the network).

[0038] For this purpose, the key generation management device 11 first performs a key generation process to generate the signature key and the verification key using the group signature scheme (S501). Subsequently, the key generation management device 11, the vehicle-internal electronic device 21, and the signature verification device 31 perform a key distribution process to distribute the generated signature key and verification key (S502). Subsequently, the vehicle-internal electronic device 21 and the signature verification device 31 perform a signature generation process to generate the signature to be added to the vehicle data using the signature key (S503).Subsequently, the key generation management device 11 and the signature verification device 31 perform the signature verification processing to verify the authenticity of the signature using the verification key (S504). Subsequently, the key generation management device 11 performs the signer verification processing to specify that the vehicle-internal electronic device 21 corresponds to the signer who generated the signature (S505).

[0039] Fig. 6 is a flowchart that details the key generation processing from the one in Fig. Step 5 illustrated in S501.

[0040] First, the key generation management device 11 starts the key generation processing (S601). Then, the key generation management device 11 determines whether a key generation instruction has been received or not (S602). For this purpose, the key generation management device 11 can receive the key generation instruction entered by the user operating the input / output device 13, such as a touchscreen display, a keyboard, or a mouse. An example of a user screen on which the user can enter the key generation instruction is described below with reference to Fig. 11 described. As another example, the key generation management device 11 can also receive key generation instructions entered via an external storage medium, such as a Digital Versatile Disc (DVD) or a Universal Serial Bus (USB) storage device, or it can receive key generation instructions entered via a network from another device (not illustrated) in the key generation management center 10 or department.

[0041] In a case where it is determined that the key generation instruction was not received, the key generation management device 11 returns to processing S602. Conversely, in a case where it is determined that the key generation instruction was received, the key generation management device 11 captures key generation-related information contained in the key generation instruction (S603). This key generation information includes information regarding the transmission destination of the verification key, the number of signature keys generated, and the parameter used to generate the signature key and the verification key. The information regarding the transmission destination of the verification key also includes, for example, a name, address, identifier, and the like of the transmission destination of the verification key.The parameter can also be a random number, a starting value, a fixed value, an algorithm name, a variable value, a public value, a secret value, or something similar. However, the key generation-related information is not limited to the above and can also be a combination of them.

[0042] Next, the key generation and management device 11 generates the signature keys and the verification key (S604). The key generation and management device 11 generates the multitude of signature keys with different values ​​and the verification key corresponding to the multitude of signature keys using the group signature scheme. The group signature scheme is a type of public key encryption where the verification key and the signature key have different values. Furthermore, the group signature scheme is an encryption scheme based, for example, on a pairing calculation that computes a mapping of a set of two points on an elliptic curve to a finite array.Furthermore, the group signature scheme is an encryption scheme in which there is a relationship between the verification key and the signature keys 1 to n. In the present embodiment, the key generation management device 11 generates the plurality of signature keys during the processing of step S604 using the plurality of parameters (corresponding to the number of signature keys generated) that were acquired during the processing of S603, and generates a verification key.

[0043] The key generation management device 11 then stores the parameters used to generate the signature keys and the verification key during the processing of step S604 in the parameter storage unit 105 (S605). Additionally, during the processing of step S605, the key generation management device 11 can store key generation-related information other than the parameters in the parameter storage unit 105. The key generation management device 11 then stores the signature keys generated during the processing of step S604 in the vehicle information storage unit 108 (S606). Furthermore, the key generation management device 11 stores the verification key generated during the processing of step S604 in the key storage unit 106 (S607).The key generation management device 11 then terminates the key generation processing (S608). The processing steps S605, S606, and S607 can be performed in any order.

[0044] Fig. 7 is a flowchart that details the key distribution processing from the one in Fig. Step 5 illustrated S502.

[0045] First, the key generation management device 11 starts the key distribution processing (S701). For this purpose, the key generation management device 11 transmits the signature keys (A701 to A703) to the vehicle's internal electronic devices 21 to which the generated signature keys are assigned, as the transmission destinations of the signature keys specified in the vehicle information stored in the vehicle information storage unit 108, via network 40. In addition, the key generation management device 11 transmits the verification key (A704) stored in the key storage unit 106 to the transmission destination of the verification key contained in the key generation-related information via network 40.

[0046] Network 40 can be a wireless communication network, such as Long Term Evolution (LTE), 4G, 5G, Wireless Fidelity (Wi-Fi), or Bluetooth, or a wired local area network (LAN), or similar. Furthermore, a communication path within network 40 can be encrypted, and one-way or mutual authentication can be performed using a communication protocol such as IPsec, Secure Socket Layer (SSL), Transport Layer Security (TLS), or Secure Shell (SSH).

[0047] Next, the respective in-vehicle electronic devices 21 of vehicles 201 to 20 will record NThe signature keys (A701 to A703) (S702 to S704). The communication units 201 of the respective vehicle-internal electronic devices 21 receive the signature keys (A701 to A703) from the network 40. Furthermore, the vehicle-internal storage units 204 of the respective vehicle-internal electronic devices 21 store the signature keys (A701 to A703) received by the communication units 201 of the respective vehicle-internal electronic devices 21. Subsequently, the signature verification device 31 captures the verification key (A704) (S705). The communication unit 301 of the signature verification device 31 also receives the verification key (A704) from the network 40. Additionally, the verification key storage unit 304 of the signature verification device 31 stores the verification key (A704) received by the communication unit 301.Subsequently, the key generation management device 11, the vehicle-internal electronic device 21, and the signature verification device 31 complete the key distribution processing (S706). The processing steps S702 to S705 can also be performed in any order, simultaneously or in parallel.

[0048] Fig. 8 is a flowchart that details the signature generation processing of the section in Fig. Step 5 illustrated in S503.

[0049] First, the vehicle's internal electronic device 21 initiates signature generation processing (S801). Signature generation processing can be initiated, in particular, when vehicle data or a predetermined number of vehicle data elements are generated. Alternatively, signature generation processing can also be initiated when the available capacity of the vehicle data storage unit 205 falls below a predetermined value, or when a predetermined time has elapsed. Alternatively, signature generation processing can also be initiated when a network bandwidth 40 is available, the vehicle 20 stops, or when the processing load of the vehicle's internal electronic device 21 falls below a predetermined value. However, the point in time at which signature generation processing is initiated is not limited to the above and can also be a combination thereof.

[0050] Next, the vehicle's internal electronic device 21 retrieves the vehicle data to be signed from the vehicle data storage unit 205 (S802). The vehicle's internal electronic device 21 then retrieves the signature key from the vehicle's internal storage unit 204 (S803). The vehicle's internal electronic device 21 then generates the signature using the signature key in the signature unit 202 and adds the generated signature to the vehicle data (S804). The vehicle's internal electronic device 21 then transmits the signature added to the vehicle data (A801) via network 40 to the signature verification device 31.

[0051] The signature verification device 31 then stores the signature (A801) transmitted by the vehicle's internal electronic device 21 in the signature storage unit 305 (S805). Subsequently, the signature verification device 31 transmits a receipt notification (A802) to inform the vehicle's internal electronic device 21 via the network 40 that the signature (A801) has been received.

[0052] The vehicle's internal electronic device 21 then determines whether the receipt notification (A802) has been received or not (S806). If it is determined that the receipt notification (A802) has been received, the vehicle's internal electronic device 21 then terminates the signature generation processing (S808). Conversely, if it is determined that the receipt notification (A802) has not been received, the vehicle's internal electronic device 21 determines whether a predetermined time has elapsed since the transmission of the signature (A801) or not (S807). If it is determined that the predetermined time has elapsed, the vehicle's internal electronic device 21 then returns to the transmission processing for the signature (A801).On the other hand, if it is determined that the predetermined time has not elapsed, the vehicle's internal electronic device 21 returns to processing step S806. The processing steps S802 and S803 can also be carried out in any order.

[0053] Fig. 9 is a flowchart that details the signature verification processing from the one in Fig. Step 5 is illustrated in S504.

[0054] First, the signature verification device 31 starts the signature verification processing (S901). Signature verification processing can also be started when a predetermined time has elapsed, when a predetermined number of signatures are stored in the signature storage unit 305, or when the signature is received from the vehicle 20. However, the time at which signature verification processing is started is not limited to the above and can also be a combination of them.

[0055] The signature verification device 31 then retrieves the signature from the signature storage unit 305 (S902). Next, the signature verification device 31 retrieves the verification key from the verification key storage unit 304 (S903). The signature verification device 31 then verifies the authenticity of the signature using the verification key (S904). Finally, the signature verification device 31 determines whether or not the execution of the signer verification process is necessary (S905).

[0056] As an example of a case where the execution of signer verification processing is necessary, there may be a situation where the authenticity of the signature cannot be verified during S904 processing, such as a case where a signature verification result indicates a mismatch. In this case, the vehicle data to which the signature, whose authenticity has not been verified, was added is used for notification and handling as a security measure.The notification and handling for a security measure includes, for example, the specification of the vehicle's internal electronic device 21 that has been subjected to a cyberattack, the analysis of a tactic, technique or procedure used in the attack, the notification of information, including the specification of another vehicle's internal electronic device 21 that may be subjected to the same attack, the planning of a specific measure and the like.

[0057] Furthermore, in a case where the authenticity of the signature was not verified during S904 processing, there is a possibility that the vehicle data to which the unverified signature was added contains a communication error. In this case, the vehicle data is used for notification and handling to confirm the communication status of vehicle 20 and for notification and handling as a security measure.

[0058] Furthermore, another example of a case where the execution of the signer verification process is necessary is a case where the authenticity of the signature was verified during S904 processing. In this case, the vehicle data to which the verified signature has been added is collected in the service provider's server after the vehicle's internal electronic device 21 has been specified. This data is used to manage the vehicle's state, which is necessary for the service provider to deliver the corresponding service. The collected vehicle data is stored in the server as a log of the vehicle 20 and used to detect failures of any component of the vehicle 20, estimate the wear or failure rate of each component, predict component failures, and so on.

[0059] Furthermore, the signature verification device 31 can determine that the execution of the signer verification processing is necessary, regardless of the result of the signature verification processing, in order to use the vehicle data for the security measure and / or the confirmation of the communication status of the vehicle 20 and / or the management of the vehicle 20's condition. However, a case in which the execution of the signer verification processing is necessary is not limited to the above and can also be a combination thereof.

[0060] In a case where, during the processing of step S905, it is determined that the execution of signer verification processing is necessary, the signature verification device 31 transmits the signature (A901) that has undergone processing by S904 to the key generation management device 11. The key generation management device 11 then stores the signature received from the communication unit 101 in the signature storage unit 107 (S906). Additionally, the key generation management device 11 transmits a receipt notification (A902) to inform the signature verification device 31 via network 40 that the signature (A901) has been received.

[0061] The signature verification device 31 then determines whether all signatures stored in the signature storage unit 305 have been verified (S907). The signature verification device 31 continues with the processing of step S907 even if the processing of step S905 determines that the execution of the signer verification process is not necessary. Examples of a procedure for performing the processing of step S907 include a procedure for deleting the signature for which signature verification has been completed from the signature storage unit 305 and for determining whether the number of signatures stored in the signature storage unit 305 has become zero.Further examples of the procedure for performing the processing of step S907 include a procedure for adding a flag to the signature stored in signature storage unit 305 when signature verification is complete, and for determining whether the number of signatures to which no flag has been added has become zero. However, the procedure for performing the processing of step S907 is not limited to the above and may also be a combination thereof.

[0062] In a case where it is determined that all signatures have been verified, the signature verification device 31 also terminates the signature verification processing (S908). Conversely, in a case where it is determined that not all signatures have been verified, the signature verification device 31 returns to processing step S902. The processing steps of S902 and S903 can also be performed in any order.

[0063] Fig. 10 is a flowchart that details the signature verification processing from the one in Fig. Step 5 illustrated in S505.

[0064] First, the key generation management device 11 starts the signer verification processing (S1001). Signer verification processing can also be started when a signature verification processing start instruction is received (entered by a user operator), when a predetermined time has elapsed, or when a predetermined number of signatures are stored in the signature storage unit 107. However, the timing of signer verification processing is not limited to the above and can also be a combination of these.

[0065] The key generation management device 11 then retrieves the signature from the signature storage unit 107 (S1002). Next, the key generation management device 11 retrieves the parameter from the parameter storage unit 105 (S1003). Furthermore, the key generation management device 11 calculates a verification value using the parameter (S1004). The verification value specifies the signature key contained in the signature. For example, the key generation-related information acquired during the processing of step S603 includes the number of verification keys to be generated in order to create a large number of verification keys.In this case, the key generation management device 11 calculates the verification values ​​as many times as the number of generated verification keys using the parameter contained in the key generation-related information.

[0066] The key generation management device 11 then determines whether the signature captured during the processing of step S1002 includes the verification value (any one of the multiple verification values ​​in a case where the multiple verification values ​​are calculated) calculated during the processing of step S1004 (S1005). If it is determined that the calculated verification value is included in the signature captured during the processing of step S1002, the key generation management device 11 then generates the signature key using the parameter captured during the processing of step S1003 (S1006).The processing of step S1006 can be carried out in a similar manner to the processing of step S604, or only a portion of the processing of step S604 can be performed, in which the verification value contained in the signature is used. However, the processing of step S1006 is also not limited to the above.

[0067] Next, the key generation management device 11 searches the vehicle information storage unit 108 using the signature key generated during the processing of step S1006 as the search key (S1007). Subsequently, the key generation management device 11 specifies a signature key that matches the signature key generated during the processing of step S1006, based on a search result. The key generation management device 11 then acquires the identification information of the vehicle's internal electronic device 21 associated with the specified signature key (S1008). As a result, the key generation management device 11 can specify the vehicle's internal electronic device 21 that corresponds to the signer who generated the signature acquired during the processing of step S1002.

[0068] Next, the key generation management device 11 performs a notification (S1009) of the identification information of the vehicle's internal electronic device 21, which was captured by the notification unit 104 during the processing of step S1008. Examples of a method for performing the processing of step S1009 include, in particular, a method for displaying the identification information of the vehicle's internal electronic device 21 on the display of the input / output device 13, although the method for performing the processing of step S1009 need not be limited to the above.

[0069] Furthermore, in a case where, during the processing of step S1005, it is determined that the calculated verification value is not included in the signature captured during the processing of step S1002, the key generation management device 11 determines whether the verification value was calculated using all parameters stored in the parameter storage unit 105 or not (S1010). Examples of a method for performing the processing of step S1010 include, in particular, a method for calculating the verification value using the parameters stored in the parameter storage unit 105 in the order of storage and for determining whether the verification value was calculated using the last stored parameter or not, although the method for performing the processing of step S1010 need not be limited to the above.

[0070] In a case where it is determined that the verification value was not calculated using all parameters, the key generation management device 11 returns to processing step S1003. Conversely, in a case where it is determined that the verification value was calculated using all parameters, the key generation management device 11 continues processing step S1009. In this case, the key generation management device 11 issues a notification that the vehicle's internal electronic device 21, corresponding to the signer, was not found by the notification unit 104 (S1009).Examples of notification content during the processing of step S1009 include, in particular, content indicating that the signature key contained in the signature captured during the processing of step S1002 is not a signature key generated by the key generation management device 11, or content indicating that there is a possibility that the vehicle data to which the signature captured during the processing of step S1002 was added has been falsified. However, the notification content within the processing of step S1009 is not limited to the above and may also be a combination thereof.

[0071] The key generation management device 11 then determines whether the signers of all signatures have been verified (S1011). Examples of a method for performing the processing of step S1011 include a method for adding a flag to the signature stored in the signature storage unit 107 when the signer verification is complete and for determining whether the number of signatures to which no flag has been added has become zero. Further examples of the method for performing the processing of step S1011 also include a method for setting the status of the signature stored in the signature storage unit 107 to a verified state when the signer verification is complete and for determining whether the status of all signatures is set to the verified state.However, the procedure for performing the processing of step S1011 is not limited to the above and can also be a combination of them.

[0072] In a case where it is determined that the signers of all signatures have been verified, the key generation management device 11 also terminates the signer verification processing (S1012). Conversely, in a case where it is determined that the signers of all signatures have not been verified, the key generation management device 11 returns to processing step S1002.

[0073] Fig. 11 is a diagram illustrating an example of a user screen 1100, which is displayed to the user by the in Fig. 1 illustrated key generation management device 11 is shown.

[0074] The user screen 1100 includes a key generation processing screen 1101 and a signer verification processing screen 1109.

[0075] The key generation processing screen 1101 displays a verification key transfer target field 1102, a generated signature key number field 1103, a parameter field 1104, a status field 1105, a key generation start button 1106, a verification key transfer button 1107 and a signature key transfer button 1108.

[0076] For example, a provider name, address, email address, telephone number, or similar information, which serves as the transmission destination for the verification key, is entered into and displayed in the verification key transmission destination field 1102. However, the content entered into and displayed in the verification key transmission destination field 1102 is not limited to the above. The number of generated signature keys is also entered into and displayed in the generated signature key number field 1103. Furthermore, a random number, a starting value, a fixed value, an algorithm name, a variable value, a public value, a secret value, or similar information, which serves as a parameter used to generate the signature key and the verification key, is entered into and displayed in the parameter field 1104.However, the content entered into and displayed in parameter field 1104 is not limited to the above and can also represent a combination thereof. Additionally, a key generation status is displayed in status field 1105. Examples of key generation statuses displayed in status field 1105 include a new entry, an ongoing key generation process, a generated key, a transmitted signature key, or a transmitted verification key. The key generation status is not limited to the above and can also represent a combination thereof.

[0077] The key generation start button 1106 is a button for receiving a press command from the user and starting the key generation process. The verification key transmission button 1107 is a button for receiving a press command from the user and transmitting the verification key to the verification key transmission destination. The signature key transmission button 1108 is a button for receiving a press command from the user and transmitting the signature key.

[0078] The following are displayed on the signer verification processing screen 1109: a user selection field 1110, a signature field 1111, a date and time of receipt field 1112, a status field 1113, a verification result field 1114, a signer verification start button 1115, a verification result notification button 1116 and an update button 1117.

[0079] The user selection field 1110 includes, in particular, a verification field where the user enters a verification marker to select the signature for which signer verification processing is to be performed, and a notification field where the user enters a verification marker to select the signature for which a notification about the result of the signer verification processing is to be sent. The signature received by the signature verification device 31 is displayed in the signature field 1111. The date and time field 1112 also displays the date and time on which the signature was received by the signature verification device 31. The display format of the date and time field 1112 is defined, for example, as ISO 8601, but is not limited to the above. The status field 1113 also displays a signer verification status.Examples of the signer verification status displayed in status field 1113 include new, verified, and notified statuses. However, the signer verification status is not limited to the above and can also represent a combination of these. The verification result field 1114 also displays a result of the signer verification processing.Examples of the signer verification processing result displayed in verification result field 1114 include the identification information of the in-vehicle electronic device 21 corresponding to the signer, information indicating that the in-vehicle electronic device 21 corresponding to the signer was not found, information indicating that the signature key is not a signature key generated by the key generation management device 11, and information indicating that there is a possibility that the vehicle data has been falsified. However, the signer verification processing result displayed in verification result field 1114 is not limited to the above and may also represent a combination thereof.

[0080] The signer verification start button 1115 is a button for receiving a press command from the user and starting the signer verification processing for the signature with the verification mark entered in the verification field of the user selection field 1110. Additionally, the verification result notification button 1116 is a button for receiving a press command from the user and sending a notification about the result of the signer verification processing for the signature with the verification mark entered in the notification field of the user selection field 1110, outside of the key generation management device 11. Furthermore, the refresh button 1117 is a button for receiving a press command from the user and refreshing each element of the signer verification processing screen 1109.In a case where the signature for signer verification is newly received from the signature verification device 31, pressing the update button 1117 adds each piece of information relating to the newly received signature to the signer verification processing screen 1109. Updating each element of the signer verification processing screen 1109 can also be performed by pressing the update button 1117, automatically periodically, or by a combination of these actions.

[0081] However, each display element of the user screen 1100, as well as the arrangement of each display element, is likewise not limited to the above.

[0082] Fig. Figure 12 is a diagram for describing vehicle information 1200 and key generation-related information 1205, which is in the Fig. 1 illustrated key generation management device 11 are stored.

[0083] The vehicle information 1200 includes in particular identification information 1201 of the vehicle 20, identification information 1202 of the vehicle's internal electronic device 21, a signature key 1203, and a generation date and time 1204.

[0084] The identification information 1201 of vehicle 20, for example, is a vehicle identifier, such as a Vehicle Identification Number (VIN), but is not limited to this. The identification information 1202 of the vehicle's internal electronic device 21 is also an internal electronic device identifier, such as an Electronic Control Unit (ECU) ID, but again, it is not limited to this. The signature key 1203 represents a value of the generated signature key. Furthermore, the generation date and time 1204 are the date and time at which the signature key 1203 is generated. The format of the generation date and time 1204 is defined, for example, as IS08601, but is not limited to this.

[0085] The key generation-related information 1205 further includes a verification key transmission target 1206, a generated signature key number 1207, a parameter 1208 and a generation date and time 1209.

[0086] The verification key transmission target 1206, for example, is a provider name, address, email address, telephone number, or similar, which is the transmission target of the verification key, although it is not limited to the above. The generated signature key number 1207 is the number of signature keys generated. The parameter 1208 is a random number, a starting value, a fixed value, an algorithm name, a variable value, a public value, a secret value, or similar, which represents a parameter used to generate the signature key and the verification key; however, it is also not limited to the above and can be a combination thereof.The generation date and time 1209 refer to the date and time at which the verification key was generated. The format of the generation date and time 1209 is defined, for example, as ISO 8601, but is not limited to this.

[0087] Fig. Figure 13 is a diagram to describe a determination processing in the key generation management device 11 based on a relationship between a result of the signature verification processing and a result of the signer verification processing.

[0088] In Fig. 13 represents an "OK" result in the signature verification process, indicating that the signature's authenticity has been verified, and an "NG" result, indicating that the signature's authenticity has not been verified. Accordingly, in Fig.13 an “OK” result in the signer verification processing indicates that the vehicle-internal electronic device 21 corresponding to the signer of the signature has been specified, and an “NG” result indicates that the vehicle-internal electronic device 21 corresponding to the signer of the signature has not been specified.

[0089] In a case where the result of the signature verification processing is "OK" and the result of the signer verification processing is also "OK", the verification target signature is an authentic signature generated using the signature key of the key generation management device 11. In this case, the signer verification processing unit 103 of the key generation management device 11 determines that the vehicle data to which the signature was added is trusted, authentic vehicle data. The vehicle data to which the signature was added is then used by the service provider for vehicle health management or similar purposes.

[0090] In a case where the result of the signature verification processing is "NG" and the result of the signer verification processing is also "NG", the verification target signature is an inauthentic signature generated using a signature key that is not the signature key of the key generation management unit 11. In this case, the signer verification processing unit 103 determines that there is a possibility that the vehicle data to which the signature was added has been falsified by a cyberattack. The notification unit 104 accordingly notifies the key generation management center 10, the service provider's security management department, or the like, of the determination result. The vehicle data to which the signature was added is then used for notification and handling in a security action.

[0091] In a case where the result of the signature verification processing is "NG" and the result of the signer verification processing is "OK", the verification target signature is considered a signature generated using the signature key of the key generation management device 11, and whose authenticity has not been verified. In this case, the signer verification processing unit 103 determines that there is a possibility that the vehicle data to which the signature was added contains a communication error. The notification unit 104 accordingly notifies the department responsible for the service provider that manages the communication status of vehicle 20, the corresponding vehicle 20, or the like, of the determination result.Furthermore, the signer verification processing unit 103 can also determine that the possibility that the vehicle data to which the signature was added has been falsified cannot be ruled out. The notification unit 104 accordingly notifies the key generation management center 10, the service provider's security management department, or similar entities of the determination result. The vehicle data to which the signature was added is then used for notification and handling to confirm the communication status of the vehicle 20 and for notification and handling to implement a security measure.

[0092] A case where the result of the signature verification process is "OK" and the result of the signer verification process is "NG" is not accepted. This is because the same signature is not generated using a multitude of signature keys with different values, which is ensured by the inherent security of the group signature scheme.

[0093] As described above, the key generation management device 11 of the present embodiment is a device that generates and manages the signature key used to generate the signature to be added to the vehicle data transmitted from the vehicle's internal electronic device 21 to the outside of the vehicle 20.The key generation management device 11 comprises the key generation unit 102, which generates the plurality of signature keys with different values ​​and the verification key corresponding to the plurality of signature keys using the group signature scheme; the communication unit 101, which receives the signature generated by the vehicle's internal electronic device 21 using the signature key and subjected to signature verification processing to verify the authenticity of the signature using the verification key; and the signer verification processing unit 103, which performs signer verification processing to specify that the vehicle's internal electronic device 21 corresponds to the signer who generated the signature on the signature received from the communication unit 101.

[0094] Consequently, the key generation management device 11 can cause the service provider performing the signature verification to verify the authenticity of the signature generated by the vehicle's in-vehicle electronic device 21 without providing information that could identify the vehicle's in-vehicle electronic device 21 as the signer. Therefore, the key generation management device 11 can enable the service provider to confirm that the vehicle data is authentic vehicle data transmitted by the authorized vehicle 20 that can use a specified service, while making it impossible to identify an individual associated with a transmission source of the vehicle data.On the other hand, in a case where the authenticity of the signature cannot be verified during signature verification, the key generation management device 11 can specify the vehicle-internal electronic device 21 corresponding to the signer based on the signature. Therefore, the key generation management device 11 can specify the vehicle-internal electronic device 21 corresponding to the signer based on the digital signature in a case where the authenticity of the digital signature cannot be verified, while simultaneously protecting privacy.

[0095] Furthermore, in the key generation management device 11 of the present embodiment, the key generation unit 102 generates the plurality of signature keys using the plurality of different parameters. For the signer verification processing, the signer verification processing unit 103 specifies which of the plurality of parameters is used to generate the signature key that was used to generate the signature received by the communication unit 101, thereby specifying that the vehicle-internal electronic device 21 corresponds to the signer.

[0096] Consequently, the key generation management device 11 can reliably generate the multitude of signature keys with different values ​​and specify which of these signature keys is used to generate the signature. Therefore, the key generation management device 11 can reliably specify that the vehicle's in-vehicle electronic device 21 corresponds to the signer. Furthermore, the key generation management device 11 can thus reliably specify, based on the digital signature, that the vehicle's in-vehicle electronic device 21 corresponds to the signer in a case where the authenticity of the digital signature cannot be verified, while simultaneously protecting privacy.

[0097] Furthermore, in the key generation management device 11 of the present embodiment, the communication unit 101 receives the signature whose authenticity has not been verified by the signature verification processing. In this case, the signer verification processing unit 103 determines, in a case where the vehicle-internal electronic device 21 corresponding to the signer could not be specified by the signer verification processing, that there is a possibility that the vehicle data to which the signature received from the communication unit 101 was added has been falsified by a cyberattack.

[0098] Consequently, in a case where the cause of a failed signature authentication verification is data corruption through a cyberattack, the key generation management device 11 can instruct the key generation management center 10, the service provider's security management department, or the like to precisely handle the anomaly where the signature's authenticity cannot be verified. Therefore, the key generation management device 11 can precisely handle the irregularity where authenticity cannot be verified while simultaneously protecting privacy and enabling the specification of the appropriate signer in a case where the digital signature's authenticity could not be verified.

[0099] Furthermore, the key generation management device 11 of the present embodiment includes the notification unit 104, which sends a notification about the result of the signer verification processing. The notification unit 104 sends a notification about a determination result indicating that there is a possibility that the vehicle data to which the signature received from the communication unit 101 was added has been falsified by a cyberattack originating outside the key generation management device 11.

[0100] Consequently, in a case where the reason for an unsuccessful verification of the signature's authenticity is data corruption through a cyberattack, the key generation management device 11 can prompt the key generation management center 10, the service provider's security management department, or the like to address the irregularity where the signature's authenticity cannot be verified precisely and quickly. Therefore, the key generation management device 11 can address the irregularity where authenticity cannot be verified precisely and quickly, while simultaneously protecting privacy and enabling the specification of the appropriate signer in a case where the digital signature's authenticity could not be verified.

[0101] Furthermore, in the key generation management device 11 of the present embodiment, the communication unit 101 receives the signature whose authenticity has not been verified by the signature verification processing. In this case, the signer verification processing unit 103 determines, in a case where the vehicle-internal electronic device 21 corresponding to the signer has been specified by the signer verification processing, that there is a possibility that the vehicle data to which the signature received from the communication unit 101 has been added contains a communication error.

[0102] Consequently, in a case where a communication error is the cause of an unsuccessful verification of the signature's authenticity, the key generation management device 11 can instruct the department responsible for the service provider, or the like, which manages the communication status of the vehicle 20, to precisely handle the irregularity in which the signature's authenticity cannot be verified. Therefore, the key generation management device 11 can precisely handle the irregularity in which authenticity cannot be verified, while simultaneously protecting privacy and enabling the specification of the appropriate signer in a case where the digital signature's authenticity could not be verified.

[0103] Furthermore, the key generation management device 11 of the present embodiment includes the notification unit 104, which sends a notification about the result of the signer verification processing. The notification unit 104 sends a notification about a determination result indicating that there is a possibility that the vehicle data to which the signature received from the communication unit 101 has been added contains a communication error originating outside the key generation management device 11.

[0104] Consequently, in a case where a communication error is the cause of an unsuccessful verification of the signature's authenticity, the key generation management device 11 can prompt the department responsible for the service provider, or the like, which manages the communication status of the vehicle 20, to address the irregularity where the signature's authenticity cannot be verified precisely and quickly. Therefore, the key generation management device 11 can address the irregularity where authenticity cannot be verified precisely and quickly, while simultaneously protecting privacy and enabling the specification of the appropriate signer in a case where the digital signature's authenticity could not be verified.

[0105] Furthermore, the signature verification system 1 of the present embodiment is a system comprising the key generation management device 11, as described above, and the signature verification device 31, which is connected to the key generation management device 11 and the vehicle's in-vehicle electronic device 21 via the network 40 and performs the signature verification processing. The key generation management device 11 transmits each of the plurality of signature keys generated by the key generation unit 102 to the vehicle's in-vehicle electronic device 21 and the verification key generated by the key generation unit 102 to the signature verification device 31.The vehicle's internal electronic device 21 further generates the signature using the signature key transmitted by the key generation management device 11, adds the signature to the vehicle data, and transmits the signature added to the vehicle data to the signature verification device 31. The signature verification device 31 also performs signature verification processing on the signature transmitted by the vehicle's internal electronic device 21 using the verification key transmitted by the key generation management device 11, determines whether or not the execution of the signer verification processing is necessary, and transmits the signature for which it is determined that the execution of the signer verification processing is necessary to the key generation management device 11.The key generation management device 11 also performs the signer verification processing on the signature transmitted by the signature verification device 31.

[0106] Consequently, the signature verification system 1 can cause the signature verification device 31 of the service provider performing the signature verification to verify the authenticity of the signature generated by the vehicle's in-vehicle electronic device 21 without providing information that could identify the vehicle's in-vehicle electronic device 21 as the signer. Therefore, the signature verification system 1 can enable the signature verification device 31 to confirm that the vehicle data is authentic vehicle data transmitted by the authorized vehicle 20 that can use a specified service, while making it impossible to identify an individual associated with a transmission source of the vehicle data.On the other hand, in a case where the authenticity of the signature cannot be verified during signature verification, the key generation management device 11 in the signature verification system 1 can specify the vehicle-internal electronic device 21 corresponding to the signer based on the signature. Similarly, in a case where the authenticity of the digital signature cannot be verified, the signature verification system 1 can specify the vehicle-internal electronic device 21 corresponding to the signer based on the digital signature, while simultaneously protecting privacy.

[0107] In the signature verification system 1 of the present embodiment, the key generation management device 11 can furthermore be implemented by a plurality of computers connected via a network in the key generation management center 10. Furthermore, the signature verification device 31 can also be implemented by a plurality of computers connected via a network in the signature verification center 30.In a case where the multitude of vehicle-internal electronic devices 21 have a hierarchical structure in the vehicles 20, the vehicle-internal electronic device 21 of the top layer can receive the vehicle data and the signature key from the vehicle-internal electronic device 21 of a lower layer, generate the signature and transmit the signature to the signature verification device 31, or each vehicle-internal electronic device 21 can generate the signature, and the vehicle-internal electronic device 21 of the top layer can transmit the signature to the signature verification device 31.

[0108] Furthermore, the vehicle 20 and the signature verification device 31 can be connected via a wireless communication network or a wired communication network. In a case where the signature verification device 31 and the key generation management device 11 receive the plurality of signatures, the signature verification device 31 and the key generation management device 11 can repeat a plurality of sets of signature verification processing (S504) and signer verification processing (S505).Alternatively, in this case, the signature verification device 31 and the key generation management device 11 can repeat the processing steps S901 to S908 in signature verification processing (S504) and the processing steps S1001 to S1012 in signer verification processing (S505) multiple times for each processing operation. Furthermore, in this case, the signature verification device 31 and the key generation management device 11 can also perform such processing operations in combination.

[0109] The present invention is not limited to the embodiment described above and may include various other modified examples. For instance, the embodiment described above has been described in such detail only to provide an easily understandable description of the present invention, and the present invention is not necessarily limited to those embodiments that have all the described configurations. Furthermore, a part of a configuration in one embodiment may be replaced by a configuration in another embodiment, and a configuration in another embodiment may also be added to a configuration in yet another embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of a configuration in any embodiment.

[0110] Furthermore, some or all of the configurations, functions, processing units, processing means, and the like described above can be implemented in hardware, for example, by design using an integrated circuit. Alternatively, each of the configurations, functions, and the like described above can also be implemented in software using a processor that interprets and executes a program to implement each function. Information, such as a program, a table, and a file to implement each function, can then be stored in a recording device, such as a memory device, a hard disk drive, or a solid-state drive (SSD), or a recording medium, such as an integrated circuit (IC), a secure digital card (SD), or a DVD.

[0111] Furthermore, only the control and information lines deemed necessary for the description were shown; not all control and information lines are necessarily included in this product. In practice, it can also be assumed that virtually all configurations are interconnected. Reference symbol list 1 Signature verification system 11 Key generation management device 101 Communication Unit 102 Key generation unit 103 Signer Verification Processing Unit 104 notification units 20 vehicles 21 vehicle-internal electronic device 31 Signature verification device 40 Network QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-201807 A

[0005]

Claims

[1] A key generation and management device that generates and manages a signature key which is used to generate a signature to be added to vehicle data that is transferred from an in-vehicle electronic device to an outside of a vehicle, the key generation and management device comprising: a key generation unit that generates a multitude of signature keys with different values ​​and a verification key corresponding to the multitude of signature keys using a group signature scheme; a communication unit that receives a signature generated by the vehicle's internal electronic device using the signature key and has been subjected to signature verification processing to verify the authenticity of the signature using the verification key; and a signer verification processing unit that performs signer verification processing to specify that the vehicle's internal electronic device corresponds to a signer that generated the signature on the signature received from the communication unit. [2] The key generation management device according to claim 1, wherein The key generation unit generates the multitude of signature keys using a multitude of different parameters, and The signer verification processing unit specifies that the vehicle's internal electronic device corresponds to the signer by specifying which of the multitude of parameters is used to generate the signature key that is used to generate the signature received by the communication unit in the signer verification processing. [3] The key generation management device according to claim 2, wherein the communication unit receives the signature whose authenticity has not been verified by the signature verification processing, and The signer verification processing unit determines that there is a possibility that vehicle data to which the signature received from the communication unit has been added has been corrupted by a cyberattack in a case where the vehicle's in-vehicle electronic device corresponding to the signer has not been specified by the signer verification processing unit. [4] The key generation management device according to claim 3, further comprising a notification unit that provides notification of a result of the signer verification processing, wherein the notification unit provides notification of a determination result indicating that there is a possibility that the vehicle data to which the signature received from the communication unit has been added has been corrupted by a cyberattack from outside the key generation management device. [5] The key generation management device according to claim 2, wherein the communication unit receives the signature whose authenticity has not been verified by the signature verification processing, and The signer verification processing unit determines that there is a possibility that the vehicle data to which the signature received from the communication unit has been added contains a communication error in a case where the vehicle's in-vehicle electronic device corresponding to the signer has been specified by the signer verification processing. [6] The key generation management device according to claim 5, further comprising a notification unit which provides notification of a result of the signer verification processing, wherein the notification unit provides notification of a determination result indicating that there is a possibility that the vehicle data to which the signature received from the communication unit has been added contains a communication error from outside the key generation management device. [7] A signature verification system, comprising: the key generation and management device according to any one of claims 1 to 6; and a signature verification device that is connected via a network to the key generation management device and the vehicle's in-vehicle electronic device and performs the signature verification processing, wherein The key generation management device transmits each of the multitude of signature keys generated by the key generation unit to the vehicle's internal electronic device and transmits the verification key generated by the key generation unit to the signature verification device. the vehicle's internal electronic device generates the signature using the signature key transmitted by the key generation management device, adds the signature to the vehicle data, and transmits the signature added to the vehicle data to the signature verification device. The signature verification device performs the signature verification processing on the signature transmitted by the vehicle's internal electronic device using the verification key transmitted by the key generation management device, determines whether or not the execution of the signer verification processing is necessary, and transmits the signature for which it is determined that the execution of the signer verification processing is necessary to the key generation management device, and The key generation management device performs the signer verification processing on the signature transmitted by the signature verification device.

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