Electronic control device, key matching method, key matching program, and key management system

Abstract

This electronic control device is mounted on a vehicle, and is provided with: a storage unit (111, 121, 211, 221, 311, 321, 411, 421) for storing a key; and a collating unit (115, 125, 215, 225, 315, 325, 415, 425) that, at a predetermined timing, collates the key stored in the storage unit with key information, which is information relating to the key stored in a distributed ledger (200) provided outside the vehicle.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Japanese Patent Application No. 2022-149536 filed on September 20, 2022, and incorporates the entire contents herein. Technical Field

[0003] The present application relates to an electronic control device, a key comparison method, a key comparison program, and a key management system involved in comparison of keys used for encryption, decryption, etc. Background Art

[0004] In recent years, technologies such as V2X, which uses vehicle-to-vehicle communication and road-to-vehicle communication, to assist in driving and control autonomous driving have attracted much attention. As vehicles have communication functions, the possibility of being attacked by hackers and other cyber attacks has increased. In addition, there is a possibility that the vehicle may lose control due to a cyber attack, so a more robust defense method is needed against cyber attacks.

[0005] A vehicle is equipped with a plurality of electronic control devices interconnected via a network. The driving of the vehicle, especially driving assistance and automatic driving control, requires the sending and receiving of information based on the communication between the plurality of electronic control devices. As a countermeasure against a network attack on the communication between the plurality of electronic control devices, for example, Patent Document 1 describes encrypting the communication object data in the communication between the plurality of control devices and managing the encryption key used for the encryption in the vehicle.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-47281

[0007] Here, the present inventors conducted detailed studies and found the following problems.

[0008] In the above-mentioned driving assistance, automatic driving control, etc., vehicle control with higher reliability is required. Therefore, a more robust countermeasure is needed for network attacks in the communication between multiple electronic control devices. Of course, the same applies to normal driving. However, in the case where the encryption key used in the communication between multiple electronic control devices is managed only in the vehicle, there is a possibility of tampering with the encryption key through a network attack in the vehicle, and there is a risk that the security of the network in the vehicle will be threatened. Summary of the invention

[0009] An object of the present disclosure is to realize an electronic control device, a key comparison method, a key comparison program, and a key management system capable of improving the reliability of an encryption key used in communication between electronic control devices of a mobile object.

[0010] An electronic control device of one embodiment of the present invention is an electronic control device mounted on a vehicle, comprising: a storage unit for storing a key; and a comparison unit for comparing the key stored in the storage unit with information related to the key, i.e., key information, stored in a distributed ledger provided outside the vehicle at a prescribed timing.

[0011] Another embodiment of the electronic control system disclosed herein is an electronic control system composed of a plurality of electronic control devices mounted on a vehicle, wherein the plurality of electronic control devices respectively include: a storage unit for storing a key; and a comparison unit for comparing the key stored in the storage unit with information related to the key stored in the distributed ledger, i.e., key information, at a prescribed timing.

[0012] Another aspect of the key management system disclosed herein is a key management system composed of an electronic control device mounted on a vehicle and a distributed ledger arranged outside the vehicle, wherein the electronic control device comprises: a storage unit for storing keys; and a comparison unit for comparing the keys stored in the storage unit with information related to the keys stored in the distributed ledger, i.e., key information, at a prescribed timing.

[0013] Another aspect of the key management system disclosed herein is a key management system composed of an electronic control device mounted on a vehicle, a distributed ledger arranged outside the vehicle, and a certification authority, wherein the electronic control device comprises: a storage unit for storing keys; a comparison unit for comparing the keys stored in the storage unit with information related to the keys stored in the distributed ledger, i.e., key information, at a prescribed timing; and a validity confirmation unit for confirming the validity of an electronic certificate related to the keys of the certification authority.

[0014] Another embodiment of the key management system disclosed herein is a key management system composed of an electronic control system, wherein the electronic control system is composed of a first electronic control unit and a second electronic control unit mounted on a vehicle, wherein the first electronic control unit comprises: a first storage unit for storing a key; and a first comparison unit for comparing the key stored in the first storage unit with information related to the key stored in the second electronic control unit, i.e., first key information, at a first prescribed timing; and the second electronic control unit comprises: a second storage unit for storing the key; and a second comparison unit for comparing the key stored in the second storage unit with information related to the key stored in a distributed ledger, i.e., second key information, at a second prescribed timing, wherein the distributed ledger is arranged outside the vehicle.

[0015] In addition, the numbers in parentheses in the claims indicate the correspondence between the present invention and the embodiments described later, and do not limit the present invention.

[0016] With the above-described configuration, it is possible to improve the reliability of encryption keys used for communication between electronic control devices of mobile objects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a diagram showing a configuration example of a key management system according to each embodiment of the present disclosure,

[0018] Figure 2 is a block diagram showing a configuration example of an electronic control system according to each embodiment of the present disclosure.

[0019] Figure 3 is a schematic block diagram showing the features of each embodiment of the present disclosure,

[0020] Figure 4 is a schematic block diagram showing the features of each embodiment of the present disclosure,

[0021] Figure 5 is a block diagram showing a configuration example of an electronic control system and an electronic control device according to Embodiment 1 of the present disclosure.

[0022] Figure 6 is a flowchart showing the operation of the electronic control device according to the first embodiment of the present disclosure.

[0023] Figure 7 is a flowchart showing the operation of the electronic control device according to the first embodiment of the present disclosure.

[0024] Figure 8 is a block diagram showing a configuration example of an electronic control system and an electronic control device according to a second embodiment of the present disclosure.

[0025] Fig. 9 is a block diagram showing a configuration example of an electronic control system and an electronic control device according to a modified example of the second embodiment of the present disclosure.

[0026] Fig.10 is a block diagram showing a configuration example of an electronic control system and an electronic control device according to a third embodiment of the present disclosure.

[0027] Fig.11 is a block diagram showing a configuration example of an electronic control system and an electronic control device according to a modified example of the third embodiment of the present disclosure.

[0028] Fig.12 is a flowchart showing the operation of the electronic control device according to the third embodiment of the present disclosure.

[0029] Fig.13is a flowchart showing the operation of the electronic control device according to the modified example of the third embodiment of the present disclosure.

[0030] Fig.14 is a block diagram schematically showing an electronic control system according to a fourth embodiment of the present disclosure.

[0031] Fig.15 This is a block diagram showing a configuration example of an electronic control system and an electronic control device according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0033] The present invention described below refers to the invention described in the claims, and is not limited to the following embodiments. In addition, at least the sentences in double quotation marks refer to the sentences described in the claims, and are not limited to the following embodiments.

[0034] The configuration and method described in the dependent clause of the claims are arbitrary configurations and methods in the invention described in the independent clause of the claims. The configuration and method of the embodiment corresponding to the configuration and method described in the dependent clause, and the configuration and method that are not described in the claims but only described in the embodiment are arbitrary configurations and methods in the present invention. The configuration and method described in the embodiment when the description in the claims is wider than the description in the embodiment are examples of the configuration and method of the present invention, and in this sense, they are also arbitrary configurations and methods in the present invention. In either case, the configuration and method become necessary for the present invention through the independent clause described in the claims.

[0035] The effects described in the embodiments are effects obtained when the configuration of the embodiments is provided as examples of the present invention, and are not necessarily effects obtained by the present invention.

[0036] In the case of multiple embodiments, the configuration disclosed in each embodiment is not limited to each embodiment, but can be combined across the embodiments. For example, the configuration disclosed in one embodiment can be combined with other embodiments. In addition, the configurations disclosed in multiple embodiments can be combined together.

[0037] The problems described in the present disclosure are not publicly known problems but are problems independently recognized by the inventors, and are facts that confirm the inventiveness of the invention together with the configuration and method of the present disclosure.

[0038] 1. Prerequisites for each implementation method

[0039] (1) Overall structure of the key management system S

[0040] use Figure 1 First, the overall structure of the key management system S is explained.

[0041] The key management system S includes an electronic control system 100 “mounted” on a “vehicle” as a mobile body, a distributed ledger 200 , and a certification authority 300 .

[0042] Here, "vehicle" refers to an object that can move, and the moving speed is arbitrary. In addition, it also includes the case where the vehicle is stopped. For example, it includes cars, two-wheeled motorcycles, bicycles, and objects mounted on them, and is not limited to these.

[0043] “Carried” includes not only the case where the item is directly fixed to the moving body, but also the case where the item moves with the moving body although it is not fixed to the moving body. For example, the item may be held by a person riding on the moving body or carried on cargo placed on the moving body.

[0044] The electronic control system 100 is composed of a plurality of electronic control devices (ECUs (Electric Control Units), hereinafter abbreviated as ECUs) and an in-vehicle network connecting the ECUs. Figure 2 The electronic control system 100 will be described in detail later.

[0045] The distributed ledger 200, also known as a shared ledger or distributed ledger technology (DLT), is digital data that is replicated, shared, and synchronized across multiple geographically different locations, countries, agencies, etc. More specifically, a portion of the database (ledger information) is shared by multiple users, and the same ledger information is maintained in the system of each user.

[0046] The distributed ledger 200 stores information related to the key used in the electronic control system 100, i.e., key information, in the key management system S of each embodiment. In each embodiment, the distributed ledger 200 is provided outside the vehicle. In each embodiment, the key is expressed as a key Xn (n is an integer), and the key information is expressed as key information Xn (n is an integer), but the key information having the same Xn as the key refers to the key information generated based on the key Xn. In addition, for X, K represents a public key, S represents a secret key, and P represents a public key, but this is an example, and other types of keys may also be used.

[0047] exist Figure 1 In the figure, the distributed ledger 200 is illustrated as a single memory, but is actually stored in multiple memories in a dispersed manner. For example, each memory is implemented by a server or a cloud server outside the vehicle. However, the distributed ledger 200 can also be set to be connected to the electronic control system 100 in the vehicle, or set inside the electronic control system 100.

[0048] The certification authority 300 issues an electronic certificate that electronically proves the authenticity of the key. For example, the certification authority 300 confirms the identity of the key owner by some method and issues an electronic certificate that guarantees the key and its owner.

[0049] In particular, in the key management system S of the third and fourth embodiments, the certification authority 300 confirms the validity of the electronic certificate in response to a request from the ECU constituting the electronic control system 100 .

[0050] For example, the certification authority 300 is realized by a server external to the vehicle or a cloud server. Examples of the external server or cloud server include servers installed by a manufacturer or a sales company of the vehicle or the electronic control system 100.

[0051] In addition, although Figure 1 In the embodiment, the distributed ledger 200 and the certification authority 300 are implemented by different devices, but the distributed ledger 200 and the certification authority 300 can also be implemented by the same server or cloud server.

[0052] The electronic control system 100 and the distributed ledger 200 , as well as the electronic control system 100 and the authentication authority 300 are connected via a communication network using wireless communication or / and wired communication.

[0053] Examples of wireless communication methods include IEEE802.11 (Wi-Fi (registered trademark)), IEEE802.16 (WiMAX (registered trademark)), W-CDMA (Wideband Code Division Multiple Access), HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution), LTE-A (Long Term Evolution Advanced), 4G, 5G, etc. Alternatively, DSRC (Dedicated Short Range Communication) can be used.

[0054] Examples of wired communication methods include LAN (Local Area Network) such as Ethernet (registered trademark), the Internet, optical lines, and fixed telephone lines. When a vehicle is parked in a parking lot or stored in a repair shop, wired communication methods can be used instead of wireless communication methods.

[0055] In addition, a communication line that combines a wireless communication line and a wired communication line may also be used. For example, the electronic control system 100 may be connected to a base station device in a cellular system via a wireless communication method such as 4G, and the base station device may be connected to the distributed ledger 200 or the certification authority 300 via a wired communication method such as a trunk line of a communication enterprise or the Internet. A gateway device may also be provided at the junction of the trunk line and the Internet.

[0056] In addition, the distributed ledger 200 and the certification authority 300 can also communicate using any line including the Internet.

[0057] (2) Overall structure of the electronic control system 100

[0058] Figure 2 : is a figure which shows the structural example of the electronic control system 100. The electronic control system 100 is comprised by several ECUs including an external communication ECU and an integrated ECU. Figure 2 Although one external communication ECU, one integrated ECU, and four individual ECUs are exemplified, the electronic control system 100 is of course constituted by an arbitrary number of ECUs. Hereinafter, ECU is used as a term to generally indicate the external communication ECU, the integrated ECU, and the individual ECUs.

[0059] The external communication ECU is an ECU that communicates with the outside. The communication method used by the external communication ECU is the wireless communication method and the wired communication method mentioned above. In addition, in order to realize multiple communication methods, multiple external communication ECUs can also be set.

[0060] The integrated ECU is an ECU that has a gateway function that mediates between individual ECUs and external communication ECUs. In addition, the integrated ECU may also be provided with functions that control the entire electronic control system 100, such as safety functions. The integrated ECU may also be called a gateway ECU (G-ECU) or a mobile computer (MC). In addition, the integrated ECU may also be a relay device or a gateway device.

[0061] The individual ECUs of the electronic control system 100 can be composed of ECUs having any functions. For example, a drive system electronic control device that controls the engine, steering wheel, brakes, etc., a body system electronic control device that controls the instrument, electric windows, etc., an information system electronic control device such as a navigation device, or a safety control system electronic control device that controls to prevent collisions with obstacles and pedestrians can be listed. In addition, the ECUs may not be arranged in parallel, but may be classified into a master and a slave.

[0062] Furthermore, the ECU may be a physically independent ECU or a virtual ECU (or sometimes called a virtual machine) that is virtually realized.

[0063] exist Figure 2 In the case of , the ECUs are connected via an in-vehicle communication network such as CAN (Controller Area Network) or LIN (Local Interconnect Network). Alternatively, they can be connected using any communication method, whether wired or wireless, such as Ethernet (registered trademark), Wi-Fi (registered trademark), or Bluetooth (registered trademark).

[0064] Furthermore, connection refers to a state in which data can be exchanged, and of course includes a case where different hardware is connected via a wired or wireless communication network, and also includes a case where virtual machines implemented on the same hardware are virtually connected to each other.

[0065] (3) Overview of each embodiment

[0066] Figure 3 as well as Figure 4 It is a diagram schematically showing the features of each embodiment.

[0067] Figure 3 (a) Corresponds to Embodiment 1. In Embodiment 1, ECU 11 and ECU 12 compare the common key used when data and the like are transmitted and received between ECU 11 and ECU 12 with the key information stored in the distributed ledger 200 .

[0068] Figure 3 (b1) and (b2) correspond to Embodiment 2. In Embodiment 2, ECU 21 or ECU 22 compares the public key used when data is transmitted and received between ECU 21 and ECU 22 with the key information stored in the distributed ledger 200 .

[0069] Figure 4 (c1) and (c2) correspond to Embodiment 3. In Embodiment 3, except Figure 3 In addition to the configuration of the second embodiment shown in (b1) and (b2), the ECU 31 or ECU 32 verifies the validity of the electronic certificate with the certification authority.

[0070] use Fig.14 In addition, the features of the fourth embodiment will be briefly described.

[0071] 2. Implementation Method 1

[0072] (1) Configuration of Electronic Control Units (ECU) 11 and 12

[0073] use Figure 5 , the configuration of ECU 11 and ECU 12 in the present embodiment will be described. Figure 3 (a) corresponds to this embodiment.

[0074] ECU11 and ECU12 may be respectively Figure 2 However, in the present embodiment, each of the ECUs is a separate ECU connected via an integrated ECU.

[0075] The ECU 11 includes a storage unit 111, a control unit 112, a transmission unit 113, and a reception unit 114. The control unit 112 also includes a comparison unit 115.

[0076] The ECU 12 includes a storage unit 121, a control unit 122, a transmission unit 123, and a reception unit 124. The control unit 122 also includes a comparison unit 125.

[0077] ECU 11, 12 can be composed of a general-purpose CPU (Central Processing Unit), a volatile memory such as RAM, a non-volatile memory such as ROM, flash memory or hard disk, various interfaces, and an internal bus connecting them. Then, by executing software on these hardware, it can be configured to play a role. Figure 5 The functions of the functional blocks described above can, of course, be realized by dedicated hardware such as LSI, etc. The same is true for the ECUs of other embodiments.

[0078] ECU11, 12 is assumed to be in the form of semi-finished electronic control devices in this embodiment, but is not limited to this. For example, as the form of components, semiconductor circuits and semiconductor modules can be listed, and as the form of finished products, personal computers (PCs), smart phones, mobile phones, and navigation systems can be listed. The same is true for ECUs in other embodiments.

[0079] Hereinafter, each module of the ECU 12 corresponding to each module of the ECU 11 will be described using the ECU 11 as a representative, except when having different operations and functions, and each module of the ECU 12 refers to the description of the module of the ECU 11 .

[0080] Storage units 111 and 121 store public keys K1 and K2 as “keys”, respectively. Public keys K1 and K2 are the same key, but are stored in different storage units and may become different keys due to tampering by one party, so different reference numerals are added here to distinguish them.

[0081] Here, "key" is data used to control the order of the encryption algorithm. Not only passwords can be used, but also digital signatures, message authentication codes (Keyed-hash, etc.), etc. The seed used for pseudo-random numbers is also a type of key. In addition, the "key" stored in the storage unit can be a key used by the electronic control device or a key used by other electronic control devices, etc. The "key" includes, for example, a public key, a secret key, a public key, etc. In addition, it can be a newly generated key or a new key that is updated from an old key. The key may also have an expiration date.

[0082] The control unit 112 controls the operations of the storage unit 111, the transmission unit 113, and the reception unit 114. In addition, the control unit 112 realizes the comparison unit 115 by itself.

[0083] In addition, the control unit 112 uses the common key K1 read from the storage unit 111 to decrypt the encrypted data transmitted from the ECU 12 to the ECU 11 , generate a message authentication code, and compare it with the received message authentication code.

[0084] The control unit 122 encrypts data transmitted from the ECU 12 to the ECU 11 and generates a message authentication code using the common key K2 read from the storage unit 121 .

[0085] The transmission unit 113 transmits data and the like to each ECU of the electronic control system 100 including the ECU 12. In addition, the transmission unit 113 transmits data and the like to the distributed ledger 200 and other devices via the external communication ECU.

[0086] The receiving unit 114 receives data and the like from each ECU of the electronic control system 100 including the ECU 12. In addition, the receiving unit 114 receives data and the like from the distributed ledger 200 and other devices via the external communication ECU.

[0087] The comparison unit 115 compares the public key K1 stored in the storage unit 111 with the "key information" K1 stored in the distributed ledger 200 at a "predetermined timing". The comparison unit 125 also compares the public key K2 stored in the storage unit 121 with the "key information" K2 stored in the distributed ledger 200 at a "predetermined timing". The comparison result of the comparison unit 115 can be stored in the storage units 111 and 121. The comparison unit 115 will be described in detail in the next item.

[0088] Here, the "predetermined timing" can be any time index based on a predetermined rule, such as expressed by time, time, clock number, counter, cycle, frequency, etc. In addition, in addition to a fixed value, it can also be a variable value that changes according to conditions.

[0089] "Key information" may be the key itself, in addition to information related to the key itself.

[0090] “Comparison” includes not only directly verifying the identity of keys, but also indirectly verifying whether key information, which is information related to the key, is derived from the key.

[0091] (2) Details of the comparison unit 115

[0092] (a) Reasons for providing the comparison unit 115

[0093] The control unit 122 of the ECU 12 encrypts the data to be sent to the ECU 11 using the public key K2 read from the storage unit 121. The transmission unit 123 transmits the encrypted data to the ECU 11 via the integrated ECU. The receiving unit 114 of the ECU 11 receives the encrypted data. Then, the control unit 112 decrypts the encrypted data using the public key K1 read from the storage unit 111.

[0094] When sending and receiving such data, if the public key K1 is tampered with by a hacker attack, the originally required data cannot be decrypted. In addition, if the public key K1 and the public key K2 are tampered with by a hacker attack, forged data may be decrypted and used. In order to prevent this, in this embodiment, in order to check whether the public key K1 has been rewritten by a hacker attack, etc., it is compared with the key information K1 stored in the distributed ledger 200.

[0095] By managing the public key K1 not only in the electronic control system 100 but also using the distributed ledger 200 provided outside the electronic control system 100, it becomes difficult to tamper with the public key K1. That is, if one wants to tamper with the public key K1, not only a hacker attack on the electronic control system 100 but also a hacker attack on the distributed ledger 200 is required. In addition, by storing the key information K1 in the distributed ledger 200 instead of in a normal server or cloud server, the key information K1 becomes less likely to be tampered with due to the characteristics of the blockchain, and even if it is tampered with, it becomes easy to detect the tampering.

[0096] (b) Key information stored in the distributed ledger 200

[0097] The key information K1 stored in the distributed ledger 200 is information related to the key K1. The key information K1 can be any information sufficient to verify the identity of the key K1. For example, the serial number of the public key K1, the MAC value of the serial number, the MAC value of the public key K1, and the attribute information of the public key K1 can be listed. Of course, the key information K1 can also be the public key K1 itself.

[0098] The method of registering the key information K1 in the distributed ledger 200, that is, storing the key information K1 in the distributed ledger 200, is arbitrary, but several examples are given for explanation.

[0099] As a first example, the ECU 11 itself may send the key information K1 to the distributed ledger 200. That is, the control unit 112 may read the public key K1 from the storage unit 111 and send the public key K1 from the sending unit 113, or the control unit 112 may obtain the serial number of the public key K1, the MAC value of the public key, etc. and send them.

[0100] When sending, the information may be sent directly to the distributed ledger 200 or indirectly to the distributed ledger 200. That is, the information may be sent from the sending unit 113 to other ECUs (e.g., DCM (Data Communication Module), other ECUs in the mobile body, etc.) in the electronic control system 100, and sent from other ECUs to the distributed ledger 200. In addition, the information may be sent via other external devices such as a server, a relay device, and the certification authority 300.

[0101] The distributed ledger 200 that receives the key information K1 can directly store the received key information K1, for example, it can also calculate the serial number of the public key K1 and the MAC value of the public key K1 based on the received public key K1 and store them.

[0102] As a second example, when a vehicle is registered or repaired, the vehicle manufacturer, dealer, or repair shop may write the public key K1 and key information K1 to the ECU 11 and the distributed ledger 200 from a computer managed by the vehicle manufacturer, dealer, or repair shop.

[0103] As a third example, the integrated ECU of the electronic control system 100 may transmit the public key K1 and the key information K1 to the ECU 11 and the distributed ledger 200 .

[0104] (c) Method of comparison

[0105] The comparison between the public key K1 stored in the storage unit 111 and the key information K1 stored in the distributed ledger 200 may be performed by the ECU 11 itself or by another device.

[0106] When the ECU 11 performs the operation by itself, the control unit 112 reads the public key K1 from the storage unit 111, and the receiving unit 114 receives the key information K1 sent from the distributed ledger 200 in response to the request for the key information sent from the sending unit 113 based on the instruction of the control unit 112. Then, the comparison unit 115 compares the public key K1 with the key information K1, and verifies whether the public key K1 has been tampered with based on the presence or absence of the common points that the public key K1 and the key information K1 should have.

[0107] As an example of the case where the comparison is performed by other devices, it is possible to cite the case where the comparison is performed by the device that manages the distributed ledger 200. The sending unit 113 generates key information K1 based on the public key K1 stored in the storage unit 111 and sends it based on the instruction of the control unit 112 of the ECU 11. Then, the device that manages the distributed ledger 200 compares the key information K1 stored in the distributed ledger 200 with the key information K1 sent from the ECU 11, and sends the result to the ECU 11. The ECU 11 receives the result through the receiving unit 114, and confirms the result through the comparison unit 115.

[0108] Examples of other devices other than the device that manages the distributed ledger 200 include other external devices and other ECUs other than the ECU 11 including the ECU 12 .

[0109] (d) Timing of control

[0110] In order to detect tampering due to a cyber attack, it is desirable that the ECU 11 performs a comparison every time it receives encrypted data from the ECU 12 .

[0111] However, the number of communications between ECUs mounted on the electronic control system 100 is very large, for example, more than ten times per second. Moreover, the vehicle equipped with the electronic control system 100 moves, so the communication with the outside is not always stable. Therefore, if the distributed ledger 200 is compared every time the ECUs communicate, the communication volume increases and the communication line is saturated, and there is a possibility that the comparison itself becomes difficult.

[0112] In addition, since communication with the outside is not performed in principle during parking, comparison cannot be performed. Therefore, it is desirable to perform comparison as soon as possible when communication with the outside is restored.

[0113] Therefore, the comparison unit 115 performs the comparison at a predetermined timing. The predetermined timing is exemplified below.

[0114] (Example 1)

[0115] When the vehicle is running, if the electronic control system 100 mounted on the vehicle can communicate with the outside, the comparison is performed once or more every predetermined time (equivalent to the "first predetermined time"), or once or more every time the number of communications between the ECU 11 and other ECUs in the electronic control system 100 reaches the specified number of communications (equivalent to the "first predetermined time"). In other words, the comparison can be either synchronized with the timing of the communication between the ECU 11 and other ECUs or asynchronous.

[0116] With the above configuration, it is possible to prevent the communication volume with the distributed ledger 200 from increasing and the communication line from being saturated, and to perform the comparison of the common key K1 more stably.

[0117] In addition, the prescribed time or prescribed number of communications can also be determined according to the speed of the vehicle. In other words, it can also change according to the speed of the vehicle. When the speed of the vehicle is faster, the communication volume between ECUs generally increases, and when the speed of the vehicle is slower, the communication volume between ECUs generally decreases, so the faster the speed of the vehicle, the shorter the prescribed time can be. For example, when the speed is faster (for example, above 40 km / h), the prescribed time can be one second, and when the speed is slower (for example, below 10 km / h), the prescribed time can be three seconds. Alternatively, it can be divided into low-speed, medium-speed, high-speed and other partitions to determine the prescribed time. The number of partitions is arbitrary. Alternatively, partitions can be omitted and made to change continuously.

[0118] The above configuration can reduce and even out the risk and damage caused by a network attack, and in particular, prevent excessive use of resources required for communication with the outside.

[0119] (Example 2)

[0120] When the electronic control system 100 mounted on the vehicle has not communicated with the outside for more than a prescribed time (equivalent to the "second prescribed time"), a comparison is performed within a prescribed time (equivalent to the "third prescribed time") from the resumption of communication with the outside. As an example of the resumption of communication, in addition to the start of communication after the communication interruption is eliminated, it also includes the start of communication accompanying the start of the vehicle such as the engine start. In addition, it also includes the case of starting communication with a new external device. The second prescribed time is, for example, an arbitrary time such as five minutes or ten minutes. For the third prescribed time, for example, it is within an arbitrary time such as within one second or within three seconds from the start of communication with the outside, preferably shorter.

[0121] With the above configuration, it is possible to quickly perform a comparison at the timing of communication recovery after a communication interruption that made comparison impossible or at the timing of starting a vehicle when the system is unstable and vulnerable to a network attack.

[0122] (Example 3)

[0123] When the vehicle is parked, if the electronic control system 100 mounted on the vehicle can communicate with the outside, the vehicle is parked in a state where the engine is turned off at intervals of a specified time (equivalent to the "fourth specified time"). When the vehicle is parked, there is often no one in the vehicle. Compared with a network attack, there is a risk of attacks such as hacker attacks caused by physical connections made by suspicious persons, so it is desirable to perform regular checks when the vehicle is parked. The fourth specified time is, for example, an arbitrary time such as one hour or two hours. Since the risk of uncontrollable vehicles is lower than when the vehicle is driving, the fourth specified time can be set to a time longer than the first specified time and the second specified time. In addition, since communication is required even when the engine is turned off, it is desirable to communicate using a communication method that consumes less power, such as LPWA (Low Power Wide Area).

[0124] With the above configuration, even when the vehicle is parked, it is possible to perform a comparison assuming the possibility of an attack on the electronic control system 100 .

[0125] (e) Vehicle communication status

[0126] The predetermined timing may also be determined according to the communication state of the vehicle. The communication state of the vehicle may change according to, for example, the driving state of the vehicle including parking, driving position, driving speed, etc. In addition, when multiple wireless communication methods are used in communication with the outside, the wireless communication method used may also be changed.

[0127] For example, the frequency of comparison when using a line with a faster communication speed may be made greater than the frequency of comparison when using a line with a slower communication speed. This can avoid saturation of the communication line.

[0128] Alternatively, the frequency of comparison when using a free or relatively inexpensive line may be made higher than the frequency of comparison when using a relatively inexpensive line.

[0129] Alternatively, when the same line is used continuously, the comparison frequency may be changed according to the response speed of the line, the SN ratio, or the reception strength of the radio waves.

[0130] (f) Control in electronic control systems

[0131] The above description focuses on ECU 11, but Figure 2 The electronic control system 100 mounted on the vehicle is generally composed of a plurality of ECUs. Furthermore, each ECU included in the electronic control system 100 independently performs the above-mentioned comparison. However, not all ECUs included in the electronic control system 100 necessarily need to perform the comparison.

[0132] The predetermined timing may be different in each ECU.

[0133] For example, the frequency of the specified timing of the external communication ECU (equivalent to the "first electronic control unit") that is the entry point is preferably higher than the frequency of the specified timing of other ECUs (equivalent to the "second electronic control unit"). In this way, the security level of the external communication ECU with a higher risk of network attack can be improved.

[0134] Alternatively, it is preferred that the frequency of the timing specified by the ECU responsible for autonomous driving and the drive system ECU (equivalent to the "first electronic control unit") is higher than the frequency of the timing specified by other ECUs (equivalent to the "second electronic control unit"). In this way, the danger caused by a cyber attack can be suppressed.

[0135] Alternatively, it is preferred that the frequency of the prescribed timing in the ECU (equivalent to the "first electronic control unit") with a larger amount of communication and a higher frequency of communication in the vehicle is higher than the frequency of the prescribed timing in other ECUs (equivalent to the "second electronic control unit"). For example, since the integrated ECU has a gateway function, the amount of communication is greater than that of other ECUs. Thus, the reliability of each communication in the vehicle can be improved.

[0136] (g) Others

[0137] In the above description of the comparison unit 115 , a case where the common key K1 is used for decrypting encrypted data is exemplified, but the common key K1 may be used for other purposes such as message authentication.

[0138] Furthermore, the comparison may be performed synchronously with or asynchronously with the transmission and reception of data.

[0139] Furthermore, although the above description of the comparison unit 115 focuses on the ECU 11 and the public key K1 that decrypt the encrypted data, the same is also true for the ECU 12 and the public key K2 that encrypt the data, and in this case, the description is replaced with the ECU 12 and the public key K2.

[0140] The vehicle ID for identifying the vehicle and the ECU ID for identifying the ECU may be stored together with the key information in the distributed ledger 200. Furthermore, when acquiring the key information from the distributed ledger, the vehicle ID and the ECU ID may be specified.

[0141] The above description of the comparison unit 115 is applicable not only to this embodiment but also to other embodiments. In other embodiments, a secret key and a public key are used, so the description of the public key K1 is replaced with the public key Pn (n is an integer).

[0142] (3) Operation of the Electronic Control Units (ECU) 11 and 12

[0143] use Figure 6 The flowchart of FIG. 1 will be used to explain the operations of comparing the common key K1 and decrypting the received data in the ECU 11 of the present embodiment.

[0144] In addition, the following operations not only show the key control method executed by ECU11, but also show the processing sequence of the key control program that can be executed by ECU11. Figure 6 That is, as long as there is no restriction such as a relationship in which a step uses the result of the previous step, the order can be changed. Figure 6 The same applies to other flowcharts.

[0145] The ECU 11 stores the common key K1 in the storage unit 111 ( S111 ).

[0146] The transmission unit 113 of the ECU 11 transmits the key information K1 which is information related to the public key K1 stored in the storage unit 111 to the distributed ledger 200 ( S112 ).

[0147] Thereafter, at an arbitrary timing, the receiving unit 114 of the ECU 11 receives the encrypted data ( S113 ). For example, when the common key K1 and the common key K2 are the same key, the receiving unit 114 of the ECU 11 receives the data encrypted by the ECU 12 using the common key K2 .

[0148] The comparison unit 115 determines whether it is a predetermined timing (S114). If it is determined to be a predetermined timing (S114: Yes), the transmission unit 113 sends a request for key information to the distributed ledger 200, and the reception unit 114 receives the key information K1 sent from the distributed ledger 200 (S115).

[0149] The comparison unit 115 compares the public key K1 read from the storage unit 111 with the key information K1 received from the distributed ledger 200 (S116). If it is determined that the public key K1 has not been tampered with (S117: Yes), the encrypted data received in S113 is decrypted using the public key K1 (S118). If it is determined that the public key K1 has been tampered with (S117: No), the encrypted data received in S113 is not decrypted (S119). In addition, if it is not determined to be the specified timing (S114: No), the encrypted data received in S113 is decrypted (S118).

[0150] In addition, as described above, the key information K1 which is information related to the public key K1 does not necessarily need to be transmitted to the distributed ledger 200 by the ECU 11, so S112 is an arbitrary step in the present embodiment.

[0151] In addition, the decryption may be performed on all data sent and received between ECUs, or only on a portion thereof, such as the data portion in an Ethernet frame.

[0152] And, although in Figure 6 The timing specified in the decryption of the encrypted data is synchronized, but it can also be asynchronous. For example, the comparison result of the comparison unit 115 can be stored in the storage unit 111, and the comparison result can be read from the storage unit 111 when the encrypted data is decrypted using the public key K1, and the control unit 112 determines whether to use the public key K1 based on the comparison result.

[0153] use Figure 7 The flowchart of will be used to explain the operation of comparing the common key K2 in the ECU 12 of this embodiment and encrypting the transmission data.

[0154] The ECU 12 stores the common key K2 in the storage unit 121 ( S121 ).

[0155] The transmission unit 123 of the ECU 12 transmits the key information K2 which is information related to the public key K2 stored in the storage unit 121 to the distributed ledger 200 ( S122 ).

[0156] The comparison unit 125 determines whether it is a predetermined timing (S123). If it is determined to be a predetermined timing (S123: Yes), the transmission unit 123 sends a request for key information to the distributed ledger 200, and the reception unit 124 receives the key information K2 sent from the distributed ledger 200 (S124).

[0157] The comparison unit 125 compares the public key K2 read from the storage unit 121 with the key information K2 received from the distributed ledger 200 (S125). If it is determined that the public key K2 has not been tampered with (S126: Yes), the data is encrypted using the public key K2 and sent (S127). If it is determined that the public key K2 has been tampered with (S126: No), the data is not encrypted and is not sent (S128). In addition, if it is not determined to be the specified timing (S123: No), the data is encrypted and sent (S127).

[0158] In addition, as described above, the key information K2, which is information related to the public key K2, does not necessarily need to be sent to the distributed ledger 200 by the ECU 12, so S122 is an arbitrary step in this embodiment.

[0159] In addition, encryption may be performed on all data sent and received between ECUs, or may be performed on only a portion of the data, such as the data portion in an Ethernet frame.

[0160] And, although in Figure 7 The timing specified in the above is synchronized with the encryption and transmission of data, but it can also be asynchronous. For example, the comparison result of the comparison unit 125 can be stored in the storage unit 121, and the comparison result can be read from the storage unit 121 when the public key K2 is used to encrypt the data, and the control unit 122 determines whether to use the public key K2 based on the comparison result.

[0161] (4) Summary

[0162] As described above, according to the present embodiment, since the key information K1 and the key information K2 are stored in the distributed ledger and compared with the public key K1 and the public key K2, tampering of the public key K1 and the public key K2 can be detected more accurately.

[0163] In addition, according to this embodiment, since the public key K1 and the key information K1, and the public key K2 and the key information K2 are compared at a predetermined timing, it is possible to prevent the communication volume with the distributed ledger 200 from increasing and saturating the communication line, and the public key K1 and the public key K2 can be compared more stably. As a result, the security of the public key K1 and the public key K2 can be ensured.

[0164] 3. Implementation Method 2

[0165] (1) Configuration of the Electronic Control Units (ECU) 21 and 22

[0166] Implementation 1 uses a public key to send and receive data in the electronic control system 100. This implementation differs from Implementation 1 in that a secret key and a public key are used instead of a public key. Hereinafter, only the parts different from Implementation 1 will be described, and the parts identical to Implementation 1 will be referred to the description of Implementation 1.

[0167] use Figure 8 , the configuration of ECU 21 and ECU 22 in the present embodiment will be described. Figure 3 (b1) corresponds to this embodiment.

[0168] ECU21 and ECU22 may be respectively Figure 2 However, in the present embodiment, each of the ECUs is a separate ECU connected via an integrated ECU.

[0169] The ECU 21 includes a storage unit 211 , a control unit 212 , a transmission unit 213 , and a reception unit 214 .

[0170] The ECU 22 includes a storage unit 221, a control unit 222, a transmission unit 223, and a reception unit 224. The control unit 222 also includes a comparison unit 225.

[0171] The storage unit 221 stores the public key P2. The storage unit 211 stores the secret key S1 and the public key P1. The public key P2 and the public key P1 are the same key, but because they are stored in different storage units and may become different keys due to tampering by one party, different reference numerals are added here for distinction.

[0172] In this embodiment, ECU 21 generates public key P1 using secret key S1. Then, transmission unit 213 transmits public key P1 to ECU 22, and reception unit 224 of ECU 22 receives public key P1. ECU 22 that has received public key P1 stores public key P1 in storage unit 221 as public key P2.

[0173] In the present embodiment, the control unit 222 of the ECU 22 encrypts the data to be sent to the ECU 21 using the public key P2 read from the storage unit 221. The sending unit 223 sends the encrypted data to the ECU 21 via the integrated ECU. The receiving unit 214 of the ECU 21 receives the encrypted data. Then, the control unit 212 decrypts the encrypted data using the secret key S1 read from the storage unit 211.

[0174] The comparison unit 225 of the ECU 22 compares the public key P2 stored in the storage unit 221 with the key information P2 stored in the distributed ledger 200 at a predetermined timing. The details of the comparison unit 225 are the same as those of the comparison unit 115 described in the first embodiment, except that the comparison unit 225 uses the public key P2 and the key information P2, so the description of the first embodiment is replaced with the premise of the present embodiment, and the description is omitted.

[0175] However, although ECU 21 also has a public key P1, ECU 21 does not usually use the public key P1 for the purpose of distributing it to other ECUs, etc. Therefore, the control unit 212 is not provided with a comparison unit. However, as in the first embodiment, a comparison unit 215 may also be provided in ECU 21 to compare the public key P1 stored in the storage unit 211 with the key information P1 stored in the distributed ledger 200.

[0176] The operation of the ECU 22 is also similar to that of the ECU 12 in the first embodiment and Figure 7 Since the present embodiment is the same as the present embodiment, the description of the first embodiment is replaced with the premise of citing the first embodiment and the description is omitted.

[0177] (2) Modification

[0178] Fig. 9 The configuration of the ECU 21 and the ECU 22 in the modified example of the present embodiment is similar to Figure 3 (b2) corresponds.

[0179] ECU21 and ECU22 may be respectively Figure 2 However, in the present embodiment, each of the ECUs is a separate ECU connected via an integrated ECU.

[0180] The ECU 21 includes a storage unit 211, a control unit 212, a transmission unit 213, and a reception unit 214. The control unit 212 also includes a comparison unit 215.

[0181] The ECU 22 includes a storage unit 221 , a control unit 222 , a transmission unit 223 , and a reception unit 224 .

[0182] The storage unit 221 stores a secret key S1 and a public key P1. The storage unit 211 stores a public key P2. The public key P1 and the public key P2 are the same key, but because they are stored in different storage units and may become different keys due to tampering by one party, different reference numerals are added here for distinction.

[0183] In this modification, ECU 22 generates public key P1 using secret key S1. Then, transmission unit 223 transmits public key P1 to ECU 21, and reception unit 214 of ECU 21 receives public key P1. ECU 21, having received the public key, stores public key P1 in storage unit 211 as public key P2.

[0184] In this embodiment, the control unit 222 of the ECU 22 generates an electronic signature for the data sent to the ECU 21 using the secret key S1 read from the storage unit 221. The sending unit 223 sends the data and the electronic signature to the ECU 21 via the integrated ECU. The receiving unit 214 of the ECU 21 receives the data and the electronic signature. Then, the control unit 212 decrypts the electronic signature using the public key P2 read from the storage unit 211.

[0185] The comparison unit 215 of the ECU 21 compares the public key P2 stored in the storage unit 211 with the key information P2 stored in the distributed ledger 200 at a predetermined timing. The details of the comparison unit 215 are the same as those of the comparison unit 115 described in the first embodiment, except that the comparison unit 215 uses the public key P2 and the key information P2, so the description of the first embodiment is replaced with the premise of the present embodiment, and the description is omitted.

[0186] However, although ECU 22 also has the public key P1, it is usually not used by ECU 22 for the purpose of distributing it to other ECUs, etc. Therefore, the control unit 222 is not provided with a comparison unit. However, as in the first embodiment, a comparison unit 225 may also be provided in ECU 22 to compare the public key P1 stored in the storage unit 221 with the key information P1 stored in the distributed ledger 200.

[0187] The operation of the ECU 21 is also similar to that of the ECU 11 in the first embodiment and Figure 6 Since the present embodiment is the same as the present embodiment, the description of the first embodiment is replaced with the premise of citing the first embodiment and the description is omitted.

[0188] (3) Summary

[0189] As described above, according to the present embodiment, the key information K1 and the key information K2 are stored in the distributed ledger and compared with the public key K1 and the public key K2, so that tampering of the public key K1 and the public key K2 can be detected more accurately.

[0190] In addition, since the public key P2 and the key information P2 are compared at a predetermined timing, it is possible to prevent the communication volume with the distributed ledger 200 from increasing and saturating the communication line, and the comparison of the public key P2 can be performed more stably. As a result, the security of the public key P2 can be ensured.

[0191] 4. Implementation Method 3

[0192] (1) Configuration of the Electronic Control Units (ECU) 31 and 32

[0193] In addition to the comparison of the public key in Implementation 2, this implementation also issues an electronic certificate of the public key and confirms the validity of the electronic certificate. Hereinafter, only the parts added to Implementation 2 and the parts different from Implementation 2 are described, and the parts identical to Implementation 2 refer to the description of Implementation 2.

[0194] use Fig.10 , the configuration of ECU 31 and ECU 32 in the present embodiment will be described. Figure 4 (c1) corresponds to this embodiment.

[0195] ECU31 and ECU32 may be respectively Figure 2 However, in the present embodiment, each of the ECUs is a separate ECU connected via an integrated ECU.

[0196] The ECU 31 includes a storage unit 311 , a control unit 312 , a transmission unit 313 , and a reception unit 314 .

[0197] The ECU 32 includes a storage unit 321, a control unit 322, a transmission unit 323, and a reception unit 324. The control unit 322 also includes a comparison unit 325 and a validity confirmation unit 326.

[0198] The storage unit 321 stores the public key P2. The storage unit 311 stores the secret key S1 and the public key P1. The public key P2 and the public key P1 are the same key, but because they are stored in different storage units and may become different keys due to tampering by one party, different reference numerals are added here for distinction.

[0199] In this embodiment, similar to Embodiment 2, ECU 31 generates public key P1 using secret key S1. Then, transmission unit 313 transmits public key P1 to ECU 32, and reception unit 324 of ECU 32 receives public key P1. ECU 32 that has received the public key stores public key P1 in storage unit 321 as public key P2.

[0200] Furthermore, in the present embodiment, ECU31 transmits the generated public key P1 from the transmission unit 313 to the certification authority 300, and the certification authority 300 issues an electronic certificate of the public key P1 and transmits it to ECU31. The electronic certificate is a certificate that guarantees the public key P1 and the device having the public key. The receiving unit 314 of ECU31 receives the public key P1 to which the electronic certificate is attached, and stores the electronic certificate in the storage unit 311. Furthermore, the transmission unit 313 of ECU31 transmits the electronic certificate to ECU32, and the receiving unit 324 of ECU32 receives the electronic certificate. ECU32, which has received the electronic certificate, stores the electronic certificate in the storage unit 321.

[0201] Furthermore, the electronic certificate may be transmitted from the ECU 31 to the ECU 32 simultaneously with the transmission of the public key P1 .

[0202] Furthermore, the electronic certificate may be sent only once for the first time or may be sent periodically.

[0203] The method for storing the key information P2 in the distributed ledger 200 can use the method exemplified in Embodiment 1, but the certification authority 300 may send the public key P1 to the distributed ledger 200, and the distributed ledger 200 may generate and store the key information P2. Alternatively, the certification authority 300 may generate and send the key information P2 based on the public key P1, and the distributed ledger 200 may store the key information P2.

[0204] In the present embodiment, the control unit 322 of the ECU 32 encrypts the data to be sent to the ECU 31 using the public key P2 read from the storage unit 321. The transmission unit 323 transmits the encrypted data to the ECU 31 via the integrated ECU. The receiving unit 314 of the ECU 31 receives the encrypted data. Then, the control unit 312 decrypts the encrypted data using the secret key S1 read from the storage unit 311.

[0205] The comparison unit 325 compares the public key P2 stored in the storage unit 321 with the key information P2 stored in the distributed ledger 200 at a predetermined timing. The details of the comparison unit 325 are the same as those of the comparison unit 115 described in Embodiment 1, except that the comparison unit 325 uses the public key P2 and the key information P2, so the description of Embodiment 1 is replaced with the premise of citing this embodiment, and the description is omitted.

[0206] The validity confirmation unit 326 confirms the validity of the electronic certificate received from the ECU 31. Specifically, the validity confirmation unit 326 sends a confirmation signal from the sending unit 323 to the certification authority 300 to inquire about the validity of the electronic certificate of the public key P2. Then, the certification authority 300 that has received the confirmation signal confirms the validity of the electronic certificate indicated by the confirmation signal and sends the confirmation result to the ECU 32. In addition to the authenticity of the electronic certificate, the validity confirmation also confirms the validity period of the electronic certificate. The receiving unit 324 of the ECU 32 receives the confirmation result.

[0207] It is preferable that the “frequency” of the validity confirmation by the validity confirmation unit 326 is lower than the “frequency” of the predetermined timing of the comparison by the comparison unit 325 .

[0208] Here, the "frequency" may directly or indirectly indicate the number of times information is transmitted within a predetermined time, and may be expressed by a cycle, time, or the like in addition to the number of times.

[0209] For example, the frequency of validity confirmation can be performed according to the legal inspection or vehicle inspection of the vehicle, or set to a longer period such as every year. In addition, the frequency of validity confirmation can also be set arbitrarily, or it can be the first time when the vehicle is started or delivered.

[0210] Alternatively, when a malfunction is detected by the comparison of the comparison unit 325 , validity confirmation may be performed.

[0211] (2) Modification

[0212] Fig.11 The configuration of the ECU 31 and the ECU 32 in the modified example of the present embodiment is the same as Figure 4 (c2) corresponds.

[0213] ECU31 and ECU32 may be respectively Figure 2 However, in the present embodiment, each of the ECUs is a separate ECU connected via an integrated ECU.

[0214] The ECU 31 includes a storage unit 311, a control unit 312, a transmission unit 313, and a reception unit 314. The control unit 312 also includes a comparison unit 315 and a validity confirmation unit 316.

[0215] The ECU 32 includes a storage unit 321 , a control unit 322 , a transmission unit 323 , and a reception unit 324 .

[0216] The storage unit 321 stores a secret key S1 and a public key P1. The storage unit 311 stores a public key P2. The public key P1 and the public key P2 are the same key, but because they are stored in different storage units and may become different keys due to tampering by one party, different reference numerals are added here for distinction.

[0217] In this embodiment, similar to the variation of Embodiment 2, ECU 32 generates public key P1 using secret key S1. Then, transmission unit 323 transmits public key P1 to ECU 31, and reception unit 314 of ECU 31 receives public key P1. ECU 31 that has received the public key stores public key P1 in storage unit 311 as public key P2.

[0218] Furthermore, in the present embodiment, ECU32 transmits the generated public key P1 from the transmission unit 323 to the certification authority 300, and the certification authority 300 issues an electronic certificate of the public key P1 and transmits it to ECU32. The electronic certificate is a certificate that guarantees the public key P1 and the device having the public key. The receiving unit 324 of ECU32 receives the public key P1 to which the electronic certificate is attached, and stores the electronic certificate in the storage unit 321. Furthermore, the transmission unit 323 of ECU32 transmits the electronic certificate to ECU31, and the receiving unit 314 of ECU31 receives the electronic certificate. ECU31, which has received the electronic certificate, stores the electronic certificate in the storage unit 311.

[0219] Furthermore, the electronic certificate may be transmitted from the ECU 32 to the ECU 31 simultaneously with the transmission of the public key P1 .

[0220] Furthermore, the electronic certificate may be sent only once for the first time or may be sent periodically.

[0221] The method for storing the key information P2 in the distributed ledger 200 can use the method exemplified in Embodiment 1, but the certification authority 300 may send the public key P1 to the distributed ledger 200, and the distributed ledger 200 may generate and store the key information P2. Alternatively, the certification authority 300 may generate and send the key information P2 based on the public key P1, and the distributed ledger 200 may store the key information P2.

[0222] In this embodiment, the control unit 322 of the ECU 32 generates an electronic signature for the data sent to the ECU 31 using the secret key S1 read from the storage unit 321. The sending unit 323 sends the data and the electronic signature to the ECU 31 via the integrated ECU. The receiving unit 314 of the ECU 31 receives the data and the electronic signature. Then, the control unit 312 decrypts the electronic signature using the public key P1 read from the storage unit 311.

[0223] The comparison unit 315 compares the public key P2 stored in the storage unit 311 with the key information P2 stored in the distributed ledger 200 at a predetermined timing. The details of the comparison unit 315 are the same as those of the comparison unit 115 described in Embodiment 1, except that the comparison unit 315 uses the public key P2 and the key information P2, so the description of Embodiment 1 is replaced with the premise of citing this embodiment, and the description is omitted.

[0224] The validity confirmation unit 316 confirms the validity of the electronic certificate received from the ECU 32. Specifically, the validity confirmation unit 316 sends a confirmation signal from the sending unit 313 to the certification authority 300 to inquire about the validity of the electronic certificate of the public key P2. Then, the certification authority 300 that has received the confirmation signal confirms the validity of the electronic certificate indicated by the confirmation signal and sends the confirmation result to the ECU 31. In addition to the authenticity of the electronic certificate, the validity confirmation also confirms the validity period of the electronic certificate. The receiving unit 314 of the ECU 31 receives the confirmation result.

[0225] (3) Operation of the Electronic Control Units (ECU) 31 and 32

[0226] use Fig.12 The flowchart of will now be described with respect to the operations of comparing the public key P2 and encrypting the transmission data in the ECU 32 of the present embodiment.

[0227] First, the operation of the ECU 31 is performed. The control unit 312 of the ECU 31 generates a public key P1 using the secret key S1 (S311).

[0228] The transmission unit 313 transmits the generated public key P1 and a request for issuance of an electronic certificate to the certification authority 300 (S312).

[0229] The receiving unit 314 receives the electronic certificate issued by the certification authority 300 ( S313 ).

[0230] Then, the transmission unit 313 transmits the public key P1 and the electronic certificate to the ECU 32 ( S314 ).

[0231] Next, it is the operation of the ECU 32. The receiving unit 324 of the ECU 32 receives the public key P1 and the electronic certificate, and stores them in the storage unit 321 as the public key P2 and the electronic certificate (S321).

[0232] The validity confirmation unit 326 determines whether it is the timing to confirm the validity of the electronic certificate (S322). If it is the timing to confirm the validity of the electronic certificate (S322: Yes), the validity confirmation unit 326 sends a confirmation signal to the certification authority 300 to inquire about the validity of the electronic certificate, and receives the certification result from the certification authority 300 (S323). If it is not the timing to confirm the validity (S322: No), it proceeds to determine whether it is the specified timing (S325).

[0233] If the electronic certificate is valid (S324: Yes), the comparison unit 325 determines whether it is a predetermined timing (S325). If it is determined to be a predetermined timing (S325: Yes), the sending unit 323 sends a request for key information to the distributed ledger 200, and the receiving unit 324 receives the key information P2 sent from the distributed ledger 200 (S326).

[0234] The comparison unit 325 compares the public key P2 read from the storage unit 321 with the key information P2 received from the distributed ledger 200 (S327). If it is determined that the public key P2 has not been tampered with (S328: Yes), the data is encrypted and sent using the public key P2 (S329). If it is determined that the public key P2 has been tampered with (S328: No), the data is not encrypted and is not sent (S330). In addition, if the electronic certificate is not valid (S324: No), the data is not encrypted and is not sent (S330). And, if it is not determined to be the specified timing (S325: No), the data is encrypted and sent using the public key P2 (S329).

[0235] use Fig.13 The flowchart of FIG. 1 will be used to explain the operation of comparing the public key P2 and decrypting the electronic signature in the ECU 31 according to the modified example of the present embodiment.

[0236] First, the operation of the ECU 32 is performed. The control unit 322 of the ECU 32 generates a public key P1 using the secret key S1 (S311).

[0237] The transmission unit 323 transmits the generated public key P1 and a request for issuance of an electronic certificate to the certification authority 300 (S312).

[0238] The receiving unit 324 receives the electronic certificate issued by the certification authority 300 ( S313 ).

[0239] Then, the transmission unit 323 transmits the public key P1 and the electronic certificate to the ECU 31 ( S314 ).

[0240] Next, it is the operation of the ECU 31. The receiving unit 314 of the ECU 31 receives the public key P1 and the electronic certificate, and stores them in the storage unit 311 as the public key P2 and the electronic certificate (S321).

[0241] Thereafter, at an arbitrary timing, the receiving unit 314 of the ECU 31 receives the encrypted data ( S322 ). For example, the receiving unit 314 of the ECU 31 receives the electronic signature and data generated by the ECU 32 based on the secret key S1 .

[0242] The validity confirmation unit 316 determines whether it is the timing to confirm the validity of the electronic certificate (S323). If it is the timing to confirm the validity of the electronic certificate (S323: Yes), the validity confirmation unit 316 sends a confirmation signal to the certification authority 300 to inquire about the validity of the electronic certificate, and receives the certification result from the certification authority 300 (S324). If it is not the timing to confirm the validity (S323: No), it proceeds to determine whether it is the specified timing (S326).

[0243] If the electronic certificate is valid (S325: Yes), the comparison unit 315 determines whether it is a predetermined timing (S326). If it is determined to be a predetermined timing (S326: Yes), the sending unit 313 sends a request for key information to the distributed ledger 200, and the receiving unit 314 receives the key information P2 sent from the distributed ledger 200 (S327).

[0244] The comparison unit 315 compares the public key P2 read from the storage unit 311 with the key information P2 received from the distributed ledger 200 (S328). If it is determined that the public key P2 has not been tampered with (S329: Yes), the data and the electronic signature are decrypted using the public key P2 (S330). If it is determined that the public key P2 has been tampered with (S329: No), the data and the electronic signature cannot be decrypted (S331). In addition, when the electronic certificate is not valid (S325: No), the data and the electronic signature are not decrypted (S331). And, when it is not determined to be the specified timing (S326: No), the data and the electronic signature are decrypted using the public key P2 (S330).

[0245] (4) Others

[0246] This embodiment and its variants are all focused on two ECUs of the electronic control system 100 and are described as ECUs on the data transmission side and the data reception side, but the same is also true for other ECUs included in the electronic control system 100. In this case, the distributed ledger and certification authority used by other ECUs may be different from the distributed ledger 200 and the certification authority 300. That is, in the case where the electronic control system 100 is mixed with ECUs manufactured by multiple manufacturers and ECUs provided as independent services, for example, the distributed ledgers and certification authorities managed by the manufacturers and service providers of each ECU may be used separately.

[0247] (5) Summary

[0248] In addition to the effects of the first or second embodiment, this embodiment includes a validity confirmation unit, so that the security of the public key P2 can be further ensured by the electronic certificate issued by the certification authority.

[0249] Furthermore, by making the frequency of the validity check by the validity confirmation unit lower than the frequency of the predetermined timing related to the comparison, the traffic volume of the communication line can be appropriately suppressed and the security of the public key P2 can be improved.

[0250] 5. Implementation Method 4

[0251] In Embodiments 1 to 3, it is assumed that the distributed ledger 200 is installed outside the vehicle. This embodiment is a case where the distributed ledger 200 is also installed inside the vehicle, that is, in other ECUs included in the electronic control system 100 mounted on the vehicle.

[0252] use Fig.14 , an overview of this embodiment is described.

[0253] Fig.14 (a) shows the counterparts of the comparison and validation confirmation in Embodiment 3. In Embodiment 3, the comparison unit 325 of the ECU 32 uses the distributed ledger 200 as the comparison destination, and the validation unit 326 uses the authentication authority 300 as the validation destination.

[0254] Fig.14 (b) and Fig.14 (c) shows the counterparts of the comparison and validation in this embodiment. In this embodiment, the comparison unit 425 of the ECU 42 uses the distributed ledger set in the storage unit 411 of the integrated ECU as the comparison destination, and the validation unit 426 uses the certification authority 300 as the validation destination.

[0255] And in Fig.14 In (c), the comparison unit 415 of the integrated ECU uses the distributed ledger 200 as the comparison destination. Fig.14 The situation of (c) is described below.

[0256] use Fig.15 , the configuration of the ECU 42 and the integrated ECU in this embodiment will be described.

[0257] ECU41 and ECU42 may be respectively Figure 2 However, in the present embodiment, the ECU 41 is an integrated ECU and the ECU 42 is an independent ECU.

[0258] The ECU 41 (integrated ECU) (corresponding to a "second electronic control unit") includes a storage unit 411, a control unit 412, a transmission unit 413, and a reception unit 414. The control unit 412 includes a comparison unit 415.

[0259] The ECU 42 (corresponding to a “first electronic control unit”) includes a storage unit 421, a control unit 422, a transmission unit 423, and a reception unit 424. The control unit 422 also includes a comparison unit 425 and a validity confirmation unit 426.

[0260] Hereinafter, only the parts different from Implementation Example 3 will be described, and the parts identical to Implementation Example 3 will refer to the description of Implementation Example 3.

[0261] In this embodiment, the storage unit 411 of the ECU 41 (integrated ECU) assumes the function of the distributed ledger observed from the ECU 42. That is, the public key P1 generated from the secret key S1 is stored in the distributed ledger set in the storage unit 411 (corresponding to the "first distributed ledger").

[0262] Moreover, the comparison unit 425 of ECU42 (equivalent to the "first comparison unit") compares the public key P2 stored in its own storage unit 421 with the public key P1 of the distributed ledger that is not stored in the distributed ledger 200 but stored in the storage unit 411 set in ECU41 (integrated ECU) at a prescribed timing (equivalent to the "first prescribed timing").

[0263] In this example, the public key P1 itself is stored in the distributed ledger set in the storage unit 411, but the key information P1 of the public key P1 may be stored.

[0264] In addition, it is not necessary to set up a distributed ledger in the storage unit 411, and it is sufficient as long as the storage unit 411 stores the public key P1 or the key information P1.

[0265] In addition, the comparison unit 415 (equivalent to the "second comparison unit") of the ECU 41 (integrated ECU) compares the public key P1 stored in the storage unit 411 with the key information P2 stored in the distributed ledger 200 (equivalent to the "second distributed ledger") at a predetermined timing (equivalent to the "second predetermined timing"). The structure and operation of the ECU 41 (integrated ECU) are the same as those of the second embodiment and the third embodiment.

[0266] Preferably, when comparing the specified timing frequency of the comparison of ECU41 (integrated ECU) with the specified timing frequency of the comparison of ECU42, the former is lower than the latter. It is relatively rare to tamper with the keys of multiple ECUs included in the electronic control system 100 at the same time, so it is usually possible to confirm the presence of tampering by comparing with the public key P1 of the integrated ECU. In addition, it is also possible to access the distributed ledger 200 outside the vehicle to confirm the presence of tampering to prevent simultaneous tampering.

[0267] This makes it possible to reduce the frequency of communication with the outside without reducing the frequency of comparison of the public key P1, and to effectively use the resources of the communication line.

[0268] In addition, this embodiment is different from Embodiment 3. Fig.10 The corresponding structure may also be the same as that of Embodiment 3. Fig.11 The corresponding composition.

[0269] 6. Other Implementation Methods

[0270] The examples of Embodiments 1 to 4 can be applied to the entire vehicle-mounted electronic control system 100 or only to a part of the electronic control system 100. For example, they can be applied only to ECUs controlling cameras, radars, and LiDARs, or between these ECUs and an integrated ECU.

[0271] 7. Summary

[0272] In the above, the features of the electronic control device, the distributed ledger, the authentication authority, etc. in each embodiment of the present disclosure have been described.

[0273] The sentences used in the embodiments are merely examples and may be replaced with sentences having the same meaning or sentences having the same function.

[0274] The block diagram used to illustrate the implementation method is a block diagram that classifies and organizes the configuration of the device according to function. The modules showing each function are implemented by any combination of hardware or software. In addition, since the functions are shown, such a block diagram can also be grasped as a disclosure of the invention of the method and the invention of the program that implements the method.

[0275] The functional blocks that can be understood as the processing, flow, and method described in each embodiment may be rearranged in order unless there is a restriction such as a relationship in which one step utilizes the result of another step in the previous stage.

[0276] The terms “first”, “second”, and “N” (N is an integer) used in each embodiment and claim are used to distinguish two or more configurations or methods of the same kind, and do not limit the order or superiority or inferiority.

[0277] In each embodiment, the electronic control device disclosed in each embodiment is described on the premise that the vehicle is equipped with the electronic control device, but the premise may also be that the electronic control device is held by a pedestrian.

[0278] In addition, the following examples can be cited as examples of the form of the electronic control device, distributed ledger, and authentication agency of the present disclosure.

[0279] Examples of the form of the component include a semiconductor element, an electronic circuit, a module, and a microcomputer.

[0280] Examples of the semi-finished product include an electronic control unit (ECU (Electric Control Unit)) and a system board.

[0281] As the form of the finished product, there can be listed a mobile phone, a smartphone, a tablet, a personal computer (PC), a workstation, a server, and a cloud server.

[0282] In addition, it also includes devices having a communication function, for example, video cameras, still cameras, and car navigation systems.

[0283] In addition, required functions such as antennas and communication interfaces can be added to electronic control devices, distributed ledgers, and certification agencies.

[0284] It is assumed that the distributed ledger and certification authority of the present disclosure are used for the purpose of providing various services. With the provision of such services, the distributed ledger and certification authority of the present disclosure are used, the method of the present disclosure is used, or / and the program of the present disclosure is executed.

[0285] In addition, the present disclosure can be implemented not only by dedicated hardware having the structure and functions described in each embodiment, but also as a combination of a program for implementing the present disclosure recorded on a recording medium such as a memory or a hard disk, and general-purpose hardware having a dedicated or general-purpose CPU and memory capable of executing the program.

[0286] Programs stored in non-migratable physical recording media (e.g., external storage devices (hard disks, USB memories, CD / BDs, etc.) or internal storage devices (RAM, ROM, etc.)) of dedicated or general-purpose hardware can also be provided to the dedicated or general-purpose hardware via the recording medium, or from a server via a communication line without using a recording medium. Thus, the latest functions can be always provided through program upgrades.

[0287] The electronic control device disclosed in the present invention is mainly described as an electronic control device for a vehicle mounted on an automobile, but can of course be applied to motorcycles, bicycles with electric motors, railways, and also to the entirety of moving objects such as pedestrians, ships, and airplanes.

Claims

1. An electronic control device (11, 12, 21, 22, 31, 32, 41, 42) mounted on a vehicle, wherein: have: a storage unit (111, 121, 211, 221, 311, 321, 411, 421) for storing a key; and The comparison unit (115, 125, 215, 225, 315, 325, 415, 425) compares the key stored in the storage unit with key information stored in a distributed ledger (200) provided outside the vehicle at a predetermined timing, wherein the key information is information related to the key.

2. The electronic control device according to claim 1, wherein: The electronic control device further comprises: a receiving unit (314, 324) for receiving the electronic certificate of the key; and The validity confirmation unit (316, 326) confirms the validity of the electronic certificate with the certification authority (300).

3. The electronic control device according to claim 2, wherein: The frequency of the validity check by the validity checking unit is lower than the frequency of the predetermined timing.

4. The electronic control device according to claim 1, wherein: The storage unit stores the comparison result of the comparison unit. When the key is used, it is determined whether to use the key based on the comparison result.

5. The electronic control device according to claim 1, wherein: In addition to the second distributed ledger as the above-mentioned distributed ledger, a first distributed ledger is set in the above-mentioned vehicle.

6. The electronic control device according to any one of claims 1 to 5, wherein: When the vehicle is capable of communicating with the outside during traveling of the vehicle, the predetermined timing is every first predetermined time.

7. The electronic control device according to claim 6, wherein: The first predetermined time is determined according to the speed of the vehicle.

8. The electronic control device according to any one of claims 1 to 5, wherein: When the vehicle does not communicate with the outside for more than the second predetermined time, the predetermined timing is within a third predetermined time from when the vehicle resumes communication with the outside.

9. The electronic control device according to any one of claims 1 to 5, wherein: When the vehicle is parked and the vehicle can communicate with the outside, the predetermined timing is every fourth predetermined time.

10. A key comparison method is a key comparison method performed in an electronic control device mounted on a vehicle, wherein: The key is stored in the storage unit (S111, S121, S321), At a predetermined timing, the key stored in the storage unit is compared with key information stored in a distributed ledger provided outside the vehicle (S116, S125, S327, S328), wherein the key information is information related to the key.

11. A key comparison program, which is executable in an electronic control device mounted in a vehicle, wherein: The key is stored in the storage unit (S111, S121, S321), At a predetermined timing, the key stored in the storage unit is compared with key information stored in a distributed ledger provided outside the vehicle (S116, S125, S327, S328), wherein the key information is information related to the key.

12. An electronic control system (100) comprising a plurality of electronic control devices mounted on a vehicle, wherein: The plurality of electronic control devices mentioned above respectively include: a storage unit for storing a key; and The comparison unit compares the key stored in the storage unit with key information, which is information related to the key and stored in a distributed ledger, at a predetermined timing.

13. The electronic control system according to claim 12, wherein: When the plurality of electronic control devices are set as a first electronic control device and a second electronic control device, The predetermined timing in the first electronic control unit is different from the predetermined timing in the second electronic control unit.

14. A key management system, comprising an electronic control device mounted on a vehicle and a distributed ledger (200) disposed outside the vehicle, wherein: The electronic control device comprises: a storage unit for storing a key; and The comparison unit compares the key stored in the storage unit with key information, which is information related to the key stored in the distributed ledger, at a predetermined timing.

15. A key management system, comprising an electronic control device mounted on a vehicle, a distributed ledger (200) disposed outside the vehicle, and a certification authority (300), wherein: The electronic control device comprises: A storage unit for storing keys; a comparison unit that compares the key stored in the storage unit with information related to the key stored in the distributed ledger, that is, key information, at a predetermined timing; and The validity confirmation unit confirms the validity of the electronic certificate related to the key with the certification authority.

16. A key management system, comprising an electronic control system, the electronic control system comprising a first electronic control device and a second electronic control device mounted on a vehicle, wherein: The first electronic control device comprises: A first storage unit storing a key; and The first comparison unit compares the key stored in the first storage unit with first key information, which is information related to the key and stored in the second electronic control unit, at a first predetermined timing. The second electronic control device comprises: A second storage unit stores the key; and The second comparison unit compares the key stored in the second storage unit with second key information stored in a distributed ledger provided outside the vehicle at a second predetermined timing, wherein the second key information is information related to the key.

17. The key management system according to claim 16, wherein: The frequency of the second predetermined timing is lower than the frequency of the first predetermined timing.

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