JP6203798B2 - In-vehicle control system, vehicle, management device, in-vehicle computer, data sharing method, and computer program - Google Patents

Description

  The present invention relates to an in-vehicle control system, a vehicle, a management device, an in-vehicle computer, a data sharing method, and a computer program.

  In recent years, automobiles have an ECU (Electronic Control Unit) and realize functions such as engine control by the ECU. The ECU is a kind of computer and realizes a desired function by a computer program. For example, Non-Patent Document 1 discloses a security technique for an in-vehicle control system configured by connecting a plurality of ECUs to a CAN (Controller Area Network).

Keisuke Takemori, “Protection of in-vehicle control systems based on secure elements-Organizing and considering elemental technologies-”, IEICE, IEICE Technical Report, vol. 114, no. 508, pp. 73-78, 2015 March

  In the security technology of the conventional in-vehicle control system, it is a problem to improve the security performance in order to further adapt to the situation where quick control is required after the engine is started. For example, when the same data is shared by a plurality of ECUs after the engine is started, one of the problems is to reduce the time required for sharing while maintaining the security strength of the data to some extent.

  The present invention has been made in consideration of such circumstances, and provides an in-vehicle control system, a vehicle, a management device, an in-vehicle computer, a data sharing method, and a computer program capable of improving security performance. Is an issue.

(1) According to one aspect of the present invention, in a vehicle-mounted control system provided in a vehicle, the vehicle includes a management device that communicates with a frame via a communication network provided in the vehicle, and a plurality of vehicle-mounted computers. A first communication unit that transmits and receives the frame via the first data storage unit, a first data storage unit that stores first data whose data length exceeds the upper limit of a data length that can be stored in one frame, and a single data frame that can be stored. A second data generating unit that generates second data having a different data length, and generating third data shared by the plurality of in-vehicle computers using the first data and the second data A third data generation unit configured to transmit the second data storage frame, which is the frame storing the second data, to the communication network. The in-vehicle computer transmits the frame via the communication network, the first data storage unit stores the first data, and the in-vehicle computer. The first data stored in the first data storage unit and the communication unit of the in-vehicle computer are stored in the second data storage frame received from the management device via the communication network. A vehicle-mounted control system comprising: a third data generation unit that generates the third data using second data.
(2) In one aspect of the present invention, in the in-vehicle control system according to (1), the communication unit of the management device transmits the second data storage frame by broadcast or multicast, and the communication unit of the in-vehicle computer Is an in-vehicle control system that receives the second data storage frame by broadcast or multicast.
(3) According to one aspect of the present invention, in the in-vehicle control system according to any one of the above (1) and (2), the in-vehicle computer uses the third data as information related to communication performed via the communication network. It is an in-vehicle control system used for the initial value.
(4) One aspect of the present invention is the in-vehicle control system according to (3), in which the communication-related information is a counter value for the frame.
(5) One aspect of the present invention is the in-vehicle control system according to (4), wherein the counter value is used to generate a message authentication code for a message exchanged via the communication network. It is.
(6) One aspect of the present invention is the vehicle-mounted control system according to any one of (1) and (2), wherein the vehicle-mounted computer uses the third data for communication performed via the communication network. It is an in-vehicle control system used for the key to be used.
(7) According to one aspect of the present invention, in the in-vehicle control system according to any one of (1) to (6), the management device includes a data update unit that changes the first data at a predetermined timing; An encryption processing unit that encrypts the first data after the change with a first key shared by the management device and the in-vehicle computer, and the communication unit of the management device is a result of the encryption. A first encrypted data storage frame, which is the frame storing the first encrypted data, is transmitted to the in-vehicle computer via the communication network, and the in-vehicle computer has the communication unit of the in-vehicle computer Cryptographic processing unit for decrypting the first encrypted data stored in the first encrypted data storage frame received from the management device via the communication network with the first key Comprises a data updating unit for updating the first data of the own-vehicle computer by the results of No. 該復, and an in-vehicle control system.
(8) According to one aspect of the present invention, in the in-vehicle control system according to (7), the data update unit of the management device changes the first key at a predetermined timing, and the encryption processing of the management device The unit encrypts the first key after the change with a second key shared by the management device and the in-vehicle computer, and the communication unit of the management device is a second result of the encryption. A second encrypted data storage frame that is the frame storing encrypted data is transmitted to the in-vehicle computer via the communication network, and the encryption processing unit of the in-vehicle computer is configured by the communication unit of the in-vehicle computer. Decrypting the second encrypted data stored in the second encrypted data storage frame received from the management device via the communication network with the second key, and The data updating unit of the computer updates the first key of the self-vehicle computer by the results of No. 該復 a vehicle control system.

(9) One aspect of the present invention is a vehicle including the vehicle-mounted control system according to any one of (1) to (8).

(10) According to one aspect of the present invention, in the management device of an in-vehicle control system provided in the vehicle including a management device that communicates by a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers, the communication network includes A communication unit that transmits and receives the frame, and a first data that is data having a data length that exceeds an upper limit of a data length that can be stored in one frame and that is shared by the management device and the in-vehicle computer A plurality of the data storage unit, a second data generation unit that generates second data having a data length that can be stored in one frame, the first data, and the second data. A third data generation unit that generates third data shared by the in-vehicle computer, and the communication unit stores the second data before The second data storage frame is a frame, and transmits to the onboard computer via the communication network, a management device.

(11) According to one aspect of the present invention, in the in-vehicle computer of the in-vehicle control system provided in the vehicle including a management device that communicates with a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers, the communication network A communication unit that transmits and receives the frame, and a first data that is data having a data length that exceeds an upper limit of a data length that can be stored in one frame and that is shared by the management device and the in-vehicle computer A data storage unit, the first data stored in the first data storage unit, and the frame received by the communication unit from the management device via the communication network and can be stored in one frame The second data stored in the second data storage frame storing the second data having a long data length. It is using the data, an in-vehicle computer and a third data generation unit for generating a third data shared by a plurality of the onboard computer, the.

(12) According to one aspect of the present invention, in the data sharing method of the in-vehicle control system provided in the vehicle including a management device that communicates with a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers, the management device includes: A first data storing step for storing first data having a data length exceeding an upper limit of a data length that can be stored in one frame; and a second data length in which the management device can store data in one frame. A second data generating step for generating the data, and a transmitting step in which the management device transmits a second data storage frame, which is the frame storing the second data, to the in-vehicle computer via the communication network. And the management device uses the first data and the second data to provide a plurality of the in-vehicle computers. A third data generating step for generating third data shared by the in-vehicle computer, a second first data storing step in which the in-vehicle computer stores the first data, and the in-vehicle computer from the management device A receiving step of receiving the second data storage frame via the communication network; and the in-vehicle computer receiving the first data stored in the second first data storing step and the first data received in the receiving step. And a second third data generation step of generating the third data using the second data stored in the two data storage frames.

(13) According to one aspect of the present invention, one frame is included in a computer of the management device of the in-vehicle control system provided in the vehicle including a management device that communicates with a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers. A first data storage function for storing data having a data length exceeding the upper limit of the data length that can be stored in the management apparatus and the first data shared by the management device and the in-vehicle computer, and can be stored in one frame Communication for transmitting a second data generation function for generating second data having a data length and a second data storage frame, which is the frame storing the second data, to the in-vehicle computer via the communication network Function, shared by the plurality of in-vehicle computers using the first data and the second data A third data generation function of generating a third data, a computer program for implementing the.

(14) According to one aspect of the present invention, a management device that communicates with a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers are stored in the in-vehicle computer of the in-vehicle control system provided in the vehicle. A data length exceeding the upper limit of possible data length, a first data storage function for storing first data shared by the management device and the in-vehicle computer, and a data length that can be stored in one frame A communication function for receiving a second data storage frame, which is the frame storing the second data, from the management device via the communication network, and the first data stored by the first data storage function. Data and the second data stored in the second data storage frame received by the communication function; Use a computer program for realizing a third data generation function of generating a third data shared by a plurality of the onboard computer.

  According to the present invention, an effect that security performance can be improved can be obtained.

It is a lineblock diagram showing in-vehicle control system 2 of car 1 concerning one embodiment of the present invention. It is a sequence chart which shows the data sharing method which concerns on one Embodiment of this invention. 1 is a configuration diagram illustrating a first embodiment of a management apparatus 10. FIG. 1 is a configuration diagram illustrating Example 1 of an ECU 50. FIG. 3 is a sequence chart illustrating a counter initial value sharing method according to the first embodiment. 3 is a sequence chart illustrating a session key sharing method according to the first embodiment. 3 is a sequence chart showing a first stage of a key exchange key update method according to Embodiment 1. 6 is a sequence chart showing a second stage of the key exchange key update method according to the first embodiment. FIG. 3 is a configuration diagram illustrating Example 2 of an automobile 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiment, a vehicle will be described as an example of a vehicle.

  FIG. 1 is a configuration diagram showing an in-vehicle control system 2 for an automobile 1 according to an embodiment of the present invention. In FIG. 1, an automobile 1 includes a management device 10 and an ECU (electronic control device) 50. The management device 10 and the ECU 50 are connected to the CAN 40. CAN is known as one of communication networks mounted on vehicles such as automobiles. In this embodiment, CAN is used for the vehicle-mounted network for controlling the automobile 1, but a communication network other than CAN may be used for the vehicle-mounted network for controlling the automobile 1.

  The ECU 50 is an in-vehicle computer provided in the automobile 1. The ECU 50 is, for example, a drive system ECU, a vehicle body system ECU, a safety control system ECU, or the like. The in-vehicle control system 2 includes a management device 10 that communicates with a frame via the CAN 40 and a plurality of ECUs 50. The CAN 40 transmits data using a frame. The management device 10 exchanges data with each ECU 50 by a frame via the CAN 40. The ECU 50 exchanges data with other ECUs 50 by means of a frame via the CAN 40.

  The CAN 40 frame defines an upper limit of the data length that can be stored in the frame. For example, in a data frame which is one of the CAN40 frame types, the upper limit of the data length that can be stored in the data field is 64 bits.

  In FIG. 1, the management device 10 includes a communication unit 11, a first data storage unit 12, a second data generation unit 13, a third data generation unit 14, a data update unit 15, and an encryption processing unit 16. The communication unit 11 transmits and receives a frame via the CAN 40. The first data storage unit 12 stores first data having a data length that exceeds the range of data length that can be stored in one frame. In the present embodiment, the first data has a data length that exceeds the upper limit “64 bits” of the data length that can be stored in the data field of the data frame. Therefore, the data length of the first data is 65 bits or more. The first data is shared between the management device 10 and the ECU 50.

  The second data generation unit 13 generates second data having a data length that can be stored in one frame. In the present embodiment, the second data has a data length that can be stored in the data field of the data frame. Therefore, the data length of the second data is 64 bits or less. The third data generation unit 14 generates the third data shared by the plurality of ECUs 50 using the first data and the second data. The data update unit 15 changes the first data and the like at a predetermined timing. The encryption processing unit 16 executes encryption processing such as data encryption.

  The communication unit 11 transmits a second data storage frame, which is a data frame in which the second data is stored in the data field, to the ECU 50 via the CAN 40. The communication unit 11 may transmit the second data storage frame by broadcast or multicast. By transmitting the second data storage frame by broadcast or multicast, the transmission time can be shortened as compared with the case where the second data storage frame is transmitted to each ECU 50 by unicast.

  In FIG. 1, the ECU 50 includes a communication unit 51, a first data storage unit 52, a third data generation unit 53, a data update unit 54, and an encryption processing unit 55. The communication unit 51 transmits and receives a frame via the CAN 40. The first data storage unit 52 stores first data shared by the management device 10 and the ECU 50. The first data stored in the first data storage unit 52 is the same as the first data stored in the first data storage unit 12 of the management device 10.

  The third data generation unit 53 stores the first data stored in the first data storage unit 52 and the second data storage frame received by the communication unit 51 from the management apparatus 10 via the CAN 40. The second data is used to generate the third data. The third data is data shared by the plurality of ECUs 50. The data update unit 54 updates the first data of the own ECU 50 and the like. The encryption processing unit 55 performs encryption processing such as decryption of encrypted data.

  Next, the data sharing operation of the in-vehicle control system 2 according to the present embodiment will be described with reference to FIG. FIG. 2 is a sequence chart showing the data sharing method according to the present embodiment. In FIG. 2, the management device 10 and the ECU 50 have first data shared in advance. The management device 10 stores the first data in the first data storage unit 12. The ECU 50 stores the first data in the first data storage unit 52.

(Step S1) In the management device 10, the second data generation unit 13 generates second data. For example, the second data generation unit 13 generates a random number having a data length of 64 bits.

(Step S2) In the management device 10, the communication unit 11 transmits a second data storage frame, which is a data frame in which the second data is stored in the data field, to the ECU 50 via the CAN 40. The communication unit 11 transmits the second data storage frame by broadcast, for example. In the ECU 50, the communication unit 51 receives the second data storage frame from the management device 10 via the CAN 40.

(Step S <b> 3) In the management device 10, the third data generation unit 14 reads the first data from the first data storage unit 12. In the ECU 50, the third data generation unit 53 reads the first data from the first data storage unit 52.

(Step S4) In the management device 10, the third data generation unit 14 uses the first data read from the first data storage unit 12 and the second data generated by the second data generation unit 13, Third data is generated. In the ECU 50, the third data generation unit 53 uses the first data read from the first data storage unit 52 and the second data stored in the second data storage frame received by the communication unit 51. Then, the third data is generated. The third data generation method is the same for the third data generation unit 14 of the management device 10 and the third data generation unit 53 of the ECU 50. Thereby, the same 3rd data can be shared by several ECU50.

  As the third data generation method, irreversible compression processing may be used. As the third data generation method, for example, encryption, generation of a hash value, or exclusive OR operation can be used. For example, a value obtained by encrypting the second data using the first data as a key may be the third data. For example, CMAC (Cipher-based Message Authentication Code) may be calculated as the encrypted value. Alternatively, a hash value of data obtained by concatenating the first data and the second data may be calculated, and the hash value may be the third data. As a hash value generation method, SHA-1 or SHA-2 can be used. Alternatively, the exclusive OR of the first data and the second data may be the third data.

  According to the present embodiment, a plurality of ECUs 50 can share the same third data. The second data transmitted from the management apparatus 10 to the ECU 50 when sharing the third data has a data length of 64 bits or less. Therefore, when the second data is transmitted to each ECU 50, it is sufficient to transmit one data frame if it is transmitted by broadcast. Then, in the management device 10 and the ECU 50, third data is generated using the second data and the first data shared by the management device 10 and the ECU 50. By setting the data length of the first data to a value that can satisfy the request for the security strength of the third data, the request for the security strength of the third data can be met. Thereby, when the same 3rd data is shared by several ECU50, the effect that the time concerning sharing can be shortened, maintaining the security intensity | strength of this 3rd data to some extent is acquired.

  Note that any ECU provided in the automobile 1 may function as the management device 10.

  Next, examples of the present embodiment will be described.

[Example 1]
FIG. 3 is a configuration diagram illustrating Example 1 of the management apparatus 10 according to the present embodiment. In FIG. 3, the management device 10 includes a communication unit 11, a key exchange key storage unit 21, a random number generation unit 22, a counter initial value generation unit 23, a session key generation unit 24, a data update unit 15, a cryptographic processing unit 16, and a common key. A storage unit 25 is provided. The communication unit 11 transmits and receives a frame via the CAN 40. The key exchange key storage unit 21 stores a key exchange key. The key exchange key is shared in advance between the management device 10 and the ECU 50. The key exchange key is an example of first data. As the key exchange key, for example, a common key based on AES (Advanced Encryption Standard) can be used. For example, the key exchange key is a common key whose key length by AES is 256 bits. The key exchange key storage unit 21 is an example of the first data storage unit 12.

  The random number generator 22 generates a random number. The random number is an example of second data. For example, the random number generation unit 22 generates a random number having a data length of 64 bits. The random number generation unit 22 is an example of the second data generation unit 13. The counter initial value generation unit 23 generates a counter initial value. The counter initial value is an example of third data. The counter initial value generation unit 23 is an example of the third data generation unit 14. The session key generation unit 24 generates a session key. The session key is an example of third data. The session key generation unit 24 is an example of the third data generation unit 14. The data update unit 15 changes the key exchange key and the like at a predetermined timing. The encryption processing unit 16 executes encryption processing such as data encryption. The common key storage unit 25 stores a common key. The common key is shared between the management device 10 and the ECU 50.

  FIG. 4 is a configuration diagram illustrating Example 1 of the ECU 50 according to the present embodiment. 4, the ECU 50 includes a transmission unit 111, a reception unit 112, a frame reception processing unit 113, a MAC (Message Authentication Code) generation unit 114, a counter unit 115, a MAC inspection unit 116, and a session key storage unit 117. A key exchange key storage unit 118, a session key generation unit 119, a counter initial value generation unit 120, a data update unit 54, an encryption processing unit 55, and a common key storage unit 121 are provided.

  The transmission unit 111 transmits the data frame to the CAN 40. The receiving unit 112 receives a data frame from the CAN 40. The transmission unit 111 and the reception unit 112 are included in the communication unit 51 of the ECU 50 shown in FIG. Data such as transmission data stored in the data frame is input to the transmission unit 111. The transmission unit 111 transmits a data frame in which the input data is stored in a corresponding part of the data frame to the CAN 40. The transmission data is stored in the data field of the data frame. The frame reception processing unit 113 performs a reception process on the data frame received from the CAN 40 by the reception unit 112. The MAC generation unit 114 generates a MAC.

  The counter unit 115 has a function as a transmission counter unit and a function as a reception counter unit. As a function of the transmission counter unit, the counter unit 115 holds a transmission counter value that is incremented by a predetermined count value each time a data frame is transmitted by the transmission unit 111. In the first embodiment, the count value is 1. Therefore, the counter unit 115 holds a transmission counter value that is incremented by 1 each time the transmission unit 111 transmits a data frame to the CAN 40. This transmission counter value is incremented by 1 every time the own ECU 50 transmits a data frame to the CAN 40.

  As a function of the reception counter unit, the counter unit 115 holds a reception counter value that is incremented by the same predetermined count value as the transmission counter unit every time the data frame is received by the reception unit 112. In the first embodiment, the count value is 1. Therefore, the counter unit 115 holds a reception counter value that is incremented by 1 every time the reception unit 112 receives a data frame from the CAN 40. This reception counter value is provided for each ID (identifier) in the data frame. The ID is an ID assigned to the ECU 50 or the management apparatus 10 that has transmitted the data frame, and is stored in an ID field in the data frame. For example, each time the receiving unit 112 receives a data frame of IDx from the CAN 40, the reception counter value of IDx is incremented by one.

  For example, the in-vehicle control system 2 includes five ECUs 50, and the IDs of the five ECUs 50 are ID1, ID2, ID3, ID4, and ID5. In this case, the counter unit 115 holds five counter values (ID1 counter value, ID2 counter value, ID3 counter value, ID4 counter value, ID5 counter value) corresponding to a total of five ID1 to ID5. In the counter unit 115, a counter value corresponding to the ID of the own ECU 50 is a transmission counter value, and a counter value corresponding to an ID other than the ID of the own ECU 50 is a reception counter value. For example, in the ECU 50 of ID1, the ID1 counter value is a transmission counter value, the ID2 counter value is a reception counter value corresponding to ID2, the ID3 counter value is a reception counter value corresponding to ID3, and the ID4 counter value is This is a reception counter value corresponding to ID4, and the ID5 counter value is a reception counter value corresponding to ID5.

  The MAC checking unit 116 checks the MAC acquired from the data frame received from the CAN 40 by the receiving unit 112. The session key storage unit 117 stores a session key. The key exchange key storage unit 118 stores a key exchange key. The key exchange key is shared in advance between the management device 10 and the ECU 50. The key exchange key is an example of first data. The key exchange key storage unit 118 is an example of the first data storage unit 52. The session key generation unit 119 generates a session key. The session key is an example of third data. The session key generation unit 119 is an example of the third data generation unit 53. The counter initial value generation unit 120 generates a counter initial value. The counter initial value generated by the counter initial value generation unit 120 is used as the initial value of the counter value of the counter unit 115. The counter initial value is an example of third data. The counter initial value generation unit 120 is an example of the third data generation unit 53.

  The data updating unit 54 updates the key exchange key of the own ECU 50 and the like. The encryption processing unit 55 performs encryption processing such as decryption of encrypted data. The common key storage unit 121 stores a common key. The common key is shared between the management device 10 and the ECU 50.

  The MAC generation unit 114 generates a MAC by using the transmission data stored in the data field in the data frame, the transmission counter value of the counter unit 115, and the session key stored in the session key storage unit 117. For example, a hash value is calculated as the MAC. As a hash value generation method, SHA-1 or SHA-2 can be used. The transmission unit 111 stores transmission data and a MAC generated using the transmission data in a predetermined part for the data frame. The transmission unit 111 transmits the data frame storing the transmission data and the MAC generated using the transmission data to the CAN 40. The counter unit 115 increases the transmission counter value by 1 by transmission of the data frame and holds it.

  The MAC inspection unit 116 acquires received data from the data field in the inspection target frame that is the data frame received by the reception unit 112. Further, the MAC inspection unit 116 acquires a reception counter value corresponding to the ID stored in the ID field in the inspection target frame from the counter unit 115. The MAC checking unit 116 generates a MAC (referred to as “calculated MAC” for convenience of explanation) by using the acquired reception data and reception counter value and the session key stored in the session key storage unit 117. This MAC generation method is calculated by the same calculation method (for example, SHA-2) as the MAC generation unit 114 described above.

  The MAC inspection unit 116 acquires the MAC from a predetermined part in the inspection target frame. The MAC inspection unit 116 performs MAC inspection using the MAC acquired from the inspection target frame and the calculated MAC for the inspection target frame. For example, it is determined whether the MAC acquired from the inspection target frame matches the calculated MAC for the inspection target frame. When the MAC inspection is successful, the MAC inspection unit 116 notifies the frame reception processing unit 113 of the inspection pass of the inspection target frame. As a result, the frame reception processing unit 113 performs a predetermined reception process on the normally received data frame on the inspection target frame received by the reception unit 112. In addition, the MAC inspection unit 116 notifies the counter unit 115 that the inspection target frame has passed the inspection. Thereby, the counter unit 115 increments the reception counter value corresponding to the ID of the inspection target frame by 1 and holds it. On the other hand, when the MAC inspection fails, a predetermined error process is executed.

  In the MAC generation and inspection described above, the counter value of the counter unit 115 is used. If the initial value of the counter value of each counter unit 115 of the plurality of ECUs 50 provided in the in-vehicle control system 2 is not the same, the result of the MAC inspection becomes unreliable. For this reason, in the first embodiment, a process of sharing the initial value of the counter value of the counter unit 115 among a plurality of ECUs 50 is executed. Hereinafter, the counter initial value sharing method according to the first embodiment will be described with reference to FIG.

  FIG. 5 is a sequence chart illustrating the counter initial value sharing method according to the first embodiment. In FIG. 5, the management device 10 and the ECU 50 have the same key exchange key shared in advance. The management device 10 stores the key exchange key in the key exchange key storage unit 21. The ECU 50 stores the key exchange key in the key exchange key storage unit 118.

  Note that when the counter initial value sharing method shown in FIG. 5 is executed, the MAC is not stored in the data frame. Therefore, the data frame receiver does not perform MAC inspection. This is because the MAC inspection is normally performed until the counter initial value used as the initial value of the counter value of the counter unit 115 of the ECU 50 is shared by the plurality of ECUs 50 by executing the counter initial value sharing method. This is because you cannot.

(Step S11) In the management device 10, the random number generation unit 22 generates a random number. For example, the random number generation unit 22 generates a random number having a data length of 64 bits.

(Step S12) In the management device 10, the communication unit 11 transmits a second data storage frame, which is a data frame in which the random number is stored in the data field, to the ECU 50 via the CAN 40. The communication unit 11 transmits the second data storage frame by broadcast, for example. In the ECU 50, the communication unit 51 receives the second data storage frame from the management device 10 via the CAN 40.

(Step S <b> 13) In the management device 10, the counter initial value generation unit 23 reads the key exchange key from the key exchange key storage unit 21. In the ECU 50, the counter initial value generation unit 120 reads the key exchange key from the key exchange key storage unit 118.

(Step S <b> 14) In the management device 10, the counter initial value generation unit 23 generates a counter initial value using the key exchange key read from the key exchange key storage unit 21 and the random number generated by the random number generation unit 22. . In the ECU 50, the counter initial value generation unit 120 uses the key exchange key read from the key exchange key storage unit 118 and the random number stored in the second data storage frame received by the communication unit 51 to generate a counter initial value. Generate a value. The counter initial value generated by the counter initial value generation unit 120 is set as the initial value of the counter value of the counter unit 115.

  The counter initial value generation method is the same for the counter initial value generation unit 23 of the management apparatus 10 and the counter initial value generation unit 120 of the ECU 50. The method for generating the counter initial value may be the same as the method for generating the third data described above. For example, a value obtained by encrypting a random number with a key exchange key (for example, CMAC) may be used as the counter initial value. Alternatively, a hash value of data obtained by concatenating a key exchange key and a random number may be calculated, and the hash value may be used as a counter initial value. Alternatively, the exclusive OR of the key exchange key and the random number may be used as the counter initial value.

  The above is the description of the counter initial value sharing method according to the first embodiment. According to the counter initial value sharing method according to the first embodiment, a plurality of ECUs 50 can share the same counter initial value. Furthermore, when the same counter initial value is shared by a plurality of ECUs 50, the time required for sharing can be reduced while maintaining the security strength of the counter initial value to some extent. This effect will be described by taking as an example a case where the data length of the counter initial value is 256 bits as a request for the security strength of the counter initial value. In this case, when the 256-bit counter initial value is transmitted to each ECU 50 in a data frame, the upper limit of the data length that can be stored in the data field of the data frame is 64 bits. Four data frames need to be transmitted.

  On the other hand, according to the first embodiment, the random number transmitted from the management device 10 to the ECU 50 has a data length of 64 bits or less. For example, a 64-bit random number. Therefore, when the random number is transmitted to each ECU 50, it is only necessary to transmit one data frame if it is transmitted by broadcast. Then, in the management device 10 and the ECU 50, a counter initial value is generated using the random number and a key exchange key shared by the management device 10 and the ECU 50. By setting the data length of the key exchange key to 256 bits, a 256-bit counter initial value can be generated using, for example, a 64-bit random number and a 256-bit key exchange key. As a result, when the same counter initial value is shared by a plurality of ECUs 50, the time required for sharing is reduced while maintaining a request for the security strength of the counter initial value (the data length of the counter initial value is 256 bits). The effect of being able to be obtained.

  Next, a session key sharing method according to the first embodiment will be described. The session key is used for communication performed via the CAN 40 such as the above-described MAC generation and inspection. If the session keys of the management device 10 and the ECU 50 provided in the in-vehicle control system 2 are not the same, communication using the session key becomes unreliable. For this reason, in the first embodiment, a process of sharing the session key between the management device 10 and the ECU 50 is executed. Hereinafter, the session key sharing method according to the first embodiment will be described with reference to FIG.

  FIG. 6 is a sequence chart illustrating the session key sharing method according to the first embodiment. In FIG. 6, the management apparatus 10 and the ECU 50 have the same key exchange key shared in advance. The management device 10 stores the key exchange key in the key exchange key storage unit 21. The ECU 50 stores the key exchange key in the key exchange key storage unit 118.

  When the session key sharing method shown in FIG. 6 is executed, the MAC is not stored in the data frame. Therefore, the data frame receiver does not perform MAC inspection. This is because the MAC inspection cannot be normally performed until the session key is shared by the plurality of ECUs 50 by executing the session key sharing method.

(Step S21) In the management device 10, the random number generation unit 22 generates a random number. For example, the random number generation unit 22 generates a random number having a data length of 64 bits.

(Step S22) In the management device 10, the communication unit 11 transmits a second data storage frame, which is a data frame in which the random number is stored in the data field, to the ECU 50 via the CAN 40. The communication unit 11 transmits the second data storage frame by broadcast, for example. In the ECU 50, the communication unit 51 receives the second data storage frame from the management device 10 via the CAN 40.

(Step S <b> 23) In the management device 10, the session key generation unit 24 reads the key exchange key from the key exchange key storage unit 21. In the ECU 50, the session key generation unit 119 reads the key exchange key from the key exchange key storage unit 118.

(Step S24) In the management device 10, the session key generation unit 24 generates a session key using the key exchange key read from the key exchange key storage unit 21 and the random number generated by the random number generation unit 22. In the ECU 50, the session key generation unit 119 uses the key exchange key read from the key exchange key storage unit 118 and the random number stored in the second data storage frame received by the communication unit 51 to obtain the session key. Generate. The session key generated by the session key generation unit 119 is stored in the session key storage unit 117. Thereby, the same session key is shared by the management apparatus 10 and ECU50.

  The session key generation method is the same for the session key generation unit 24 of the management apparatus 10 and the session key generation unit 119 of the ECU 50. The session key generation method may be the same as the third data generation method described above. For example, a value obtained by encrypting a random number with a key exchange key (for example, CMAC) may be used as the session key. Alternatively, a hash value of data obtained by concatenating a key exchange key and a random number may be calculated, and the hash value may be used as a session key. Alternatively, the exclusive OR of the key exchange key and the random number may be used as the session key.

  The above is the description of the session key sharing method according to the first embodiment. According to the session key sharing method according to the first embodiment, a plurality of ECUs 50 can share the same session key. Furthermore, when the same session key is shared by a plurality of ECUs 50, the time required for sharing can be shortened while maintaining the security strength of the session key to some extent. This effect is obtained for the same reason as in the case of the counter initial value described above.

  In the first embodiment described above, the counter initial value or the session key sharing timing may be, for example, a timing immediately after the engine of the automobile 1 is started. While the engine of the automobile 1 is starting, there is a possibility that the power supply to the ECU 50 in the automobile 1 becomes insufficient and the operation of the ECU 50 becomes unstable. When the operation of the ECU 50 becomes unstable, there is a possibility that data stored in a volatile memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory) in the ECU 50 may not be maintained normally. For this reason, when the counter value and the session key are stored in the volatile memory, it is avoided to share the counter initial value and the session key before starting the engine of the automobile 1 and during the starting, and the ECU 50 after starting the engine. It is preferable to share the counter initial value and the session key in a state where the operation is stable. Furthermore, it is preferable that sharing of the counter initial value and the session key is completed in a period from when the engine is started to when traveling is started. This is because control such as engine control and brake control is executed while the automobile 1 is traveling, so that the MAC inspection is normally executed in order to maintain the reliability of messages exchanged between the ECUs 50.

  In the counter initial value sharing method shown in FIG. 5 described above, the counter initial value is generated using the key exchange key. However, a session key may be used instead of the key exchange key. When the initial counter value is generated using the session key, the counter initial value is shared after the management apparatus 10 and the ECU 50 share the same session key.

  Next, a key exchange key update method according to the first embodiment will be described. If the key exchange key is repeatedly used by the counter initial value sharing method or the session key sharing method described above, the key exchange key may be leaked by performing analysis such as leakage electromagnetic wave analysis. As a countermeasure, in the first embodiment, the key exchange key is updated by the multilayer common key method shown in FIGS. The key exchange key update method according to the first embodiment will be described below with reference to FIGS.

  First, the first stage of the key exchange key update method will be described with reference to FIG. FIG. 7 is a sequence chart showing a first stage of the key exchange key update method. In FIG. 7, the management device 10 and the ECU 50 have a current key exchange key (N) that is an Nth key exchange key shared in advance. The management device 10 stores the current key exchange key (N) in the key exchange key storage unit 21. The ECU 50 stores the current key exchange key (N) in the key exchange key storage unit 118.

  Moreover, the management apparatus 10 and ECU50 have (alpha) present common key (N) which is the Nth common key of alpha system shared previously. The α-system common key is an example of a first key. Moreover, the management apparatus 10 and ECU50 have (beta) present common key (N) which is the Nth common key of (beta) system shared previously. The β system common key is an example of the second key. The management apparatus 10 stores the α current common key (N) and the β current common key (N) in the common key storage unit 25. The ECU 50 stores the α current common key (N) and the β current common key (N) in the common key storage unit 121.

(Step S31) In the management apparatus 10, the data updating unit 15 generates a new key exchange key (N + 1) that is a new “N + 1” -th key exchange key at a predetermined timing. The data updating unit 15 rewrites the key exchange key stored in the key exchange key storage unit 21 from the current key exchange key (N) to the new key exchange key (N + 1). For example, when the number of times the current key exchange key (N) has been used reaches a specified number, the management apparatus 10 changes the key exchange key from the current key exchange key (N) to the new key exchange key (N + 1). May be.

(Step S32) In the management apparatus 10, the encryption processing unit 16 encrypts the new key exchange key (N + 1) with the α current common key (N).

(Step S33) In the management apparatus 10, the communication unit 11 stores the first encrypted data that is a data frame storing the first encrypted data (N + 1) that is the result of the encryption of the new key exchange key (N + 1). The frame is transmitted to the ECU 50 via the CAN 40. The communication unit 11 transmits the first encrypted data storage frame by broadcast, for example. In the ECU 50, the communication unit 51 receives the first encrypted data storage frame from the management device 10 via the CAN 40.

(Step S <b> 34) In the ECU 50, the encryption processing unit 55 converts the first encrypted data (N + 1) stored in the first encrypted data storage frame received by the communication unit 51 from the management apparatus 10 to the α current common key ( Decrypt in N). In the ECU 50, the data update unit 54 rewrites the key exchange key stored in the key exchange key storage unit 118 from the current key exchange key (N) based on the result of the decryption. As a result, the key exchange key stored in the key exchange key storage unit 118 of the ECU 50 is updated from the current key exchange key (N) to the new key exchange key (N + 1).

  Next, the second stage of the key exchange key update method will be described with reference to FIG. FIG. 8 is a sequence chart showing a second stage of the key exchange key update method. If the α current common key (N) is repeatedly used in the first step of the key exchange key updating method described above, the α current common key (N) may be leaked by performing analysis such as leakage electromagnetic wave analysis. There is. As a countermeasure, in the first embodiment, the α-system common key is updated by the second stage of the key exchange key updating method shown in FIG. Hereinafter, the second stage of the key exchange key update method according to the first embodiment will be described with reference to FIG. In FIG. 8, the management apparatus 10 and the ECU 50 have an α current common key (N) and a β current common key (N) shared in advance. The management apparatus 10 stores the α current common key (N) and the β current common key (N) in the common key storage unit 25. The ECU 50 stores the α current common key (N) and the β current common key (N) in the common key storage unit 121.

(Step S41) In the management apparatus 10, the data updating unit 15 generates an α new common key (N + 1) that is a new “N + 1” -th common key of the α system at a predetermined timing. The management apparatus 10 rewrites the α-system common key stored in the common key storage unit 25 from the α current common key (N) to the α new common key (N + 1). For example, when the number of times the α current common key (N) is used reaches the specified number, the management apparatus 10 changes the α system common key from the α current common key (N) to the α new common key (N + 1). You may change to

(Step S42) In the management apparatus 10, the encryption processing unit 16 encrypts the α new common key (N + 1) with the β current common key (N).

(Step S43) In the management apparatus 10, the communication unit 11 stores the second encrypted data that is a data frame storing the second encrypted data (N + 1) that is the result of the encryption of the α new common key (N + 1). The frame is transmitted to the ECU 50 via the CAN 40. The communication unit 11 transmits the second encrypted data storage frame by broadcast, for example. In the ECU 50, the communication unit 51 receives the second encrypted data storage frame from the management device 10 via the CAN 40.

(Step S44) In the ECU 50, the encryption processing unit 55 converts the second encrypted data (N + 1) stored in the second encrypted data storage frame received by the communication unit 51 from the management device 10 into the β current common key ( Decrypt in N). In the ECU 50, the data updating unit 54 rewrites the α-system common key stored in the common key storage unit 121 from the α current common key (N) based on the result of the decryption. Accordingly, the α-system common key stored in the common key storage unit 121 of the ECU 50 is updated from the α current common key (N) to the α new common key (N + 1).

  According to the key exchange key update method based on the multilayer common key method shown in FIGS. 7 and 8 described above, the high speed of the common key method can be obtained and the same processing routine can be used repeatedly. By repeatedly using the same processing routine, the program code can be simplified, which is suitable for the CPU performance and memory capacity of the ECU 50, which are limited computer resources.

  In the first embodiment described above, the management apparatus 10 includes the units related to the generation and inspection of the MAC illustrated in FIG. 4, and the MAC generated in the data frame to be transmitted and the MAC stored in the received data frame This inspection may be executed.

  Also, any ECU provided in the automobile 1 may function as the management device 10.

[Example 2]
FIG. 9 is a configuration diagram illustrating Example 2 of the automobile 1 according to the present embodiment. In FIG. 9, the automobile 1 includes a gateway 10 a, a CAN 40, an ECU 50, a diagnosis port 70, and an infotainment device 200. Examples of the infotainment device 200 include those having a navigation function, a location information service function, a multimedia playback function such as music and video, a voice communication function, a data communication function, and an Internet connection function. The infotainment device 200 is connected to the external device 220 and exchanges data with the external device 220. Examples of the external device 220 include a mobile communication terminal and an audio visual device.

  The diagnostic port 70 connects the diagnostic tool 210. The diagnostic tool 210 executes installation of an update program such as the ECU 50 and data setting change via the diagnostic port 70. As the diagnostic port 70, for example, an OBD (On-board Diagnostics) port may be used.

  The gateway 10a is connected to the CAN 40. The infotainment device 200 transmits / receives data to / from the ECU 50 connected to the CAN 40 via the gateway 10a. The gateway 10a monitors data transmission / reception between the infotainment device 200 and the ECU 50. The diagnostic tool 210 transmits / receives data to / from the ECU 50 connected to the CAN 40 via the diagnostic port 70 and the gateway 10a. The gateway 10a monitors transmission / reception of data between the diagnostic tool 210 and the ECU 50.

  The gateway 10a has the function of the management apparatus 10 according to the present embodiment. The gateway 10 a includes a secure element 61. The ECU 50 includes a secure element 62. The secure elements 61 and 62 have tamper resistance. In the gateway 10a, the secure element 61 may include a first data storage unit 12, a third data generation unit 14, a data update unit 15, and an encryption processing unit 16 among the units of the management apparatus 10 illustrated in FIG. Alternatively, in the gateway 10a, the secure element 61 includes the key exchange key storage unit 21, the counter initial value generation unit 23, the session key generation unit 24, the data update unit 15, and the encryption process among the units of the management apparatus 10 illustrated in FIG. Unit 16 and common key storage unit 25 may be provided.

  In the ECU 50, the secure element 62 may include a first data storage unit 52, a third data generation unit 53, a data update unit 54, and an encryption processing unit 55 among the units of the ECU 50 shown in FIG. Alternatively, in the ECU 50, the secure element 62 includes a key exchange key storage unit 118, a counter initial value generation unit 120, a session key generation unit 119, a session key storage unit 117, and a data update unit 54 among the units of the ECU 50 illustrated in FIG. The encryption processing unit 55 and the common key storage unit 121 may be provided.

  For example, a SIM (Subscriber Identity Module) or an eSIM (Embedded Subscriber Identity Module) may be used as the secure element. SIM and eSIM are secure elements and have tamper resistance. SIM and eSIM are a kind of computer, and a desired function is realized by a computer program. Alternatively, a tamper-resistant cryptographic processing chip may be used as the secure element. As a cryptographic processing chip having tamper resistance, for example, a cryptographic processing chip called HSM (Hardware Security Module), TPM (Trusted Platform Module), or SHE (Secure Hardware Extension) is known.

  For example, SIM or eSIM may be used as the secure element 61 of the gateway 10a. In this case, the gateway 10a may include a communication module that performs wireless communication using a SIM or eSIM. Moreover, you may use HSM, TPM, or SHE as the secure element 62 of ECU50.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  For example, in the above-described embodiment, an automobile is taken as an example of a vehicle, but the present invention can also be applied to vehicles other than automobiles such as a motorbike and a railway vehicle.

Further, a computer program for realizing the functions of the management device 10, ECU 50 or gateway 10a described above is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. You may do it. Here, the “computer system” may include an OS and hardware such as peripheral devices.
“Computer-readable recording medium” refers to a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disc), and a built-in computer system. A storage device such as a hard disk.

Further, the “computer-readable recording medium” means a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Automobile, 2 ... Vehicle-mounted control system, 10 ... Management apparatus, 10a ... Gateway (management apparatus), 11, 51 ... Communication part, 12, 52 ... 1st data storage part, 13 ... 2nd data generation part, 14, 53, third data generation unit, 15, 54, data update unit, 16, 55, encryption processing unit, 21, 118, key exchange key storage unit, 22 ... random number generation unit, 23, 120 ... counter initial value generation unit, 24, 119 ... session key generation unit, 25, 121 ... common key storage unit, 40 ... CAN (communication network), 50 ... ECU (in-vehicle computer), 61, 62 ... secure element, 70 ... diagnostic port, 111 ... transmission unit , 112 ... reception unit, 113 ... frame reception processing unit, 114 ... MAC (message authentication code) generation unit, 115 ... counter unit, 116 ... MAC (message authentication code)査部, 117 ... the session key storage unit, 200 ... infotainment equipment

Claims (14)

In the in-vehicle control system provided in the vehicle,
A management device that communicates with a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers;
The management device
A communication unit that transmits and receives the frame via the communication network;
A first data storage unit for storing first data having a predetermined data length exceeding an upper limit of a data length that can be stored in one frame;
A second data generation unit that generates second data having a data length that can be stored in one frame;
A third data generation unit that generates the third data of the predetermined data length shared by the plurality of in-vehicle computers using the first data and the second data;
The communication unit transmits a second data storage frame, which is the frame storing the second data, to the in-vehicle computer via the communication network;
The in-vehicle computer is
A communication unit that transmits and receives the frame via the communication network;
A first data storage unit for storing the first data;
The first data stored in the first data storage unit of the vehicle-mounted computer and the communication unit of the vehicle-mounted computer are stored in the second data storage frame received from the management device via the communication network. A third data generation unit that generates the third data using the second data.
In-vehicle control system. The communication unit of the management device transmits the second data storage frame by broadcast or multicast,
The communication unit of the in-vehicle computer receives the second data storage frame by broadcast or multicast;
The in-vehicle control system according to claim 1. The in-vehicle computer uses the third data as an initial value of information related to communication performed via the communication network.
The vehicle-mounted control system of any one of Claim 1 or 2. The information related to the communication is a counter value for the frame.
The in-vehicle control system according to claim 3. The counter value is used to generate a message authentication code for messages exchanged over the communication network.
The in-vehicle control system according to claim 4. The in-vehicle computer uses the third data as a key used for communication performed via the communication network.
The vehicle-mounted control system of any one of Claim 1 or 2. The management device
A data update unit for changing the first data at a predetermined timing;
An encryption processor that encrypts the first data after the change with a first key shared by the management device and the in-vehicle computer,
The communication unit of the management device transmits a first encrypted data storage frame, which is the frame storing the first encrypted data as a result of the encryption, to the in-vehicle computer via the communication network,
The in-vehicle computer is
Cryptographic processing for decrypting the first encrypted data stored in the first encrypted data storage frame received by the communication unit of the in-vehicle computer from the management device via the communication network with the first key. And
A data update unit that updates the first data of the in-vehicle computer according to the result of the decoding,
The in-vehicle control system according to any one of claims 1 to 6. The data update unit of the management device changes the first key at a predetermined timing,
The encryption processing unit of the management device encrypts the changed first key with a second key shared by the management device and the in-vehicle computer,
The communication unit of the management device transmits a second encrypted data storage frame, which is the frame storing the second encrypted data as a result of the encryption, to the in-vehicle computer via the communication network,
The encryption processing unit of the in-vehicle computer stores the second encrypted data stored in the second encrypted data storage frame received by the communication unit of the in-vehicle computer from the management device via the communication network. Decrypt with the second key,
The data updating unit of the in-vehicle computer updates the first key of the in-vehicle computer with the result of the decryption,
The in-vehicle control system according to claim 7.   A vehicle provided with the vehicle-mounted control system of any one of Claim 1 to 8. In the management device of the in-vehicle control system provided in the vehicle including a management device that communicates by a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers,
A communication unit that transmits and receives the frame via the communication network;
A first data storage unit that stores data having a predetermined data length that exceeds an upper limit of a data length that can be stored in one frame and is shared by the management device and the in-vehicle computer;
A second data generation unit that generates second data having a data length that can be stored in one frame;
A third data generation unit that generates the third data of the predetermined data length shared by the plurality of in-vehicle computers using the first data and the second data;
The communication unit transmits a second data storage frame, which is the frame storing the second data, to the in-vehicle computer via the communication network.
Management device. In the in-vehicle computer of the in-vehicle control system provided in the vehicle including a management device that communicates by a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers,
A communication unit that transmits and receives the frame via the communication network;
A first data storage unit that stores data having a predetermined data length that exceeds an upper limit of a data length that can be stored in one frame and is shared by the management device and the in-vehicle computer;
The first data stored in the first data storage unit and the communication unit receive the frame from the management device via the communication network and have a data length that can be stored in one frame. The second data stored in the second data storage frame storing the second data is used to generate the third data having the predetermined data length shared by the plurality of in-vehicle computers. 3 data generators;
In-vehicle computer equipped with. In the data sharing method of the in-vehicle control system provided in the vehicle including a management device that communicates by a frame via a communication network provided in the vehicle and a plurality of in-vehicle computers,
A first data storage step in which the management device stores first data having a predetermined data length exceeding an upper limit of a data length that can be stored in one frame;
A second data generation step in which the management device generates second data having a data length that can be stored in one frame;
A transmission step in which the management device transmits a second data storage frame, which is the frame storing the second data, to the in-vehicle computer via the communication network;
A third data generation step in which the management device generates third data of the predetermined data length shared by the plurality of in-vehicle computers using the first data and the second data;
A second first data storing step in which the in-vehicle computer stores the first data;
A receiving step in which the in-vehicle computer receives the second data storage frame from the management device via the communication network;
The in-vehicle computer uses the first data stored in the second first data storage step and the second data stored in the second data storage frame received in the reception step. A second third data generating step for generating the third data;
Data sharing method. In the computer of the management device of the in-vehicle control system provided in the vehicle including a management device and a plurality of in-vehicle computers that communicate with each other through a communication network provided in the vehicle,
A first data storage function that stores data having a predetermined data length that exceeds an upper limit of a data length that can be stored in one frame and is shared by the management device and the in-vehicle computer;
A second data generation function for generating second data having a data length that can be stored in one frame;
A communication function for transmitting a second data storage frame, which is the frame storing the second data, to the in-vehicle computer via the communication network;
Using the first data and the second data, a third data generation function for generating third data of the predetermined data length shared by the plurality of in-vehicle computers;
Computer program for realizing. In the in-vehicle computer of the in-vehicle control system provided in the vehicle including a management device and a plurality of in-vehicle computers that communicate by a frame via a communication network provided in the vehicle,
A first data storage function that stores data having a predetermined data length that exceeds an upper limit of a data length that can be stored in one frame and is shared by the management device and the in-vehicle computer;
A communication function for receiving a second data storage frame, which is the frame storing second data having a data length that can be stored in one frame, from the management device via the communication network;
A plurality of the in-vehicle computers using the first data stored by the first data storage function and the second data stored in the second data storage frame received by the communication function A third data generation function for generating third data of the predetermined data length shared by
Computer program for realizing.

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