Communication device

Abstract

To provide a communication device that can reduce authentication time.SOLUTION: An ECU 3 communicates with another apparatus via a bus 5 capable of transmitting and receiving a CANFD frame. A data part of the CANFD frame can store a Classic CAN frame and dynamically changes. The ECU 3 comprises a transmission and reception unit 12, an authentication unit 13, and a switching unit 14. The transmission and reception unit 12 transmits and receives the CANFD frame. When the transmission and reception unit 12 receives the CANFD frame, the authentication unit 13 can execute message authentication for a current reception frame that is the received CANFD frame. The switching unit 14 dynamically switches whether to cause the authentication unit 13 to execute the message authentication on the basis of determination information given from another apparatus that has transmitted the current reception frame. The determination information is information representing what type of data Classic CAN data included in the current reception frame is.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a communication device that communicates with other devices via a bus capable of transmitting and receiving CAN FD frames. [Background technology]

[0002] For example, CAN communication can be cited as one method of communication between vehicles, such as automobiles, i.e., vehicle communication. CAN is an abbreviation for Controller Area Network and is a registered trademark. In recent years, technology has become widely used in vehicle communication to prevent unauthorized attacks from outside by adding an authenticator to CAN messages sent and received. However, authentication requires a lot of processing, and there is a demand for reducing the authentication time.

[0003] Furthermore, in recent years, the amount of data communicated in vehicle communications has tended to increase, and CANFD communication, which has a larger data area than CAN communication, has been increasingly adopted. In this specification, traditional CAN is sometimes referred to as ClassicCAN to clearly distinguish it from CANFD. Despite this, not all electronic control units installed in vehicles are CANFD compatible, and some electronic control units do not support CANFD. In this specification, electronic control units are sometimes abbreviated to ECU.

[0004] Therefore, vehicles are now appearing that incorporate a technology in which ClassicCAN frames are stored in the data section of a CANFD frame for transmission and reception, thereby bundling ClassicCAN frames and transmitting them as a CANFD frame on a CANFD-compatible bus, which enables higher speeds. Hereinafter, such conventional technology may be simply referred to as the "conventional technology." Patent Document 1, which is related to the above-mentioned conventional technology, discloses a technology in which a ClassicCAN frame is stored in an Ethernet frame. Note that Ethernet is a registered trademark. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-91585 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional technology, the combination of CANFD frames and ClassicCAN frames is statically determined, but the order in which ClassicCAN frames are stored and which frames are stored change dynamically for each communication. In conventional technology, message authentication is performed on such frames, and if authentication is successful, meaning the message was not sent as a result of an unauthorized attack, the CANFD frame is divided into ClassicCAN units, and the data is used for its own control or the frame is transferred to an adjacent ECU.

[0007] In conventional technology, CANFD frames received by a specific ECU may contain ClassicCAN frames that are unnecessary for that ECU, i.e., the ECU itself. Therefore, when dividing the frame into ClassicCAN units, a decision is made to discard the unnecessary frames without using them for control. Furthermore, in conventional technology, if the CANFD frame itself, i.e., all of the ClassicCAN frames contained within it, are unnecessary for the ECU itself, in other words, if it is sufficient to simply forward the frame to another ECU, the forwarding process is carried out without authentication. For this reason, in conventional technology, there are cases where the time required for authentication is wasted, and there is room for improvement in terms of reducing authentication time.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication device that can reduce authentication time. [Means for solving the problem]

[0009] The communication device described in claim 1 communicates with other devices via a bus capable of transmitting and receiving CANFD frames. The data section of the CANFD frame can store ClassicCAN frames and is dynamically changeable. The communication device includes a transmitter / receiver (12), an authentication section (13), and a switching section (14).

[0010] The transmitting / receiving unit transmits and receives the CAN FD frame. When the transmitting / receiving unit receives the CAN FD frame, the authentication unit can perform message authentication on the currently received frame, which is the received CAN FD frame. The switching unit dynamically switches whether or not to cause the authentication unit to perform the message authentication based on determination information provided by another device that transmitted the currently received frame. The determination information is information that indicates what type of ClassicCAN data is included in the currently received frame.

[0011] The above configuration provides the following advantages. In other words, in the prior art, message authentication was always performed when a CAN FD frame that was both a target for reception and a target for authentication was received. However, even if the CAN FD frame was a target for reception, there were cases where the data contained therein was unnecessary for the device itself. In such cases, the frame was discarded after authentication and confirmation of the data therein, resulting in unnecessary authentication time.

[0012] In contrast, the above configuration makes it possible to dynamically switch whether or not to perform message authentication, and to determine whether the data contained therein is necessary for the device before performing authentication. In this way, when a CAN FD frame is received that does not contain data necessary for the device, the frame can be discarded without performing authentication. In other words, the above configuration eliminates the need for unnecessary authentication, thereby reducing processing time. Therefore, the above configuration has the excellent effect of reducing authentication time compared to conventional techniques. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a communication system according to an embodiment. [Figure 2] FIG. 10 is a diagram showing a specific example of a pattern of ClassicCAN stored in the data section of a CANFD frame according to an embodiment. [Figure 3] FIG. 1 is a diagram schematically illustrating a specific configuration related to a function as a communication device in an ECU according to an embodiment. [Figure 4] FIG. 10 is a diagram for explaining a first specific example of a switching method performed by a switching unit according to an embodiment. [Figure 5] FIG. 10 is a diagram for explaining a second specific example of a switching method performed by a switching unit according to an embodiment. [Figure 6] FIG. 10 is a diagram for explaining a third specific example of a switching method performed by a switching unit according to an embodiment. [Figure 7] FIG. 10 is a diagram showing an example of processing content executed by an ECU according to a comparative example at the time of transmission; [Figure 8] FIG. 1 is a diagram illustrating an example of processing executed by an ECU during transmission according to an embodiment. [Figure 9] FIG. 2 is a diagram illustrating an example of processing executed by an ECU during transmission according to an embodiment. [Figure 10] FIG. 10 is a diagram showing an example of processing content executed by an ECU according to a comparative example upon reception; [Figure 11] FIG. 1 is a diagram illustrating an example of processing executed by an ECU according to an embodiment upon reception. [Figure 12] FIG. 2 illustrates an example of processing executed by the ECU upon reception according to an embodiment. [Figure 13] FIG. 3 shows an example of processing executed by the ECU upon reception according to an embodiment. [Figure 14] FIG. 10 is a diagram illustrating why it can be determined that there is no problem in determining whether or not data of a message to which an authenticator is attached needs to be received before authentication according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of a communication device will be described with reference to the drawings. 1, a communication system 1 of this embodiment is mounted on a vehicle such as an automobile, and includes a plurality of ECUs 2A, 2B, 2C, 3D, 3E, and 3F, a bus 4 interconnecting ECUs 2A to 2C and 3E, and a bus 5 interconnecting ECUs 3D to 3F. The communication system 1 uses ClassicCAN or CANFD as a communication protocol.

[0015] The bus 4 functions as a communication path capable of transmitting and receiving ClassicCAN frames. The bus 5 functions as a communication path capable of transmitting and receiving CANFD frames. Each of the ECUs 2A to 2C and 3D functions as a communication device that communicates with other devices via the bus 4. Each of the ECUs 3D to 3F functions as a communication device that communicates with other devices via the bus 5. In the following description, when it is not necessary to distinguish between the ECUs 2A to 2C and the ECUs 3D to 3F, the final alphabet will be omitted and they will be referred to collectively.

[0016] ECU2 is configured to be able to send and receive only ClassicCAN data, while ECU3 is configured to be able to send and receive CANFD data as well. In this case, the data portion of a CANFD frame can store a ClassicCAN frame. Therefore, data is exchanged between ECU2 and ECU3 by storing a ClassicCAN frame in a CANFD frame.

[0017] The combination of CANFD frames and ClassicCAN frames is statically determined, but the order in which ClassicCAN frames are stored and which ClassicCAN frames are stored change dynamically for each communication. In other words, the data section of a CANFD frame changes dynamically. Figure 2 shows a specific example of a pattern in which ClassicCAN frames are stored in the data section of a CANFD frame. In the first pattern, ClassicCAN_A, ClassicCAN_B, ClassicCAN_C, and an authenticator are stored in that order in the data section of a CANFD_A frame. The authenticator is an encrypted version of the data section.

[0018] In the second pattern, the data section of the CANFD_A frame stores ClassicCAN_B and an authenticator in this order. In the third pattern, the data section of the CANFD_A frame stores ClassicCAN_A, ClassicCAN_C, and an authenticator in this order. In the fourth pattern, the data section of the CANFD_A frame stores ClassicCAN_C, ClassicCAN_A, ClassicCAN_B, and an authenticator in this order. In this way, although it is the same CANFD_A frame, the ClassicCAN frame and DLC inside it change dynamically. DLC is an abbreviation for Data Length Code.

[0019] As a specific configuration of the ECU 3 relating to the function as a communication device, for example, a configuration example shown in Fig. 3 can be adopted. As shown in Fig. 3, the ECU 3 includes functional blocks such as a control unit 11 that executes predetermined control, a transceiver unit 12 that transmits and receives CANFD frames, an authentication unit 13, a switching unit 14, a transfer unit 15, and a decomposition unit 16. Each functional block of the ECU 3 is realized by a CPU included in the ECU 3 executing a computer program stored in a non-transitory tangible storage medium and performing processing corresponding to the computer program, that is, by software. Note that at least a portion of each functional block may be realized by hardware.

[0020] When the transceiver 12 receives a CAN FD frame, the authentication unit 13 can perform message authentication on the currently received frame, which is the received CAN FD frame. In this case, the message authentication can be performed using the authenticator included in the data portion described above. The switching unit 14 dynamically switches whether or not to have the authentication unit 13 perform message authentication based on judgment information provided by another device that sent the currently received frame. The judgment information described above is information that indicates what type of ClassicCAN data is included in the currently received frame.

[0021] When the transmitting / receiving unit 12 receives a CAN FD frame, the transferring unit 15 can transfer the currently received frame to another device regardless of whether or not message authentication is performed by the switching unit 14. The decomposing unit 16 decomposes the data portion of the CAN FD frame received by the transmitting / receiving unit 12 into Classic CAN frames.

[0022] Based on the determination information, the switching unit 14 determines whether the currently received frame contains data necessary for the device itself. If the switching unit 14 determines that the necessary data is included, it causes the authentication unit 13 to perform message authentication, and if it determines that the necessary data is not included, it does not cause the authentication unit 13 to perform message authentication. If the switching unit 14 causes the authentication unit 13 to perform message authentication, it outputs the data included in the currently received frame to the control unit 11, and if message authentication is not performed, it discards the currently received frame.

[0023] Specifically, any of the following specific examples can be adopted as the switching method by the switching unit 14. In the following description, an ECU that transmits a CANFD frame will be referred to as a transmitting ECU, and an ECU that receives a CANFD frame will be referred to as a receiving ECU.

[0024] [1] First example In the first specific example, the determination information is information included in a frame different from the currently received frame among the CANFD frames received by the transceiver 12. As shown in Fig. 4, in the first specific example, ECU 3D, which is the transmitting ECU, transmits a CANFD frame including determination information I1 before transmitting the CANFD frame to be identified.

[0025] In this case, the determination information I1 is information indicating whether the next frame contains the ClassicCAN required by the receiving ECU, ECU3E, and can be, for example, data of the receiving ECU, i.e., data for identifying the receiving ECU. More specifically, the determination information I1 can be, for example, identification information such as a CAN ID corresponding to the receiving ECU. According to the first specific example, the receiving ECU, ECU3E, can check the previously received CANFD information to determine whether the data of the next frame to be received is necessary.

[0026] [2] Second specific example In the second specific example, the determination information is information contained in the currently received frame. As shown in Figure 5, in the second specific example, the transmitting ECU embeds the determination information I2 in the data section of the CANFD. In Figure 5, the determination information I2 is embedded at the beginning of the data section, but the position at which the determination information I2 is embedded may be changed as appropriate as long as it is easily accessible, such as at the end of the data section.

[0027] In this case, the judgment information I2 is 4-bit data, and if the 0th bit of the data is "1", it indicates that data to be received by the receiving ECU, ECU3E, is included, and if the 0th bit is "0", it indicates that data to be received by the receiving ECU, ECU3E, is not included.

[0028] [3] Third Specific Example In the third specific example, the determination information is the information contained in the currently received frame. As shown in Fig. 6, in the third specific example, the transmitting ECU assigns the determination information I3 using "res", which is a reserved bit in CANFD. Note that in Fig. 6, the "CRC Delimiter" is abbreviated to "CRC D", and the "ACK Delimiter" is abbreviated to "ACK D".

[0029] The reserved bit is currently unused and is 1-bit data. In this case, the determination information I3 indicates that if the reserved bit is "1", there is data required for the receiving ECU, and if the reserved bit is "0", there is no data required for the receiving ECU.

[0030] [4] Fourth Specific Example In the fourth specific example, the determination information is information contained in the ClassicCAN frame disassembled by the disassembly unit 16. That is, in the fourth specific example, the transmitting ECU transmits the CANFD frame without embedding any special information in it. On the other hand, when the receiving ECU receives the CANFD frame, it disassembles it into ClassicCAN frames before performing authentication. The receiving ECU then checks the disassembled ClassicCAN frame to determine whether the data is necessary before performing authentication.

[0031] The control flow performed by the ECU 3 having the above configuration when transmitting a CANFD frame and the control flow performed when receiving a CANFD frame will be described. For comparison, the control flow performed by an ECU in a comparative example corresponding to the prior art when transmitting and receiving will also be described.

[0032] [1-0] Control flow during transmission in the comparative example In the comparative example, the transmitting ECU executes a series of processes as shown in FIG. 7 at the timing of frame creation. In step S101, it is determined whether it is the timing to transmit a CAN FD frame. If it is not the timing to transmit a CAN FD frame, the result in step S101 is "NO" and this process ends. On the other hand, if it is the timing to transmit a CAN FD frame, the result in step S101 is "YES" and the process proceeds to step S102.

[0033] In step S102, the latest data of the ClassicCAN frame for which transmission is requested is packed into a CAN FD frame. Note that in the following description and drawings, the ClassicCAN frame for which transmission is requested is sometimes referred to as the target ClassicCAN frame. After step S102 is executed, the process proceeds to step S103, and the CAN FD frame in which the ClassicCAN frame is packed is transmitted. After step S103 is executed, this process ends.

[0034] [1-1] Control flow when sending when the first concrete example is adopted When the first specific example is adopted as the switching method by the switching unit 14, the transmitting ECU executes a series of processes as shown in Fig. 8 at the timing of frame creation. This control flow differs from the control flow in the comparative example shown in Fig. 7 in that steps S111, S112, and S113 are added.

[0035] In this case, after step S102 is executed, the process proceeds to step S111, where it is confirmed which ECU receives the target ClassicCAN frame, i.e., the information the target ClassicCAN frame desires. After step S111 is executed, the process proceeds to step S112, where the determination information is stored in the CANFD frame. After step S112 is executed, the process proceeds to step S113, where the CANFD frame with the determination information stored is transmitted. After step S113 is executed, the process proceeds to step S103, where the CANFD frame with the ClassicCAN frame packed is transmitted. After step S103 is executed, this process ends.

[0036] [1-2] Control flow when sending when the second or third specific example is adopted When the second or third specific example is adopted as the switching method by the switching unit 14, the transmitting ECU executes a series of processes as shown in Fig. 9 at the timing of frame creation. This control flow differs from the control flow in the comparative example shown in Fig. 7 in that steps S111 and S121 are added.

[0037] In this case, after step S102 is executed, the process proceeds to step S111, where it is confirmed which ECU receives the target ClassicCAN frame, i.e., the information the target ClassicCAN frame desires. After step S111 is executed, the process proceeds to step S121, where the determination information is stored in a predetermined location in the CANFD frame. After step S121 is executed, the process proceeds to step S103, where the CANFD frame in which the ClassicCAN frame is packed is transmitted. After step S103 is executed, this process ends.

[0038] [1-4] Control flow when sending when the fourth specific example is adopted When the fourth specific example is adopted as the switching method by the switching unit 14, the transmitting ECU executes the series of processes shown in FIG. 7 at the timing of frame creation, as in the comparative example.

[0039] [2-0] Control flow during reception in the comparative example In the comparative example, the receiving ECU executes a series of processes as shown in Fig. 10 at the timing of receiving a frame. In step S201, it is determined whether the received frame is a message that is subject to message authentication. If the received frame is a message that is subject to message authentication, the result in step S201 is "YES" and the process proceeds to step S202. On the other hand, if the received frame is not a message that is subject to message authentication, the result in step S201 is "NO", so step S202 is skipped and the process proceeds to step S203.

[0040] In step S202, message authentication is performed. After step S202 is executed, the process proceeds to step S203. In step S203, the decomposition unit 16 decomposes the CANFD frame and extracts the ClassicCAN frame from the frame. After step S203 is executed, the process proceeds to step S204, where it is determined whether the extracted ClassicCAN frame is a message required by the device itself, i.e., the ECU itself.

[0041] If the extracted ClassicCAN frame is a message required by the ECU itself, the result in step S204 is "YES" and the process proceeds to step S205. On the other hand, if the extracted ClassicCAN frame is not a message required by the ECU itself, the result in step S204 is "NO", step S205 is skipped, and the process proceeds to step S206. In step S205, the message is received. After step S205 is executed, the process proceeds to step S206.

[0042] In step S206, it is determined whether there is a ClassicCAN frame that has not yet been extracted in the data section of the CAN FD frame, that is, whether there is an unacquired frame. If there is a ClassicCAN frame that has not yet been extracted in the data section, the result in step S206 is "YES" and the process returns to step S203. On the other hand, if there is no ClassicCAN frame that has not yet been extracted in the data section, the result in step S206 is "NO" and this series of processes ends.

[0043] [2-1] Control flow when receiving when the first concrete example is adopted When the first specific example is adopted as the switching method by the switching unit 14, the receiving ECU executes a series of processes as shown in Fig. 11 at the timing of receiving a frame. This control flow differs from the control flow in the comparative example shown in Fig. 10 in that steps S211 and S212 are added and step S204 is omitted.

[0044] In this case, step S211 is executed at the beginning of this series of processes. In step S211, it is determined whether the next CANFD frame to be transmitted is a frame in which a message required by the own ECU is stored, based on the determination information stored in the received CANFD frame. Here, if the frame does not contain a message required by the own ECU, step S211 becomes "NO", and this series of processes ends.

[0045] On the other hand, if the frame contains a message required by the ECU itself, the result in step S211 is "YES" and the process proceeds to step S212. In step S212, the next frame is received. After step S212 is executed, the process proceeds to step S201, and steps S201 to S203 are executed. In this case, after step S203 is executed, the process proceeds to step S205, and steps S205 to S206 are executed. After step S206 is executed, this series of processes ends.

[0046] [2-2] Control flow when receiving when the second or third specific example is adopted When the second or third specific example is adopted as the switching method by the switching unit 14, the receiving ECU executes a series of processes as shown in Fig. 12 at the timing of frame reception. This control flow differs from the control flow in the comparative example shown in Fig. 10 in that step S221 is added and step S204 is omitted. In this case, step S221 is executed at the beginning of this series of processes.

[0047] In step S221, it is determined based on the determination information stored in the received CAN FD frame whether the CAN FD frame is a frame in which a message required by the ECU itself is stored. If the frame does not contain a message required by the ECU itself, step S221 results in "NO" and this series of processes ends. On the other hand, if the frame contains a message required by the ECU itself, step S221 results in "YES", the process proceeds to step S201, and steps S201 to S203 are executed. In this case, after step S203 is executed, the process proceeds to step S205, and steps S205 to S206 are executed. After step S206 is executed, this series of processes ends.

[0048] [2-3] Control flow when receiving when the fourth specific example is adopted When the fourth specific example is adopted as the switching method by the switching unit 14, the receiving ECU executes a series of processes as shown in Fig. 13 at the timing of frame reception. This control flow differs from the control flow in the comparative example shown in Fig. 10 in that step S231 is added and step S204 is omitted. In this case, step S203 is executed first in this series of processes.

[0049] After step S203 is executed, the process proceeds to step S231, where it is determined whether the extracted ClassicCAN frame is a frame that the ECU wants to receive, i.e., whether it is a necessary frame. If the extracted ClassicCAN frame is a frame that the ECU wants to receive, the result in step S231 is "YES," and the process proceeds to step S201. On the other hand, if the extracted ClassicCAN frame is not a frame that the ECU wants to receive, the result in step S231 is "NO," and the process proceeds to step S206.

[0050] In this case, if step S206 returns "YES," the process returns to step S203, and if step S206 returns "NO," this series of processes ends. Also, in this case, if step S201 returns "YES," the process proceeds to step S202, and if step S201 returns "NO," the process proceeds to step S205. Also, in this case, after step S202 is executed, the process proceeds to step S205. After step S205 is executed, this series of processes ends.

[0051] According to the present embodiment described above, the following effects can be obtained. The ECU 3 of this embodiment includes a transceiver unit 12 that transmits and receives CANFD frames, an authentication unit 13 that can perform message authentication, and a switching unit 14. The switching unit 14 dynamically switches whether or not to cause the authentication unit 13 to perform message authentication based on determination information provided by another device that transmitted the currently received frame. The determination information is information that indicates what type of ClassicCAN data is included in the currently received frame.

[0052] The ECU3 configured as described above provides the following advantages. In other words, in the prior art, message authentication was always performed when a CANFD frame to be received and authenticated was received. However, even if the CANFD frame was to be received, there were cases where the data contained therein was unnecessary for the device itself. In such cases, the frame was discarded after authentication and confirmation of the data therein, resulting in unnecessary authentication time.

[0053] In contrast, the ECU 3 of this embodiment can dynamically switch whether or not to perform message authentication, and can determine whether the data contained in the message is necessary for the device before performing authentication. That is, when the ECU 3 of this embodiment receives a message, it determines in advance whether or not the message is necessary for the device before performing authentication, and can dynamically switch whether or not to perform authentication based on the determination result.

[0054] In this way, when a CAN FD frame that does not contain data required for the device itself is received, the frame can be discarded without authentication. In other words, the configuration of this embodiment eliminates the need for unnecessary authentication, thereby reducing processing time. In other words, the configuration of this embodiment dynamically switches between performing and not performing authentication, as opposed to the conventional technology where authentication is performed uniformly. This reduces the processing load and shortens the processing time, i.e., the elapsed time from transmission by the transmitting ECU to use in control by the receiving ECU. Therefore, this embodiment has the excellent effect of reducing authentication time compared to the conventional technology.

[0055] In the ECU 3 of this embodiment, whether or not the data of the message to which the authenticator is assigned needs to be received by the own device, i.e., the own ECU, is determined before authentication, but no problems arise in this regard, as shown in Fig. 14. In Fig. 14, a message that needs to be received by the own ECU is referred to as a "message to be received," and a message that does not need to be received by the own ECU is referred to as a "message not to be received."

[0056] That is, for a message that needs to be received by the ECU itself, if the authentication result is NG, the message is excluded from the list of messages to be received by the authentication after the above-mentioned determination, so no problem occurs, and if the authentication result is OK, the authentication is OK, so no problem occurs. Also, for a message that does not need to be received by the ECU itself, if the authentication result is NG, the message is authenticated at the transfer destination, and as a result, the message is excluded from the list of messages to be received, so no problem occurs, and if the authentication result is OK, the authentication is OK, so no problem occurs.

[0057] In this embodiment, the switching unit 14 provided in the ECU 3 determines whether the currently received frame contains data necessary for the device based on the judgment information, and if it determines that the necessary data is included, it causes the authentication unit 13 to perform message authentication, but if it determines that the necessary data is not included, it does not cause the authentication unit 13 to perform message authentication.

[0058] As a result, the ECU 3 of this embodiment can acquire determination information indicating whether the contents of the received CAN FD frame contain data necessary for the device before performing authentication, and can switch whether to perform authentication based on the acquired information. With this configuration, it is possible to determine whether a CAN FD frame contains only data unnecessary for the device based on the information acquired in advance, and in that case, it is possible to discard the received frame without performing authentication. As a result, there is no need to perform authentication unnecessarily, and processing time can be reduced.

[0059] In this embodiment, the ECU 3 includes a transfer unit 15 that can transfer the currently received frame to another device when the transceiver unit 12 receives a CAN FD frame, regardless of whether message authentication is performed or not, performed by the switch unit 14. This configuration makes it possible to achieve the above-described reduction in authentication time while also achieving relaying of CAN FD frames equivalent to conventional methods.

[0060] (Other embodiments) The present invention is not limited to the embodiments described above and illustrated in the drawings, but can be arbitrarily modified, combined, or expanded without departing from the spirit of the invention. The numerical values ​​and the like shown in the above embodiment are examples and are not limited to these.

[0061] The present invention is not limited to the ECU 3 used in the communication system 1 described in the above embodiment, but can be applied to any communication device that communicates with other devices via a bus capable of sending and receiving CANFD frames.

[0062] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0063] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0064] In addition to the inventions set forth in the claims, the present disclosure includes the following inventions. [1] A communication device that communicates with other devices via a bus capable of transmitting and receiving CAN FD frames, The data section of the CAN FD frame can store a Classic CAN frame and is dynamically changed. a transceiver (12) that transmits and receives the CAN FD frame; When the transmitting / receiving unit receives the CAN FD frame, an authentication unit (13) that can perform message authentication on the currently received frame, which is the received CAN FD frame; a switching unit (14) that dynamically switches whether or not to cause the authentication unit to perform the message authentication based on determination information provided from the other device that transmitted the currently received frame; Equipped with The determination information is information indicating what type of ClassicCAN data is included in the currently received frame. [2] The switching unit is determining whether the currently received frame contains data necessary for the device itself based on the determination information; If it is determined that the necessary data is included, the authentication unit performs the message authentication; The communication device according to [1], wherein if it is determined that the required data is not included, the authentication unit is not made to perform the message authentication. [3] The switching unit is When the authentication unit has performed the message authentication, the data included in the currently received frame is output to a control unit (11) that executes predetermined control; The communication device according to [1] or [2], wherein if the message authentication is not performed, the currently received frame is discarded. [4] Further, the communication device according to any one of [1] to [3], further comprising a transfer unit (15) that, when the transceiver unit receives the CAN FD frame, can transfer the currently received frame to another device regardless of whether or not the switching unit switches the message authentication. [5] The communication device according to any one of [1] to [4], wherein the judgment information is included in a frame of the CAN FD frames received by the transceiver unit that is different from the currently received frame. [6] The communication device according to any one of [1] to [4], wherein the determination information is included in the currently received frame. [7] Further, a decomposition unit (16) is provided that decomposes the data portion of the CAN FD frame received by the transceiver unit into the Classic CAN frame, The communication device according to any one of [1] to [4], wherein the determination information is included in the ClassicCAN frame decomposed by the decomposition unit. [Explanation of symbols]

[0065] 3, 3D, 3E, 3F...ECU, 5...bus, 11...control unit, 12...transmitting / receiving unit, 13...authentication unit, 14...switching unit, 15...transfer unit, 16...decomposition unit.

Claims

1. A communication device that communicates with other devices via a bus capable of transmitting and receiving CAN FD frames, The data section of the CAN FD frame is capable of storing a Classic CAN frame and is dynamically changed; a transmitting / receiving unit (12) for transmitting and receiving the CAN FD frame; an authentication unit (13) that, when the transceiver unit receives the CAN FD frame, performs message authentication on the currently received frame, which is the received CAN FD frame; a switching unit (14) that dynamically switches whether or not to cause the authentication unit to perform the message authentication based on determination information provided from another device that has transmitted the currently received frame; Equipped with The determination information is information indicating what type of ClassicCAN data is included in the currently received frame.

2. The switching unit is determining whether the currently received frame contains data necessary for the device itself based on the determination information; If it is determined that the necessary data is included, the authentication unit performs the message authentication; 2. The communication device according to claim 1, wherein if it is determined that necessary data is not included, the authentication unit is not made to perform the message authentication.

3. The switching unit is When the authentication unit performs the message authentication, the data included in the currently received frame is output to a control unit (11) that executes a predetermined control; The communication device according to claim 2 , wherein the currently received frame is discarded if the message authentication is not performed.

4. The communication device according to claim 1, further comprising a transfer unit (15) that, when the transceiver unit receives the CAN FD frame, can transfer the currently received frame to another device regardless of whether or not the switching unit switches between performing message authentication.

5. The communication device according to claim 1 , wherein the determination information is included in one of the CAN FD frames received by the transmitting / receiving unit that is different from the currently received frame.

6. The communication device according to claim 1 , wherein the determination information is included in the currently received frame.

7. Further, a decomposition unit (16) is provided that decomposes the data portion of the CAN FD frame received by the transceiver unit into the Classic CAN frame, The communication device according to claim 1 , wherein the determination information is included in the Classic CAN frame decomposed by the decomposing unit.

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