KR20220144550A - Device and method for vehicle communication - Google Patents

Abstract

The present invention relates to a vehicle communication device and a method thereof. The vehicle communication device comprises: a data position determining unit for receiving input values randomly selected among sensor values generated in a vehicle and substituting the input values for at least one preset position determining function to determine data and position information of length information of the data; and a message processing unit for identifying a start position of the data and an insertion position of the length information in a CAN message based on the position information.

Description

Vehicle communication device and method thereof

The present disclosure relates to a vehicle communication apparatus and a method thereof, and more particularly, to a CAN communication-based vehicle communication apparatus and a method thereof.

The infotainment system communicates with other electronic control units (ECUs) through an open communication channel, a controller area network (CAN) bus, and is vulnerable to hacking.

A hacker can read and decode CAN messages transmitted and received between the infotainment system and other ECUs from the CAN bus and then inject the messages into the CAN bus to cause system malfunction. A hacker can physically connect to the CAN bus, access the CAN bus using an on-board diagnostics (OBD) port, and attempt to decode/reverse engineer.

An object to be solved through the embodiment is to provide a vehicle communication device and method capable of increasing defense against illegal access to the CAN bus and limiting system damage even when the CAN bus is exposed to illegal access.

A vehicle communication device according to an embodiment for solving the above problem receives input values arbitrarily selected from among sensor values generated in a vehicle, and substitutes the input values into at least one preset positioning function to obtain data and the data It may include a data position determining unit for determining the position information of the length information, and a message processing unit for identifying the start position of the data and the insertion position of the length information in the CAN message based on the position information.

The CAN message has a data payload of a fixed length, and dummy data may be inserted into at least one byte other than a byte into which the data and the length information are inserted in the data payload.

A fixed value corresponding to the fixed length of the data payload may be inserted into a data length code (DLC) of the CAN message.

The input values and the positioning function may be shared with other electronic control devices. The input values may be changed every predetermined time.

The vehicle communication device may further include a transceiver. The message processing unit generates the CAN message by inserting transmission data and length information of the transmission data into the CAN message based on a start position of the data and an insertion position of the length information, and generates the CAN message generated by the message processing unit. The CAN message may be broadcast on a CAN bus by the transceiver.

The transceiver receives the CAN message transmitted from another electronic control device through the CAN bus, and the message processing unit, based on the start position of the data and the insertion position of the length information, the CAN received through the CAN bus It is also possible to extract received data and length information of the received data from the message.

In addition, the vehicle communication method of the in-vehicle electronic control device according to an embodiment includes receiving input values arbitrarily selected from among sensor values generated in the vehicle, substituting the input values into at least one preset positioning function to obtain data and determining the position information of the length information of the data, and based on the position information, identifying the start position of the data and the insertion position of the length information in the CAN message transmitted and received with another electronic control device. may include

In the vehicle communication method, the CAN message has a data payload of a fixed length, and dummy data may be inserted into at least one byte other than a byte into which the data and the length information are inserted in the data payload. .

In the vehicle communication method, a fixed value corresponding to the fixed length of the data payload may be inserted into a data length code (DLC) of the CAN message.

In the vehicle communication method, the input values and the positioning function may be shared with other electronic control devices. The input values may be changed every predetermined time.

The vehicle communication method includes generating the CAN message by inserting transmission data and length information of the transmission data into the CAN message based on a start position of the data and an insertion position of the length information, and the generated CAN message. The method may further include broadcasting the message to the CAN bus.

The vehicle communication method includes the steps of receiving a CAN message transmitted from another electronic control device through the CAN bus, and based on a start position of the data and an insertion position of the length information, the CAN received through the CAN bus The method may further include extracting received data and length information of the received data from the message.

According to an embodiment, it is possible to increase defense against illegal access to the CAN bus, and to limit system damage even if the CAN bus is exposed to illegal access.

1 schematically illustrates a vehicle communication device according to an embodiment.
2 illustrates an example of a CAN message used in a vehicle communication device according to an embodiment.
3 illustrates an example of a vehicle system including a vehicle communication device according to an embodiment.
4 schematically illustrates a communication method of a vehicle according to an exemplary embodiment.

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but identical or similar components are given the same and similar reference numerals, and overlapping descriptions thereof will be omitted.

The suffixes "module" and/or "~ part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have distinct meanings or roles by themselves. In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Terms including ordinal numbers such as first, second, etc. may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

In the present application, terms such as “comprises” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

In addition, terms such as "unit", "unit", "module", and "means" described in the specification mean a unit that processes at least one function or operation, which is hardware or software or hardware and software It can be implemented by combining

1 schematically illustrates a vehicle communication device according to an embodiment.

Referring to FIG. 1 , a vehicle communication device 10 according to an embodiment includes a data location determining unit 12 , a message processing unit 13 , an encoder 13 , a decoder 14 , and a transceiver 15 . ) may be included.

The data positioning unit 12 receives at least one input value (x1, x2, ??, xn) arbitrarily selected from various data (eg, sensor values) generated in the vehicle, and receives the received input By substituting the values into a positioning function, which is an arbitrary mathematical function, a start position of data in a CAN message (or a CAN data frame) and a position where length information of the corresponding data is inserted can be determined.

Equation 1 below shows an example of a positioning function used by the data positioning unit 12 .

[Equation 1]

F(x1, x2, x3, x4) = (x1×55 + x2×x3 + x4×x1) MOD 8

When the positioning function of Equation 1 is used, four input values (x1 to x4) may be input to the data positioning unit 12 . For example, when each input value has a value of x1=5, x2=8, x3=12, x4=2, the location information F(x1, x2, x3, x4) derived through the above number 1 is 5 can have a value of When the position information thus determined is position information corresponding to the start position of data in the CAN message, the data is the 5th byte among bytes constituting the data payload (or data field) of the CAN message can be located from Meanwhile, Equation 1 above is an example of a positioning function, and the positioning function may be variously modified in the number of input values, complexity of the function, and the like.

Since the data and the length information of the data must be inserted at different positions, the data positioning unit 12 uses two different positioning functions to determine the start position of the data and the position where the length information of this data is inserted. may be determined independently of each other.

In this embodiment, the types or values of the input values input to the data positioning unit 12 for positioning may be changed every predetermined time. Accordingly, when a predetermined time has elapsed, the position at which data and length information thereof are inserted into the CAN message is dynamically changed, so that it is possible to increase the defense against hacking of the CAN message.

In addition, in this embodiment, the input values input to the data positioning unit 12 for positioning and the positioning functions for determining the start position of data and the insertion position of the data length information based on this are the vehicle communication device ( 10) and all other electronic control units (ECUs) connected via the CAN bus 5 may be shared. That is, the same input values for positioning may be input to all ECUs connected to the vehicle communication device 10 and the CAN bus 5 through the CAN bus 5 . In addition, all ECUs connected via the vehicle communication device 10 and the CAN bus 5 use the same positioning function as the vehicle communication device 10, and the start position of data and length information of the data are inserted from the input values. position can be obtained. In this way, all ECUs communicating with the vehicle communication device 10 share the same input values and the same positioning function, so that the vehicle communication device 10 and other ECUs transmit and receive data transmitted and received through the CAN bus 5 and the length thereof. You can share location information for your information.

The message processing unit 13 receives the position information (P, K) indicating the start position of data and the insertion position of the data length information in the CAN message from the data position determining unit 12, and based on this, the CAN transmitted and received It is possible to identify the start position of data and the insertion position of data length information in the message.

When a CAN message is to be transmitted from the vehicle communication device 10 to another ECU, the message processing unit 13 receives data to be transmitted and Its length information may be allocated (or inserted) in the data payload of the CAN message.

When the vehicle communication device 10 receives a CAN message from another ECU, the message processing unit 13 receives the received CAN message based on the position information P of the data length information received from the data position determining unit 12 . It is possible to obtain information on the actual length of the received data from the data payload of . In addition, the message processing unit 13 may extract only the actual received data from the data payload of the CAN message based on the thus obtained length information and the start position information (K) of the data received from the data position determining unit 12. have.

In this embodiment, the length of the data payload included in the CAN message, that is, the number of bytes, has a fixed value regardless of the actual length of the transmitted data or the received data, and A data length code (DLC) may also have a fixed value inserted according to the fixed length of the data payload. For example, the length of the data payload of the CAN message is fixed to 8 bytes, and accordingly, a value indicating 8 bytes may be inserted into the DLC.

As the data payload of the CAN message has a fixed length, the message processing unit 13 randomizes the bytes other than the bytes into which the actual transmission data and length information thereof are inserted in the data payload of the CAN message when the CAN message is transmitted. You can insert dummy data created with . In addition, when the CAN message is received, bytes other than the actual received data and the byte into which the length information is inserted among bytes constituting the data payload of the CAN message may be determined as dummy data.

FIG. 2 illustrates an example of a CAN message used in the vehicle communication device 10 of FIG. 1 , illustrating a CAN message for transmitting 2-byte RPM data as an example. The frame configuration of the CAN message shown in FIG. 2 is an example for description, and embodiments of the present invention are not limited thereto. For example, the CAN message may further include an additional field such as a Cyclic Redundancy Check (CRC) field.

Referring to FIG. 2 , regardless of the length (eg, 2 bytes) of data to be actually transmitted/received through the CAN message 20 , the data payload in the CAN message 20 has a fixed length of 8 bytes, , corresponding to the DLC field 24 may also have a value indicating 8 bytes.

In addition, among 8 bytes constituting the data payload, bytes (Byte 5, Byte 6) allocated to the actual data 22 and bytes (Byte 3) allocated to the length information 21 of the corresponding data Randomly generated dummy data 23 may be inserted into the remaining bytes except for Byte 1, Byte 2, Byte 4, Byte 7, and Byte 8.

As such, the CAN message 20 according to the embodiment has a data payload of a fixed length irrespective of the length of the actual data, and bytes not used for transmission of actual data and length information thereof in the data payload include: It may be constructed by inserting dummy data. Accordingly, even if the CAN message 20 is exposed to the hacker, it may be difficult for the hacker to obtain actual data from the CAN message by misrecognizing that data transmitted through the CAN message 20 has a length of 8 bytes. . In addition, since actual transmission/reception data and dummy data are randomly mixed in the data payload, even if the CAN message is exposed to hackers, decoding may be difficult. In addition, since the hacker cannot know where the actual data and length information thereof are inserted in the data payload, even if a spoofing message is injected into the CAN bus, illegal intrusion can be easily detected by ECUs.

Again, referring to FIG. 1 , when a CAN message is transmitted from the vehicle communication device 10 to another ECU, the CAN message in which the transmission data and length information thereof are inserted in the message processing unit 13 is then transmitted to the encoder 13 . It may be encoded by the encoder 13 and then broadcast to the CAN bus 5 by the transceiver 15 . In this embodiment, the vehicle communication device 10 may transmit/receive CAN messages to and from other ECUs by a broadcasting method, not an addressing method.

When the vehicle communication device 10 receives a CAN message from another ECU, the transceiver 15 receives the CAN message broadcast to the CAN bus 5 by the other ECU, and the decoder 14 receives the transceiver 15 After decoding the CAN message received by , it can be transmitted to the message processing unit 12 .

The vehicle communication device 10 having the above-described structure may be included in each ECU of the vehicle.

FIG. 3 shows an example of a vehicle system including the vehicle communication device 10 of FIG. 1 .

Referring to FIG. 3 , the vehicle communication device 10 described above is included in each ECU 1a , 1b , 1c of a vehicle system, so that each ECU 1a , 1b , 1c communicates with another ECU and a CAN bus 5 . It can perform a function of transmitting and receiving CAN messages through the

Referring to FIG. 3 , the vehicle communication devices 10 of each ECU 1a, 1b, and 1c use the same input values ( x1, x2, ??, xn) can be input. In addition, by substituting the same input values (x1, x2, ??, xn) to the same positioning function, the position where the data starts in the CAN message and the position where the length information thereof is inserted can be identified equally. have.

In addition, the types or values of input values input to the vehicle communication device 10 of each ECU 1a, 1b, and 1c for positioning the transmission/reception data may be changed at predetermined time intervals, and accordingly, the CAN A position at which data and length information thereof are inserted within a message may be dynamically changed. Here, the timing of re-determining the location information using the new input values may be notified by the master ECU among the ECUs 1a, 1b, and 1c of the vehicle. In this case, the positioning of all ECUs 1a, 1b, 1c is synchronized, so that positioning can be performed using the same input values.

4 schematically illustrates a communication method of a vehicle according to an exemplary embodiment. The vehicle communication method of FIG. 4 may be performed by the vehicle communication device 10 described above with reference to FIG. 1 as a CAN communication method.

Referring to FIG. 4 , the vehicle communication device 10 receives input values arbitrarily selected for positioning among sensor values generated in the vehicle (S11), and substitutes them into preset positioning functions within the CAN message. Position information into which data and length information thereof are inserted may be determined (S12). Here, the input values input for positioning and the positioning functions for determining the position information therefrom may share the same values and the same positioning function in all ECUs in the vehicle. Accordingly, the location information determined through the step S12 may also be shared by all ECUs.

The vehicle communication device 10 identifies the work currently in progress (S13), and if the currently in progress work is a transmission job, transmit data and its length information in the CAN message based on the location information determined through the step S12. It can be arranged to generate a CAN message (S14).

In step S14, the data payload into which the transmission data is inserted in the CAN message has a fixed length (eg, 8 bytes), and dummy data is included in the remaining bytes other than the bytes into which the transmission data and its length information are inserted. It may be inserted to generate a CAN message.

The CAN message thus generated may be encoded (S15) by the encoder 13 and then transmitted to the CAN bus 5 through the transceiver 15, ie, broadcast (S16).

In step S13 , if the currently ongoing job is identified as a reception job, the vehicle communication device 10 may receive a CAN message broadcast from another ECU from the CAN bus 5 through the transceiver 15 ( S17 ). ). In addition, the vehicle communication device 10 decodes the CAN message received from the CAN bus 5 (S18), and then receives data and its length information from the decoded CAN message based on the location information determined through the step S12. can be extracted (S19).

The vehicle communication method according to the above-described embodiment may be executed through software. When executed in software, the constituent means of the present invention are code segments that perform the necessary tasks. The program or code segments may be stored on a processor readable medium or transmitted by a computer data signal coupled with a carrier wave in a transmission medium or a communication network.

The computer-readable recording medium includes all types of recording devices in which data readable by a computer system is stored. Examples of the computer-readable recording device include ROM, RAM, CD-ROM, DVD_ROM, DVD_RAM, magnetic tape, floppy disk, hard disk, and optical data storage device. In addition, the computer-readable recording medium may be distributed to network-connected computer devices to store and execute computer-readable codes in a distributed manner.

The drawings and detailed description of the described invention referenced so far are merely exemplary of the present invention, which are only used for the purpose of explaining the present invention, and are used to limit the meaning or limit the scope of the present invention described in the claims. it is not Therefore, those of ordinary skill in the art can easily select from it and replace it. In addition, those skilled in the art may omit some of the components described herein without degrading performance or add components to improve performance. In addition, those skilled in the art may change the order of the method steps described herein according to the process environment or equipment. Accordingly, the scope of the present invention should be determined by the claims and their equivalents rather than the described embodiments.

1a, 1b, 1c: ECU
5: CAN bus
10: vehicle communication device
11: Data positioning unit
12: message processing unit
13: encoder
14: decoder
15: transceiver

Claims (14)

A vehicle communication device comprising:
A data positioning unit that receives input values arbitrarily selected from among sensor values generated in the vehicle and determines location information of data and length information of the data by substituting the input values into at least one preset location determining function, and
and a message processing unit for identifying a start position of the data and an insertion position of the length information in a CAN message based on the position information. According to claim 1,
The CAN message has a data payload of a fixed length,
In the data payload, dummy data is inserted into at least one byte other than a byte into which the data and the length information are inserted. 3. The method of claim 2,
and a fixed value corresponding to the fixed length of the data payload is inserted into a data length code (DLC) of the CAN message. According to claim 1,
and the input values and the positioning function are shared with other electronic control devices. 4. The method of claim 3,
and the input values vary every predetermined time. According to claim 1,
further comprising a transceiver,
The message processing unit generates the CAN message by inserting transmission data and length information of the transmission data into the CAN message based on a start position of the data and an insertion position of the length information,
The CAN message generated by the message processing unit is broadcast to a CAN bus by the transceiver. 7. The method of claim 6,
The transceiver receives a CAN message transmitted from another electronic control device through the CAN bus,
The message processing unit may be configured to extract received data and length information of the received data from the CAN message received through the CAN bus, based on a start position of the data and an insertion position of the length information. A vehicle communication method for an electronic control device in a vehicle, comprising:
receiving input values arbitrarily selected from among sensor values generated in the vehicle;
determining position information of data and length information of the data by substituting the input values into at least one preset position determining function, and
and identifying a start position of the data and an insertion position of the length information in a CAN message transmitted and received with another electronic control device based on the position information. 9. The method of claim 8,
The CAN message has a data payload of a fixed length,
In the data payload, dummy data is inserted into at least one byte other than a byte into which the data and the length information are inserted. 10. The method of claim 9,
and a fixed value corresponding to the fixed length of the data payload is inserted into a data length code (DLC) of the CAN message. 9. The method of claim 8,
and the input values and the positioning function are shared with other electronic control devices. 12. The method of claim 11,
The input values are changed every predetermined time, the vehicle communication method. 9. The method of claim 8,
generating the CAN message by inserting transmission data and length information of the transmission data into the CAN message based on the start position of the data and the insertion position of the length information, and
The vehicle communication method further comprising the step of broadcasting the generated CAN message to a CAN bus. 14. The method of claim 13,
receiving a CAN message sent from another electronic control device via the CAN bus; and
and extracting received data and length information of the received data from the CAN message received through the CAN bus based on the start position of the data and the insertion position of the length information.

Images