KR101740957B1

KR101740957B1 - Data certification and acquisition method for vehicle

Info

Publication number: KR101740957B1
Application number: KR1020160005555A
Authority: KR
Inventors: 우사무엘; 이동훈; 조효진
Original assignee: 고려대학교 산학협력단
Priority date: 2016-01-15
Filing date: 2016-01-15
Publication date: 2017-05-30

Abstract

The gateway electronic control unit (GECU) and the general electronic control unit (ECU_i) authenticate the vehicle data in a vehicle communication system including at least one general electronic control unit and a gateway electronic control unit (GECU) A method for acquiring an image is disclosed. The method for authenticating and acquiring vehicle data includes a session encryption key and a session authentication key based on a symmetric key stored in advance in the vehicle manufacturing step by the gateway electronic control unit (GECU) and the general electronic control unit (ECU_i) (GECU) or the general electronic control unit (ECU_i) transmits vehicle data including a message authentication code, a data frame counter, and a cipher text (C) to the gateway electronic control unit , And authenticating and acquiring the vehicle data by verifying the message authentication code and decrypting the cipher text by another device of the gateway electronic control unit (GECU) or the general electronic control unit (ECU_i) .

Description

TECHNICAL FIELD [0001] The present invention relates to a data authentication and acquisition method,

The embodiment according to the concept of the present invention relates to a method of authenticating and acquiring vehicle data, and more particularly, to an electronic control apparatus (ECU_i) performing data communication with a gateway electronic control unit (GECU) And carries out authentication and encryption / decryption of vehicle data by using the session key, thereby assuring confidentiality of data and authentication of vehicle data.

Recently released cars are changing to electronic control environment to improve driving safety and fuel efficiency. Electronic control systems mounted inside a car are composed of one or more electronic control units (ECUs). Electronic control devices belonging to each electronic control system constitute a communication environment for mutual data transmission. In order to establish the communication environment between the electronic control devices in the automobile, standard communication protocols such as CAN (Controller Area Network), CAN FD (Controller Area Network with Flexible Data rate) and FlexRay are used.

CAN uses a BUS network structure to drastically reduce communication lines inside the vehicle. In addition, it provides communication speed of 1Mbps (Mega bit per second), but also has strong advantages against external electromagnetic waves and noise. However, as automobile-IT convergence has increased and services connecting automobiles and home appliances (eg, tablet PCs, smart phones) have become commercially available, traffic load on the internal network of automobiles has increased sharply. In particular, CAN uses 8 byte (byte) limited data payload, which makes it impossible to meet the data transmission demands of all IT technologies and devices in the latest automobiles.

In order to overcome these limitations, the CAN FD (CAN with Flexible Data rate), which extends the data rate and data payload in 2012, has been developed. CAN FD has increased transmission speed and data payload while using the same communication method as existing CAN. The CAN FD supports up to 10 Mbps (megabits per second) transmission speed and 64 byte (byte) data payload, which can meet the data transmission demand among automotive internal ECUs due to automotive-IT convergence technology.

However, in terms of security, CAN and CAN FD have several weaknesses. Since CAN and CAN FD use a broadcast communication method, all data on the communication is exposed to the outside. In addition, because it does not provide data confidentiality, it can analyze the meaning of all data on the communication, does not provide data authentication, can not prevent falsification-tampering of data transmitted on the communication, and is not safe from retransmission attacks . In addition, since there is no access control function, all nodes connected to the communication line can monitor all data on the communication and can transmit desired data. In other words, the CAN FD does not have a security mechanism to prevent eavesdropping, up / modulating and retransmission of data, so that a malicious attacker can arbitrarily control the vehicle or acquire important internal data using it.

In order to solve these problems, there is a need for a security technology that ensures the confidentiality and authentication of the vehicle control data using the CAN FD supporting the communication speed and the data payload and considering the computing power of the ECU.

In the prior art document cited below, a method of generating a session key based on a certificate and performing authentication of vehicle data using the same is disclosed.

In this specification, a method is proposed in which a session key is generated based on a symmetric key unique to an ECU, and a message counter is added to a data frame to more efficiently authenticate the vehicle data.

KR 10-1481403 B1

An object of the present invention is to provide a vehicle data authentication method that facilitates authentication of vehicle data transmitted and received during network communication between ECUs included in an in-vehicle communication system.

And to provide a CAN FD data frame structure that provides data confidentiality and authentication.

The method for authenticating and acquiring the vehicle data by the first electronic control device for transmitting the vehicle data and the second electronic control device for receiving the vehicle data in the vehicle communication system according to the embodiment of the present invention is characterized in that the first electronic control device Distributing a session key including a session encryption key and a session authentication key based on a symmetric key previously stored in the vehicle manufacturing step by the second electronic control device, (C) by encrypting the data (M) to be transmitted using a data frame counter and a cryptographic function of the data frame counter and the cryptographic function. Wherein the first electronic control device generates a message authentication code using the data frame counter, the cipher text (C), and a cryptographic hash function, the first electronic control device generates the message authentication code, , And transmitting the ciphertext (C) to the second electronic control device, the second electronic control device sending the message authentication code (C) to the second electronic control device using the data frame counter, the cipher text (C) And when the message authentication code is verified, the second electronic control unit decrypts the cipher text (C) using the data frame counter, the cipher text (C), and the cryptographic hash function And obtaining the data (M).

Further, in the vehicular communication system including at least one general electronic control device, a gateway electronic control device (GECU), and a communication bus connecting the at least one general electronic control device (GECU) according to an embodiment of the present invention, the gateway electronic control device (ECU_i) authenticates and acquires data for the vehicle, the method comprising the steps of: generating a session encryption key and a session authentication key based on a symmetric key pre-stored in the vehicle manufacturing step by the gateway electronic control unit (GECU) and the general electronic control unit Distributing a session key comprising a key, and

Wherein either the gateway electronic control unit (GECU) or the general electronic control unit (ECU_i) transmits vehicle data including a message authentication code, a data frame counter, and a cipher text (C) (GECU) or another device of the general electronic control unit (ECU_i) verifies the message authentication code and decrypts the cipher text, thereby authenticating and acquiring the vehicle data.

According to the automobile data authentication method according to the embodiment of the present invention, since the ECU is authenticated based on the symmetric key stored in all the ECUs in the automobile manufacturing step, only the legitimate ECU can participate in the communication and the confidentiality is assured.

In addition, by using the data payload field of the CAN FD data frame field as a space for the message authentication code, it is possible to provide data confidentiality and authentication, and also to provide the data payload field of the CAN FD data frame field as a data frame counter So that synchronization can be omitted.

There is an effect of preventing an abnormal automobile control through a data retransmission attack by using a counter value when a message authentication code is generated.

In addition, real-time processing of communication data between ECUs can be guaranteed while providing data confidentiality and authentication by using CAN FD data frames that can efficiently load message authentication codes, message counters, and ciphertexts.

Further, by periodically updating the session key using the update key, it is possible to prevent abnormal automobile control through data retransmission attack.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to more fully understand the drawings recited in the detailed description of the present invention, a detailed description of each drawing is provided.
1 shows a communication system for a vehicle according to an embodiment of the present invention.
Figure 2 shows the CAN FD data frame format.
Fig. 3 is a functional block diagram of the vehicle data authenticating and acquiring apparatus shown in Fig. 1. Fig.
4 is a flowchart for explaining a vehicle data authentication and acquisition method of the vehicle data authentication and acquisition apparatus shown in FIG.
FIG. 5 is a flow chart illustrating step S200 of FIG. 4 in more detail, and FIG. 6 is a flowchart illustrating step S300 of FIG. 4 in more detail.

It is to be understood that the specific structural or functional description of embodiments of the present invention disclosed herein is for illustrative purposes only and is not intended to limit the scope of the inventive concept But may be embodied in many different forms and is not limited to the embodiments set forth herein.

The embodiments according to the concept of the present invention can make various changes and can take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. It should be understood, however, that it is not intended to limit the embodiments according to the concepts of the present invention to the particular forms disclosed, but includes all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example, without departing from the scope of the right according to the concept of the present invention, the first element may be referred to as a second element, The component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like are used to specify that there are features, numbers, steps, operations, elements, parts or combinations thereof described herein, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings attached hereto.

1 shows a vehicle communication system according to an embodiment of the present invention. The vehicle communication system 10 may mean a communication system for a vehicle, specifically, a CAN (Flexible Data Rate) communication system. However, the present invention is not limited to the type of vehicle communication system 10, and the communication system may be a CAN (Controller Area Network), a Flexlay, a Local Interconnect Network (LIN), or a Multimedia Oriented Systems Transport (MOST) Or a communication system.

1, the communication system 10 includes a plurality of electronic control units (ECUs) 100, a gateway ECUs (GECUs 100G), and a bus 12. The GECU means an ECU having a higher performance than a general ECU and acting as a gateway.

The plurality of ECUs includes a first ECU (ECU_1), a second ECU (ECU_2), a third ECU (ECU_3), and a fourth ECU (ECU_4). Although four electronic control devices (ECU_i, i is an ID of an ECU) are shown in Fig. 1, the number of electronic control units (ECU_i) included in the communication system 10 is n have.

Each of the plurality of electronic control units (ECU_i) can control the operation of the corresponding electronic device, and can communicate with other ECUs via the bus (12). The electronic control unit ECU_i is connected to the bus 12 (for example, a CAN FD communication bus) and communicates in a broadcast manner.

All ECUs, including GECU, share a symmetric key in a secure environment. When fabricating the ECU and the GECU, a symmetric key may be mounted on the ECU and the GECU. The symmetric key includes a symmetric key SK_i for authentication and a symmetric key SK_G for key generation. Specifically, all ECUs including GECU share a symmetric key (SK_G) for key generation. A first authentication symmetric key SK_1 is mounted on the first ECU, and a second authentication symmetric key SK_2 is mounted on the second ECU. The third ECU and the fourth ECU are equipped with a third authentication symmetric key SK_3 and a fourth authentication symmetric key SK_4, respectively. The gateway ECU (GECU) is equipped with authentication symmetric keys (SK_1, SK_2, SK_3, SK_4) corresponding to a plurality of ECUs connected to the GECU. That is, the symmetric key SK_i for authentication means an ECU (ECU_i) having ID i and an authentication key previously shared by the GECU, and the symmetric key SK_G for key generation is a key for all ECUs including GECU Means the key generation key that is shared.

FIG. 2 illustrates a data frame structure of a CAN FD protocol according to an exemplary embodiment of the present invention. The data frame includes an arbitration field including ID information for identifying a sender of a data frame, a control field Field, and a data payload. The CAN FD data frame supports data payloads of up to 64 bytes and can transfer 64 bytes of data at a time.

The data payload of the CAN FD data frame according to an exemplary embodiment of the present invention includes a total of three areas. The first area is a message authentication code (MAC) loading area. In the first area, a message authentication code (MAC) generated using a ciphertext and a data frame counter is loaded. The size of the first area is 16 bytes.

The second area is a data frame counter loading area. The data frame counter (CTR_ECU_i) indicates the number of transmissions of the data frame transmitted by the specific ECU. For example, when the ECU_i transmits a total of four data frames and then transmits a fifth data frame, the data frame counter (CTR_ECU_i) of the ECU_i is set to five. The size of the second area is 4 bytes. The sizes of the first area and the second area are fixed. 44 bytes (bytes) excluding the first area and the second area can be used for data transmission.

The third area is a cipher text area. The cipher text (C) is generated by encrypting the plaintext (M) using the encryption key (EK_k) for the session.

3 is a functional block diagram of an apparatus 100 for performing authentication and acquisition of vehicle data according to an embodiment of the present invention. The vehicle data authenticating and acquiring apparatus according to an embodiment of the present invention may be an electronic control unit (ECU) 100 for a vehicle.

3, an apparatus 100 for authenticating and acquiring vehicle data for performing authentication and acquisition of vehicle data includes a session key management unit 110, an authentication unit 130, an encryption unit 150, a decryption unit 160, A communication unit 170, a storage unit 180, and a control unit 190.

The session key management unit 110 includes a session key generation unit and an update management unit. Under the control of the control unit 190,

The authentication unit 130 includes a message authentication code generation unit and a message authentication code verification unit, generates a message authentication code under the control of the control unit 190, and verifies the message authentication code to perform authentication of vehicle data.

Under the control of the control unit 190, the encryption unit 150 encrypts the data (CAN FD data) to be transmitted to the authentication and acquisition apparatus of other vehicle data using the encryption key EK_k of the data frame counter and the session key .

The decryption unit 160 decrypts the cipher text received from the other vehicle data authentication and acquisition apparatus using the data frame counter and the encryption key EK_k of the session key, and acquires a plain text.

The communication unit 170 can communicate with a plurality of vehicle data authentication and acquisition apparatuses (ECU or GECU 100) using a communication bus (CAN FD bus) 12 under the control of the control unit 190. [ That is, CAN FD data can be received from each ECU (ECU_i) and GECU, and CAN FD data including a message authentication code, a data frame counter, and a cipher text can be transmitted to each ECU (ECU_i) and GECU . Unlike the present embodiment, the communication unit may be implemented separately from the corresponding electronic control unit.

The storage unit 180 stores functions, keys, authentication values, vehicle data, and the like necessary for vehicle data authentication and acquisition under the control of the control unit 190. [

The control unit 190 controls the overall operation of an electronic control unit (ECU) 100 that performs authentication and acquisition of vehicle data. That is, the operation of the session key management unit 110, the authentication unit 130, the encryption unit 150, the decryption unit 160, the communication unit 170, and the storage unit 180 can be controlled.

4 is a flowchart illustrating a method of authenticating and acquiring vehicle data of an electronic control device that performs authentication and acquisition of vehicle data according to an embodiment of the present invention.

Referring to FIG. 4, a method for authenticating and acquiring vehicle data determines whether symmetric key sharing step S100, session key distribution step S200, vehicle data authentication and acquisition step S300, and session key updating (redistribution) (S400). And repeats the data authentication and acquisition steps during the session using the session key corresponding to the session. Also, the session key is periodically updated according to a predetermined criterion, and the data authentication and acquisition steps are repeated using the updated session key.

First, prior to performing authentication and acquisition of vehicle data in the vehicle communication system 10, all ECUs including the GECU share a symmetric key in a secure environment (SlOO). The manufacturer of the ECU can mount the symmetric key on the ECU and the GECU when manufacturing the ECU and the GECU. Specifically, the symmetric key includes a symmetric key SK_i for authentication and a symmetric key SK_G for key generation. All ECUs including GECU securely share the symmetric key SK_G for key generation, each ECU_i securely stores an authentication symmetric key SK_i corresponding to each ECU_i, and GECU authenticates all ECU_i associated with GECU Lt; RTI ID = 0.0 > SK_i < / RTI >

Next, the vehicle data authentication and acquisition apparatus distributes the session key before transmitting and receiving the vehicle data (S200). The session key distribution step includes an initial session key distribution step and a session key redistribution (update) step. When the vehicle is started, the initial session key (first session key) is distributed first.

Figure 5 is a more detailed view of the initial session key distribution process.

Referring to FIG. 5, there are two session keys: a k-th session encryption key EK_k and a k-th session authentication key AK_k. In this case, k represents the order of the session to be currently communicated. The session key distribution process proceeds in the order of the IDs of the ECUs. When a specific ECU_i performs a session key distribution process with the GECU, other ECUs wait for their order without participating in the communication. The session key generated through the initial session key distribution process is the first session encryption key EK_1 and the first session authentication key AK_1, and the used Seed is Seed_1. The session key to be used in the kth session is a kth session encryption key (EK_k) and a kth session authentication key (AK_k), and Seed used at this time is Seed_k. The session key distribution process performed between ECU_i and GECU is as follows.

First, in order to start the initial session key distribution process, the ECU_i generates a first random number R_i (S210) and transmits it to the GECU (S220).

Next, the GECU receiving the first random number R_i generates a second random number Seed_1 (S231).

Next, the GECU generates the first authentication value MAC_1 using the random number and the second random number (S233). The formula for generating the first authentication value MAC_1 is as follows.

At this time, H _SK _{_i} () refers to the one-way hash function that uses a 'SK_i' key.

Next, the GECU transmits the second random number (Seed_1) and the first authentication value (MAC_1) to the ECU_i (S240).

Next, the ECU_i verifies the received first authentication value MAC_1 (S251). The first authentication value (MAC_1) verification method is the same as that of Equation (1). All ECUs and the GECU can perform generation and verification of the first authentication value (MAC_1) since they share the authentication symmetric key SK_i and the hash function.

If the verification of the first authentication value (MAC_1) is normally completed, the ECU_i generates a session key using the second random number (Seed_1) (S253). The session key corresponding to the k-th session includes a k-th session encryption key EK_k used for data frame encryption and a k-th session authentication key AK_k used for data frame authentication. In the initial session key distribution process, (MAC_1), and then generates a first session key including a first session encryption key EK_1 and a first session authentication key AK_1. The method of generating the session key of the first session is shown in Equation (2).

In this case, _SK _{_G} KDF () denotes a key generation function that uses a 'SK_G' key (or key derivation function, public key derivation function).

Next, the ECU_i that has completed the session key generation generates the second authentication value MAC_2 (S255). The second authentication value MAC_2 generation method is expressed by Equation (3).

Next, the ECU_i transmits the second authentication value MAC_2 to the GECU (S260).

After receiving the second authentication value MAC_2, GECU performs a second authentication value MAC_2 verification using Equation (3) (S271).

If the verification of the second authentication value MAC_2 is normally completed, the GECU generates the first session key EK_1 and AK_1 using the second random number Seed_1 (S273). The method of generating the session key is the same as that of Equation (3).

If all the above steps are performed, the initial session key distribution process between GECU and ECU_i ends. All ECUs perform the same initial session key distribution process as ECU_i. If all the ECUs perform the above procedure normally, the initial session key distribution process is terminated.

After the initial session key distribution process is normally completed, the car performs data encryption and authentication (S300) to establish a secure communication environment. Next, it is determined whether or not to update the session key according to a predetermined criterion (S400), and a new session key is distributed (S200). For example, a time point at which a specific time T elapses while the initial session key is used, or a time at which the data frame counter CTR_ECU_i of the sending ECU is initialized to '0' And determines whether to update the session key based on the determination result, and then performs a session key update step. The session key update step performs the same process as the initial session key distribution step. The session key update method performed in the k-th session is as follows.

ECU_i generates an arbitrary first random number R_i_k of the k-th session and transmits it to the GECU, and the GECU receiving the first random number R_i_k of the k-th session generates a second random number Seed_k of the k-th session . GECU the first authentication value in the k-th session of the ECU_i (MAC _ik _1) the generated and the first authentication value in the k-th session of the second random number (Seed_k) and ECU_i of k-th session (MAC _ik _1 To ECU_i. The first authentication value in the k-th session of the ECU_i (MAC _ik _1) generation method is as follows.

ECU_i verifies the first authentication value (MAC _1 _ik) of the k-th session of the ECU_i using the equation (4) received. All GECU ECU and may perform the generation and verification of the first authentication value in the k-th session of the ECU_i (MAC _ik _1) because they share the SK_i and hash function.

The first authentication value in the k-th session of the ECU_i (MAC _ik _1) verification After normal shutdown ECU_i the k-th using the second random number (Seed_k) of the session the k-th session encryption key (EK_k) and the k-th session authentication And generates a k-th session key including the key AK_k. The k < th > session key generation method is as shown in Equation (5).

The ECU_i completing the session key k generated is sent to the GECU generates a second authentication value (MAC _2 _ik) of the k-th session. Second authentication value from the k-th session of the ECU_i (MAC _ik _2) generation method is shown in equation (6).

Next, GECU is the mathematical When verifying the second authentication value (MAC _ik _2) of the k-th session of the received ECU_i transmitted using Equation 6, and the verification is ended normally GECU the second random number and said k-th session And generates a k-th session key (EK_k, AK_k) using Equation (5).

If all the above steps are performed, the session key updating process between GECU and ECU_i is terminated. Perform the same procedure for all ECUs. If all the ECUs perform the above procedure normally, the session key update process is terminated.

The GECU and all ECUs that have performed the initial session key distribution process or the key update process normally store two session keys. That is, in the k-th session, the GECU and all the ECUs store the k-th session key including the k-th session encryption key EK_k and the k-th session authentication key AK_k.

Next, the vehicle data is authenticated and acquired using the k-th session key (S300). The transmitting ECU performs data frame encryption and authentication when transmitting a data frame, and the receiving ECU performs a message authentication code (MAC) verification of the received data frame, and then decrypts the decrypted data.

FIG. 6 is a diagram showing in more detail the security data transmission / reception process and the authentication / acquisition process for the vehicle. Referring to FIG. 6, the transmission ECU (ECU_s) generates a cipher text C using its data frame counter (CTR_ECU_s) and the plaintext M to be transmitted (S311). The method of generating the cipher text is shown in Equation (7) below.

In this case, E _EK _{_k} () denotes the encryption function using the 'EK_k' key.

Next, the transmission ECU (ECU_s) generates a message authentication code MAC_s using the data frame counter (CTR_ECU_s) and the cipher text (C) (S313). The method of generating the message authentication code (MAC_s) is shown in Equation (8).

Next, the transmission ECU (ECU_s) transmits a data frame including the message authentication code MAC_s, the data frame counter CTR_ECU_s and the cipher text C to the reception ECU (ECU_r) (S330) Increases the data frame counter (CTR_ECU_s) by one.

The reception ECU (ECU_r) receives the data frame transmitted from the transmission ECU (ECU_s) and acquires the message authentication code (MAC_s), the data frame counter (CTR_ECU_s), and the cipher text (C) from the data frame.

The receiving ECU (ECU_r) verifies the message authentication code MAC_s using the mathematical expression 8 (S351).

If the verification of the message authentication code (MAC_s) normally ends, the plaintext (M) is obtained using Equation (7) (S353).

The vehicle data authentication and acquisition method described above can be implemented as a program that can be executed by a computer and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

A vehicle data authentication and acquisition program stored in a recording medium and generating a session key based on a symmetric key and performing encryption, authentication, and decryption of vehicle data using the session key, the program being executed in a computing system A set of instructions for distributing a session key, an instruction set for updating a session key, a set of instructions for performing data encryption, a set of instructions for performing data authentication using a message authentication code, and a set of instructions for performing decryption of encrypted data .

The vehicle data authentication and analysis program is stored in the recording medium, and the recording medium may be a magnetic storage medium (e.g., a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (e.g., a CD- And the like. In addition, the recording medium may be distributed and distributed to a network-connected computer system so that a computer-readable instruction set can be stored and executed in a distributed manner.

The block diagrams disclosed herein may be construed to those skilled in the art to conceptually represent circuitry for implementing the principles of the present invention. Likewise, any flow chart, flow diagram, state transitions, pseudo code, etc., may be substantially represented in a computer-readable medium to provide a variety of different ways in which a computer or processor, whether explicitly shown or not, It will be appreciated by those skilled in the art.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Vehicle communication system
12: Bus
100: vehicle data authentication and acquisition device, ECU
110: session key management unit 130:
150: Encryption unit 160: Decryption unit
170: communication unit 180:
190:

Claims

A method for authenticating and acquiring vehicle data, comprising: a first electronic control unit for transmitting vehicle data using a CAN (Controller Area Network with Flexible Data Rate) communication system and a second electronic control unit for receiving the vehicle data,
The first electronic control device and the second electronic control device distribute the session key including the session encryption key and the session authentication key with the gateway electronic control device (GECU) based on the symmetric key stored in advance in the vehicle manufacturing step A session key distribution step;
Generating a cipher text (C) by encrypting data (M) to be transmitted using the data frame counter and the encryption function of the first electronic control unit;
The first electronic control device generating a message authentication code using the data frame counter, the cipher text (C), and a cryptographic hash function;
The first electronic control device transmitting the message authentication code, the data frame counter, and the ciphertext (C) to the second electronic control device;
The second electronic control device verifying the message authentication code using the data frame counter, the cipher text (C), and the cryptographic hash function; And
If the message authentication code is verified, the second electronic control unit decrypts the cipher text (C) using the data frame counter, the cipher text (C), and the cryptographic hash function to generate the data (M) Comprising the steps of:
Wherein the session key distribution step comprises:
The first electronic control device or the second electronic control device selecting a first random number;
The first electronic control device or the second electronic control device transmitting the first random number to the gateway electronic control device (GECU);
Selecting a second random number by the gateway electronic control unit (GECU) and generating a first authentication value according to Equation (1) below;
(Equation 1) MAC = H _ik _1 _{SK_i} (R_i_k Seed_k ||)
(Where, i is the one-way hash function, R_i_k is ECU_i using the first authentication value, H _{SK_i} is a symmetric key for authentication of ECU_i SK_i in k beonjje session to the ID, MAC _ik _1 is ECU_i the ECU key The second random number in the k-th session for ECU_i), Seed_k is the second random number in the k-
Sending the second random number and the first authentication value to the first electronic control device or the second electronic control device;
The first electronic control device or the second electronic control device verifying the first authentication value using Equation (1);
The first electronic control device or the second electronic control device generating a session key in a kth session including a session encryption key (EK_k) and a session authentication key (AK_k) according to Equation (2) below;
(2) KDF _{SK_G} (Seed_k) = EK_k || AK_k
(Where KDF _{SK_G} is a key generation function that uses SK_G, which is a symmetric key for key generation, as a key)
The first electronic control device or the second electronic control device generating a second authentication value by Equation (3) below;
(Equation 3) MAC = H _ik _2 _{SK_i} (Seed_k)
(Here, MAC _ik _2 the second authentication value from the k beonjje session for ECU_i)
The first electronic control device or the second electronic control device transmitting the second authentication value to the gateway electronic control device (GECU);
Verifying the second authentication value using the Equation (3) by the gateway electronic control unit (GECU); And
Wherein the gateway electronic control unit (GECU) generates the session key in the k-th session including the session encryption key (EK_k) and the session authentication key (AK_k) according to Equation (2) Authentication and acquisition of data.

The method according to claim 1,
Before performing the session key distribution step,
Wherein the first electronic control device and the second electronic control device store the encryption function and the cryptographic hash function.

The method according to claim 1,
The first electronic control device loads the message authentication code, the data frame counter, and the ciphertext (C) in the data payload area of the CAN FD data frame and sends it to the second electronic control device,
Wherein the data payload area includes a first area for loading the message authentication code, a second area for loading the data frame counter, and a third area for loading the ciphertext (C) .

The method according to claim 1,
Determining whether the first electronic control device or the second electronic control device performs an update of the session key; And
Wherein the first electronic control device and the second electronic control device distribute an update session key including an update session encryption key and an update session authentication key based on the symmetric key when it is determined to perform the session key update Further comprising: < RTI ID = 0.0 > a < / RTI >

5. The method of claim 4,
Wherein the encryption function performs encryption with a session encryption key or an update session encryption key corresponding to a session in which the first electronic control device transmits vehicle data,
Wherein the cryptographic hash function generates the message authentication code with a session authentication key or an update session authentication key corresponding to a session in which the first electronic control device transmits vehicle data.

The gateway electronic control unit (GECU) and the general electronic control unit (ECU_i) authenticate the vehicle data in a vehicle communication system including at least one general electronic control unit and a gateway electronic control unit (GECU) In the method of obtaining,
A session key distribution step of distributing a session key including a session encryption key and a session authentication key based on a symmetric key stored in advance in the vehicle manufacturing step by the gateway electronic control unit (GECU) and the general electronic control unit (ECU_i) ; And
Wherein either the gateway electronic control unit (GECU) or the general electronic control unit (ECU_i) transmits vehicle data including a message authentication code, a data frame counter, and a cipher text (C) Authenticating and acquiring the vehicle data by verifying the message authentication code and decrypting the cipher text by another device of the general electronic control unit (GECU) or the general electronic control unit (ECU_i)
Wherein the session key distribution step comprises:
Selecting the first random number by the general electronic control unit (ECU_i);
The general electronic control unit (ECU_i) transmitting the first random number to the gateway electronic control unit (GECU);
Selecting a second random number by the gateway electronic control unit (GECU) and generating a first authentication value according to Equation (1) below;
(Equation 1) MAC = H _ik _1 _{SK_i} (R_i_k Seed_k ||)
(Here, MAC _ik _1 is the first authentication value in the k beonjje session for ECU_i, H _{SK_i} is one-way hash function using a key to a symmetric key for authentication of ECU_i SK_i, R_i_k is at k beonjje session for ECU_i Seed_k is the second random number in the k-th session for ECU_i)
Transmitting the second random number and the first authentication value to the general electronic control unit (ECU_i) by the gateway electronic control unit (GECU);
Verifying the first authentication value using the Equation (1) by the general electronic control unit (ECU_i);
The general electronic control unit ECU_i generates a session key in a kth session including a session encryption key EK_k and a session authentication key AK_k according to Equation 2 below:
(2) KDF _{SK_G} (Seed_k) = EK_k || AK_k
(Where KDF _{SK_G} is a key generation function that uses SK_G, which is a symmetric key for key generation, as a key)
The general electronic control unit ECU_i generates a second authentication value according to Equation (3) below;
(Equation 3) MAC = H _ik _2 _{SK_i} (Seed_k)
(Here, MAC _ik _2 the second authentication value from the k beonjje session for ECU_i)
The general electronic control unit (ECU_i) transmitting the second authentication value to the gateway electronic control unit (GECU);
Verifying the second authentication value using the Equation (3) by the gateway electronic control unit (GECU); And
Wherein the gateway electronic control unit (GECU) generates the session key in the k-th session including the session encryption key (EK_k) and the session authentication key (AK_k) according to Equation (2) Authentication and acquisition of data.

The method according to claim 6,
The gateway electronic control unit GECU and the general electronic control unit ECU_i communicate using a Controller Area Network (CAN) Flexible Data Rate (CAN FD) communication system,
The gateway electronic control unit GECU or the general electronic control unit ECU_i loads the message authentication code, the data frame counter and the cipher text C into the data payload area of the CAN FD data frame, ECU_i) or the gateway electronic control unit (GECU)
Wherein the data payload area includes a first area for loading the message authentication code, a second area for loading the data frame counter, and a third area for loading the ciphertext (C) .

The method according to claim 6,
The symmetric key stored in the general electronic control unit ECU_i includes a symmetric key SK_i for authentication and a symmetric key SK_G for key generation specific to the general electronic control unit ECU_i,
The symmetric key stored in the gateway electronic control unit GECU includes symmetric keys SK_i for authentication of general electronic control units ECU_i communicating with the gateway electronic control unit GECU, 0.0 > SK_G) < / RTI >

The method according to claim 6,
Determining whether the gateway electronic control unit (GECU) or the general electronic control unit (ECU_i) performs update of the session key,
Wherein the gateway electronic control unit (GECU) and the general electronic control unit (ECU_i) repeatedly perform the step of distributing the session key when it is determined to perform the update of the session key.