KR102425929B1 - Method for preventing relay attack by analyzing moving distance of key fob - Google Patents

Abstract

Disclosed is a method for detecting a relay attack by calculating a moving distance of a smart key. The relay attack detection method includes: a vehicle transmitting a first message to a smart key; in response to the first message, the smart key transmitting a first response message to the vehicle; calculating a first distance between the vehicle and the smart key based on transmitting, to the vehicle, a second response message including a movement distance of the smart key or information for calculating the movement distance and a response value corresponding to the query value, based on the response value, determining whether the smart key is a valid key, if the smart key is determined to be a valid key, calculating, by the vehicle, a second distance between the vehicle and the smart key based on the second response message; and Relay attack by comparing the movement distance calculated using the information for calculating the movement distance or the movement distance included in the second response message and the movement distance calculated using the difference between the first distance and the second distance determining whether or not

Description

Method of preventing relay attack by calculating the movement distance of the key pop {METHOD FOR PREVENTING RELAY ATTACK BY ANALYZING MOVING DISTANCE OF KEY FOB}

The present invention relates to a method for preventing a relay attack in a PKES (Passive Keyless Entry and Start) system, and in particular, it is calculated using a MEMS (Micro-Electro Mechanical System) sensor in a key fob. A method of detecting a relay attack by comparing a moving distance and a moving distance calculated based on RSSI (Received Signal Strength Indication) of a signal received from a vehicle.

The PKES (Passive Keyless Entry and Start) system communicates with the driver's key fob to increase the driver's convenience, It is a system that allows opening and closing and/or starting of the door). In the PKES system, the vehicle and the smart key use two frequency channel signals to communicate with each other. The vehicle uses a short LF (Low Frequency) signal with a reach of 2 to 3 meters, and Key Pop uses an Ultra High Frequency (UHF) signal with a reach of 20 to 50 meters to control the vehicle from a long distance.

First, the vehicle periodically transmits an LF signal (checking the existence of a key pop and/or a wake up signal) around the vehicle, and the received key pop is a response signal to the LF signal received while waking up. Transmits a UHF signal (presence confirmation signal) to the vehicle. When the existence of the key pop is confirmed, the vehicle transmits the LF signal including the challenge information to the key pop again, and the key pop transmits the UHF signal including the response information corresponding to the query to the vehicle. do. When the received response information is checked normally, the vehicle performs vehicle control (opening/closing of a door, starting, etc.).

In such a PKES system, an attacker can perform a relay attack. The relay attack uses two signal repeaters between the vehicle and the driver's key pop to amplify the signals transmitted from the vehicle and the key pop, respectively, so that the vehicle and the key pop at a distance greater than the normal distance are judged to be close to each other. It means an attack that performs vehicle control (door opening and closing, starting, etc.) in the same way as in the process. This attack is possible because the vehicle cannot determine whether the response signal corresponding to the query transmitted by the key pop is actually a signal transmitted by a legitimate key pop.

Republic of Korea Patent Publication No. 10-2016-0149500 Republic of Korea Patent Registration No. 10-1562124

An object of the present invention is to provide a method and system for preventing a relay attack by comparing movement distance information of a key pop and movement distance information measured based on a signal received from a vehicle.

A relay attack detection method according to an embodiment of the present invention includes: a vehicle transmitting a first message to a smart key; in response to the first message, the smart key transmitting a first response message to the vehicle; Calculating a first distance between the vehicle and the smart key based on the first response message, the vehicle transmitting a second message including a query value to the smart key, and responding to the second message to transmit, by the smart key, a second response message including a movement distance of the smart key or information for calculating the movement distance and a response value corresponding to the query value to the vehicle, based on the response value to determine, by the vehicle, whether the smart key is a valid key, if the smart key is determined to be a valid key, the vehicle based on the second response message A second distance between the vehicle and the smart key calculating a movement distance calculated using information for calculating the movement distance or movement calculated using the movement distance included in a second response message and a difference between the first distance and the second distance and determining whether to attack the relay by comparing the distances.

A relay attack detection method according to another embodiment of the present invention comprises the steps of: a vehicle transmitting a wake up message to a smart key using a low frequency (LF) band; in response to the wakeup message, the smart key is transmitting an existence confirmation message to the vehicle using an Ultra High Frequency (UHF) band, the vehicle calculating a first distance between the vehicle and the smart key using the RSSI of the presence confirmation message; sending, by a vehicle, a challenge message to the smart key using the LF band; in response to the inquiry message, sending a response message including a movement distance of the smart key by the smart key to the smart key transmitting to the vehicle using the UHF band, the vehicle calculating a second distance between the vehicle and the smart key using the RSSI of the response message, and the vehicle calculating the second distance between the first distance and the second distance. and determining whether to perform a relay attack by comparing the moving distance calculated using the difference between the two distances with the moving distance included in the response message.

According to the relay attack prevention method through the calculation of the movement distance of the key pop according to an embodiment of the present invention, it is possible to prevent a relay attack by a malicious user.

In addition, it is possible to establish a safe PKES system that provides convenience to the driver and prevents vehicle theft accidents by the driver and the theft of goods inside the vehicle.

In order to more fully understand the drawings recited in the Detailed Description of the Invention, a detailed description of each drawing is provided.
1 shows a PKES system according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a relay attack detection method performed in the vehicle illustrated in FIG. 1 .
FIG. 3 is a flowchart illustrating a relay attack detection method performed by the smart key shown in FIG. 1 .
FIG. 4 is a functional block diagram of the vehicle shown in FIG. 1 .
FIG. 5 is a functional block diagram of the smart key shown in FIG. 1 .

Specific structural or functional descriptions for the embodiments according to the concept of the present invention disclosed in this specification are only exemplified for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention are It may be implemented in various forms and is not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention may have various changes and may have various forms, the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes all modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another, for example without departing from the scope of the inventive concept, a first component may be termed a second component and similarly a second component A component may also be referred to as a first component.

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 mentioned 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. Other expressions describing the relationship between elements, such as "between" and "immediately between" or "neighboring to" and "directly adjacent to", etc., should be interpreted similarly.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described herein is present, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, 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 a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these examples. Like reference numerals in each figure indicate like elements.

1 shows a PKES system according to an embodiment of the present invention, FIG. 2 is a flowchart for explaining a relay attack detection method performed in the vehicle shown in FIG. 1, and FIG. 3 is a smart key shown in FIG. It is a flowchart to explain the relay attack detection method performed in

1 to 3 , the PKES system includes a vehicle and a smart key (which may also be referred to as a smart key, key fob). The vehicle and the smart key may communicate with each other using a predetermined frequency band. That is, the vehicle may transmit a signal of the first frequency band to the smart key, and the smart key may transmit a signal of the second frequency band to the vehicle. The first frequency band and the second frequency band may be different from each other, the same, or some bands may overlap each other. For example, the vehicle transmits predetermined information to the smart key through a low frequency (LF) signal with a short reach of 2 to 3 meters, and the smart key uses a UHF (Ultra High Frequency) signal with a reach of 20 to 50 meters. It is possible to transmit predetermined information to the vehicle.

The vehicle and smart key on the PKES system can authenticate the legitimate smart key (or legitimate driver) through the following actions and detect relay attacks targeting the vehicle and/or smart key.

First, the vehicle transmits a first signal (which may also be called a first message, a wake-up signal, or a wake-up message, etc.) to the smart key. The first signal may be a signal of the first frequency band, and may mean a smart key existence confirmation and/or a wake-up signal. Also, the first signal may be transmitted periodically or aperiodically.

When the smart key exists within the reach of the first signal, the smart key receives the first signal and receives a first response signal corresponding to the first signal (a first response message, an ACK signal, an ACK message, an existence confirmation signal, or It may also be called an existence confirmation message, etc.) to the vehicle. The first response signal may be a signal of the second frequency band, and may mean an existence confirmation signal indicating that the smart key exists within the reach of the first signal. In addition, the smart key includes location information (eg, coordinates of the smart key) and/or acceleration information (eg, acceleration of the smart key) of the smart key at the time when the first signal is received or when the first response signal is transmitted ( t1 ) ) can be stored in the smart key. To this end, the smart key may include a GPS receiver for calculating location information and/or an acceleration sensor for calculating acceleration information. According to an embodiment, t1 may mean a time point at which the first signal is received or may mean an arbitrary time point between a time point at which the first signal is received and a time point at which the first response signal is transmitted. For example, the time t1 may mean a point in time when a predetermined time has elapsed from the time when the first signal is received, or a time in which a predetermined time advances from the time when the first response signal is transmitted.

The vehicle receiving the first response signal from the smart key uses the RSSI (Received Signal Strength Indication) of the first response signal to communicate with the vehicle at time t1 (eg, when the smart key transmits the first signal). The distance d1 of the smart key can be calculated. Since a method of calculating the distance from RSSI is widely known, a detailed description thereof will be omitted.

Also, the vehicle transmits a second signal (which may also be called a second message, an inquiry signal, or an inquiry message, etc.) to the smart key. The second signal may be a signal of the first frequency band, and may include a query value for confirming whether the smart key is a valid smart key and/or vehicle identification information (eg, vehicle ID).

The smart key receiving the second signal may transmit a second response signal (which may be referred to as a second response message or the like) to the vehicle. The second signal may be a signal of the second frequency band. The second signal may include a response value to a query value received from the vehicle and/or information about the moving distance of the smart key or information capable of calculating the moving distance.

Specifically, the smart key is a position at t2, which is a time point at which the second signal is received, a time point at which the second response signal is transmitted, or an arbitrary time point between the time point at which the second signal is received and the time point at which the second response signal is transmitted. Information and/or acceleration information may be measured and/or stored. For example, time t2 may mean a time when a predetermined time has elapsed from the time when the second signal is received, or may mean a time when a predetermined time is ahead of the time when the second response signal is transmitted.

Also, the smart key may calculate the moving distance of the smart key (or a driver holding the smart key) using the acceleration at time t1 and the acceleration at time t2. To this end, the smart key may calculate the moving distance (dk) of the smart key by integrating the acceleration information twice. For example, the smart key generates a linear function related to the acceleration of the smart key using the acceleration at time t1 and the acceleration at time t2, and then calculates the moving distance of the smart key through two integrations at time t1 and time t2. can According to an embodiment, the smart key measures acceleration at at least one time point t3 between time t1 and time t2, and generates an n (n is a natural number)-order function for the acceleration of the smart key, then time t1 and time t2 It is also possible to calculate the moving distance of the smart key through two integrations. As an example, the order n of the generated function may have a value obtained by adding '1' to the number of time points t3.

If the smart key is equipped with a GPS receiver, the smart key may calculate the moving distance of the smart key based on the location at time t1 and the location at time t2.

In addition, the moving distance of the smart key may be transmitted by being included in the second response signal after being encrypted using a symmetric key previously shared between the vehicle and the smart key.

According to another embodiment, the smart key may transmit information for calculating the moving distance by including it in the second response signal. The information for calculating the moving distance includes acceleration information at time t1 and time t2, and may include acceleration information at at least one time point t3 between time t1 and time t2. In this case, the vehicle may calculate the moving distance of the smart key through the same process as that of calculating the moving distance of the smart key. In addition, when the smart key is equipped with a GPS receiver, the smart key may transmit location information at time t1 and time t2 by including the second response signal. In addition, information capable of calculating the moving distance may be similarly encrypted using a symmetric key and then included in the second response signal.

When the response value included in the second response signal received from the smart key is a value corresponding to the query value, the vehicle determines that the smart key that transmitted the second response signal and/or the first response signal is a valid key, and determines whether to attack the relay. judge If the response value does not correspond to the query value, the vehicle may stop the protocol progress.

In order to detect a relay attack after being determined as a legitimate smart key, the vehicle decodes the movement distance dk included in the second response signal. Of course, if the movement distance dk is not encrypted, this operation may be omitted.

In addition, the vehicle calculates the distance d1 from the RSSI of the first response signal to the smart key at time t1 and the distance d2 from the RSSI of the second response signal to the smart key at time t2. Thereafter, the distance dv moved by the smart key between time t1 and time t2 is calculated using the difference between d1 and d2.

The vehicle determines the presence or absence of a relay attack according to whether the difference between the movement distance dk received from the smart key and the calculated movement distance dv is less than or equal to a predetermined threshold value (δ). That is, when the difference in the movement distance is less than or equal to the threshold value, it may be determined that the relay attack is not applied, and in this case, continuous vehicle control (opening/closing, starting, etc.) of the vehicle is possible. When the difference in the moving distance exceeds the threshold, it may be determined that a relay attack has been applied, and in this case, continuous vehicle control may not be performed. Of course, when information capable of calculating the moving distance is received from the vehicle, the moving distance dk of the smart key may be calculated through the same operation as that of the smart key.

FIG. 4 is a functional block diagram of the vehicle shown in FIG. 1 .

Referring to FIG. 4 , the vehicle 100 includes at least one of a communication unit 110 , an authenticator 120 , an attack detection unit 130 , a control unit 140 , a storage unit 150 , and a vehicle control unit 160 . It can be implemented to include

The communication unit 110 may transmit a signal or message and receive a signal or message corresponding thereto under the control of the control unit 140 . That is, the communication unit 110 may transmit a signal of a first frequency band and receive a signal of a second frequency band. Specifically, the communication unit 110 may transmit a first signal of a first frequency band and receive a first response signal of a second frequency band corresponding to the first signal. Also, the communication unit 110 may transmit a second signal of a first frequency band and receive a second response signal of a second frequency band corresponding to the second signal. A signal or message transmitted and received by the communication unit 110 may be stored in the storage unit 150 . According to an embodiment, the communication unit 110 may measure the RSSI of the first response signal and the second response signal, and store the measured RSSI in the storage unit 150 .

The authentication unit 120 performs an authentication operation on the smart key based on the second response signal received by the communication unit 110 or the second response signal stored in the storage unit 150 under the control of the control unit 140 . It can decide whether or not a legitimate smart key is available. Specifically, when the response value included in the second response signal corresponds to the query value included in the second signal, the authenticator 120 determines whether the smart key that has transmitted the first response signal and/or the second response signal is valid. It can be judged as a smart key.

The attack detection unit 130 may detect whether a relay attack occurs under the control of the control unit 140 . That is, when the authentication operation by the authenticator 120 is successfully performed, the controller may control the attack detector 130 to detect the presence or absence of a relay attack. Specifically, the attack detection unit 130 calculates the distance d1 between the vehicle and the smart key at time t1 from the RSSI of the first response message, and the distance between the vehicle and the smart key at time t2 from the RSSI of the second response message ( d2) can be calculated. As a result, the attack detector 130 may calculate the moving distance dv of the smart key by using the difference between the distance d1 at time t1 and the distance d2 at time t2. In addition, when the difference between the movement distance dk included in the second response signal and the calculated movement distance dv is distributed within the threshold value, the attack detection unit 130 determines that the relay attack has not been performed, and the threshold value If it exceeds , it can be determined that a relay attack has progressed. Of course, when the movement distance dk is encrypted, it is possible to determine whether a relay attack exists after decryption using the smart key and the symmetric key shared in advance.

According to an embodiment, the second response signal may include information for calculating the moving distance. In this case, the attack detection unit 130 may calculate the movement distance dk of the smart key by performing the same operation as that of the smart key.

The controller 140 may control the overall operation of the vehicle 100 . Specifically, the controller 140 may control the operation of at least one of the authenticator 120 , the attack detector 130 , the storage 150 , and the vehicle controller 160 .

The storage unit 150 contains a signal or message transmitted and received by the communication unit 110 (ie, the first signal, the first response signal, the second signal, and the second response signal), and the result of the authentication operation by the authenticator 120 . , an attack detection result by the attack detection unit 130, the calculated distances (d1, d2), the calculated movement distances (dk, dv), a symmetric key, and the like may be stored.

The vehicle control unit 160 generates a control signal for a control operation of the vehicle (opening/closing of a door, starting, etc.) under the control of the control unit 150, and transmits it through the vehicle's internal network, thereby performing a control operation of the vehicle. can work as much as possible. In this case, the generation of the control signal by the vehicle control unit 160 may be performed when it is determined that authentication of the smart key is completed and the relay attack is not performed, and the control of the vehicle control unit 160 is performed by the control unit 140 . can be performed by

FIG. 5 is a functional block diagram of the smart key shown in FIG. 1 .

Referring to FIG. 5 , the smart key 300 is implemented to include at least one of a communication unit 310 , an acceleration sensor unit 320 , a movement distance calculation unit 330 , a control unit 340 , and a storage unit 350 . can be

The communication unit 310 may receive a signal or message under the control of the control unit 340 and transmit a signal or message corresponding thereto. That is, the communication unit 310 may receive the signal of the first frequency band and transmit the signal of the second frequency band. Specifically, the communication unit 310 may receive a first signal of a first frequency band and transmit a first response signal of a second frequency band corresponding to the first signal. Also, the communication unit 310 may receive the second signal of the first frequency band and transmit a second response signal of the second frequency band corresponding to the second signal. A signal or message transmitted and received by the communication unit 310 may be stored in the storage unit 350 .

The acceleration sensor unit 320 may measure acceleration at each time point (eg, t1 and/or t2 ) under the control of the controller 340 , and the measured acceleration may be stored in the storage unit 350 . According to an embodiment, the acceleration sensor unit 320 may measure the acceleration at at least one time point t3 between time t1 and time t2 and store the measured acceleration in the storage unit 350 . In addition, the smart key 300 may be provided with a GPS receiver irrespective of the acceleration sensor unit 320 (that is, at least one of the acceleration sensor unit and the GPS receiver may be implemented). In this case, the GPS receiver is each Position information at each viewpoint may be calculated based on the GPS signal at the viewpoint, and the calculated position information may be stored in the storage unit 350 .

The movement distance calculation unit 330 uses the acceleration information measured by the acceleration sensor unit 320 and/or the location information calculated by the GPS receiver to move the smart key 300 between time t1 and time t2. distance can be calculated. Since the operation for this overlaps with the previous description, it will be omitted. According to an embodiment, the moving distance may be calculated by the vehicle 100 , and in this case, the moving distance calculating unit 330 may be omitted.

The control unit 340 controls the configuration of the smart key 300 , that is, the operation of at least one of the communication unit 310 , the acceleration sensor unit 320 , the GPS receiving unit, the moving distance calculating unit 330 , and the storage unit 350 . can do.

The storage unit 350 includes a signal or message transmitted and received by the communication unit 310 (ie, a first signal, a first response signal, a second signal, a second response signal), a transmission/reception time of a signal or message transmitted and received, and an acceleration sensor. Acceleration at each point in time measured by the unit 320, location information at each point in time received by the GPS receiver, the moving distance (dv) calculated by the moving distance calculating unit 330, a symmetric key, etc. will be stored. can

Each of the components of the vehicle 100 and the smart key 300 shown in FIGS. 4 and 5 are functionally and logically separable, and each component must be divided into a separate physical device or a separate code. An average expert in the technical field of the present invention can easily infer that it is not meant to be written as .

In addition, in the present specification, '~ part' may mean a functional and structural combination of hardware for carrying out the technical idea of the present invention and software for driving the hardware. For example, the module may mean a logical unit of a predetermined code and a hardware resource for executing the predetermined code, and does not necessarily mean physically connected code or one type of hardware.

The device described above may be implemented as a hardware component, a software component, and/or a set of hardware components and software components. For example, the devices and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), and a PLU. It may be implemented using one or more general purpose computers or special purpose computers, such as a Programmable Logic Unit (Programmable Logic Unit), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications executed on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For convenience of understanding, although one processing device is sometimes described as being used, one of ordinary skill in the art will recognize that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that may include For example, the processing device may include a plurality of processors or one processor and one controller. Other Processing Configurations are also possible, such as a Parallel Processor.

The software may include a computer program, code, instructions, or a combination of one or more of these, and configure the processing device to operate as desired or process it independently or in combination (Collectively) You can command the device. The software and/or data may be any type of machine, component, physical device, virtual equipment, computer storage medium or device, to be interpreted by or provide instructions or data to the processing device. , or may be permanently or temporarily embodied in a transmitted signal wave (Signal Wave). The software may be distributed over networked computer systems and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or preferably. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magnetic media such as floppy disks. - Includes hardware devices specially configured to store and execute program instructions, such as Magneto-optical Media, ROM, RAM, Flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the present invention has been described with reference to the embodiment shown in the drawings, which is merely exemplary, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. For example, the described techniques are performed in an order different from the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result. Accordingly, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: vehicle 110: communication department
120: authentication unit 130: attack detection unit
140: control unit 150: storage unit
160: vehicle control unit 300: smart key
310: communication unit 320: acceleration sensor unit
330: movement distance calculation unit 340: control unit
350: storage

Claims (10)

sending, by the vehicle, a first message to the smart key;
sending, by the smart key, a first response message to the vehicle in response to the first message;
calculating, by the vehicle, a first distance between the vehicle and the smart key based on a received signal strength indication (RSSI) of the first response message;
transmitting, by the vehicle, a second message including a query value to the smart key;
In response to the second message, the smart key sends a second response message including information for calculating the second movement distance of the smart key or the second movement distance and a response value corresponding to the query value to the vehicle sending to
determining, by the vehicle, whether the smart key is a valid key based on the response value;
calculating, by the vehicle, a second distance between the vehicle and the smart key based on a received signal strength (RSSI) of the second response message when the smart key is determined to be a valid key; and
Calculated using the second movement distance calculated using information for calculating the second movement distance, or the second movement distance included in the second response message and the difference between the first distance and the second distance Comprising the step of determining whether to attack the relay by comparing the first movement distance,
The first message and the second message are transmitted using a first frequency band,
The first response message and the second response message are transmitted using a second frequency band,
The first frequency band and the second frequency band are different from each other,
The information for calculating the second movement distance includes the first location information of the smart key at any one point in the interval from the time when the smart key receives the first message to the time when the first response message is transmitted. and second location information of the smart key at any one point in the interval from the time when the smart key receives the second message to the time when the second response message is transmitted,
How to detect relay attacks.
delete delete According to claim 1,
The second movement distance or information for calculating the second movement distance included in the second response message is encrypted using a symmetric key previously shared between the vehicle and the smart key,
How to detect relay attacks.
According to claim 1,
When it is determined that the smart key is not a valid key in the step of determining whether the key is a valid key, the vehicle stops the progress of the protocol,
How to detect relay attacks.
According to claim 1,
In the determining whether the relay attack is performed, a difference between the first movement distance calculated from the difference between the first distance and the second distance and the second movement distance included in the second response message is a predetermined threshold value. If it exceeds, it is determined that the relay attack has occurred,
How to detect relay attacks.
delete delete transmitting, by the vehicle, a wake up message to the smart key using a low frequency (LF) band;
transmitting, by the smart key, an existence confirmation message to the vehicle using an Ultra High Frequency (UHF) band in response to the wakeup message;
calculating, by the vehicle, a first distance between the vehicle and the smart key using the RSSI of the existence confirmation message;
transmitting, by the vehicle, a challenge message to the smart key using the LF band;
transmitting a response message including a second movement distance of the smart key by the smart key to the vehicle using the UHF band in response to the inquiry message;
calculating, by the vehicle, a second distance between the vehicle and the smart key using the RSSI of the response message; and
Comprising the step of the vehicle comparing the first movement distance calculated using the difference between the first distance and the second distance with the second movement distance included in the response message to determine whether to perform a relay attack,
The second moving distance is the first position of the smart key and the smart key at any one point in the interval from when the smart key receives the wakeup message to when the existence confirmation message is transmitted. Calculated based on the difference in the second position of the smart key at any one point in the interval from the time of receiving the response message to the time of transmitting the response message,
How to detect relay attacks.
10. The method of claim 9,
The second movement distance included in the response message is encrypted using a symmetric key previously shared between the vehicle and the smart key,
How to detect relay attacks.

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