Relay attack prevention device

Abstract

The present invention provides a relay attack prevention device that can automatically prevent relay attacks while also ensuring that smart entry functions effectively. [Solution] A relay attack prevention device connected to an in-vehicle device having functions essential for unlocking and / or driving the vehicle, comprising: a wireless communication module capable of measuring the distance to a paired key terminal; a switching module capable of switching the state of a signal line and / or power line for activating the in-vehicle device between disconnected and connected; and a main control module, wherein the main control module controls the switching module to disconnect the signal line and / or power line when the distance between the wireless communication module and the key terminal becomes greater than a second distance, and controls the switching module to return the state of the signal line and / or power line to connected when the distance between the wireless communication module and the key terminal becomes within a first distance less than the second distance.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device for preventing relay attacks. BACKGROUND ART

[0002] In recent years, smart key systems that enable locking / unlocking of vehicle doors, starting of engines, and the like without using a physical key have become widespread.

[0003] However, automobiles equipped with smart key systems have a problem of the risk of theft by so-called relay attacks. Here, a relay attack is a method in which, by using a repeater that relays and amplifies radio waves from a smart key, a door can be unlocked and an engine can be started even when the smart key is not at hand.

[0004] To prevent relay attacks, measures such as setting the smart key to a power saving mode that weakens radio waves transmitted therefrom, or storing the smart key in a case that blocks radio waves have been implemented. However, these methods require manual setting and storage by a user, and have the problem that the user may forget to perform the setting or storage due to carelessness or the like.

[0005] Under such circumstances, Patent Document 1 discloses a technology relating to a blocking device that prevents relay attacks by stopping detection waves transmitted from the vehicle side to the smart key and eliminating the detection area related to the detection waves. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0006] Patent Document 1 Japanese Unexamined Patent Publication No. 2021-070915 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0007] Patent Document 1 describes a method for preventing relay attacks even if the power saving mode is not set or the device is not placed back into its case. However, this technology has the problem that the smart entry function is also disabled because it stops the detection wave.

[0008] In view of the above, the present invention aims to provide a relay attack prevention device that can automatically prevent relay attacks and in which smart entry functions effectively. [Means for solving the problem]

[0009] The relay attack prevention device according to the present invention is A relay attack prevention device connected to an in-vehicle device that has a function essential for unlocking and / or driving the vehicle, A wireless communication module capable of measuring the distance to the paired key terminal, A switching module capable of switching the state of signal lines and / or power lines for activating the in-vehicle device between disconnection and connection, It includes a main control module, The main control module controls the switching module so that the signal line and / or power line are disconnected when the distance between the wireless communication module and the key terminal exceeds a second distance. When the distance between the wireless communication module and the key terminal becomes less than the second distance (a first distance), the switching module is controlled to return the signal line and / or power line to a connected state.

[0010] Furthermore, the relay attack prevention device further comprises a door lock control module. The main control module controls the door lock control module to lock the vehicle doors when the distance between the wireless communication module and the key terminal becomes greater than the second distance.

[0011] Furthermore, the main control module controls the door lock control module to unlock the vehicle doors when the distance between the wireless communication module and the key terminal becomes within the first distance.

[0012] Furthermore, the door lock control module is a module that controls the drive of the vehicle's door lock motor and / or a module that controls the operation of the vehicle's central door locking device.

[0013] Furthermore, the in-vehicle device may be a door handle button, an accelerator sensor, or a gear.

[0014] Furthermore, the relay attack prevention program according to the present invention is a relay attack prevention program that is executed using the above-mentioned relay attack prevention device, A measurement step of measuring the distance between the relay attack prevention device and the key terminal, A disconnection step in which the state of the signal line and / or the power line is disconnected when the distance between the wireless communication module and the key terminal becomes greater than the second distance, A recovery step in which, when the distance between the wireless communication module and the key terminal becomes within the first distance, the state of the signal line and / or the power line is restored to a connected state, It is equipped with.

[0015] Furthermore, the system further includes a signal connection detection step for detecting the status of the signal line and / or the power line, If the state of the signal line and / or power line detected in the signal connection detection step is disconnected, the disconnection step is not performed. If the signal line and / or power line detected in the signal connection detection step is in a connected state, the recovery step is not performed.

[0016] The system further includes a door lock step that locks the vehicle doors when the distance between the wireless communication module and the key terminal exceeds the second distance.

[0017] Further, the method further comprises an unlocking step of unlocking a vehicle door when the distance between the wireless communication module and the key terminal is equal to or less than the first distance.

[0018] Further, the method further comprises a lock detection step of detecting a locked / unlocked state of a vehicle door, the unlocking step is not performed when the door state detected in the lock detection step is an unlocked state, the door locking step is not performed when the door state detected in the lock detection step is a locked state. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1] Figure 1 is a block diagram showing a relay attack prevention device according to an embodiment of the present invention. [Figure 2] Figure 2 is a diagram showing a relationship between the operation of the relay attack prevention device according to an embodiment of the present invention and the distance to a key terminal. [Figure 3] Figure 3 is a flowchart showing the operation of the relay attack prevention device according to an embodiment of the present invention. MODES FOR CARRYING OUT THE INVENTION

[0020] As shown in Figure 1, a relay attack prevention device 1 according to an embodiment of the present invention is connected between an in-vehicle device 120 having functions essential for unlocking and / or driving a vehicle and a vehicle ECU (Electronic Control Unit) 101. A plurality of vehicle ECUs are normally provided in a vehicle, and Figure 1 shows two vehicle ECUs 101 and 102 as an example.

[0021] The relay attack prevention device 1 comprises a wireless communication module 30 capable of measuring the distance to a key terminal 130 paired with the relay attack prevention device 1, a switching module 20 capable of switching the state of the signal line and / or power line for activating the in-vehicle device 120 between disconnection and connection, and a main control module 10. The distance to the key terminal 130 may be calculated by the wireless communication module 30 itself, or it may be calculated by another module such as the main control module 10 from the state of communication between the key terminal 130 and the wireless communication module 30 (communication strength, communication speed, etc.). In Figure 1, the switching module 20 is provided to switch the state of the signal line for activating the in-vehicle device 120 between disconnection and connection.

[0022] Referring to Figure 2, the main control module 10 controls the switching module 20 to disconnect the signal line for activating the in-vehicle device 120 when the distance between the wireless communication module 30 and the key terminal 130 becomes greater than the second distance R2, and controls the switching module 20 to restore at least one signal connection between the in-vehicle device 120 and the vehicle ECU 101 to a connected state when the distance between the wireless communication module 30 and the key terminal 130 becomes within the first distance R1, which is less than the second distance R2.

[0023] In this way, when the distance between the wireless communication module 30 and the key terminal 130 becomes greater than the second distance R2, the signal line for activating the in-vehicle device 120 is cut, so that even if a relay attack occurs, the in-vehicle device 120 cannot be used, and the functions essential for unlocking and / or driving the vehicle will not be performed, making it impossible to steal the vehicle.

[0024] Furthermore, if the distance between the wireless communication module 30 and the key terminal 130 becomes less than the second distance R2 (i.e., within the first distance R1), the signal line and / or power line for activating the in-vehicle device 120 are restored to a connected state. This ensures that even if the signal connection to the in-vehicle device 120, which has a function related to unlocking, is disconnected, the smart entry function can be used after the connection is restored. Also, if the line connected to the in-vehicle device 120, which has a function related to driving, is disconnected, the smart entry (automatic door unlock) function can be used even before the connection is restored, and the driving functions will not be impaired after the connection is restored.

[0025] This second distance R2 may be set to be equal to the distance R3 which is the limit of connectivity with the wireless communication module 30, or the distance R3 which is the limit of connectivity may be greater than the second distance R2.

[0026] The main control module 10 can use any known processing device, such as a microcontroller.

[0027] The wireless communication module 30 can use a known wireless communication device capable of measuring the distance to the key terminal 130. For example, it can use a wireless communication device that communicates using communication protocols such as Bluetooth®, Bluetooth Low Energy (BLE), Near Field Communication (NFC), and Ultra Wide Band (UWB). It may also use multiple types of communication protocols, switching between them depending on the function.

[0028] The key terminal 130 may be a dedicated terminal for the relay attack prevention device 1, and may also be a smartphone, tablet, or other device capable of the above-mentioned wireless communication, and these may be used in combination. Smartphones, etc., should be paired in advance before use, and a dedicated application for the relay attack prevention device 1 may be installed.

[0029] Furthermore, regardless of the first distance R1 and the second distance R2, the state of the signal lines and / or power lines may be switched between disconnected and connected by operating a key terminal (such as by pressing a dedicated button or operating on an application screen).

[0030] The in-vehicle device 120 has functions essential for unlocking and / or driving the vehicle, and can be, for example, a vehicle door handle button 121, an accelerator sensor 122, or a gear 123. These are examples, and other in-vehicle devices 120 may be targeted. The relay attack prevention device 1 may target one in-vehicle device 120, or two or more. By using a switching module 20 (door button signal line relay module 21, accelerator pedal signal line relay module 22, gear signal line relay module 23) that can disconnect / connect the signal lines connected to the targeted in-vehicle device 120, for example, it is possible to prevent unlocking or driving the vehicle in the event of a relay attack, thereby preventing vehicle theft.

[0031] Furthermore, the activation of the in-vehicle device 120's functions may be prevented by methods other than disconnecting (cutting) the signal lines between the in-vehicle device 120 and the vehicle ECU 101, such as disconnecting the power lines supplying power to the in-vehicle device 120. Also, the relay module as a switching module is an example, and other switching means may be used. In addition, the installation location of the relay attack prevention device 1 may be set appropriately according to the location and wiring of the in-vehicle device 120 that is the target of the switching.

[0032] The main control module 10 can measure the distance to the key terminal 130 using, for example, the strength of the communication between the wireless communication module 30 and the key terminal 130, although other measurement methods may also be used. The first distance R1 and the second distance R2 can be set as appropriate, and the third distance R3, which is the limit of connectivity, can be set as appropriate or the default of the communication protocol can be used, for example, R1 can be 2m, R2 can be 5m, and R3 can be 20m. Note that in Figure 2, the distance is shown from the center of the vehicle, but the reference position for distance measurement will change depending on the actual installation location of the relay attack prevention device 1 (wireless communication module 30).

[0033] Here, by making the first distance R1 greater than the distance at which the automatic door unlock function of the vehicle's (original) smart entry function is activated, the automatic door unlock function of the smart entry function can be made to activate more reliably. Also, by making the second distance R2 greater than the distance at which the automatic door lock function of the vehicle's smart entry function is activated, the reliability of the theft prevention switching after the automatic door lock function is activated is increased. Note that if the relay attack prevention device 1 has an automatic door lock / unlock function, and the vehicle does not have an (original) smart entry function, then such settings are not necessary.

[0034] The relay attack prevention device 1 according to an embodiment of the present invention may further include a door lock motor control module 40, a central door lock control module 50, a power supply module 70, a CAN transceiver 80, and the like. These are illustrative examples, and some modules may be removed and / or additional modules may be added.

[0035] The door lock motor control module 40 controls the lock / unlock operation of the vehicle's door lock motor 140, and can be, for example, a relay module that switches between disconnecting and connecting the unlock signal line and the lock signal line between the door lock motor 140 and the vehicle ECU 102.

[0036] The central door lock control module 50 controls the lock / unlock operation of the vehicle's central door lock device 150. For example, it can be located on the unlock signal line and lock signal line between the central door lock device 150 and the vehicle ECU 102, and can be configured to simulate the switch operation of the central door lock device 150 (for example, to reproduce the voltage change caused by the switch operation).

[0037] By equipping the vehicle with such door lock control modules (door lock motor control module 40, central door lock control module 50), the main control module 10 can control the door lock control modules to automatically lock the vehicle doors when the distance between the wireless communication module 30 and the key terminal 130 becomes greater than the second distance R2. Furthermore, the main control module 10 can control the door lock control modules to automatically unlock the vehicle doors when the distance between the wireless communication module 30 and the key terminal 130 becomes within the first distance R1. In other words, a smart entry function (automatic door locking and unlocking) using the key terminal 130 can be realized, separate from the genuine smart entry function.

[0038] The power module 70 supplies power to the relay attack prevention device 1 and is connected to the power wiring from the vehicle's battery.

[0039] The CAN transceiver 80 is connected to the CAN (Controller Area Network) bus inside the vehicle and can send information communicated on the CAN bus to the main control module 10.

[0040] In an embodiment of the present invention, for example, when using Bluetooth, the number of key terminals 130 that can be simultaneously connected to the relay attack prevention device is 1. In this case, the key terminal 130 that is authenticated first takes priority, and other key terminals 130 will not be authenticated (connected) to the relay attack prevention device until the connection of the key terminal 130 that was authenticated first is lost.

[0041] In other words, if the switching module 20 is disconnected and one key terminal 130 is located at a distance of R3 or less and further than the first distance R1, and has already been authenticated, the switching module 20 will not return to a connected state when another key terminal 130 is at or below the first distance R1. If a smart entry function is provided by the key terminal 130, the door will not be unlocked.

[0042] If the switching module 20 is connected and a previously authenticated key terminal 130 is within a first distance R1, the switching module 20 will not become disconnected if another key terminal 130 is located beyond a second distance R2. If a smart entry function is provided by the key terminal 130, the doors will not be locked.

[0043] If the switching module 20 is connected and an unauthenticated key terminal 130 is within a first distance R1, the switching module 20 will become disconnected when an authenticated key terminal 130 moves beyond a second distance R2 (if a smart entry function using the key terminal 130 is provided, the door will be locked). This state will be maintained as long as the authenticated key terminal 130 is beyond the first distance R1 but within a third distance R3. Subsequently, if the key terminal 130 moves beyond the third distance R3, the connection between the key terminal 130 and the relay attack prevention device 1 will be broken, authentication will be performed with the unauthenticated key terminal 130, and if this key terminal 130 is within the first distance R1, the switching module 20 will return to a connected state (if a smart entry function using the key terminal 130 is provided, the door will be unlocked). In other words, the key terminal 130 that connects the switching module 20 and the key terminal 130 that disconnects the switching module 20 may be the same or different.

[0044] Furthermore, if there are no unauthenticated key terminals 130, and multiple unauthenticated key terminals 130 enter the third distance R3 simultaneously, there is no particular priority order for which key terminal 130 will be authenticated; it is determined by factors such as the use of communication standards.

[0045] The operation of the relay attack prevention program, which is performed using the relay attack prevention device 1, will be explained below using the flowchart in Figure 3.

[0046] The process begins when the relay attack prevention device 1 is properly connected and power supply starts. Although the termination conditions are not shown in Figure 3, the process may end when the vehicle starts driving (engine starts and detection of vehicle speed exceeding 0 km / h) and restart when the vehicle stops (engine stops and detection of vehicle speed exceeding 0 km / h).

[0047] When the relay attack prevention device 1 is activated, the wireless communication module 30 starts detecting the key terminal 130 (S101). It determines whether or not there is a signal from the paired key terminal 130 (S102). If there is a signal from the paired key terminal 130 (Yes in S102), the key terminal 130 is authenticated, and communication between the wireless communication module 30 and the key terminal 130 begins (S103). The authentication method is an example and should be performed in accordance with the communication protocol adopted. If there is no signal from the paired key terminal 130 (No in S102), S101 and S102 are repeated until there is a signal from the paired key terminal 130. The prior pairing method should also be performed in accordance with the communication protocol.

[0048] When communication between the wireless communication module 30 and the key terminal 130 begins, the main control module 10 measures the distance between the wireless communication module 30 and the key terminal 130, for example, from the strength of the communication between the wireless communication module 30 and the key terminal 130 (S104).

[0049] The main control module 10 determines whether the distance between the wireless communication module 30 and the key terminal 130 is R1 or less (S105).

[0050] If R is less than or equal to 1 (Yes in S105), the main control module 10 determines whether the door is locked or not (S106). If the door is locked (Yes in S106), the main control module 10 controls the operation of the door lock motor control module 40 and the central door lock control module 50 to unlock the door (S107).

[0051] If the door is unlocked (No in S106) or after the door is unlocked (S107), the main control module 10 determines whether the relay of the switching module 20 is disconnected (S108). If it is disconnected (Yes in S108), the main control module 10 controls the switching module 20 to reset the relay (S109). After No in S108 and after S109, the process returns to S104.

[0052] If R is not less than or equal to R1 (No in S105), it is determined whether the distance between the wireless communication module 30 and the key terminal 130 is less than or equal to R2 (S110).

[0053] If R2 is greater than (No in S110), the main control module 10 determines whether the door is locked or not (S111). If it is unlocked (No in S111), the main control module 10 controls the operation of the door lock motor control module 40 and the central door lock control module 50 to lock the door (S112). If R2 is less than or equal to (Yes in S110), the process returns to S104.

[0054] If the door is locked (Yes in S111) or after the door is locked (S112), the main control module 10 determines whether the relay of the switching module 20 is disconnected (S113). If it is connected (No in S113), the main control module 10 controls the switching module 20 to disconnect the relay (S114).

[0055] After No in S113 and after S114, it is determined whether the authentication of the key terminal has expired (S115). If it has expired (Yes in S115), the process returns to S101; if it has not expired (No in S115), the process returns to S104.

[0056] The processes from S101 to S115 are repeated. These processes may be performed at predetermined intervals or without intervals, but considering power consumption, it is preferable to perform them at predetermined intervals. The predetermined interval can be set arbitrarily, such as 5 seconds or 10 seconds.

[0057] In embodiments of the present invention, the door unlocking steps (S106, 107) and the door locking steps (S111, S112) are not essential elements. Furthermore, the order of the unlocking steps (S106, 107) and the return steps (S108, S109), and the order of the door locking steps (S111, S112) and the cutting steps (S113, S114) are not limited to the above description and may be reversed or performed simultaneously. If cutting prevents the door from being locked / unlocked, the return step is performed before the unlocking step, and the door locking step is performed before the cutting step.

[0058] Furthermore, the order in which the determination that the distance is R1 or less (S105) and the determination that the distance is R1 or greater and R2 or less (S110) are made is not limited to the above explanation; they may be made in reverse order or simultaneously.

[0059] The determination of the door lock status (S106, S111) can be performed in any way; for example, it may be determined from information such as the CAN bus, or it may be determined by storing the history of lock and unlock processes, flags for status determination, etc.

[0060] Similarly, the determination of the relay status (S108, S113) can be performed in any way; for example, it may be determined from information such as the CAN bus, or it may be determined by storing the history of lock and unlock processes, flags for status determination, etc.

[0061] For example, if a switching module prevents the gear shift position from being changed from parking or neutral, the vehicle will not move even if the engine is running and the parking brake is applied, and the necessary measures to keep the vehicle stationary are taken, allowing the driver to leave the vehicle until the interior temperature is optimal using the air conditioner or other means. When leaving the vehicle under such conditions, higher security is important, and this can be achieved with the relay attack prevention device of the present invention.

[0062] In embodiments of the present invention, the number of key terminals that can be simultaneously connected to the relay attack prevention device may be two or more. However, to prevent conflicting processing, it is preferable to limit the number of simultaneously connectable key terminals to one, or to assign a priority to the simultaneously connected key terminals and perform processing based only on the highest-priority key terminal. In this case, the priority can be determined in any way, such as prioritizing the key terminal authenticated first, the key terminal authenticated later, the key terminal closest in distance, or the key terminal furthest away among those authenticated.

[0063] The concepts described herein can be implemented in other forms without departing from their spirit and characteristics. The specific embodiments disclosed should be considered illustrative rather than restrictive. Accordingly, the scope of the invention should be determined by the appended claims rather than by these prior descriptions. Any modifications within the language of the claims and equivalent scope shall fall within the scope of the claims. [Explanation of Symbols]

[0064] 1. Relay attack prevention device 10 Main control module 20 switching modules 21 Door button signal wire relay module 22. Accelerator pedal signal wire relay module 23 Gear signal wire relay module 30 Wireless Communication Modules 40 Door lock motor control module 50 Central Door Lock Control Module 70 Power Modules 80 CAN Transceiver 101 Vehicle ECU 102 Vehicle ECU 120 In-vehicle equipment 121 Door handle button 122 Accelerator sensor 123 gears 130 Key Terminals 140 Door lock motor 150 Central Door Locking System

Claims

1. A relay attack prevention device connected to an in-vehicle device that has a function essential for unlocking and / or driving the vehicle, A wireless communication module capable of measuring the distance to the paired key terminal, A switching module capable of switching the state of signal lines and / or power lines for activating the in-vehicle device between disconnection and connection, It includes a main control module, The main control module controls the switching module so that the signal line and / or power line are disconnected when the distance between the wireless communication module and the key terminal exceeds a second distance. When the distance between the wireless communication module and the key terminal becomes less than the second distance (a first distance), the switching module is controlled to return the signal line and / or power line to a connected state. Relay attack prevention device.

2. The relay attack prevention device further comprises a door lock control module, The relay attack prevention device according to claim 1, wherein the main control module controls the door lock control module to lock the vehicle doors when the distance between the wireless communication module and the key terminal becomes greater than the second distance.

3. The relay attack prevention device according to claim 2, wherein the main control module controls the door lock control module to unlock the vehicle doors when the distance between the wireless communication module and the key terminal becomes within the first distance.

4. The relay attack prevention device according to claim 2, wherein the door lock control module is a module that controls the drive of the vehicle's door lock motor and / or a module that controls the operation of the vehicle's central door locking device.

5. The relay attack prevention device according to any one of claims 1 to 4, wherein the in-vehicle device is a vehicle door handle button, an accelerator sensor, or a gear.

6. A relay attack prevention program to be executed using the relay attack prevention device described in any one of claims 1 to 4, A measurement step of measuring the distance between the relay attack prevention device and the key terminal, A disconnection step in which the state of the signal line and / or the power line is disconnected when the distance between the wireless communication module and the key terminal becomes greater than the second distance, A recovery step in which, when the distance between the wireless communication module and the key terminal becomes within the first distance, the state of the signal line and / or the power line is restored to the connected state, A relay attack prevention program equipped with [this feature].

7. The system further includes a signal connection detection step for detecting the status of the signal line and / or the power line, If the state of the signal line and / or power line detected in the signal connection detection step is disconnected, the disconnection step is not performed. The relay attack prevention program according to claim 6, wherein the recovery step is not performed if the state of the signal line and / or power line detected in the signal connection detection step is in a connected state.

8. The relay attack prevention program according to claim 6, further comprising a door lock step of locking the vehicle doors when the distance between the wireless communication module and the key terminal becomes greater than the second distance.

9. The relay attack prevention program according to claim 8, further comprising an unlock step of unlocking the vehicle doors when the distance between the wireless communication module and the key terminal becomes within the first distance.

10. The system further includes a lock detection step that detects the locked / unlocked status of the vehicle doors, If the door state detected in the lock detection step is unlocked, the unlock step is not performed. The relay attack prevention program according to claim 9, wherein the door lock step is not performed if the door state detected in the lock detection step is in a locked state.

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