Relay attack prevention device

Abstract

To provide a relay attack prevention device capable of automatically preventing relay attacks and enabling smart entry to function effectively. [Solution] A relay attack prevention device connected to an in-vehicle device having functions essential for unlocking and / or driving a 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 the signal line and / or power line for enabling 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 that is smaller than the second distance.

Description

[Technical Field]

[0001] The present invention relates to a device for preventing relay attacks. [Background technology]

[0002] In recent years, smart key systems that allow vehicle doors to be locked / unlocked and the engine to be started without using a physical key have become widespread.

[0003] However, automobiles equipped with smart key systems face the risk of theft through so-called relay attacks, which are a method of unlocking the doors and starting the engine without the smart key by using a repeater that relays and amplifies radio waves from the smart key.

[0004] To prevent relay attacks, smart keys are set to a power-saving mode that weakens the radio waves they emit, or they are stored in a case that blocks radio waves. However, these methods require the user to manually set or store the smart key, and there is a problem that users may forget to set or store the key due to carelessness, etc.

[0005] In this context, Patent Document 1 discloses a technology related to a blocking device that prevents relay attacks by stopping the detection waves transmitted from the vehicle to the smart key and eliminating the detection area related to the detection waves. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-070915 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 1 discloses that relay attacks can be prevented even if you forget to set the power saving mode or put the device in a case. However, this technology has the problem that the smart entry function is also disabled because the detection wave is stopped.

[0008] In view of the above, an object of the present invention is 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 comprises: A relay attack prevention device connected to an in-vehicle device having a function essential for unlocking and / or driving a vehicle, a wireless communication module capable of measuring the distance to a key terminal to be paired; a switching module capable of switching between disconnection and connection of a signal line and / or a power line for enabling the in-vehicle device; a main control module; the main control module controls the switching module to disconnect the signal line and / or the power line when the distance between the wireless communication module and the key terminal becomes greater than a second distance; When the distance between the wireless communication module and the key terminal becomes within a first distance that is smaller than the second distance, the switching module is controlled to restore the state of the signal line and / or the power line to a connected state.

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

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

[0012] The door lock control module is a module that controls the driving of a door lock motor of a vehicle and / or a module that controls the operation of a central door locking device of a vehicle.

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

[0014] Further, a relay attack prevention program according to the present invention is a relay attack prevention program executed by the above-mentioned relay attack prevention device, a measuring step of measuring a distance between the relay attack prevention device and the key terminal; a disconnection step of disconnecting the signal line and / or the power line when the distance between the wireless communication module and the key terminal becomes greater than the second distance; a restoring step of restoring the state of the signal line and / or the power line to a connected state when the distance between the wireless communication module and the key terminal becomes within the first distance; Equipped with.

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

[0016] The method further includes a door locking step of locking the vehicle doors when the distance between the wireless communication module and the key terminal becomes greater than the second distance.

[0017] The method further includes an unlocking step of unlocking the vehicle doors when the distance between the wireless communication module and the key terminal is within the first distance.

[0018] The method further includes a lock detection step of detecting a locked / unlocked state of a door of the vehicle, If the state of the door detected in the lock detection step is an unlocked state, the unlock step is not performed, If the state of the door detected in the lock detection step is a locked state, the door lock step is not performed. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a block diagram showing a relay attack prevention device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the relationship between the operation of the relay attack prevention device according to the embodiment of the present invention and the distance from the key terminal. [Figure 3] FIG. 3 is a flowchart showing the operation of the relay attack prevention device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] As shown in Fig. 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 usually provided in a vehicle, and Fig. 1 shows two vehicle ECUs 101 and 102 as an example.

[0021] The relay attack prevention device 1 includes 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 a signal line and / or a power line for enabling 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 may be calculated by another module such as the main control module 10 based on the state of communication (communication strength, communication speed, etc.) between the key terminal 130 and the wireless communication module 30. In FIG. 1, the switching module 20 is configured to be capable of switching the state of the signal line for enabling the in-vehicle device 120 between disconnection and connection.

[0022] Referring to Figure 2, when the distance between the wireless communication module 30 and the key terminal 130 becomes greater than a second distance R2, the main control module 10 controls the switching module 20 to disconnect the signal line for activating the in-vehicle device 120, and when the distance between the wireless communication module 30 and the key terminal 130 becomes within a first distance R1 that is smaller than the second distance R2, the main control module 10 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.

[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 off, so that even in the event of a relay attack, the in-vehicle device 120 remains unusable, preventing functions essential for unlocking and / or driving the vehicle, and making it impossible to steal the vehicle.

[0024] Furthermore, when the distance between the wireless communication module 30 and the key terminal 130 becomes within a first distance R1, which is smaller than the second distance R2, the signal line and / or power line for enabling the in-vehicle device 120 is restored to a connected state. As a result, even if the signal connection with the in-vehicle device 120 having a function related to unlocking is cut off, the smart entry function becomes usable after restoration. Furthermore, when the line connected to the in-vehicle device 120 having a function related to driving is cut off, the smart entry (automatic door unlock) function remains usable even before restoration, and the driving-related functions are not impaired after restoration.

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

[0026] The main control module 10 may be 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, such as a wireless communication device that communicates using a communication protocol such as Bluetooth (registered trademark), Bluetooth Low Energy (BLE), Near Field Communication (NFC), or Ultra Wide Band (UWB), and may also use multiple types of communication protocols, selectively depending on the function.

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

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

[0030] The in-vehicle device 120 has a function essential for unlocking and / or driving the vehicle, and may be, for example, a door handle button 121, an accelerator sensor 122, or a gear 123 of the vehicle. These are merely examples, and the relay attack prevention device 1 may target another in-vehicle device 120. The relay attack prevention device 1 may target one in-vehicle device 120, or may target two or more in-vehicle devices. By using, for example, 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 signal lines connected to the target in-vehicle device 120, it is possible to prevent unlocking or driving the vehicle in the event of a relay attack, and thus prevent vehicle theft.

[0031] Note that the activation of the function of the in-vehicle device 120 may be prevented by a method other than disconnecting (cutting off) the signal line between the in-vehicle device 120 and the vehicle ECU 101, such as disconnecting the power line that supplies power to the in-vehicle device 120. Also, the relay module as the switching module is an example, and other switching means may be used. Also, the installation location of the relay attack prevention device 1 may be set appropriately depending on the position and wiring of the in-vehicle device 120 to be switched.

[0032] The main control module 10 can measure the distance to the key terminal 130, for example, using the strength of 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 may be set as appropriate, and the third distance R3, which is the limit of connectable range, may be set as appropriate or may use the default value of the communication protocol; for example, R1 may be 2 m, R2 may be 5 m, and R3 may be 20 m. Note that while FIG. 2 shows the distance from the center of the vehicle, the reference position for distance measurement will vary 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 larger than the distance at which the automatic door unlock function of the vehicle's (genuine) smart entry function is activated, the automatic door unlock function of the smart entry function can be more reliably activated. Also, by making the second distance R2 larger than the distance at which the automatic door lock function of the vehicle's smart entry function is activated, the reliability of performing anti-theft switching after the automatic door lock function is activated increases. Note that when the relay attack prevention device 1 is equipped with an automatic door lock / unlock function, such a setting is not necessary if the vehicle does not have an (genuine) smart entry function.

[0034] The relay attack prevention device 1 according to the 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, etc. These are merely examples, and some modules may be omitted 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 locking control module 50 controls the locking / unlocking operation of the vehicle's central door locking device 150, and can be arranged, for example, on the unlock signal line and lock signal line between the central door locking device 150 and the vehicle ECU 102, and can be configured to simulate the switch operation of the central door locking device 150 (for example, to reproduce the voltage change due to the switch operation).

[0037] By including 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 module 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 module 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 lock, automatic unlock) using the key terminal 130 can be realized, separate from the genuine smart entry function.

[0038] The power supply module 70 supplies power to the relay attack prevention device 1 and is connected to a power line extending from a battery in the vehicle.

[0039] The CAN transceiver 80 is connected to a CAN (Controller Area Network) bus in 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 Bluetooth is used, 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 is given 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 disconnected.

[0041] In other words, if the switching module 20 is in a disconnected state and one key terminal 130 is present and authenticated at a distance equal to or less than the third distance R3 but greater than the first distance R1, the switching module 20 will not return to a connected state if another key terminal 130 becomes equal to or less than the first distance R1. If the key terminal 130 has a smart entry function, the door will not be unlocked.

[0042] If the switching module 20 is connected and a previously authenticated key terminal 130 is within the first distance R1, the switching module 20 will not become disconnected if another key terminal 130 moves further away than the second distance R2. If the key terminal 130 has a smart entry function, the door will not be locked.

[0043] When the switching module 20 is in a connected state and an unauthenticated key terminal 130 is present within the first distance R1, if the authenticated key terminal 130 moves away from the switching module 20 by more than the second distance R2, the switching module 20 enters a disconnected state (if the key terminal 130 has a smart entry function, the door is locked). This state is then maintained as long as the authenticated key terminal 130 is within the third distance R3, exceeding the first distance R1. If the key terminal 130 then moves away from the relay attack prevention device 1 by more than the third distance R3, the connection between the key terminal 130 and the relay attack prevention device 1 is severed, and the unauthenticated key terminal 130 is authenticated. If the unauthenticated key terminal 130 is within the first distance R1, the switching module 20 returns to a connected state (if the key terminal 130 has a smart entry function, the door is 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 simultaneously enter within the third distance R3, there is no particular priority for which key terminal 130 will be authenticated, and it is determined by the use of communication standards, etc.

[0045] The operation of the relay attack prevention program executed by the relay attack prevention device 1 will be described below with reference to the flowchart of FIG.

[0046] Processing begins when the relay attack prevention device 1 is properly connected and power supply begins. Although Fig. 3 does not show the termination conditions, the processing may end when the vehicle starts to operate (when the engine starts and the vehicle speed exceeds 0 km / h), and may restart when the vehicle stops (when the engine stops and the vehicle speed reaches 0 km / h).

[0047] When the relay attack prevention device 1 is started, the wireless communication module 30 starts detecting the key terminal 130 (S101). It is determined 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 may be performed in accordance with the communication protocol used. 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. Note that the preliminary pairing method may 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 equal to or less than R1 (S105).

[0050] If it is less than R1 (Yes in S105), the main control module 10 determines whether the door is locked (S106), and if it 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 unlocking the door (S107), the main control module 10 determines whether the relay of the switching module 20 is disconnected (S108), and if it is disconnected (Yes in S108), the main control module 10 controls the switching module 20 to restore the relay (S109). After No in S108 and after S109, the process returns to S104.

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

[0053] If it is greater than R2 (No in S110), the main control module 10 determines whether the doors are locked (S111), and if they are 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 doors (S112). If it is less than R2 (Yes in S110), the process returns to S104.

[0054] If the door is locked (Yes in S111) or after locking the door (S112), the main control module 10 determines whether the relay of the switching module 20 is disconnected (S113), and 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 or not authentication of the key terminal has expired (S115). If it has expired (Yes in S115), the process returns to S101, and if it has not expired (No in S115), the process returns to S104.

[0056] The processes from S101 to S115 are repeatedly performed. 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 intervals may be set arbitrarily, such as 5 seconds, 10 seconds, etc.

[0057] In an embodiment of the present invention, the door unlocking steps (S106, S107) and the door locking steps (S111, S112) are not essential elements. Furthermore, the order of the unlocking steps (S106, S107) and the restoration steps (S108, S109), and the order of the door locking steps (S111, S112) and the disconnection steps (S113, S114) are not limited to those described above, and may be reversed or performed simultaneously. If the doors cannot be locked / unlocked due to disconnection, the restoration step is performed before the unlocking step, and the door locking step is performed before the disconnection step.

[0058] Furthermore, the order in which the determination that the distance is less than or equal to R1 (S105) and the determination that the distance is between R1 and R2 (S110) is performed is not limited to the above description, and may be reversed or performed simultaneously.

[0059] The determination of the door lock status (S106, S111) may be performed in any manner, for example, it may be determined from information such as the CAN bus, or it may be determined by storing a history of locking and unlocking processes, a flag for determining the status, etc.

[0060] Similarly, the state of the relay (S108, S113) can be determined in any manner, for example, from information such as the CAN bus, or by storing a history of locking and unlocking processes, flags for determining the state, etc.

[0061] For example, if the switching module prevents the gear shift position from being changed from park or neutral, the vehicle will not move even if the driver leaves the vehicle with the parking brake on and the engine running, and it is possible to leave the vehicle until the temperature inside the vehicle is at an optimum level using the air conditioner, etc., while taking necessary measures to keep the vehicle stopped. When leaving the vehicle under such conditions, higher security is important, and this can be achieved by the relay attack prevention device of the present invention.

[0062] In an embodiment 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 processes, it is preferable to limit the number of key terminals that can be simultaneously connected to one, or to prioritize the key terminals that can be simultaneously connected and perform processing based only on the key terminal with the highest priority. In this case, the priority can be determined in any way, such as giving priority to the key terminal authenticated first, the key terminal authenticated last, the key terminal that is closest, or the key terminal that is farthest from among the authenticated key terminals.

[0063] The concepts described herein may be implemented in other forms without departing from their spirit and character. The specific embodiments disclosed should be considered illustrative rather than limiting. Accordingly, the scope of the invention should be determined by the appended claims, rather than by the foregoing description. All changes within the literal language and range of equivalency of the claims are intended to be within their scope. [Explanation of symbols]

[0064] 1. Relay attack prevention device 10 Main Control Module 20 Switching Module 21 Door button signal line relay module 22 Accelerator pedal signal line relay module 23 Gear signal line relay module 30 Wireless communication module 40 Door Lock Motor Control Module 50 Central door locking control module 70 Power Supply Module 80 CAN transceiver 101 Vehicle ECU 102 Vehicle ECU 120 In-vehicle equipment 121 Door handle button 122 Accelerator sensor 123 gears 130 key terminal 140 Door lock motor 150 Central door locking device

Claims

1. A relay attack prevention device connected to an in-vehicle device having a function essential for unlocking and / or driving a vehicle, a wireless communication module capable of measuring the distance to a key terminal to be paired; a switching module capable of switching a state of a signal line for enabling the in-vehicle device between disconnection and connection; a main control module; the main control module controls the switching module to disconnect the signal line when the distance between the wireless communication module and the key terminal becomes greater than a second distance; When the distance between the wireless communication module and the key terminal becomes within a first distance that is smaller than the second distance, the switching module is controlled to return the state of the signal line to a connected state. Relay attack prevention device.

2. A relay attack prevention device connected to an in-vehicle device having a function essential for unlocking and / or driving a vehicle, a wireless communication module capable of measuring the distance to a key terminal to be paired; a switching module capable of switching between disconnection and connection of a signal line and / or a power line for enabling the in-vehicle device; a main control module; a door lock control module; the main control module controls the switching module to disconnect the signal line and / or the power line when the distance between the wireless communication module and the key terminal becomes greater than a second distance; when the distance between the wireless communication module and the key terminal is within a first distance that is smaller than the second distance, controlling the switching module to restore the state of the signal line and / or the power line to a connected state; A relay attack prevention device in which 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. 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 is within the first distance.

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

5. A relay attack prevention device connected to an in-vehicle device having a function essential for unlocking and / or driving a vehicle, a wireless communication module capable of measuring the distance to a key terminal to be paired; a switching module capable of switching between disconnection and connection of a signal line and / or a power line for enabling the in-vehicle device; a main control module; the main control module controls the switching module to disconnect the signal line and / or the power line when the distance between the wireless communication module and the key terminal becomes greater than a second distance; when the distance between the wireless communication module and the key terminal is within a first distance that is smaller than the second distance, controlling the switching module to restore the state of the signal line and / or the power line to a connected state; The relay attack prevention device, wherein the in-vehicle device is a door handle button, an accelerator sensor, or a gear of the vehicle.

6. A relay attack prevention program executed by the relay attack prevention device according to any one of claims 2 to 5, comprising: a measuring step of measuring a distance between the relay attack prevention device and the key terminal; a disconnection step of disconnecting the signal line and / or the power line when the distance between the wireless communication module and the key terminal becomes greater than the second distance; a restoring step of restoring the state of the signal line and / or the power line to a connected state when the distance between the wireless communication module and the key terminal becomes within the first distance; A relay attack prevention program that includes the above.

7. a signal connection detection step of detecting a state of the signal line and / or the power line; If the state of the signal line and / or the power line detected in the signal connection detection step is a disconnected state, the disconnection step is not performed; 7. The relay attack prevention program according to claim 6, wherein the restoring step is not performed when the state of the signal line and / or the power line detected in the signal connection detecting step is a connected state.

8. A relay attack prevention program executed using the relay attack prevention device according to any one of claims 2 to 4, a measuring step of measuring a distance between the relay attack prevention device and the key terminal; a disconnection step of disconnecting the signal line and / or the power line when the distance between the wireless communication module and the key terminal becomes greater than the second distance; a restoring step of restoring the state of the signal line and / or the power line to a connected state when the distance between the wireless communication module and the key terminal becomes within the first distance; a door lock step for locking the vehicle doors when the distance between the wireless communication module and the key terminal becomes greater than the second distance.

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

10. The method further includes a lock detection step of detecting a locked / unlocked state of a door of the vehicle, If the state of the door detected in the lock detection step is an unlocked state, the unlock step is not performed, 10. The relay attack prevention program according to claim 9, wherein the door locking step is not performed if the state of the door detected in the lock detection step is a locked state.

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