JP2017160703A - Electronic key system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic key system capable of preventing a relay attack on a vehicle and portable apparatus that are during storage.SOLUTION: A portable apparatus 2 includes a stop state determination unit 5 that when it is determined on the basis of a detection result of a motion detection unit 4 that the portable apparatus 2 has been stopped for a definite period of time, turns on a stop state flag. When a reception unit 6 of the portable apparatus 2 receives a polling signal, a transmission unit 7 transmits a response signal including identification information unique to the portable apparatus 2 and the state of the stop state flag to an on-vehicle apparatus. The on-vehicle apparatus 3 includes an authentication processing unit 10 that when the portable apparatus 2's identification information included in the response signal agrees with identification information registered in advance and the state of the stop state flag included in the response signal is an OFF state, authenticates an apparatus by which the response signal is transmitted as an authorized portable apparatus 2. Because it is taken as a condition for successful authentication that the portable apparatus 2 has not been stopped for the definite period of time, a relay attack can be prevented from being successful in the case that the portable apparatus 2 has not been moved for a long time such as in the case that the vehicle and the portable apparatus 2 are during storage.SELECTED DRAWING: Figure 1

Description

  The present invention includes a portable device (smart key) carried by a user and an in-vehicle device mounted on a vehicle, and the in-vehicle device authenticates the portable device by performing wireless communication between the portable device and the in-vehicle device. The present invention relates to an electronic key system.

  2. Description of the Related Art An electronic key system (also called a smart key system) that performs user authentication through wireless communication between a portable device carried by a user and an in-vehicle device mounted on a vehicle is used. The in-vehicle device periodically transmits a polling signal, and when the portable device receives the polling signal, it returns unique identification information to the in-vehicle device. The in-vehicle device performs authentication by comparing the identification information received from the portable device with the identification information registered in advance. The reach of radio waves transmitted from the in-vehicle device is limited to the vicinity of the vehicle. Normally, the portable device is authenticated only when the portable device is within a range where wireless communication with the in-vehicle device is possible.

  As a method for stealing a vehicle equipped with such an electronic key system, a method called a relay attack is known. In the relay attack, the polling signal reaches the portable device outside the radio wave reachable range of the in-vehicle device by relaying the polling signal transmitted from the in-vehicle device using the repeater. When the portable device returns identification information as a response to the polling signal, the authentication is successful, so that the theft can unlock the door lock and start the engine.

Japanese Patent Laying-Open No. 2015-218457

  When a vehicle user parks and stores a vehicle in a parking lot, the portable device is often stored in a predetermined place in the house. In this case, since the portable device exists within a range where the radio waves of the vehicle-mounted device can be relayed using the repeater, the relay attack is successful.

  Therefore, an object of the present invention is to provide an electronic key system that can prevent a relay attack during storage of a vehicle and a portable device.

The present invention relates to an electronic key system including a portable device that performs authentication processing via wireless communication and an in-vehicle device. The portable device determines whether or not the portable device has stopped for a certain period of time based on the detection result of the movement detector and the motion detection unit that detects the movement of the portable device. When the determination is made, the stop state flag is turned on, and when it is determined that the portable device is not stopped, the stop state determination unit that turns the stop state flag off, the first receiving unit that receives the polling signal, When the 1 reception unit receives the polling signal, the first reception unit includes a response signal including identification information unique to the portable device and the state of the stop state flag to the in-vehicle device. The in-vehicle device includes a second transmission unit that transmits a polling signal, a second reception unit that receives a response signal, and identification information of the portable device included in the response signal that is identical to the identification information registered in advance in the in-vehicle device. And an authentication processing unit that authenticates that the device that transmitted the response signal is a legitimate portable device when the state of the stop state flag included in the response signal is OFF.

  In the present invention, the mobile device (smart key) includes, in the response signal to the polling signal, information indicating whether or not the mobile device has been stopped for a certain period of time, in addition to identification information unique to the mobile device. The in-vehicle device performs authentication when the identification information matches that registered in advance based on the information included in the response signal and the portable device has not been stopped for a certain period of time. As described above, it is possible to prevent the relay attack from succeeding when the portable device is not moved for a long time.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic key system which can prevent the relay attack during storage of a vehicle can be provided.

The block diagram which shows schematic structure of the electronic key system which concerns on embodiment State transition diagram of the portable device shown in FIG. State transition diagram of the in-vehicle device shown in FIG.

[Overview]
In the electronic key system of the present invention, a motion detection unit such as a motion sensor provided in the portable device monitors whether the portable device has stopped for a certain period of time, and the portable device stops in response to a polling signal from the in-vehicle device. Include information on whether or not In-vehicle devices, when the identification information of the portable device is successfully verified and the portable device is not stopped for a certain period of time, authentication is performed so that the portable device can move for a certain period of time, such as during storage of the vehicle and the portable device. Prevent successful relay attacks if not done.

  FIG. 1 is a block diagram illustrating a schematic configuration of an electronic key system according to an embodiment.

  The electronic key system 1 includes a portable device 2 carried by a user and an in-vehicle device 3 mounted on the vehicle. The in-vehicle device 3 performs wireless communication with the portable device 2 and authenticates the portable device 2 based on the response signal received from the portable device 2.

  The portable device 2 includes a motion detection unit 4, a stop state determination unit 5, a reception unit 6, and a transmission unit 7.

  The motion detection unit 4 is a motion sensor such as an acceleration sensor, an angular velocity sensor, or a vibration sensor, and detects the movement of the portable device 2. The motion detection unit 4 may be any device that can detect the motion of the portable device 2, and may use a GPS receiver, an electronic compass, or the like in addition to the motion sensor. In the following description, the case where the motion detection unit 4 is configured by an acceleration sensor will be described as an example.

  The stop state determination unit 5 determines whether or not the portable device 2 has been stopped for a predetermined time based on the output of the motion detection unit 4. For example, when the motion detection unit 4 is an acceleration sensor, the stop state determination unit 5 determines whether the level of the output signal output from the motion detection unit 4 is equal to or less than a predetermined threshold value. When the level of the output signal is equal to or less than the threshold value for a predetermined time, the stop state determination unit 5 turns on the stop state flag. This stop state flag is a flag indicating whether or not the portable device 2 has been stopped for a certain period of time, and the initial value is OFF. When the level of the output signal of the motion detection unit 4 exceeds the threshold value, the stop state determination unit 5 turns off the stop state flag.

  The receiving unit 6 receives a polling signal from the in-vehicle device 3. When receiving the polling signal, the reception unit 6 instructs the transmission unit 7 to transmit a response signal.

  When the reception unit 6 receives the polling signal, the transmission unit 7 includes the unique identification information stored in advance in the portable device 2 and the state of the stop state flag set by the stop state determination unit 5 (on state or off state) ) Is transmitted to the in-vehicle device 3. The transmission unit 7 transmits a response signal by RF (high frequency) communication, for example.

  The in-vehicle device 3 includes a transmission unit 8, a reception unit 9, and an authentication processing unit 10.

  The transmission unit 8 periodically transmits a polling signal to search for the portable device 2 existing around the vehicle. The transmission unit 8 transmits a polling signal by, for example, LF (long wave) communication.

  The receiving unit 9 receives the response signal transmitted from the portable device 2. When receiving the response signal, the receiving unit 9 instructs the authentication processing unit 10 to execute the authentication process.

  When the receiving unit 9 receives the response signal, the authentication processing unit 10 collates the identification information included in the response signal with the identification information registered in the in-vehicle device 3 in advance. Further, the authentication processing unit 10 determines whether or not the state of the stop state flag included in the response signal is an off state. The authentication processing unit 10 succeeds in collating the identification information included in the response signal, and when the stop state flag is in the off state, the device that transmitted the response signal is the authorized portable device 2 And the regular user determination flag is turned on. The regular user determination flag is a flag indicating whether or not the portable device 2 is correctly authenticated, and an operation for unlocking the vehicle door without key and an operation for starting the engine without key are performed by the user. The vehicle door is unlocked and the engine is allowed to start only when it is in the on state. The authentication processing unit 10 authenticates the portable device 2 that has transmitted the response signal when the verification of the identification information included in the response signal fails or when the state of the stop state flag is on. Is not authenticated, and the regular user determination flag is kept off.

  Hereinafter, the state transition of the portable device 2 and the in-vehicle device 3 will be described with reference to FIGS.

  FIG. 2 is a state transition diagram of the portable device shown in FIG.

  State A shown in FIG. 2 is a state in which it is determined whether or not the portable device 2 is stopped. State B is a state in which it is determined that the portable device is stopped.

  When the portable device 2 is in the state A, if the stop state determination unit 5 determines that the output signal of the motion detection unit 4 is equal to or less than a threshold for a certain time (for example, 30 minutes), the state transitions to the state B and stops The status flag is raised on. When the portable device 2 is in the state B, if the stop state determination unit 5 determines that the output signal of the motion detection unit 4 exceeds the threshold value, the state transitions to the state A, and the stop state flag is turned off.

  FIG. 3 is a state transition diagram of the in-vehicle device shown in FIG.

  A state W illustrated in FIG. 3 is a state in which the transmission unit 8 of the in-vehicle device 3 periodically transmits a polling signal to search for the portable device 2 around the vehicle. The state X is a state in which the authentication processing unit 10 determines whether or not the identification information (ID) included in the response signal matches that registered in advance. The state Y is a state in which the authentication processing unit 10 determines whether or not the portable device 2 has been stopped for a certain time based on the state of the stop state flag included in the response signal. The state Z is a state in which the authentication processing unit 10 determines that the portable device 2 that has transmitted the response signal is legitimate.

  When the in-vehicle device 3 is in the state W and receives a response signal from the portable device 2, the state changes to the state X.

  When the in-vehicle device 3 is in the state X, the authentication processing unit 10 transitions to the state Y when it is determined that the identification information (ID) included in the response signal matches that registered in advance. On the other hand, when the in-vehicle device 3 is in the state X, the authentication processing unit 10 transitions to the state W if it is determined that the identification information (ID) included in the response signal does not match that registered in advance.

  When the in-vehicle device 3 is in the state Y, the authentication processing unit 10 determines that the state of the stop state flag included in the response signal is an off state (that is, a state in which the portable device 2 has not stopped for a certain period of time). Then, the state transitions to state Z. On the other hand, when the vehicle-mounted device 3 is in the state Y, the authentication processing unit 10 determines that the state of the stop state flag included in the response signal is on (that is, the state where the portable device 2 is stopped for a certain period of time) If determined, the state transitions to state W.

  When the in-vehicle device 3 is in the state Z, the authentication processing unit 10 sets the authorized user determination flag to ON, and keyless vehicle door unlocking and engine starting are permitted. When the ignition switch is turned off and all the doors of the vehicle are locked from the outside of the vehicle, the authentication processing unit 10 lowers the regular user determination flag to off and makes a transition from the state Z to the state W.

  As described above, in the electronic key system 1 according to the present embodiment, the fact that the portable device 2 is not stopped for a certain period of time is used as a condition for the authentication process. Thus, when the portable device 2 exists within a range in which the repeater can relay the radio waves of the in-vehicle device 3, and the portable device 2 is not moved for a long time such as during storage of the vehicle, the relay attack is performed. Can be prevented. When the user unlocks the vehicle door or starts the engine, the user usually carries the portable device 2. In this case, since the portable device 2 is not moved and stopped for a certain period of time, if the verification of the identification information is successful, the authentication is successful (transition from state Y to state Z in FIG. 3).

  The present invention can be used as an electronic key system mounted on a vehicle.

1 Electronic key system 2 Mobile device (smart key)
3 In-vehicle device 4 Motion detection unit 5 Stop state determination unit 6 Reception unit 7 Transmission unit 8 Transmission unit 9 Reception unit 10 Authentication processing unit

Claims (1)

An electronic key system including a portable device and an in-vehicle device that perform authentication processing via wireless communication,
The portable device is
A motion detector for detecting the movement of the portable device;
Based on the detection result of the motion detection unit, it is determined whether or not the portable device has been stopped for a certain period of time, and when it is determined that the portable device has been stopped for a certain period of time, a stop state flag is turned on, A stop state determination unit that turns off the stop state flag when it is determined that the portable device is not stopped;
A first receiver for receiving a polling signal;
When the first reception unit receives the polling signal, the first reception unit transmits a response signal including identification information unique to the portable device and a state of the stop state flag to the in-vehicle device,
The in-vehicle device is
A second transmitter for transmitting the polling signal;
A second receiver for receiving the response signal;
When the identification information of the portable device included in the response signal matches the identification information registered in advance in the vehicle-mounted device, and the state of the stop state flag included in the response signal is OFF And an authentication processing unit that authenticates that the device that transmitted the response signal is a legitimate portable device.

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