JP6747751B1 - Vehicle authentication device, vehicle authentication system, and vehicle authentication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vehicle authentication device capable of preventing an illegal act such as a relay attack even in a place where GPS reception is difficult. A transmitter 23 that transmits an authentication request signal, a receiver 24 that receives a response signal from a mobile device 3, a wireless LAN detector 25 that detects the SSID and radio field intensity of a wireless LAN, and a mobile device are authenticated. In the case where the ID code of the mobile device matches the ID code to be authenticated, the SSID included in the response signal and the SSID detected by the wireless LAN detection unit are the same. And the number of SSIDs that are determined to match and that the SSIDs of the two SSIDs match if the difference between the field intensity detected in the response signal corresponding to the same SSID and the detected field intensity is within a preset range. Authenticates the mobile device when is greater than or equal to a preset ratio with respect to the number of detected SSIDs. [Selection diagram] Figure 1

Description

The present application relates to a vehicle authentication device, a vehicle authentication system, and a vehicle authentication method.

2. Description of the Related Art In recent years, a keyless entry system in which a door of a vehicle such as an automobile is locked and unlocked by pressing a button of an electronic key has been widely used. This keyless entry system requires a dedicated electronic key. As a further advanced keyless entry system, a smart keyless entry system that locks and unlocks the vehicle door has been introduced by performing verification by comparing the ID code through communication between the vehicle and a mobile device such as a smartphone. .. In this smart keyless entry system, a low frequency signal is output from the vehicle by pressing a switch provided on the door. The mobile device receives the low frequency signal and responds with the high frequency signal to control the locking and unlocking of the door.

However, there is a problem that a vehicle equipped with a smart keyless entry system is stolen or intruded by a method called a relay attack. This relay attack intentionally installs a repeater to enable wireless communication between the mobile device and the vehicle even when the mobile device is in a distance where radio waves do not reach the vehicle, such as unlocking the vehicle door. It is a dishonesty of doing.

As a method for preventing such fraud, as a conventional vehicle authentication system, the distance between the vehicle and the portable device is measured using GPS (Global Positioning System), and the distance between the vehicle and the portable device is not within an appropriate range. In this case, a vehicle authentication system that does not accept door unlocking or the like is disclosed (for example, see Patent Document 1).

JP, 2014-150425, A

However, the conventional vehicle authentication system has a problem that it cannot be properly authenticated in a place where GPS reception is difficult such as an indoor parking lot or an underground parking lot.

The present application has been made in order to solve the above-described problems, and an object thereof is to obtain a vehicle authentication device that can prevent an illegal act such as a relay attack even in a place where GPS reception is difficult.

A vehicle authentication device according to the present application includes a transmission unit that transmits an authentication request signal to a mobile device, a reception unit that receives a response signal transmitted from the mobile device in response to the authentication request signal, an SSID of a wireless LAN, and A wireless LAN detection unit that detects the radio field intensity, and an authentication unit that authenticates the mobile device based on the response signal received by the reception unit and the SSID and radio field intensity of the wireless LAN detected by the wireless LAN detection unit are provided. It is a thing. Furthermore, when the ID code of the mobile device included in the response signal matches the ID code to be authenticated, the authenticating unit determines the SSID of the wireless LAN included in the response signal and the wireless LAN detected by the wireless LAN detecting unit. The difference between the radio field intensity of the wireless LAN included in the response signal having the same SSID and corresponding to the SSID of the same wireless LAN and the radio field intensity of the wireless LAN detected by the wireless LAN detection unit is within a preset range. In this case, it is determined that the SSID of the wireless LAN included in the response signal matches the SSID of the wireless LAN detected by the wireless LAN detection unit, and the number of SSIDs of the wireless LAN determined to match is detected by the wireless LAN detection unit. The mobile device is authenticated when the ratio is equal to or more than a preset ratio with respect to the number of SSIDs of the wireless LAN.

In the vehicle authentication device of the present application, when the ID code of the mobile device included in the response signal matches the ID code to be authenticated, the SSID of the wireless LAN included in the response signal and the wireless LAN detection unit detect the SSID of the wireless LAN. The SSID of the wireless LAN is the same and the difference between the wireless LAN signal intensity included in the response signal corresponding to the same wireless LAN SSID and the wireless LAN signal intensity detected by the wireless LAN detection unit is a preset range If the SSID of the wireless LAN included in the response signal matches the SSID of the wireless LAN detected by the wireless LAN detection unit, the number of wireless LAN SSIDs determined to match is determined by the wireless LAN detection unit. Since the portable device is authenticated when the ratio is greater than or equal to a preset ratio with respect to the number of detected SSIDs of the wireless LAN, it is possible to prevent an illegal act such as a relay attack even in a place where GPS reception is difficult. it can.

1 is a block diagram showing a configuration of a vehicle authentication system according to a first embodiment. 6 is a flowchart illustrating an authentication procedure according to the first embodiment. FIG. 3 is an explanatory diagram showing a wireless LAN access point and radio field intensity with respect to the positional relationship between the vehicle and the user in the first embodiment. FIG. 3 is a diagram showing a table listing SSIDs and radio field intensities of wireless LAN access points according to the first embodiment. FIG. 3 is an explanatory diagram showing a wireless LAN access point and radio field intensity with respect to the positional relationship between the vehicle and the user in the first embodiment. FIG. 3 is a diagram showing a table listing SSIDs and radio field intensities of wireless LAN access points according to the first embodiment. FIG. 7 is an explanatory diagram showing a wireless LAN access point and radio field intensity with respect to a positional relationship between a vehicle and a user in the second embodiment. FIG. 9 is a diagram showing a table listing SSIDs and radio field intensities of wireless LAN access points according to the second embodiment. FIG. 9 is a diagram showing a table listing SSIDs and radio field intensities of wireless LAN access points according to the second embodiment.

Hereinafter, a vehicle authentication device and a vehicle authentication system according to embodiments for carrying out the present application will be described in detail with reference to the drawings. In each drawing, the same reference numerals indicate the same or corresponding parts.

Embodiment 1.
FIG. 1 is a block diagram showing the configuration of the vehicle authentication system according to the first embodiment. The vehicle authentication system of the present embodiment is a vehicle authentication system used in a smart keyless entry system. As shown in FIG. 1, the vehicle authentication system 1 according to the present embodiment includes a vehicle authentication device 2 and a mobile device 3. The vehicle authentication device 2 is mounted on a vehicle such as an automobile.

The vehicle authentication device 2 includes a switch 21, a first controller 22, a first transmitter 23, a first receiver 24, a first wireless LAN detector 25, and a first transmission antenna 26 connected to the first transmitter 23. , A first receiving antenna 27 connected to the first receiving section 24 and a first wireless LAN receiving antenna 28 connected to the first wireless LAN detecting section 25.

The mobile device 3 includes a second controller 32, a second transmitter 33, a second receiver 34, a second wireless LAN detector 35, a second transmission antenna 36 connected to the second transmitter 33, and a second receiver. A second receiving antenna 37 connected to 34 and a second wireless LAN receiving antenna 38 connected to the second wireless LAN detector 35 are provided. The mobile device 3 is, for example, a mobile terminal dedicated to a smart keyless entry system, a tablet terminal, a smartphone, or the like.

The operation of each component of the vehicle authentication device 2 will be described.
The switch 21 receives an instruction to activate the authentication operation of the vehicle authentication device 2. In response to the activation of the authentication operation, the first transmitter 23 transmits an authentication request signal via the first transmission antenna 26. The authentication request signal is, for example, a radio signal of a first frequency (LF: Low Frequency). The first receiving unit 24 receives the response signal transmitted from the mobile device 3 via the first receiving antenna 27. The response signal is, for example, a radio signal of the second frequency (RF: Radio Frequency). The first wireless LAN detection unit 25 sends the SSID of the wireless LAN access points around the vehicle authentication device 2 and the radio field intensity of the radio waves transmitted from the wireless LAN access points via the first wireless LAN receiving antenna 28. To detect. Here, a wireless LAN (Local Area Network) is a computer network constructed wirelessly. A wireless LAN access point is a device that transmits and receives radio waves that is installed to construct the computer network. Furthermore, SSID (Service Set Identifier) is an identification name for identifying a wireless LAN access point. The first controller 22 controls the switch 21, the first transmitter 23, the first receiver 24, and the first wireless LAN detector 25, and has a function of an authenticator that authenticates the mobile device 3 described later. There is.

Next, the operation of each component of the mobile device 3 will be described.
The second receiving unit 34 receives the authentication request signal transmitted by the vehicle authentication device 2 via the second receiving antenna 37. This authentication request signal is, for example, a radio signal of the first frequency (LF). The second wireless LAN detection unit 35 detects, via the second wireless LAN receiving antenna 38, the SSID of the wireless LAN access point around the mobile device 3 and the radio field intensity of the radio wave transmitted from the wireless LAN access point. .. The second control unit 32 controls the second transmission unit 33, the second reception unit 34, and the second wireless LAN detection unit 35, and at the same time, the wireless LAN around the mobile device 3 detected by the second wireless LAN detection unit 35. It has a function of a response signal generation unit that generates a response signal including the SSID and radio field intensity of the access point and the ID code (identification code) of the mobile device 3. The ID code is an identification code assigned to each individual mobile device to identify the individual mobile device. The second transmission unit 33 transmits the response signal generated by the second control unit 32 via the second transmission antenna 36. This response signal is, for example, a radio signal of the second frequency (RF).

In the vehicle authentication system of the present embodiment, in the operation of the smart keyless entry system, authentication is performed by the following two-way communication. That is, when the switch 21 of the vehicle authentication device 2 is turned on, the vehicle authentication device 2 transmits the authentication request signal from the first transmission unit 23. On the other hand, in the mobile device 3, the second reception unit 34 receives the authentication request signal, and the second transmission unit 33 transmits the response signal. In the vehicle authentication device 2, the first reception unit 24 receives the response signal and starts the authentication operation.

Next, an authentication procedure in the vehicle authentication system of the present embodiment will be described.
FIG. 2 is a flowchart illustrating an authentication procedure in the vehicle authentication system of this embodiment. In FIG. 2, the operations of the vehicle authentication device 2 and the mobile device 3 are shown separately. In step S10, the vehicle authentication device 2 determines whether the switch 21 has been operated. Here, the switch 21 is a switch or a touch sensor provided on a door handle outside the vehicle, an engine start switch in the vehicle, or the like. In step S10, if the switch is not operated (NO), the process returns to step S10 and waits for the switch 21 to be operated. On the other hand, if the switch is operated (YES), the process proceeds to step S20.

In step S20, the vehicle authentication device 2 uses the information indicating that the switch 21 has been operated, for example, the LF signal of the preset binary data (H, L) sequence as the authentication request signal, as the first transmission unit. Send from 23. Here, the first transmission unit 23 modulates the binary data string and outputs a low frequency signal such as a binary ASK (Amplitude Shift Keying) modulated wave in the LF (Low Frequency) band. The low-frequency signal output from the first transmitting unit 23 is radiated into space as a radio wave via the first transmitting antenna 26.

In step S100, the mobile device 3 receives the low-frequency signal transmitted in step S20 at the second receiving unit 34. The reception by the second receiving unit 34 is, for example, receiving the low frequency signal radiated through the first transmitting antenna 26 through the second receiving antenna 37 and demodulating the low frequency signal.

Next, in step S110, the mobile device 3 detects the SSID and the radio field intensity of the wireless LAN access points around the mobile device 3. When a plurality of wireless LAN access points are detected, a table listing SSIDs and radio wave intensities of a predetermined number of wireless LAN access points is created. The detection operation and the table will be described later.

In subsequent step S120, mobile device 3 transmits a response signal including the unique ID code of mobile device 3 and the SSID and radio field intensity of the wireless LAN access point detected in step S110 as an RF signal from second transmission unit 33. .. Here, the second transmission unit 33 modulates both the unique ID code of the mobile device 3, the SSID of the wireless LAN access point, and the radio field intensity, and, for example, a binary FSK (Frequency) in the UHF (Ultra High Frequency) band. A high frequency signal such as a shift keying (modulated) wave is output. The high frequency signal output from the second transmitting unit 33 is radiated into space as a radio wave via the second transmitting antenna 36.

On the other hand, in step S30, the vehicle authentication device 2 detects the SSID and the radio field intensity of the wireless LAN access points around the vehicle. When a plurality of wireless LAN access points are detected, a table listing the SSIDs and radio wave intensities of the wireless LAN access points is created.

Next, in step S40, the first control unit 22 of the vehicle authentication device 2 determines whether or not a response signal has been received. When the response signal is not received (NO), the process proceeds to step S80, and when the response signal is received (YES), the process proceeds to step S50.

Next, in step S50, the first control unit 22 of the vehicle authentication device 2 authenticates the unique ID code of the mobile device included in the response signal received in step S40 and the authentication registered in advance in the vehicle authentication device 2. The ID code to be verified is collated, and it is determined whether the collation is successful. If the collation is unsuccessful (NO), the process proceeds to step S80, and if the collation is successful (YES), the process proceeds to step S60.

Next, in step S60, the first control unit 22 of the vehicle authentication device 2 determines the SSID and radio field intensity of the wireless LAN access point included in the response signal received in step S40, and the wireless LAN access point detected in step S30. It is determined whether or not the number of matches between the SSID and the radio field intensity is equal to or higher than a predetermined ratio. When the number of matches is less than the predetermined ratio (NO), the process proceeds to step S80, and when the number of matches is more than the predetermined ratio (YES), the mobile device 3 is authenticated and the process proceeds to step S70. .. Details of the authentication method in step S60 will be described later.

Next, in step S70, the first control unit 22 of the vehicle authentication device 2 permits an operation on the vehicle. The operation permitted here is a predetermined operation, and if the switch in step S10 is a switch provided on the door handle outside the vehicle or a touch sensor, it is an unlocking of the door, and the switch is inside the vehicle. In the case of the engine start switch, it is the start of the engine.

On the other hand, in step S80, it is determined whether or not the elapsed time exceeds a predetermined time. Here, the elapsed time may be, for example, the elapsed time after the authentication request signal is transmitted in step S20. If the elapsed time does not exceed the predetermined time (NO), the process returns to step S40 to wait for the reception of the response signal, and if the elapsed time exceeds the predetermined time (YES), the mobile device Assuming that the authentication has failed, this series of processing ends.

Next, details of the authentication method in step S60 will be described.
First, the SSID and radio field intensity of the wireless LAN access point will be described. The wireless LAN access point is set with an SSID for identifying each wireless LAN access point, and periodically sends a message with the SSID. The first wireless LAN detection unit 25 and the second wireless LAN detection unit 35 receive the message with the SSID from all the wireless LAN access points in the communicable range, and detect the SSID and its radio field intensity. The radio field intensity can be indicated in the unit of dBm (decibels millimeter). The radio wave intensity is represented by a negative value, and the closer to 0, the stronger the radio wave. Generally, the closer to the wireless LAN access point, the stronger the radio wave.

FIG. 3 is an explanatory diagram showing the wireless LAN access point and the radio field intensity with respect to the positional relationship between the vehicle equipped with the vehicle authentication device 2 and the user who carries the portable device 3 in the present embodiment. FIG. 3 shows the wireless LAN access point and the radio field intensity when the user 101 is close to the vehicle 100. As shown in FIG. 3, it is assumed that there are four wireless LAN access points 110, 111, 112, and 113 around. Radio waves transmitted from these four wireless LAN access points are received by the vehicle authentication device 2 mounted on the vehicle 100 and the mobile device 3 carried by the user 101. In FIG. 3, a solid line arrow indicates a radio wave from the wireless LAN access point to the portable device 3 owned by the user 101, and a solid line underlined numerical value indicates the radio wave intensity. The broken line arrow indicates the radio wave from the wireless LAN access point to the vehicle authentication device 2 mounted on the vehicle 100, and the underlined numerical value of the broken line indicates the radio wave intensity.

FIG. 4 is a table listing SSIDs and radio field intensities of wireless LAN access points received by the vehicle authentication device 2 mounted on the vehicle 100 and the mobile device 3 owned by the user 101 in the positional relationship shown in FIG. FIG. As shown in FIG. 4, on the vehicle authentication device side, the SSID transmitted from the wireless LAN access point 110 is <lanpoint001>, the radio wave intensity is -50 dBm, and the SSID transmitted from the wireless LAN access point 111 is <lanpoint002. >, the radio wave intensity is -40 dBm, the wireless LAN access point 112 has an SSID <lanpoint003>, and the radio wave intensity is -30 dBm. The radio wave transmitted from the wireless LAN access point 113 cannot be detected. Shows the case. On the portable device side, the SSID transmitted from the wireless LAN access point 110 is <lanpoint001> and the radio field intensity is -50 dBm, and the SSID transmitted from the wireless LAN access point 111 is <lanpoint002> and the radio field intensity is -39 dBm. Radio wave, the SSID transmitted from the wireless LAN access point 112 is <lanpoint003> and the radio wave intensity is -31 dBm, and the SSID transmitted from the wireless LAN access point 113 is the <lanpoint004> radio wave whose intensity is -99 dBm is detected. It shows the case where it was done.

Assuming that the number of wireless LAN access points transmitted from the mobile device as a response signal is 5, in the example shown in FIG. 4, the SSID and radio field intensity of the four wireless LAN access points received by the mobile device are included in the response signal. To send. The information of the wireless LAN access point to be transmitted is selected in descending order of radio field intensity. The first control unit of the vehicle authentication device sets the SSID and radio field intensity of the wireless LAN access point included in the received response signal to the SSID and radio field intensity of the wireless LAN access point detected by the first wireless LAN detection unit. Determine whether you are doing. For example, it is determined that SSIDs having the same SSID and a difference in radio field strength within ±3 dBm match. Moreover, SSID whose radio field intensity of either one is smaller than -85 dBm is excluded from the determination target. By using this determination criterion, in the example shown in FIG. 4, it can be determined that the wireless LAN access point detected by the vehicle authentication device and the wireless LAN access point detected by the mobile device match at three points. .. Specifically, there are three locations where the SSID is <lanpoint003>, the SSID is <lanpoint002>, and the SSID is <lanpoint001>. The three SIDs have the same SSID and the difference in radio field intensity is within ±3 dBm.

Next, a case where the user 101 is away from the vehicle 100 will be described. FIG. 5 shows the wireless LAN access point and the radio field intensity when the user 101 is far from the vehicle 100. The distance between the vehicle and the user shown in FIG. 5 is set such that the response signal of the mobile device 3 does not directly reach the vehicle authentication device 2. As shown in FIG. 5, it is assumed that there are four wireless LAN access points 110, 111, 112 and 113 in the surrounding area. Radio waves transmitted from these four wireless LAN access points are received by the vehicle authentication device 2 mounted on the vehicle 100 and the mobile device 3 carried by the user 101. In FIG. 5, a solid line arrow indicates a radio wave from the wireless LAN access point to the portable device 3 owned by the user 101, and a solid line underlined numerical value indicates the radio wave intensity. The broken line arrow indicates the radio wave from the wireless LAN access point to the vehicle authentication device 2 mounted on the vehicle 100, and the underlined numerical value of the broken line indicates the radio wave intensity.

FIG. 6 is a table listing SSIDs and radio field intensities of wireless LAN access points received by the vehicle authentication device 2 mounted on the vehicle 100 and the mobile device 3 owned by the user 101 in the positional relationship shown in FIG. FIG. As shown in FIG. 6, on the vehicle authentication device side, the SSID transmitted from the wireless LAN access point 110 is <lanpoint001>, the radio field intensity is -50 dBm, and the SSID transmitted from the wireless LAN access point 111 is <lanpoint002. >, the radio wave intensity is -40 dBm, the wireless LAN access point 112 has an SSID <lanpoint003>, and the radio wave intensity is -30 dBm. The radio wave transmitted from the wireless LAN access point 113 cannot be detected. Shows the case. On the portable device side, the SSID transmitted from the wireless LAN access point 110 is <lanpoint001> and the radio field intensity is −75 dBm, and the SSID transmitted from the wireless LAN access point 111 is <lanpoint002> and the radio field intensity is −40 dBm. , The radio wave transmitted from the wireless LAN access point 113 has an SSID of <point 004> and the radio wave intensity of -30 dBm is detected, and the radio wave transmitted from the wireless LAN access point 112 cannot be detected.

Assuming that the number of wireless LAN access points transmitted from the mobile device as a response signal is 5, in the example shown in FIG. 6, the SSID and radio field intensity of the three wireless LAN access points received by the mobile device are included in the response signal. To send. The distance between the vehicle and the user shown in FIG. 5 is the distance at which the response signal of the portable device 3 does not reach the vehicle authentication device 2 directly, but the vehicle authentication device 2 is used due to a fraudulent act such as a relay attack using a repeater. Is able to receive the response signal of the mobile device 3. The information of the wireless LAN access point to be transmitted is selected in descending order of radio field intensity. The first control unit of the vehicle authentication device sets the SSID and radio field intensity of the wireless LAN access point included in the received response signal to the SSID and radio field intensity of the wireless LAN access point detected by the first wireless LAN detection unit. Determine whether you are doing. For example, it is determined that SSIDs having the same SSID and a difference in radio field strength within ±3 dBm match. Moreover, SSID whose radio field intensity of either one is smaller than -85 dBm is excluded from the determination target. By using this determination criterion, in the example shown in FIG. 6, it can be determined that the wireless LAN access point detected by the vehicle authentication device and the wireless LAN access point detected by the mobile device match at one location. .. Specifically, there is only one location where the SSID is <lanpoint002>. Only in this one place, the SSID is the same and the difference in radio field intensity is within ±3 dBm.

The positional relationship between the vehicle and the user shown in FIG. 3 is when the authorized user performs an operation such as unlocking the vehicle. On the other hand, in the positional relationship between the vehicle and the user shown in FIG. 5, the vehicle authentication device 2 cannot receive the response signal from the mobile device 3 unless there is a fraudulent act such as a relay attack. The number of matching SSIDs of the wireless LAN access points detected by the vehicle authentication device and SSIDs of the wireless LAN access points detected by the mobile device was three in the positional relationship between the vehicle and the user shown in FIG. However, there is only one location in the positional relationship between the vehicle and the user shown in FIG. There are three wireless LAN access points detected by the vehicle authentication device in total. If two or more of the wireless LAN access points match, the device is authenticated as a legitimate user's mobile device, and if less than two places, the legitimate user's mobile device is identified. And will not authenticate. According to this authentication condition, in the case of the positional relationship between the vehicle and the user shown in FIG. 3, the mobile device is authenticated as an authorized user. However, in the case of the positional relationship between the vehicle and the user shown in FIG. Even if communication between the vehicle authentication device and the mobile device becomes possible due to fraud, the mobile device of the authorized user is not authenticated. In this way, if the number of SSIDs of the wireless LAN determined to match based on the SSID of the wireless LAN and the radio field intensity is equal to or more than a predetermined ratio with respect to the number of SSIDs of the wireless LAN detected by the vehicle authentication device. By authenticating with a legitimate user's mobile device, it is possible to prevent illegal acts such as relay attacks.

As described above, the vehicle authentication device according to the present embodiment includes the transmitting unit that transmits the authentication request signal to the mobile device and the receiving unit that receives the response signal transmitted from the mobile device in response to the authentication request signal. And a wireless LAN detection unit that detects the SSID and radio field intensity of the wireless LAN, and the portable device is authenticated based on the response signal received by the reception unit and the SSID and radio field intensity of the wireless LAN detected by the wireless LAN detection unit. And an authentication unit that does. Furthermore, when the ID code of the mobile device included in the response signal matches the ID code to be authenticated, the authenticating unit determines the SSID of the wireless LAN included in the response signal and the wireless LAN detected by the wireless LAN detecting unit. The difference between the radio field intensity of the wireless LAN included in the response signal having the same SSID and corresponding to the SSID of the same wireless LAN and the radio field intensity of the wireless LAN detected by the wireless LAN detection unit is within a preset range. In this case, the wireless LAN SSID included in the response signal and the wireless LAN SSID detected by the wireless LAN detection unit are determined to match, and the number of wireless LAN SSIDs determined to be matched is detected by the wireless LAN detection unit. Since the mobile device is authenticated when the ratio is a preset ratio or more with respect to the number of SSIDs of the wireless LAN, it is possible to prevent an illegal act such as a relay attack even in a place where GPS reception is difficult.

In other words, when the ID code of the mobile device included in the response signal matches the ID code to be authenticated, the authentication unit of the vehicle authentication device according to the present embodiment detects the mobile device included in the response signal. The table on the portable device side that lists the SSID and the radio field strength of the wireless LAN that has been identified is collated with the table on the vehicle authentication device side that lists the SSID and the radio field strength of the wireless LAN detected by the wireless LAN detection unit, The SSID of the wireless LAN is the same between the table on the mobile device side and the table on the vehicle authentication device side, and the radio field intensity of the wireless LAN on the table on the mobile device side corresponding to the SSID of the same wireless LAN and the vehicle authentication device side When the difference between the radio field intensity of the wireless LAN in the table of 1 is within a preset range, it is determined that the SSID of the wireless LAN detected by the wireless LAN detection unit matches the SSID of the wireless LAN included in the response signal. The mobile device is authenticated when the number of SSIDs of the wireless LAN determined to match is greater than or equal to a preset ratio with respect to the number of SSIDs in the table on the vehicle authentication device side.

In the present embodiment, in the case of the positional relationship between the vehicle authentication device and the mobile device shown in FIG. 3, when the vehicle authentication device detects three wireless LAN SSIDs and two or more SSIDs match, the mobile device is carried. You have authenticated the device. On the other hand, in the case of the positional relationship in which the response signal of the mobile device does not directly reach the vehicular authentication device unless a fraudulent act such as the relay attack shown in FIG. 5 is performed, the SSIDs of the three wireless LANs detected by the vehicular authentication device are detected. However, the mobile device is not authenticated even if only one location matches. As described above, the vehicle authentication device of the present embodiment authenticates the mobile device when the number of SSIDs of the wireless LAN determined to match based on the SSID of the wireless LAN and the radio field intensity is equal to or higher than a predetermined ratio. If the ratio is less than that ratio, the mobile device is not authenticated, and thus it is possible to prevent a fraudulent act such as a relay attack.

Further, since the vehicle authentication device of the present embodiment performs authentication by using the information of the wireless LAN access points existing around the vehicle, even if it is difficult to receive GPS, a fraudulent act such as a relay attack can be performed. Can be stopped. For example, even in a place where GPS reception is difficult such as an indoor parking lot or an underground parking lot in a store, a wireless LAN access point such as a wireless LAN in the store and a portable wireless LAN router owned by a parking lot user Can be used.

In the present embodiment, the authentication request signal is transmitted or received as the LF signal radio wave and the response signal is transmitted as the RF signal radio wave, but the present invention is not limited to this. For example, infrared rays and ultrasonic waves other than radio waves can be used for transmission and reception. Further, in the authentication procedure shown in FIG. 2, step S60 is performed after step S50, but step S50 may be performed after step S60.

The table on the mobile device side shown in FIGS. 4 and 6 may be created by the mobile device or the vehicle authentication device. When the table for the mobile device is created by the vehicular authentication device, the mobile device transmits the response signal including all the SSID and radio field intensity of the wireless LAN access point detected by the mobile device. The vehicle authentication device uses the SSID and radio field intensity information of all the wireless LAN access points detected by the mobile device included in the response signal to select the radio field intensity in descending order and display the table on the mobile device side. create.

Further, in the present embodiment, the difference in radio field intensity is within ±3 dBm as a criterion for determining that the SSIDs of the wireless LANs match, but the difference in radio field intensity may be within ±5%, for example. .. In the case of the vehicle authentication device, even if the distance from the wireless LAN access point is the same due to the installation position of the first wireless LAN receiving antenna and the material around the first wireless LAN receiving antenna, the first wireless LAN detecting unit detects the same. The received radio field intensity changes. Similarly, in the case of a mobile device, the radio field intensity detected by the second wireless LAN detection unit changes depending on the material around the mobile device, such as the mobile device being stored in a bag or a pocket. In consideration of such a situation, it is preferable to set the criterion for determining the difference in radio field intensity. Furthermore, although the SSID whose radio wave intensity detected by the vehicle authentication device or the radio wave intensity detected by the mobile device is smaller than a predetermined value of -85 dBm, the SSID is excluded from the judgment. The value may be changed appropriately.

If the number of matching SSIDs of the wireless LAN is equal to or greater than a predetermined ratio, the number of SSIDs used as a reference when authenticating with a portable device owned by an authorized user is the wireless LAN access detected by the vehicle authentication device. The number of SSIDs of points. In the example shown in FIGS. 3 and 5, the position of the stopped vehicle is the same, so the number of wireless LAN access points detected by the vehicle authentication device is the same, but the wireless LAN detected by the portable device that moves with the user. This is because the number of access points changes.

In the present embodiment, an example in which there is a wireless LAN access point around the vehicle and the user is shown, but there is no wireless LAN access point around the vehicle and the user, and vehicle authentication is performed. If both the device and the mobile device cannot detect any one wireless LAN access point, authentication may be performed only with the ID code of the mobile device. Authentication is possible even when there are no shops or houses around.

Embodiment 2.
Cars can be moved anywhere. For example, there are many wireless LAN access points such as wireless LANs used in shops or houses, public wireless LANs, and portable wireless LAN routers owned by individuals in the city. May be detected. In the second embodiment, a case will be described in which there are many wireless LAN access points with substantially the same radio field intensity around the vehicle.

FIG. 7 is an explanatory diagram showing the wireless LAN access point and the radio field intensity with respect to the positional relationship between the vehicle equipped with the vehicle authentication device 2 and the user who carries the portable device 3 in the present embodiment. FIG. 7 shows the wireless LAN access point and the radio field intensity when the user 101 is close to the vehicle 100. As shown in FIG. 7, it is assumed that there are seven wireless LAN access points 110, 111, 112, 113, 114, 115, and 116 around. Radio waves transmitted from these seven wireless LAN access points are received by the vehicle authentication device 2 mounted on the vehicle 100 and the mobile device 3 carried by the user 101. In FIG. 7, a solid line arrow indicates a radio wave from the wireless LAN access point to the portable device 3 owned by the user 101, and a solid line underlined numerical value indicates the radio wave intensity. The broken line arrow indicates the radio wave from the wireless LAN access point to the vehicle authentication device 2 mounted on the vehicle 100, and the underlined numerical value of the broken line indicates the radio wave intensity.

As shown in FIG. 7, in the vehicle authentication device 2, the SSID transmitted from the wireless LAN access point 110 is <lanpoint001> and the radio wave intensity is -50 dBm, and the SSID transmitted from the wireless LAN access point 111 is <lanpoint002. >, the radio wave intensity is −40 dBm, the SSID transmitted from the wireless LAN access point 112 is <lanpoint003>, the radio wave intensity is −30 dBm, and the SSID transmitted from the wireless LAN access point 114 is <lanpoint005>. Of -53 dBm, the SSID transmitted from the wireless LAN access point 115 is <lanpoint006> and the radio field intensity is -55 dBm, and the SSID transmitted from the wireless LAN access point 116 is <lanpoint007> and the radio field intensity is -58 dBm. Radio waves are detected, and radio waves transmitted from the wireless LAN access point 113 cannot be detected. In the mobile device 3, the SSID transmitted from the wireless LAN access point 110 is <lanpoint001> and the radio field intensity is -50 dBm, and the SSID transmitted from the wireless LAN access point 111 is <lanpoint002> and the radio field intensity is -39 dBm. Radio wave, the SSID transmitted from the wireless LAN access point 112 is <lanpoint003> and the radio wave intensity is −31 dBm, and the SSID transmitted from the wireless LAN access point 113 is the <lanpoint004> radio wave intensity is −99 dBm. The SSID transmitted from the LAN access point 114 is <lanpoint005> and the radio field intensity is -56 dBm, the SSID transmitted from the wireless LAN access point 115 is <lanpoint006>, the radio field intensity is -58 dBm, the wireless LAN access point 116. The SSID transmitted from the device is <lanpoint007> and the radio wave intensity is -55 dBm.

If the number of wireless LAN access points transmitted from the portable device 3 as a response signal is 5, then 5 are selected in descending order of radio field intensity, and a table listing the SSIDs and radio field intensities of the wireless LAN access points is created. To be done. Similarly, in the vehicle authentication device 2, five tables are selected in descending order of radio field intensity to create a table.

FIG. 8 is a diagram showing a table listing SSIDs and radio field intensities of wireless LAN access points received by the vehicle authentication device 2 mounted on the vehicle 100 and the portable device 3 owned by the user 101. The first control unit of the vehicle authentication device sets the SSID and radio field intensity of the wireless LAN access point included in the received response signal to the SSID and radio field intensity of the wireless LAN access point detected by the first wireless LAN detection unit. Determine whether you are doing. For example, it is assumed that SSIDs having the same SSID and a difference in radio field intensity within ±3 dBm are determined to be coincident, and one of the SSIDs having a radio field intensity smaller than −85 dBm is not used for the determination. Using this determination criterion, in the example shown in FIG. 8, it can be determined that the wireless LAN access point detected by the vehicle authentication device and the wireless LAN access point detected by the mobile device are in coincidence at four points. .. Specifically, there are four locations, the SSID is <lanpoint003>, the SSID is <lanpoint002>, the SSID is <lanpoint001>, and the SSID is <lanpoint005>. The four SIDs have the same SSID and the difference in radio field intensity is within ±3 dBm.

If there are many wireless LAN access points with almost the same radio wave intensity around the vehicle, select the five wireless LAN access points in descending order of radio field intensity, and if four or more of them match, select If you authenticate with your mobile device and if you do not authenticate with the mobile device owned by the authorized user if there are less than four locations, then you will carry the mobile device owned by the authorized user in the case of the positional relationship between the vehicle and the user shown in FIG. Can authenticate with the device.

In this way, when there are many wireless LAN access points having almost the same radio field intensity, the list of the SSID and radio field intensity of the wireless LAN access points included in the response signal of the mobile device and the wireless LAN detected by the vehicle authentication device. It is possible to determine that the SSIDs match even if the order of the wireless LAN access points with the smallest radio field strength is different from the list of SSIDs and radio field strengths of the access points, so prevent erroneous determinations. You can

In the present embodiment, an example is shown in which the table on the portable device side and the table on the vehicle authentication device side are selected and listed in descending order of radio field strength. The number of SSIDs placed on the table may be increased. FIG. 9 is a diagram showing an example in which the number of SSIDs in the table on the vehicle authentication device side is one more than the number of SSIDs in the table on the mobile device side. In this case, it is possible to determine that the SSID on the portable device side matches <lanpoint007> and the SSID on the vehicle authentication device side matches <lanpoint007>. As a result, the number of SSIDs having the same SSID and a difference in radio field intensity of within ±3 dBm increases to five places. By increasing the number of matching SSIDs, it is possible to further prevent erroneous determination.

Since the vehicle authentication device configured in this way performs authentication using information of wireless LAN access points existing around the vehicle, it prevents fraudulent acts such as relay attacks even in places where GPS reception is difficult. can do.

The tables on the mobile device side shown in FIGS. 8 and 9 may be created by the mobile device or the vehicle authentication device. When the table for the mobile device is created by the vehicular authentication device, the mobile device transmits the response signal including all the SSID and radio field intensity of the wireless LAN access point detected by the mobile device. The vehicle authentication device uses the SSIDs and radio field intensity information of all the wireless LAN access points detected by the mobile device included in the response signal to select the radio field intensity in descending order and display the table on the mobile device side. create.

Although the present application describes various exemplary embodiments, various features, aspects, and functions described in one or more embodiments are limited to the application of the particular embodiment. Instead, it is applicable to the embodiments alone or in various combinations.
Therefore, innumerable variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and at least one component is extracted and combined with the components of other embodiments.

DESCRIPTION OF SYMBOLS 1 Vehicle authentication system, 2 Vehicle authentication device, 3 Portable device, 21 Switch, 22 1st control part, 23 1st transmission part, 24 1st reception part, 25 1st wireless LAN detection part, 26 1st transmission antenna , 27 1st receiving antenna, 28 1st wireless LAN receiving antenna, 32 2nd control part, 33 2nd transmitting part, 34 2nd receiving part, 35 2nd wireless LAN detecting part, 36 2nd transmitting antenna, 37 2nd Receiving antenna, 38 Second wireless LAN receiving antenna, 100 Vehicle, 101 User, 110, 111, 112, 113, 114, 115, 116 Wireless LAN access point.

Claims (6)

A transmission unit for transmitting an authentication request signal to the mobile device,
A receiver for receiving a response signal transmitted from the portable device in response to the authentication request signal,
A wireless LAN detection unit that detects the SSID and radio field strength of the wireless LAN;
A vehicle authentication device comprising: an authentication unit that authenticates the mobile device based on the response signal received by the reception unit and the SSID and radio field intensity of the wireless LAN detected by the wireless LAN detection unit. hand,
The authentication unit is
When the ID code of the mobile device included in the response signal matches the ID code to be authenticated, the SSID of the wireless LAN included in the response signal and the wireless LAN detected by the wireless LAN detection unit. SSID of the wireless LAN is the same and the difference between the wireless LAN field strength included in the response signal corresponding to the same wireless LAN SSID and the wireless LAN field strength detected by the wireless LAN detection unit is set in advance. If the SSID of the wireless LAN included in the response signal and the SSID of the wireless LAN detected by the wireless LAN detection unit match each other within the specified range, the SSID of the wireless LAN determined to match The authentication device for a vehicle, characterized in that the portable device is authenticated when the number is equal to or more than a preset ratio with respect to the number of SSIDs of the wireless LAN detected by the wireless LAN detection unit. The authentication unit is
If at least one of the radio field intensity of the wireless LAN included in the response signal and the radio field intensity of the wireless LAN detected by the wireless LAN detection unit is smaller than a predetermined value, the radio field intensity corresponding to the radio field intensity The vehicle authentication device according to claim 1, wherein the SSID of the wireless LAN is excluded from the determination target. A vehicle authentication system having a vehicle authentication device and a mobile device,
The vehicle authentication device includes a first transmission unit that transmits an authentication request signal to the mobile device, and a first reception unit that receives a response signal transmitted from the mobile device in response to the authentication request signal. A first wireless LAN detection unit that detects SSID and radio field intensity of the wireless LAN, the response signal received by the first reception unit, and the SSID and radio field intensity of the wireless LAN detected by the first wireless LAN detection unit And an authentication unit that authenticates the mobile device based on
The mobile device includes a second reception unit that receives the authentication request signal, a second wireless LAN detection unit that detects the SSID and radio field intensity of the wireless LAN, and a wireless LAN that is detected by the second wireless LAN detection unit. A response signal generation unit that generates the response signal that includes the SSID and the radio field intensity and the ID code of the mobile device, and a second transmission unit that transmits the response signal generated by the response signal generation unit are included. ,
The authentication unit is
When the ID code of the portable device included in the response signal matches the ID code to be authenticated, the SSID of the wireless LAN included in the response signal and the first wireless LAN detection unit detected. The SSID of the wireless LAN is the same, and the radio field intensity of the wireless LAN included in the response signal corresponding to the same SSID of the wireless LAN and the radio field intensity of the wireless LAN detected by the first wireless LAN detection unit. When the difference is within a preset range, it is determined that the SSID of the wireless LAN included in the response signal and the SSID of the wireless LAN detected by the first wireless LAN detection unit match, and it is determined that they match. The portable device is authenticated when the number of SSIDs of the wireless LAN is equal to or more than a preset ratio with respect to the number of SSIDs of the wireless LAN detected by the first wireless LAN detection unit. Vehicle authentication system that does. The authentication unit is
Corresponding to the radio field intensity when at least one of the radio field intensity of the wireless LAN included in the response signal and the radio field intensity of the wireless LAN detected by the first wireless LAN detection unit is smaller than a predetermined value. The vehicle authentication system according to claim 3, wherein the SSID of the wireless LAN that does not belong to the determination target. A transmission step of transmitting an authentication request signal to the mobile device,
A receiving step of receiving a response signal transmitted from the portable device in response to the authentication request signal,
A detection step of detecting the SSID and radio field strength of the wireless LAN,
A vehicle authentication method comprising: an authentication step of authenticating the mobile device based on the response signal received in the reception step and the SSID and radio field intensity of the wireless LAN detected in the detection step,
The authentication step includes
When the ID code of the mobile device included in the response signal matches the ID code to be authenticated, the SSID of the wireless LAN included in the response signal and the SSID of the wireless LAN detected in the detecting step. Is the same and the difference between the radio field intensity of the wireless LAN included in the response signal corresponding to the same SSID of the wireless LAN and the radio field intensity of the wireless LAN detected in the detecting step is within a preset range. If the SSID of the wireless LAN included in the response signal and the SSID of the wireless LAN detected in the detecting step match, the number of SSIDs of the wireless LAN determined to match is the detecting step. The authentication method for a vehicle, wherein the portable device is authenticated when the ratio is equal to or more than a preset ratio with respect to the number of SSIDs of the wireless LAN detected in. The authentication step includes
When at least one of the radio field intensity of the wireless LAN included in the response signal and the radio field intensity of the wireless LAN detected in the detecting step is smaller than a predetermined value, the radio LAN intensity corresponding to the radio field intensity The vehicle authentication method according to claim 5, wherein SSID is excluded from the target of the determination.

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