JP2014190046A - Unauthorized communication establishment prevention system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unauthorized communication establishment prevention system in which the service life of a power supply for an electronic key can be extended.SOLUTION: An electronic key 2 is provided with an acceleration sensor 20 that detects operation occurring in the electronic key 2. An acceleration determiner 21 in the electronic key 2 determines whether an operation occurring in the electronic key 2 is an authorized one or not on the basis of an acceleration signal from the acceleration sensor 20. A transmission controller 22 in the electronic key 2, when smart communication between a vehicle 1 and the electronic key 2 is tried, notifies the vehicle 1 of determination result notification data Ddc, as a result of operation determination, attached to an ID signal Sid. The determination result notification data Ddc are signals that simply notify the vehicle 1 of the operation determination results and constituted, for example, of bit signals of "0" and "1".

Description

  The present invention relates to a communication fraud establishment preventing system that prevents unauthorized communication establishment in an electronic key.

  2. Description of the Related Art Conventionally, an electronic key system for performing ID verification by wirelessly transmitting an electronic key ID from an electronic key to a vehicle in a vehicle or the like is well known. By the way, in this kind of electronic key system, there is a fraudulent act using a repeater (see a repeater use fraud: see Patent Document 1, etc.) as a fraudulent act intended to establish ID verification without depending on the user's will. is there. For example, when the electronic key is located at a location far from the vehicle, the repeater use fraudulent act is an act of establishing a communication between these two parties by connecting the electronic key to the vehicle by a plurality of repeaters and relaying radio waves. is there. Therefore, since ID verification is established without the user's knowledge, there is a possibility that the door unlocking or the engine is illegally started by a third party.

  As countermeasures against unauthorized communication using this repeater, for example, an acceleration sensor is built in the electronic key, and the validity of the communication is determined by determining the movement of the electronic key based on the acceleration detected by the acceleration sensor. The technology is well known (see, for example, Patent Document 2). Patent Document 2 transmits acceleration data detected by an acceleration sensor using an electronic key to a vehicle in the process of ID verification communication. Then, the vehicle determines the legitimacy of the movement of the electronic key based on the received acceleration data. For example, when the acceleration is greater than “0” and less than or equal to the threshold value, the vehicle door is permitted to be unlocked.

JP 2006-161545 A JP 2010-216079 A

  By the way, Patent Document 2 wirelessly transmits the acceleration data itself detected by the electronic key to the vehicle during the ID verification communication process. For this reason, since the amount of data transmitted from the electronic key to the vehicle at the time of communication increases, the power consumed by the electronic key increases, which leads to deterioration of the battery life of the electronic key. The ID verification communication is preferably encryption communication for security reasons, but the encryption of acceleration data having a large data amount consumes a large amount of power in the electronic key. Therefore, also from this point, the battery life of the electronic key tends to be shortened.

  An object of the present invention is to provide a communication fraud prevention system capable of extending the life of an electronic key.

  The communication fraud prevention system that solves the above problem is performed at the time of ID verification when the electronic key is wirelessly transmitted from the electronic key to the vehicle upon communication from the vehicle, and the electronic key is ID verified. In the configuration for confirming the validity of communication, the electronic key is a key movement validity determination that determines the validity of the movement of the electronic key based on the detection signal of the movement detection unit capable of detecting the movement of the electronic key. And a transmission control unit that wirelessly transmits a signal based on the determination result of the key movement determination unit to the vehicle, and the vehicle performs the ID verification based on the signal received from the electronic key. A collation establishment permission determination unit for determining whether approval is permitted is provided.

  According to this configuration, in the configuration in which the validity of the movement of the electronic key is determined based on the detection signal of the movement detection unit provided on the electronic key to prevent the establishment of unauthorized communication, The signal based on the determination result is transmitted from the electronic key to the vehicle. For this reason, since only the determination result needs to be transmitted from the electronic key to the vehicle, the power of the electronic key required for this communication can be reduced. Therefore, it is possible to reduce the power consumption of the electronic key power supply, which contributes to the extension of the life of the electronic key power supply.

  In the communication fraud prevention system, it is preferable that the electronic key encrypts the signal based on the determination result of the key movement determination unit and wirelessly transmits the signal to the vehicle. According to this configuration, the signal based on the determination result of the key movement determination unit is encrypted and transmitted from the electronic key to the vehicle. For this reason, it becomes possible to transmit the determination result of the key movement determination unit from the electronic key to the vehicle with high security. In addition, when the signal is transmitted after being encrypted, power for encrypting the signal on the electronic key side is required. However, if only a determination result is transmitted from the electronic key to the vehicle as in this configuration. Since the amount of information to be encrypted is small, it can be said that this is advantageous for power saving of the power source of the electronic key.

  In the communication fraud establishment prevention system, it is preferable that the transmission control unit wirelessly transmits determination result notification data, which is a determination result of the key movement determination unit, from the electronic key to the vehicle. According to this configuration, whether the motion determination result is valid or invalid, the determination result notification data is transmitted from the electronic key to the vehicle as the electronic key motion determination result performed with the electronic key. Therefore, it becomes possible to notify the vehicle of the motion determination result more accurately.

  In the communication fraud prevention system, when the movement of the electronic key is determined to be valid, the transmission control unit transmits the electronic key ID registered in the electronic key to the vehicle, and the movement of the electronic key It is preferable not to execute transmission of the electronic key ID when it is determined to be invalid. According to this configuration, the vehicle-side control is the same as that of the conventional system. Therefore, it is possible to take measures against unauthorized communication by changing only the electronic key without changing the system on the vehicle side.

  In the communication tampering prevention system, it is preferable that the motion detection unit is activated when the electronic key enters the communication area of the vehicle and receives a radio wave. According to this configuration, the electronic key before entering the communication area can be set in a standby state in which the power is turned off, which further contributes to extending the life of the power supply of the electronic key.

  In the communication fraud establishment prevention system, it is preferable that the motion detection unit switches to a standby state in which the power is turned off when signal transmission from the electronic key to the vehicle is completed. According to this configuration, when the signal transmission from the electronic key to the vehicle is completed, the electronic key is placed in a standby state in which the power is turned off. This further contributes to the extension of the life of the electronic key power source.

  According to the present invention, in the communication fraud prevention system, the power source of the electronic key can be extended.

The block diagram of the communication fraud establishment prevention system of one Embodiment. The state figure when a key holder approaches a vehicle outside a vehicle. (A)-(c) is a waveform diagram of acceleration showing specific processing of movement determination of an electronic key. The schematic diagram which shows the smart collation outside a vehicle at the time of normal communication. The schematic diagram which shows the smart collation outside a vehicle at the time of unauthorized communication. (A), (b) is an illustration figure of the communication fraud establishment prevention system of another example. (A), (b) is an illustration figure of the communication fraud establishment prevention system of another example.

Hereinafter, an embodiment of a communication fraud establishment prevention system will be described with reference to FIGS.
As shown in FIG. 1, a vehicle 1 is equipped with an electronic key system 3 that performs ID verification wirelessly with an electronic key 2. The electronic key system 3 is a key operation free system that performs ID collation (smart collation) by narrow-band radio (communication distance: several m) triggered by communication from the vehicle 1.

  In this case, the vehicle 1 is provided with a verification ECU (Electronic Control Unit) 4 that performs ID verification with the electronic key 2, a body ECU 5 that manages the power source of the in-vehicle electrical components, and an engine ECU 6 that controls the engine 7. These are connected through a bus 8. An electronic key ID of the electronic key 2 registered in the vehicle 1 is written and stored in a memory (not shown) of the verification ECU 4. The verification ECU 4 receives an out-of-vehicle transmitter 9 capable of transmitting LF (Low Frequency) band radio waves outside the vehicle, an in-vehicle transmitter 10 capable of transmitting LF radio waves into the car, and UHF (Ultra High Frequency) band radio waves. A possible vehicle receiver 11 is connected. Connected to the verification ECU 4 are a touch sensor 13 for detecting a touch operation of the vehicle exterior door handle 12 and a door lock button 14 provided on the vehicle exterior door handle 12. The body ECU 5 is connected to a door lock motor 15 serving as a drive source when switching between locking and unlocking of the vehicle door. Connected to the verification ECU 4 is a push momentary engine switch 16 that is operated when the power state of the vehicle 1 is switched.

  The electronic key 2 is provided with a key control unit 17 that controls the operation of the electronic key 2. An electronic key ID unique to each key is written and stored in a memory (not shown) of the key control unit 17. The key control unit 17 is connected to a reception antenna 18 capable of receiving LF radio waves and a transmission antenna 19 capable of transmitting UHF radio waves.

  When the electronic key 2 is located outside the vehicle, the vehicle outside transmitter 9 transmits the request signal Srq LF around the vehicle body outside the vehicle. In addition, when the electronic key 2 is located in the vehicle, the in-vehicle transmitter 10 transmits the request signal Srq to the entire vehicle area by LF. The electronic key 2 is activated upon receiving the request signal Srq, and transmits the ID signal Sid by UHF. The ID signal Sid is a signal including an electronic key ID registered in the electronic key 2. When the ID signal Sid of the electronic key 2 is received by the vehicle receiver 11, the verification ECU 4 performs ID verification (smart verification) based on the ID signal Sid. If ID verification is established, the verification ECU 4 performs door locking / unlocking and power transition operations. Permit or execute.

  The electronic key system 3 is provided with a communication fraud establishment prevention function (communication fraud establishment prevention system) that prevents the establishment of unauthorized communication using a repeater, for example. In the case of this example, the electronic key 2 is provided with an acceleration sensor 20 that detects acceleration generated in the electronic key 2. The acceleration sensor 20 is always activated, for example, monitors the acceleration generated in the electronic key 2 during activation, and outputs the detected acceleration signal (acceleration data) to the key control unit 17. The acceleration sensor 20 is an example of a motion detection unit.

  The key control unit 17 includes an acceleration determination unit 21 that determines the movement of the electronic key 2 based on an acceleration signal input from the acceleration sensor 20, and a transmission control unit 22 that wirelessly transmits the determination result of the acceleration determination unit 21 to the vehicle 1. And are provided. The acceleration determination unit 21 determines whether or not to take a motion that can occur when the electronic key 2 is carried by a legitimate user by checking the acceleration signal of the acceleration sensor 20. The transmission control unit 22 wirelessly notifies the vehicle 1 by adding, as the determination result of the acceleration determination unit 21, for example, determination result notification data Ddc including a 1-bit signal of “0” or “1” to the ID signal Sid. . The electronic key 2 encrypts the ID signal Sid and wirelessly transmits it to the vehicle 1. The acceleration determination unit 21 is an example of a key movement validity determination unit.

  The verification ECU 4 is provided with a verification establishment permission determination unit 23 that determines whether or not the ID verification that is currently being performed is permitted based on the determination result notification data Ddc in the received ID signal Sid. When the verification establishment permission determination unit 23 reads, for example, a bit signal of “0” as the determination result notification data Ddc, it recognizes that the electronic key 2 has taken a normal movement, and for example, a bit of “1” as the determination result notification data Ddc. When the signal is read, it is recognized that the electronic key 2 is not operating normally. The verification ECU 4 determines the validity of the final ID verification based on the verification result of the ID verification and the reading result of the determination result notification data Ddc.

Next, the operation of the communication fraud establishment prevention system will be described with reference to FIGS. Here, for example, the operation when unlocking the vehicle door is taken as an example.
[Normal ride operation]
As shown in FIG. 2, when the authorized user gets on the vehicle 1 in the parked state (vehicle door locking, engine stop), the user approaches the vehicle 1 with the electronic key 2 held, that is, the vehicle-side transmitter 9 forms. The operation of approaching the outside communication area of the request signal Srq is taken. In the case of this example, the acceleration sensor 20 is always activated and sequentially outputs the acceleration signal to the key control unit 17. For this reason, the acceleration determination unit 21 sequentially determines whether or not the movement generated in the electronic key 2 is a movement according to the possession of the authorized user, based on the acceleration signal input from the acceleration sensor 20. .

  As shown in FIG. 3A, as an example of the determination of the movement of the electronic key 2, for example, there is a situation where the acceleration is equal to or higher than the lower limit threshold within the determination time, that is, the electronic key 2 has moved to some extent. There is a process of periodically determining whether or not. This is for confirming that the electronic key 2 is not in a completely stopped state. As shown in FIG. 3B, as another example of the movement determination of the electronic key 2, for example, the acceleration is less than the upper limit threshold within the determination time, that is, the acceleration generated in the electronic key 2 is a predetermined value. There is a process of periodically determining whether or not it is within the range. This is for confirming whether the electronic key 2 is not moved too much. Further, as shown in FIG. 3C, as another example of the movement determination of the electronic key 2, whether or not the acceleration change waveform matches the reference waveform of the acceleration change that can be taken by the authorized user. There is a matching decision.

  As shown in FIG. 4, when the electronic key 2 enters the communication area outside the vehicle for the request signal Srq, the electronic key 2 responds to the request signal Srq and enters the reply operation for the ID signal Sid. At this time, when the electronic key 2 transmits the ID signal Sid to the vehicle 1, the transmission control unit 22 outputs a bit signal of “0” or “1” as the determination result notification data Ddc that is a determination result of the acceleration determination unit 21. By adding to the ID signal Sid, the determination result of the acceleration determination unit 21 is notified to the vehicle 1. The transmission control unit 22 adds, for example, “0” as a bit signal if the movement determination of the electronic key 2 is determined to be valid, and as a bit signal if the movement determination of the electronic key 2 is determined to be invalid. For example, “1” is added. Therefore, the ID signal Sid is a signal including the electronic key ID registered in the electronic key 2 and 1-bit determination result notification data Ddc. Further, the ID signal Sid is encrypted and wirelessly transmitted from the electronic key 2 to the vehicle 1.

  Incidentally, when challenge response authentication is also performed in the ID verification, the response code is included in the ID signal Sid as a result of the challenge code calculation. In the case of challenge response authentication, a challenge code is transmitted from the vehicle 1 to the electronic key 2, the challenge code is calculated using the encryption key of the electronic key 2, and the calculation result is returned from the electronic key 2 to the vehicle 1 as a response code. Similarly, the vehicle 1 calculates a challenge code by using the encryption key of itself, calculates a response code, and compares this with the response code of the electronic key 2. If they match, challenge-response authentication is established.

  When the electronic key 2 returns an ID signal Sid as a response to the request signal Srq at the time of ID verification with the electronic key 2 possessed by the authorized user, the transmission control unit 22 notifies the determination result that is the determination result of the acceleration determining unit 21 A bit signal of “0” is added to the ID signal Sid as data Ddc and transmitted. At the time of normal ID collation, the ID signal Sid is transmitted as a signal having, for example, an electronic key ID and determination result notification data Ddc “0”. The ID signal Sid is encrypted by the key control unit 17 and transmitted to the vehicle 1.

  When the ID signal Sid transmitted from the electronic key 2 is received by the vehicle receiver 11, the verification ECU 4 executes ID verification outside the vehicle (smart vehicle verification outside the vehicle) based on the electronic key ID included in the ID signal Sid. At this time, the collation ECU 4 compares the electronic key ID included in the ID signal Sid with the electronic key ID registered in the ID signal Sid. On the other hand, if these electronic key IDs do not match, ID verification is processed as not established.

  Further, when the vehicle receiver 11 receives the ID signal Sid, the verification establishment permission determination unit 23 reads the determination result notification data Ddc included in the ID signal Sid and confirms “0” or “1”. The validity of the movement of the electronic key 2 is confirmed. If the determination result notification data Ddc is “0”, the verification establishment permission determination unit 23 permits ID verification to be established, and if the determination result notification data Ddc is “1”, does not permit ID verification. Here, since an operation example of a regular user is described, the determination result notification data is “0”, and establishment of ID verification is permitted. Thereby, the unlocking / unlocking of the vehicle door is permitted. For example, when the touch operation of the outside door handle 12 is detected by the touch sensor 13, the vehicle door is unlocked.

  In the case of this example, the validity of the movement of the electronic key 2 is determined by the electronic key 2, and only the determination result is notified from the electronic key 2 to the vehicle 1 as a 1-bit signal of “0” and “1”. For this reason, since the data amount of the signal transmitted from the electronic key 2 to the vehicle 1 is reduced at the time of ID collation, the power consumption when transmitting the signal of the electronic key 2 can be reduced. Therefore, it is advantageous for ensuring the battery life of the electronic key 2. Further, since ID verification is encrypted communication, if the amount of signal data is small, the amount of data that needs to be encrypted is small. Therefore, less power is consumed when the key control unit 17 performs encryption, which is also advantageous in this respect.

[Example of unauthorized communication operation using a repeater]
As shown in FIG. 5, for example, by relaying radio waves with a relay 24 interposed between the vehicle 1 and the electronic key 2, ID verification communication between the vehicle 1 and the electronic key 2 is illegally established. To do. At this time, the request signal Srq transmitted from the vehicle 1 reaches the electronic key 2 via the relay 24, and the ID signal Sid returned from the electronic key 2 reaches the vehicle 1 again via the relay 24. Thereby, although the electronic key 2 does not exist in the communication area of the request signal Srq of the vehicle 1, ID verification communication (smart communication) is established by the repeater 24.

  By the way, in the case of unauthorized communication using the repeater 24, the electronic key 2 should not have moved according to the operation that the authorized user takes when unlocking the vehicle door. For example, the electronic key 2 is placed at home and no acceleration is generated, or even if there is a movement, an acceleration different from when the user gets on the vehicle is generated. Therefore, the acceleration determination unit 21 at this time determines that the movement is not due to possession of the authorized user in the movement determination performed based on the acceleration signal of the acceleration sensor 20.

  When the electronic key 2 returns the ID signal Sid as a response to the request signal Srq during the unauthorized communication using the repeater 24, the transmission control unit 22 uses the determination result notification data Ddc that is the determination result of the acceleration determination unit 21. A bit signal of “1” is added to the ID signal Sid and transmitted. During unauthorized communication using the repeater 24, the ID signal Sid is transmitted as a signal having, for example, an electronic key ID and determination result notification data Ddc “1”. The ID signal Sid is encrypted by the key control unit 17 and transmitted to the vehicle 1.

  When the vehicle receiver 11 receives the ID signal Sid, the verification establishment permission determination unit 23 reads “1” as the determination result notification data Ddc included in the ID signal Sid, thereby disapproving establishment of ID verification. . For this reason, even if ID collation is established during illegal communication using the repeater 24, ID collation is not permitted according to the motion determination result, and as a result, ID collation is not established. Therefore, even if communication is illegally established by a third party using a repeater, the vehicle door need not be unlocked.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) In the communication fraud establishment prevention function for preventing the establishment of unauthorized communication by determining the validity of the movement of the electronic key 2 based on the acceleration signal of the acceleration sensor 20 provided in the electronic key 2, the movement determination of the electronic key 2 Is performed on the electronic key 2 side, and determination result notification data Ddc including a bit signal is transmitted from the electronic key 2 to the vehicle 1 as the movement determination result. For this reason, since only a bit signal of “0” and “1” needs to be transmitted from the electronic key 2 to the vehicle 1 as a motion determination result, the power of the electronic key 2 required for this communication can be reduced. Therefore, power saving of the power source of the electronic key 2 can be achieved, and the life of the power source of the electronic key 2 can be extended.

  (2) The ID signal Sid returned by the electronic key 2 as a response to the received request signal Srq, that is, the signal including the electronic key ID and the determination result notification data Ddc is encrypted and transmitted from the electronic key 2 to the vehicle 1 . Therefore, the ID signal Sid and thus the determination result notification data Ddc can be transmitted from the electronic key 2 to the vehicle 1 with high security.

  (3) When the ID signal Sid (determination result notification data Ddc) is encrypted and transmitted from the electronic key 2 to the vehicle 1, power for encrypting the transmission signal on the electronic key 2 side is required. As described above, if only a bit signal is transmitted as the determination result notification data Ddc, the amount of information to be encrypted can be reduced. Therefore, it can be said that it is advantageous for power saving of the power source of the electronic key 2.

  (4) When it is determined that the movement of the electronic key 2 is valid, “0” is notified from the electronic key 2 to the vehicle 1 as the determination result notification data Ddc, and when the movement of the electronic key 2 is determined to be invalid. The electronic key 2 notifies the vehicle 1 of “1” as the determination result notification data Ddc. In this way, since the electronic key 2 notifies the vehicle 1 of whether the movement generated in the electronic key 2 is legitimate / unjustified, the movement determination result is notified more accurately from the electronic key 2 to the vehicle 1. Can do.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
As shown in FIGS. 6A and 6B, when the electronic key 2 is determined to be normal communication from the movement of the electronic key 2, only the electronic key ID (that is, the determination result notification data Dds is not included) is determined. The ID signal Sid may be wirelessly transmitted to the vehicle 1, and when the unauthorized communication is determined from the movement of the electronic key 2, the ID signal Sid may not be wirelessly transmitted to the vehicle 1. In this case, the control performed on the vehicle 1 side may be the same as in the conventional system in which the electronic key 2 is not provided with the acceleration sensor 20. Therefore, it is possible to take measures against unauthorized communication by the repeater 24 by changing only the electronic key 2 without changing the structure on the vehicle 1 side.

  As shown in FIGS. 7A and 7B, when the electronic key 2 enters the communication area of the request signal Srq, first, smart verification is performed. For example, when the user touches the outside door handle 12, The determination result notification data Ddc may be transmitted from the electronic key 2 to the vehicle 1. In this case, when the user touches the door handle 12 outside the vehicle, the determination result notification data Ddc is returned from the electronic key 2 by transmitting a determination result notification transmission request from the vehicle 1 to the electronic key 2.

  Normally, the acceleration sensor 20 may be in a standby state in which the power is turned off, and when the electronic key 2 is activated upon receiving the request signal Srq, the acceleration sensor 20 may be switched to the activated state. In this case, the power of the electronic key 2 can be saved.

  The acceleration sensor 20 may be switched to a power-off standby state after notifying the vehicle 1 of the determination result notification data Ddc from the electronic key 2. In this case, it is advantageous for power saving of the power source of the electronic key 2.

“1” may be notified when the movement is valid, and “0” may be notified when the movement is inappropriate.
The determination result notification data Ddc may be a signal constructed from several bits.

The determination result notification data D dc may be a signal constructed from information that can notify the other party of the movement determination result.
-A motion detection part is not limited to the acceleration sensor 20, It can change into other sensors, such as an inclination sensor.

The key operation free system may be such that when the electronic key 2 approaches the vehicle 1, the vehicle door is automatically unlocked, and when the electronic key 2 leaves the vehicle 1, the vehicle door is automatically locked.
-The key operation free system, for example, has transmitters on the right and left sides of the vehicle body, and determines the inside / outside determination of the electronic key 2 by checking the combination of responses of the electronic key 2 to the radio waves transmitted from these transmitters. You can do it. In this case, fewer transmitters are installed in the vehicle 1.

  -The key operation free system is not limited to the frequency of radio waves being different between the forward path and the return path, and may be the same. The frequency of the radio wave is not limited to LF or UHF, and can be changed to other frequencies.

The movement determination of the electronic key 2 is not limited to the determination when the electronic key 2 is located outside the vehicle, but may be the determination when the electronic key 2 is located inside the vehicle.
The determination method for confirming the correctness of the movement of the electronic key 2 is not limited to the technique described in the embodiment, and various techniques can be adopted as long as the correctness of the movement of the electronic key 2 can be determined. is there.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Electronic key, 20 ... Acceleration sensor as a motion detection part, 21 ... Acceleration determination part as a key movement correctness determination part, 22 ... Transmission control part, 23 ... Collation establishment permission determination part, Ddc ... Determination Result notification data.

Claims (6)

In a communication fraud prevention system for confirming the validity of communication performed at the time of ID verification when the electronic key ID is wirelessly transmitted from the electronic key to the vehicle triggered by communication from the vehicle and the ID of the electronic key is verified. ,
The electronic key is
Based on the detection signal of the motion detection unit capable of detecting the movement of the electronic key, a key movement validity determination unit that determines the validity of the movement of the electronic key;
A transmission control unit that wirelessly transmits a signal based on the determination result of the key movement determination unit to the vehicle;
The vehicle is
An unauthorized communication establishment prevention system comprising: a verification establishment permission determination unit that determines whether or not the ID verification establishment permission is permitted based on the signal received from the electronic key. The communication fraud establishment prevention system according to claim 1, wherein the electronic key encrypts the signal based on a determination result of the key movement determination unit and wirelessly transmits the signal to the vehicle. The system for preventing unauthorized establishment of communication according to claim 1 or 2, wherein the transmission control unit wirelessly transmits determination result notification data, which is a determination result of the key movement determination unit, from the electronic key to the vehicle. . The transmission control unit causes the vehicle to transmit an electronic key ID registered in the electronic key when it is determined that the movement of the electronic key is valid, and when the movement of the electronic key is determined to be inappropriate, 3. The unauthorized communication prevention system according to claim 1, wherein transmission of the electronic key ID is not executed. 5. The communication fraud prevention according to claim 1, wherein the motion detection unit is activated when the electronic key enters a communication area of the vehicle and receives a radio wave. system. 6. The communication fraud according to claim 1, wherein when the signal transmission from the electronic key to the vehicle is completed, the motion detection unit switches to a standby state in which the power is turned off. Establishment prevention system.