JP6507042B2 - Communication fraud establishment prevention system - Google Patents

Description

  The present invention relates to an unauthorized communication establishment prevention system which prevents an unauthorized communication establishment in ID collation communication.

  2. Description of the Related Art Conventionally, in a vehicle or the like, there is known an electronic key system in which an electronic key ID is wirelessly transmitted from the electronic key to the vehicle to perform ID verification. By the way, in this type of electronic key system, there is a case that fraudulent activity using repeaters (referring to fraudulent use of repeaters: refer to Patent Document 1 etc.) as fraudulent acts against persuading the establishment of ID collation regardless of the user's will is there. For example, when the electronic key is located at a location far from the vehicle, the relay use fraudulent act is to connect the electronic key to the vehicle by a plurality of relays, relay radio waves, and establish communication between these two parties. is there. Therefore, since ID collation is established where the user is not aware, there is a possibility that the third party may illegally unlock the door or start the engine.

JP, 2006-161545, A

  As measures against unauthorized communication using a relay, for example, a motion sensor (acceleration sensor) is provided on an electronic key, and there is one that permits establishment of ID collation only when vibration can be detected by the same sensor. . However, in the case of this measure, for example, if the electronic key stands still for a long time, ID collation will not be established, and it will not be possible to open the vehicle door or start the engine, thus the convenience There was a problem with

  An object of the present invention is to provide a communication fraud prevention system capable of detecting fraudulent communication by a method other than providing a motion sensor on an electronic key to detect the presence or absence of vibration.

In the communication fraud establishment prevention system which solves the above problem, when the electronic key ID is wirelessly transmitted from the electronic key to the communication party in response to the communication from the communication party and the electronic key ID is collated, A communication establishment determination unit configured to determine whether communication of the ID collation is established in order to confirm whether the electronic key has entered the communication area of ID collation in the configuration for judging whether the ID is correct or not; A distance measuring unit for measuring the distance between the communication partner and the object using a radar provided on the communication partner of the electronic key, a timing at which communication of the ID collation is established, and the distance measured by the distance measuring unit And a communication correctness judging unit which judges whether the communication of the ID collation is correct or not based on the timing when it is judged that the object has entered into the communication area of the ID collation.

  According to this configuration, the timing at which the electronic key enters the ID verification communication area and communication is established is compared with the timing at which it is determined that the object has entered the communication area from the radar measurement distance, and these are correlated. Sometimes, the communication partner and the electronic key communication are determined to be valid, and when they are not correlated, the communication is treated as unfair. Therefore, for example, when unauthorized communication is performed by a third party using a repeater, there is a high possibility that the correlation of these timings is broken, so it is determined that communication at this time is invalid, and establishment of ID collation is permitted. do not do. Therefore, it becomes possible to detect unauthorized communication by a method other than providing a motion sensor on the electronic key and detecting the presence or absence of vibration.

  In the communication fraud establishment prevention system, the communication correctness determining unit determines that the ID is immediately or sufficiently short after determining that the object is positioned within the communication area of the ID collation in the distance measurement by the radar. It is preferable to determine whether the communication is correct or not by confirming whether the verification communication is established. According to this configuration, if it is a legitimate user who possesses an electronic key, communication of ID collation should be established in a short time after the radar detects the entry of an object into the communication area. By monitoring the transition of this state, it is possible to determine the correctness of communication more correctly.

  In the communication fraud establishment prevention system, when the electronic key receives a wake signal periodically transmitted from the communication party, the ID collation transmits an ACK signal as a response to reception of the wake signal when the electronic key receives the wake signal. The communication is established by transmitting to the other party, and the verification is performed specifically after that, and the communication correctness determination unit determines that the object is within the communication area of the ID comparison in the distance measurement by the radar. When it is determined that the position is determined, whether the acknowledgment signal can be received from the electronic key in response to the first or several wake signals transmitted from the communication party is determined to determine whether the communication is correct or not. Is preferred. According to this configuration, it is determined whether the communication is correct or not by monitoring whether or not an acknowledgment to the first or a few wake signals can be received. By not performing the authentication of (1), it is possible to make the establishment of the ID collation impossible.

  In the communication fraud establishment prevention system, the communication correctness determining unit transmits the wake signal several times when it is determined that the object is located in the communication area of the ID collation in the distance measurement by the radar. It is preferable to ignore this and continue the determination even if a state in which the acknowledgment signal can not be received continues. According to this configuration, since the reception error of the wake signal is allowed, it is possible to prevent the communication from being determined as wasteful in spite of the establishment of the communication.

In the communication fraud establishment prevention system, the distance measuring unit senses the surroundings by transmitting radio waves at a constant cycle, continuously excludes a stationary object from the determination, and sets only a moving object as a determination target. Is preferred. According to this arrangement, upon monitoring an object in the radar, to exclude from the determination of the object to rest continuously, since only the moving object becomes possible to target the determination, the communication partner and the body of the electronic key It is advantageous to accurately detect the distance between As a result, it is also advantageous to accurately determine whether the ID collation communication is correct or not.

In the communication fraud establishment prevention system, preferably , when a plurality of objects are detected, the communication correctness determining unit performs the determination using information of the object having the highest correlation of the timing. According to this configuration, even if a plurality of objects approach the vehicle, it is possible to determine whether the communication is correct.

  According to the present invention, unauthorized communication can be detected by a method other than providing a motion sensor on an electronic key to detect the presence or absence of vibration.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the communication fraud establishment prevention system of one Embodiment. Communication area figure of LF electric wave formed in vehicles. Explanatory drawing which shows the relationship of the measurement area by radar, and the communication area figure of LF electromagnetic wave. Communication sequence at the time of normality by regular operation. The communication sequence diagram at the time of the fraud which used the repeater etc. FIG. Explanatory drawing which shows how to obtain | require the radar measurement distance of another example. The communication sequence diagram of another example.

Hereinafter, an embodiment of a communication fraud establishment prevention system will be described according to FIGS. 1 to 5.
As shown in FIG. 1, the vehicle 1 includes an electronic key 2 and an electronic key system 3 that performs ID verification wirelessly. In the electronic key 2, an electronic key ID is written and stored as an ID unique to the key. The electronic key system 3 of this example is a key operation free system that executes ID collation with the electronic key 2 through short range communication triggered by communication from the vehicle 1. Generally, ID verification implemented in a key operation free system is called "smart verification", and its communication is called "smart communication".

  The vehicle 1 includes a verification ECU (Electronic Control Unit) 4 that performs ID verification (smart verification), a body ECU 5 that manages power supply and drive of on-vehicle electrical components, and an engine ECU 6 that controls the engine 7. These ECUs are electrically connected through a communication line 8 in the vehicle. The communication line 8 is made of, for example, a controller area network (CAN) or a local interconnect network (LIN). In the collation ECU 4, the electronic key ID of the electronic key 2 registered in the vehicle 1 is written and stored in a memory (not shown). The vehicle 1 includes an outdoor transmitter 9 that transmits radio waves outside, an indoor transmitter 10 that transmits radio waves indoors, and a radio wave receiver 11 that receives radio waves in the vehicle 1. The outdoor transmitter 9 and the indoor transmitter 10 transmit radio waves in, for example, a low frequency (LF) band. The radio receiver 11 receives, for example, radio waves in the UHF (Ultra High Frequency) band. The electronic key 2 can receive LF radio waves and can transmit UHF radio waves. The body ECU 5 switches locking and unlocking of the vehicle door by controlling the operation of the door lock mechanism 12 provided on the vehicle door.

  The electronic key 2 includes a key control unit 15 that controls the operation of the electronic key 2, a receiving unit 16 that enables radio wave reception in the electronic key 2, and a transmitting unit 17 that enables radio wave transmission in the electronic key 2. . In the key control unit 15, an electronic key ID is written and stored in a memory (not shown) as an ID unique to the key. The receiving unit 16 receives, for example, LF radio waves. The transmitter 17 transmits, for example, UHF radio waves.

  When the electronic key 2 enters the communication area of the outdoor transmitter 9 and communication (smart communication outside the car) is established between the vehicle 1 and the electronic key 2, smart collation (smart collation outside the car) by two-way communication of LF-UHF It is started. The smart verification includes vehicle code verification for authenticating a unique vehicle code of the vehicle 1, challenge response authentication using an encryption key (authentication key), and electronic key ID verification for authenticating an electronic key ID. When the collation ECU 4 confirms that all of the collation and the authentication with the electronic key 2 located outside the vehicle are satisfied, the collation ECU 4 regards the smart collation outside the vehicle as a registration and permits or executes, for example, locking and unlocking of the vehicle door.

  When the electronic key 2 enters the communication area of the indoor transmitter 10 and communication (in-vehicle smart communication) is established, the verification ECU 4 executes the same smart verification (in-vehicle smart verification) as when outside the vehicle. When the verification ECU 4 confirms that in-vehicle smart verification is established, the verification ECU 4 permits the transition of the vehicle power supply by the operation of the engine switch (not shown).

  The electronic key system 3 includes a communication fraud establishment prevention function (communication fraud establishment prevention system 20) for preventing fraudulent establishment of communication (smart communication) of ID verification using a relay device by a third party, for example. The unauthorized communication establishment prevention system 20 of this example measures the distance Lx between the object and the radar 22 mounted on the communication partner 21 of the electronic key 2 (the radar measurement distance: see FIG. 3), and the distance Lx is ID verification At the timing when it comes within the range of the communication area Ea (see FIG. 2), whether the communication of ID collation is established or not is judged to determine whether the communication is correct or not.

  The unauthorized communication establishment prevention system 20 includes a communication establishment determination unit 25 that determines whether communication of ID verification (in this example, smart verification) has been established. The communication establishment determination unit 25 is provided in the verification ECU 4. The communication establishment determination unit 25 of this example monitors the ID signal communication area Ea by monitoring whether or not the ack signal Sack has been received from the electronic key 2 in response to the wake signal Swk transmitted from the vehicle 1 (see FIG. 2) check if the electronic key 2 has entered. The wake signal Swk is an LF radio wave periodically transmitted as a trigger for activating the electronic key 2 on standby. The acknowledgment signal Sack is a UHF radio wave for notifying the vehicle 1 that the electronic key 2 has been activated.

The unauthorized communication establishment prevention system 20 includes a radar 22 provided on the other party 21 of the electronic key 2 (in this example, the vehicle 1). The radar 22 is mounted, for example, in the vicinity of an outside door handle of a vehicle door, so that the distance to an object outside the vehicle can be measured. The radar 22 should preferably be capable of measuring the distance to an object, for example, 3 m or more, regardless of the method in particular. Examples of the radar 22 include millimeter wave radar, ultra wide band (UWB) radar, laser radar, ultrasonic sonar and the like. The radar 22 is preferably disposed in the vicinity of the outdoor transmitter 9 by being provided in the vicinity of the outside door handle.

  The unauthorized communication establishment prevention system 20 includes a distance measurement unit 26 that measures a distance (a radar measurement distance) Lx between the communication counterpart 21 and an object using the radar 22. The distance measurement unit 26 is provided in the verification ECU 4. The distance measuring unit 26 measures the distance Lx between the radar 22 and the object located outside the room (ie, the user who holds the electronic key 2) by transmitting radio waves to the outside. It is preferable that the distance measuring unit 26 senses the surroundings by transmitting radio waves at a constant cycle, excludes a continuously stationary object from the determination, and sets only a moving object as a target of the determination.

The communication fraud establishment prevention system 20 includes a communication correctness determination unit 27 that determines the correctness of the ID verification communication based on the timing at which the ID verification communication is established and the distance Lx measured by the radar 22. The communication correctness determination unit 27 is provided in the verification ECU 4. After determining that the object is located within the ID verification communication area Ea in the distance measurement by the radar 22, the communication correctness determination unit 27 determines whether or not the ID verification communication is established immediately or soon. It is preferable to determine whether the communication is correct or not. In this example, the communication propriety determining unit 27, when the radar measurement distance Lx is judged to have become the communication area Ea equivalent, with respect to the wake signal Swk from the communication partner 21 to first or several first transmitted, the electronic It is preferable to determine whether the communication is correct or not by confirming whether or not the acknowledgment signal Sack can be received from the key 2.

Next, the operation of the unauthorized communication prevention system 20 will be described with reference to FIGS.
As shown in FIG. 2, the verification ECU 4 transmits an LF radio wave of smart communication from the outdoor transmitter 9 at the execution timing of the smart verification to form a communication area Ea of the LF radio wave around the vehicle. Specifically, when the vehicle 1 is parked (door locking and engine stop), the outdoor transmitter 9 regularly or irregularly checks whether the electronic key 2 exists around the vehicle 1 or not. In the present embodiment, the LF band wake signal Swk is transmitted. The communication area Ea of the LF radio wave is, for example, a narrow area of about several meters from the vehicle 1.

  When the electronic key 2 enters the communication area Ea of the wake signal Swk, the electronic key 2 is activated by receiving the wake signal Swk, and transmits an acknowledgment signal Sack to the vehicle 1 by UHF. Thus, when smart communication is established between the vehicle 1 and the electronic key 2, the vehicle 1 and the electronic key 2 perform smart verification. At this time, when confirming that the acknowledgment signal Sack in response to the wake signal Swk has been received from the electronic key 2 at this time, the communication establishment determination portion 25 recognizes that the electronic key 2 has entered the smart verification communication area Ea.

  As shown in FIG. 3, for example, when the vehicle 1 is parked, the radar 22 senses an object in the vicinity of the vehicle by periodically searching the surroundings. Then, the distance measurement unit 26 identifies an object present around the vehicle 1 based on the detection signal input from the radar 22. When the distance measuring unit 26 continuously detects an object that is stationary, it may be recognized as a pillar or a parked vehicle next to the object, and may be excluded from the determination. The distance measuring unit 26 recognizes a moving object as a human body, and measures the distance Lx with the human body. The distance measurement by the radar 22 is performed at least once or more by executing a plurality of radio wave transmissions from the radar 22.

  By the way, the electronic key 2 is normally owned by a human (user) and should come closer to the vehicle 1 at the same time as the human. That is, the timing when it is determined that the radar measurement distance Lx has entered the ID collation (smart collation) communication area Ea, and the timing when the ID collation (smart collation) communication by LF-UHF communication is established (established). Should have a correlation. Therefore, the present example determines whether the ID verification communication is correct or not by confirming whether these timings match or approximate.

FIG. 4 illustrates the operation logic when determining whether the ID collation communication is correct. In the figure, "Hi" in the timing chart of object detection by radar 2 2 represents when there are people, "Lo" indicates the time no one. Further, in the timing chart of the wake signal Swk, “Hi” indicates that the same signal is being transmitted, and “Lo” indicates that the same signal is not being transmitted. Similarly, in the timing chart of the acknowledgment signal Sack, "Hi" indicates that the same signal is being transmitted, and "Lo" indicates that the same signal is not being transmitted.

  In the case of the present example, since a mere passerby is also a detection target of the radar 22, the vehicle 1 does not operate when communication of ID collation is not established although the object is detected by the radar 22. When the user carrying the electronic key 2 enters the communication area Ea of the wake signal Swk, the object detection by the radar 22 determines that the object has entered the communication area Ea from the radar measurement distance Lx.

  At this time, since it is assumed that a regular user approaches the vehicle 1, the electronic key 2 immediately returns an acknowledgment signal Sack to the wake signal Swk transmitted from the vehicle 1. Thus, the communication establishment determination unit 25 determines that the ID verification communication has been established (established). Note that, depending on the communication environment, it may be assumed that after the object is detected by the radar 22, a state in which the acknowledgment response to the wake signal Swk can not be received continues several times, so the acknowledgment response to the wake signal Swk can not be received. Even if the state continues several times, communication is accepted without being judged as invalid. The sufficiently short time after determining that the object is positioned in the communication area Ea mentioned above means a time in which the state in which the above-mentioned acknowledgment can not be received continues several times.

Communication propriety determining unit 27, when the radar measurement distance Lx is judged to have become the communication area Ea equivalent, with respect to the wake signal Swk from the communication partner 21 to first or several first transmitted, acknowledge signal from the electronic key 2 If the Sack can be received, the ID verification communication is permitted. As a result, the authentication of the ID verification after the receipt of the ack (challenge response authentication, electronic key ID verification, etc.) is continued, and the ID verification is shifted to establishment. As a result, since the vehicle door is unlocked when the outdoor door handle of the vehicle door is touch-operated, a regular user can shift to boarding without delay.

  As shown in FIG. 5, for example, when a plurality of third parties cooperate to illegally establish communication by a relay, a person who approaches the vehicle 1 although the electronic key 2 remains stopped. Should be detected by the radar 22 first. Therefore, there is a high possibility that the correlation between the timing when it is determined that the object has entered the communication area Ea by the radar 22 and the timing when the communication of the ID verification by the LF-UHF communication is actually established is broken. That is, an ack response is received by the n-th wake signal Swk after a while for a while after the object detection by the radar 22 has been performed.

When the communication correctness determination unit 27 determines that the object has entered the communication area Ea of the wake signal Swk by the object detection by the radar 22, the response of the ack signal Sack is received by the wake signal Swk up to the first or several times after detection. If it can not be received, the ID verification communication is invalidated. That is, even if it can be determined that there are people in by Ri communication area Ea radar 22, when can receive acknowledge signal Sack by n-th wake signal Swk is unjust communication ID verification. At this time, the authentication of the subsequent ID collation is not continued. Therefore, since it is not necessary for the third party to establish the ID collation improperly, security against unauthorized use of the vehicle 1 is secured.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) The electronic key 2 enters the ID verification (smart verification) communication area Ea and compares the timing when communication is established with the timing when it is determined from the radar measurement distance Lx that an object has entered the communication area Ea. When these are correlated, the ID collation communication is determined to be valid, and when they are not correlated, the communication is treated as unfair. For this reason, for example, when unauthorized communication using a relay device by a third party or the like is performed, there is a high possibility that the correlation of these timings is broken, so it is determined that communication at this time is invalid and establishment of ID collation is completed. not allowed. Therefore, unauthorized communication can be detected by a method other than providing a motion sensor on the electronic key 2 and detecting the presence or absence of vibration.

  (2) After the communication correctness determination unit 27 determines that the object is located within the ID collation (smart collation) communication area Ea in the distance measurement by the radar 22, the ID collation communication is performed immediately or for a sufficiently short time. It is determined whether the communication is correct or not by confirming whether or not to establish. Therefore, if it is an authorized user who possesses the electronic key 2, ID matching communication should be established without a lapse of time after the radar 22 detects the entry of an object into the communication area Ea. By monitoring the transition of the state, it is possible to determine the correctness of the communication more correctly.

  (3) When the communication correctness determination unit 27 determines that the object has entered the communication area Ea of the ID verification (smart verification) in the distance measurement by the radar 22, the first or several times (sufficiently short time) transmitted from the vehicle 1 It is determined whether the communication is correct or not by confirming whether or not the acknowledgment signal Sack can be received from the electronic key 2 in response to the wake signal Swk up to (d). Therefore, in the determination of whether the communication is correct or not in this example, when the communication is determined to be invalid, establishment of ID collation can not be performed, for example, by not performing subsequent authentication (challenge response authentication or electronic key ID collation). It can be done.

  (4) When the communication correctness determination unit 27 determines that the object is within the communication area Ea of ID verification (smart verification) in the distance measurement by the radar 22, the ack is transmitted although the wake signal Swk is transmitted several times. Even if the signal Sack can not be received, this determination is ignored and the determination is continued. Therefore, in the case of this example, since the reception error of the wake signal Swk is allowed, it is not necessary to make the communication uselessly determined to be invalid although the communication is established.

  (5) The distance measurement unit 26 senses the surroundings by transmitting radio waves at a constant cycle, continuously excludes the stationary object from the determination, and sets only the moving object as the determination target. Therefore, it is advantageous to accurately perform this when determining the distance to the human body. As a result, it is also advantageous to accurately determine whether the ID collation communication is correct or not.

The embodiment is not limited to the configuration described above, and may be changed to the following modes.
As shown in FIG. 6, the radar 22 is not limited to being disposed on the driver's side, and may be disposed on the passenger's side. In this case, the distance L1 (= L2−L3) outside the driver's seat may be measured by canceling the in-vehicle distance L3 from the distance L2 measured by the radar 22.

  As shown in FIG. 7, when a plurality of objects can be detected by the radar 22, information of the object having the highest timing correlation may be taken as an object of determination. Specifically, as shown in the figure, for example, when two persons approach the vehicle 1, the person approaching earlier does not have the electronic key 2, and the person approaching later has the electronic key 2. If two people can be measured by the radar 22, it may be determined that the correlation with the person approaching later is correct. In this way, even when a plurality of objects approach the vehicle 1, it is possible to determine whether the communication is correct.

The criterion for determining that the object has entered the communication area Ea by the radar 22 is not limited to the same as the communication area Ea, but may be a smaller value.
The radar 22 may be disposed at any position on the vehicle body.

An object sensing algorithm by the radar 22 is arbitrary as long as it can detect an object.
If the communication area Ea is formed around the vehicle, the number, the location, and the like can be changed as appropriate.

· Even if a predetermined radio wave (trigger) is wirelessly transmitted from the electronic key 2 and it is determined that communication has been established based on the fact that the electronic key 2 can receive the radio wave that the vehicle 1 responds to for this radio wave. Good.

  The determination of whether the communication is correct may be performed, for example, as a process of confirming whether or not ID verification (smart verification) can be completed. That is, the determination as to whether or not the ID verification communication is established can be appropriately changed to various modes as long as exchange of a predetermined radio wave can be confirmed between the vehicle 1 and the electronic key 2.

The radio waves used to determine the establishment of communication can be changed to radio waves of various frequencies.
The electronic key system 3 arranges LF antennas on the left and right of the vehicle body, for example, and checks the combination of responses from the electronic key 2 to radio waves transmitted from these antennas, thereby performing the internal / external determination of the electronic key 2 May be.

The specific authentication performed after establishment of communication is not limited to challenge response authentication or electronic key ID verification, but can be appropriately changed to other authentication or verification.
The communication unauthorizedness prevention system 20 may be used for in-vehicle smart verification communication as well as being applied to the out-of-vehicle smart verification communication.

The determination of whether the communication is correct or not may be performed not only on the side of the vehicle 1 but also on the side of the electronic key 2.
The electronic key 2 can be changed to another terminal such as a high-performance mobile phone.

  The communication partner 21 is not limited to the vehicle 1 and can be changed to another device or device.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle which is an example of a communicating party, 2 ... Electronic key, 20 ... Communication fraud establishment prevention system, 22 ... Radar, 25 ... Communication establishment determination part, 26 ... Distance measurement part, 27 ... Communication correctness determination part, Ea ... Communication Area, Lx ... distance (radar measurement distance), Swk ... wake signal, Sack ... ack signal.

Claims (6)

When the electronic key ID is wirelessly transmitted from the electronic key to the communication party triggered by the communication from the communication party and the electronic key ID is collated, in the communication fraud establishment prevention system, the correctness of the communication of ID collation is determined
A communication establishment determination unit that determines whether communication of the ID collation is established in order to confirm whether the electronic key has entered the communication area of ID collation;
A distance measuring unit that measures the distance between the communication partner and the object using a radar provided on the communication partner of the electronic key;
Based on the timing at which the ID verification communication is established and the timing at which it is determined from the distance measured by the distance measuring unit that the object has entered the ID verification communication area, whether the ID verification communication is correct or not A communication fraud establishment prevention system comprising: a communication correctness judging unit which judges the communication. Whether the communication of the ID collation is established immediately or for a sufficiently short time after the communication correctness judging unit judges that the object is located in the communication area of the ID collation in the distance measurement by the radar The system according to claim 1, wherein the communication correctness is determined by confirming whether the communication is correct or not. In the ID collation, when the electronic key receives a wake signal periodically transmitted from the communication party, the electronic key transmits an acknowledgment signal to the communication party as a response to the reception of the wake signal. A verification that is established and thereafter a specific authentication is performed,
When it is determined that the object is located within the communication area of the ID collation in the distance measurement by the radar, the communication correctness determination unit responds to the wake signal up to the first or several times transmitted from the communication partner, 3. The system according to claim 1, wherein the communication correctness is determined by confirming whether the acknowledgment signal can be received from the electronic key. When the communication correctness determination unit determines that the object is located within the communication area of the ID collation in the distance measurement by the radar, the ACK signal can not be received although the wake signal is transmitted several times. 4. The system according to claim 3, wherein the determination is continued by ignoring this, even if it continues. The distance measuring unit senses the surroundings by transmitting radio waves at a constant cycle, continuously excludes a stationary object from the determination, and sets only a moving object as a target of the determination. The communication fraud establishment prevention system according to any one of the above 4. The communication correctness determination unit performs the determination using information of an object having the highest correlation in timing when a plurality of objects are detected, according to any one of claims 1 to 5, Communication fraud establishment prevention system of statement.