JP2017218723A - Communication fraud enactment prevention system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication fraud enactment prevention system capable of accurately detecting fraud communication.SOLUTION: A transmission radio wave Sa is transmitted from a vehicle 1, and an electronic key 2 transmits a response radio wave Sb. The authenticity of the communication is determined by measuring delay time in the transmission and reception of the radio wave. The authenticity of the communication is determined while considering whether the communication uses altered carrier frequency by changing the carrier frequency of the radio wave at irregular timing when transmitting and receiving the radio wave for delay time estimation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a communication fraud establishment preventing system that prevents unauthorized communication establishment.

  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.

JP 2006-161545 A

In taking measures against unauthorized communication using a repeater, there was a need to reliably detect unauthorized communication.
An object of the present invention is to provide a communication fraud establishment preventing system capable of accurately detecting fraudulent communication.

  The communication fraud prevention system that solves the above problem receives the reply radio wave after transmitting the transmission radio wave by causing the terminal to receive the radio wave transmitted from the communication master and returning the reply radio wave from the terminal. A parameter setting unit for setting a parameter of a carrier wave in the reply radio wave or the transmission radio wave, and the received reply radio wave Alternatively, a correct / incorrect determination unit that determines whether the communication is correct by checking the parameter of the carrier wave in the transmission radio wave is provided.

  According to this configuration, in confirming the correctness of the communication by confirming the delay time of the radio wave transmitted and received between the communication master and the terminal, the carrier parameter of the return radio wave or the transmission radio wave is changed, and the carrier wave parameter of the transmission radio wave Whether communication is correct or not is determined based on the carrier parameter of the return radio wave. By the way, in the case of unauthorized communication using a repeater, there is no correlation between both carrier parameters, and it is possible to determine that the communication at this time is unauthorized communication using a repeater. Therefore, it is possible to detect unauthorized communication with high accuracy.

  In the communication fraud establishment prevention system, the process of measuring the delay time by transmitting and receiving radio waves between the communication master and the terminal is executed in a plurality of cycles, and the parameter setting unit has a cycle in a plurality of cycles. It is preferable to change the parameters of the carrier wave in the carrier wave. According to this configuration, since the carrier parameter of a predetermined cycle among the plurality of cycles is changed, it is possible to make it difficult to predict at which cycle the carrier parameter changes. Therefore, it is further advantageous to make it difficult to establish unauthorized communication.

  In the communication fraud prevention system, the communication master transmits the transmission radio wave at a plurality of carrier frequencies, and through communication for causing the terminal to return the reply radio waves having a plurality of carrier frequencies according to the radio waves, It is preferable to measure the delay time. According to this configuration, since a plurality of carrier frequencies are provided, it is more advantageous to detect unauthorized communication more correctly than when, for example, the carrier frequency is one.

  In the communication fraud prevention system, it is preferable that the parameter setting unit changes a carrier frequency in a carrier wave having a certain period when setting a carrier wave parameter. According to this configuration, it is possible to detect unauthorized communication with high accuracy by the process of changing the carrier frequency.

  In the communication improper establishment prevention system, it is preferable that the parameter setting unit changes a transmission order of carrier frequencies within one period in a carrier having a certain period when setting the carrier parameter. According to this configuration, it is possible to detect unauthorized communication with high accuracy by the process of changing the transmission order of the carrier frequency.

  In the communication fraud prevention system, the parameter setting unit preferably changes a combination of carrier frequencies within one period in a carrier having a certain period when setting the carrier parameter. According to this configuration, it is possible to detect unauthorized communication with high accuracy by the process of changing the combination of carrier frequencies.

  In the communication fraud prevention system, it is preferable that the parameter setting unit changes an amplitude ratio between carrier frequencies within one period in a carrier having a certain period when setting the carrier parameter. According to this configuration, it is possible to detect unauthorized communication with high accuracy by the process of changing the amplitude ratio between carrier frequencies.

  In the communication improper establishment prevention system, it is preferable that the parameter setting unit changes an initial phase of a carrier frequency in a carrier wave having a certain period when setting a carrier wave parameter. According to this configuration, it is possible to detect unauthorized communication with high accuracy by the process of changing the initial phase of the carrier frequency.

  In the communication improper establishment prevention system, it is preferable that the parameter setting unit changes a frequency interval of a carrier frequency within one period in a carrier having a certain period when setting the carrier parameter. According to this configuration, it is possible to detect unauthorized communication with high accuracy by the process of changing the frequency interval of the carrier frequency.

  In the communication fraud prevention system, it is preferable that the process of changing the carrier parameter to determine whether the communication is correct is executed a plurality of times. According to this configuration, the determination as to whether or not the communication is unauthorized is performed over a plurality of cycles, which is advantageous for more correctly detecting unauthorized communication.

  In the communication fraud prevention system, the carrier parameter setting is preferably performed on the terminal side. According to this configuration, since it is not necessary to provide the communication master with a function for changing the carrier parameter, the configuration of the communication master does not have to be complicated.

  In the communication fraud prevention system, the carrier parameter setting is preferably executed on the communication master side. According to this configuration, even in an unauthorized communication in which the transmission radio wave from the communication master is relayed by a repeater, even if an action that delays a time different from the actual delay time and establishes the communication illegally is performed. Can be detected as unauthorized communication. Therefore, it becomes more advantageous for prevention of unauthorized communication.

  According to the present invention, unauthorized communication can be detected with high accuracy.

The block diagram of the communication fraud establishment prevention system of 1st Embodiment. (A), (b) is explanatory drawing which shows the specific example of unauthorized communication. The communication sequence diagram of delay time estimation. The communication sequence figure of delay time estimation of 2nd Embodiment. The communication sequence figure of delay time estimation of 3rd Embodiment. The communication sequence figure of delay time estimation of 4th Embodiment. (A), (b) is a wave form diagram which shows the initial phase of the carrier frequency of 5th Embodiment. The communication sequence diagram of delay time estimation. The communication sequence figure of delay time estimation of 6th Embodiment. Explanatory drawing which shows the specific example of the unauthorized communication which uses a repeater. The block diagram of the communication fraud establishment prevention system of 7th Embodiment. The communication sequence diagram of delay time estimation.

(First embodiment)
Hereinafter, a first embodiment of a communication fraud establishment prevention system will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 includes an electronic key system 3 that performs wireless ID verification with the electronic key 2. The electronic key system 3 of this example is a key operation free system that implements ID collation with the electronic key 2 through narrow area communication triggered by communication from the vehicle 1. Generally, ID collation performed in a key operation free system is called “smart collation”, and the communication is called “smart communication”.

  The vehicle 1 includes a collation ECU (Electronic Control Unit) 4 that performs ID collation (smart collation), 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 ECUs are connected through a communication line 8 in the vehicle. The communication line 8 is composed of, for example, a CAN (Controller Area Network) or a LIN (Local Interconnect Network). In the verification ECU 4, the electronic key ID and the encryption key of the electronic key 2 registered in the vehicle 1 are written and stored in a memory (not shown). The encryption key is used in challenge response authentication performed in the process of ID verification.

  The vehicle 1 includes an outdoor transmitter 11 that transmits radio waves outdoors, an indoor transmitter 12 that transmits radio waves indoors, and a radio receiver 13 that receives radio waves in the vehicle 1. The outdoor transmitter 11 and the indoor transmitter 12 transmit, for example, radio waves in the LF (Low Frequency) band. The radio wave receiver 13 receives, for example, UHF (Ultra High Frequency) band radio waves. The electronic key system 3 authenticates the electronic key 2 by LF-UHF bidirectional communication. The body ECU 5 switches the locking and unlocking of the vehicle door by controlling the operation of the door lock mechanism 14 provided on the vehicle door.

  The electronic key 2 includes a key control unit 17 that controls the operation of the electronic key 2, a reception unit 18 that receives radio waves in the electronic key 2, and a transmission unit 19 that transmits radio waves in the electronic key 2. In the key control unit 17, an electronic key ID as an ID unique to the key and an encryption key used in challenge response authentication for ID verification are written and stored in a memory (not shown). The receiving unit 18 receives, for example, LF radio waves. The transmission unit 19 transmits, for example, UHF radio waves.

  The verification ECU 4 periodically LF-transmits the wake signal Swk from the outdoor transmitter 11 or the indoor transmitter 12 and monitors communication establishment with the electronic key 2. When the verification ECU 4 receives the ACK signal Sack from the electronic key 2 that has received the wake signal Swk, the verification ECU 4 executes specific verification communication. For the ID verification performed at the time of verification communication, for example, the electronic key ID verification for confirming whether the electronic key ID registered in the electronic key 2 is correct or the challenge code is calculated with the encryption key in both the vehicle 1 and the electronic key 2 It is preferable that challenge response authentication for confirming the response code is included.

  When the electronic key 2 is outdoors, outdoor smart verification is executed with the vehicle 1, and if the verification is established, locking and unlocking of the vehicle door by the body ECU 5 is permitted or executed. Also, when the electronic key 2 is indoors, indoor smart verification is executed with the vehicle 1, and if the verification is established, a vehicle power supply transition operation (engine start operation or the like) is permitted.

  The electronic key system 3 includes a communication fraud establishment prevention function (communication fraud establishment prevention system 22) that prevents unauthorized establishment of communication. The communication fraud establishment prevention system 22 of this example causes the terminal 24 (in this example, the electronic key 2) to receive the transmission radio wave Sa from the communication master 23 (in this example, the verification ECU 4), and responds to the transmission radio wave Sa from the terminal 24. The reply radio wave Sb is returned. Then, the communication fraud establishment prevention system 22 measures a delay time Tx from when the transmission radio wave Sa is transmitted until the return radio wave Sb is received, and delay time estimation for determining whether the communication between the two parties is correct from the delay time Tx. To determine whether the communication is correct or not. Thus, the communication fraud establishment prevention system 22 of this example performs delay time estimation by a half-duplex method in which radio waves are alternately transmitted between the communication master 23 and the terminal 24. The delay time Tx corresponds to the propagation time from when the radio wave is transmitted from the vehicle 1 until the response of the electronic key 2 to the radio wave is received. The communication fraud establishment prevention system 22 determines whether or not the ID verification communication is correct by confirming whether or not the delay time Tx falls within the specified time. In addition, it is preferable that the process which transmits / receives an electromagnetic wave between the communication master 23 and the terminal 24, and measures delay time Tx is implemented in multiple times.

  The communication fraud establishment prevention system 22 includes a parameter setting unit 26 that sets a parameter of a carrier wave in the return radio wave Sb or the transmission radio wave. In this example, the carrier wave parameter setting is executed on the terminal 24 (electronic key 2 in this example) side. For this reason, the parameter setting unit 26 is provided in the key control unit 17 and sets a carrier wave parameter of the reply radio wave Sb transmitted from the electronic key 2 to the vehicle 1.

  The communication fraud prevention system 22 of this example sets the carrier parameter based on the timing information St that is data indicating which transmission pattern the carrier parameter is set to. That is, the carrier parameter determination method is shared in advance by both the communication master 23 and the terminal 24, and it is confirmed whether or not the radio wave transmitted from the other party takes a regular pattern. In this case, the communication master 23 (in this example, the verification ECU 4) is provided with an information notification unit 27 that notifies the terminal 24 of the timing information St. The timing information St may be any information that can notify the transmission pattern of the carrier wave parameter to the other party.

  The communication fraud establishment prevention system 22 includes a correctness determination unit 28 that determines the correctness of communication by confirming the parameter of the carrier wave in the received return radio wave Sb or the transmitted radio wave Sa. The correctness determination unit 28 of this example is provided in the verification ECU 4. The correctness determination unit 28 determines whether communication is correct by performing delay time estimation for confirming whether the delay time Tx falls within the specified time and carrier parameter authentication for confirming the carrier parameter of the return radio wave Sb received from the electronic key 2. Determine. In addition, the communication master 23 performs ID verification for confirming whether the ID (electronic key ID) registered in the terminal 24 (electronic key 2) is correct, delay time estimation, and carrier wave parameter authentication, all of which are established. If it is confirmed, communication establishment is permitted.

Next, the operation and effect of the communication fraud establishment prevention system 22 will be described with reference to FIGS. 2 and 3.
As illustrated in the flow from FIG. 2A to FIG. 2B, as an example in which a third party illegally establishes ID verification communication, for example, a third party possesses a repeater 29, There is an act of illegally establishing communication with the electronic key 2 possessed by the user. In this case, for example, after the radio wave from the vehicle 1 is relayed to the electronic key 2 through the repeater 29 and the verification communication between the vehicle 1 and the electronic key 2 is established, even if the authorized user leaves the vehicle 1, the delay When the time Tx is estimated, there is a case where the third party sends the radio wave back by the repeater 29, and the smart verification is illegally established. This example is a countermeasure for preventing this unauthorized communication.

  As shown in FIG. 3, in the case of this example, in performing smart communication, the verification ECU 4 periodically transmits a wake signal Swk. When the electronic key 2 is activated by receiving the wake signal Swk, the electronic key 2 transmits the ack signal Sack by UHF. When the verification ECU 4 receives the ACK signal Sack within a specified time after transmitting the wake signal Swk, the verification ECU 4 starts verification communication for confirming whether the electronic key 2 is correct.

  The verification ECU 4 first performs challenge response authentication as verification communication. At this time, the verification ECU 4 transmits to the electronic key 2 a challenge signal Sch including a challenge code (random number) whose value changes every time it is transmitted. Upon receiving the challenge signal Sch, the electronic key 2 calculates a response code by passing the challenge code through its own encryption key. When the verification ECU 4 transmits the challenge signal Sch to the electronic key 2, it itself calculates the response code. When the verification ECU 4 receives the response code from the electronic key 2, the verification ECU 4 compares the response code with its own response code to confirm whether the response code is correct. When the verification ECU 4 confirms that these response codes match, the verification ECU 4 processes challenge response authentication as established.

  After the challenge response authentication is established, the verification ECU 4 also executes delay time estimation. In the case of this example, timing information St, which is data indicating which parameter (carrier parameter) is used to return the carrier wave of the reply radio wave Sb used for delay time estimation, is notified to the other party, and the reply radio wave Sb is based on this timing information St. Set the carrier parameter of. In particular, this example is a method in which the timing information St is transmitted from the communication master 23 to the terminal 24 in advance to the other party, and the carrier wave parameter of the return radio wave Sb is determined.

  Further, in estimating the delay time, the communication master 23 of the present example transmits the transmission radio wave Sa at a plurality of carrier frequencies, and through communication that causes the terminal 24 to return a reply radio wave Sb having a plurality of carrier frequencies according to the radio waves. The delay time Tx is measured. The process of transmitting and receiving radio waves between the communication master 23 and the terminal 24 and measuring the delay time Tx is executed in a plurality of cycles. Then, the parameter setting unit 26 of this example changes the parameter of the carrier wave in a carrier wave of a certain period (second period in this example) among a plurality of periods. The carrier parameter in this example is a carrier frequency.

  After the challenge response authentication is established, the information notification unit 27 transmits the timing information St related to the carrier wave parameter of the return radio wave Sb from the outdoor transmitter 11 by LF. The timing information St of this example designates the carrier frequency of the return radio wave Sb in the first cycle as “f1, f2, f3”, and sets the carrier frequency of the return radio wave Sb in the second cycle to “f1 ′, f2 ′”. , F3 ′ ”. Thereby, the carrier wave parameter of the return radio wave Sb is set by the timing information St notified from the verification ECU 4 to the electronic key 2.

  After transmitting the timing information St, the verification ECU 4 LF-transmits a transmission radio wave Sa for estimating the delay time from the outdoor transmitter 11 to the electronic key 2. The transmission radio wave Sa may be a radio wave including any information as long as it can instruct the electronic key 2 to transmit the return radio wave Sb. When receiving the transmission radio wave Sa, the electronic key 2 sends a reply radio wave Sb from the transmission unit 19 to the vehicle 1 as a response to the transmission radio wave Sa. At this time, the parameter setting unit 26 transmits the return radio wave Sb with a carrier wave pattern determined from the timing information St.

  In this example, since it is instructed to transmit the reply radio wave Sb at the carrier frequency “f1, f2, f3” in the first period, the electronic key 2 sends the reply radio wave Sb to the carrier frequency “f1, f2, f3”. f3 "is transmitted simultaneously.

  When the verification ECU 4 receives the reply radio wave Sb in the first cycle from the electronic key 2, the verification ECU 4 measures the delay time Tx required from the transmission radio wave Sa to the reception of the reply radio wave Sb in the first cycle. The verification ECU 4 may measure the delay time Tx using, for example, a counter provided in the verification ECU 4.

  Further, the correctness determination unit 28 confirms the carrier frequency of the received reply electric wave Sb in the first cycle. That is, since the reply radio wave Sb in the first cycle is determined to be transmitted with the carrier frequency “f1, f2, f3”, the carrier wave frequency of the received reply radio wave Sb is “f1, f2, f3”. Check if it exists. If the correctness determination unit 28 can confirm that the reply radio wave Sb in the first cycle is returned at the designated carrier frequency, the communication is continued and the reply radio wave Sb in the first cycle is not sent back at the designated carrier frequency. If it is confirmed, the communication is forcibly terminated. Here, since valid communication is assumed, the return radio wave Sb is returned at the regular carrier frequency, and the process shifts to radio wave transmission / reception in the second cycle.

  Subsequently, the verification ECU 4 transmits again the transmission radio wave Sa for estimating the delay time in the second period. The electronic key 2 performs an operation of returning a response of the reply radio wave Sb when the transmission radio wave Sa is received. In this example, the reply radio wave Sb in the second cycle has a carrier frequency of “f1 ′, f2 ′, f3 ′”. The electronic key 2 transmits the reply radio wave Sb at the same time with the carrier frequencies “f1 ′, f2 ′, f3 ′”.

  When the verification ECU 4 receives the reply radio wave Sb in the second cycle from the electronic key 2, the verification ECU 4 measures the delay time Tx required from the transmission radio wave Sa to the reception of the reply radio wave Sb in the second cycle.

  Further, the correctness determination unit 28 confirms the carrier frequency of the received reply electric wave Sb in the second period. That is, since the reply radio wave Sb in the second cycle is determined so that the carrier wave frequencies are transmitted with “f1 ′, f2 ′, f3 ′”, the carrier frequency “f1 ′, It is confirmed that the reply is made with “f2 ′, f3 ′”. If the correctness determination unit 28 can confirm that the reply radio wave Sb in the second cycle is returned at the designated carrier frequency, the communication is continued and the reply radio wave Sb in the second cycle is not sent back at the designated carrier frequency. If it is confirmed, the communication is forcibly terminated. Here, since valid communication is assumed, the return radio wave Sb is returned at the regular carrier frequency, and the process shifts to radio wave transmission / reception in the third cycle.

  The electronic key 2 and the verification ECU 4 repeat the same radio wave transmission / reception after the third period, and perform delay time estimation and carrier frequency determination. If the verification ECU 4 can confirm that the delay time Tx is within the determination threshold value (specified time) in all received reply radio waves Sb, the verification ECU 4 establishes the delay time estimation. In addition, when the verification ECU 4 confirms that the carrier wave frequency of the return radio wave Sb takes a prescribed change according to the timing information St, the carrier wave frequency determination is established.

  When the verification ECU 4 confirms that challenge response authentication, electronic key ID verification, delay time estimation, and carrier frequency determination are all established, the verification ECU 4 establishes smart verification. As a result, the verification ECU 4 permits the operation of the vehicle 1. That is, if smart verification is established with the electronic key 2 outside the vehicle, the locking / unlocking operation of the vehicle door is permitted or executed. If smart verification is established with the electronic key 2 in the vehicle, a vehicle power supply transition operation (engine start operation) is permitted.

  By the way, if the smart verification communication is illegally established using the repeater 29, the repeater 29 can transmit and receive data, but the carrier frequency is switched along the pattern based on the timing information St. Can not be sent to. That is, the repeater 29 simply sends the transmission radio wave Sa received from the vehicle 1 back to the vehicle 1 as it is. For this reason, in the case of unauthorized communication using the repeater 29, carrier frequency determination is not established, and establishment of smart verification is not permitted. Therefore, it is possible to prevent unauthorized communication from being established using the repeater 29 by a third party.

  The process of transmitting and receiving radio waves between the communication master 23 and the terminal 24, that is, between the vehicle 1 and the electronic key 2 and measuring the delay time Tx is executed in a plurality of cycles. Then, the parameter setting unit 26 changes the parameter of the carrier wave in the carrier wave having a certain period among the plurality of periods. This makes it difficult to predict at which period the carrier parameter changes. Therefore, it is further advantageous to make it difficult to establish unauthorized communication.

  The communication master 23 (verification ECU 4) transmits the transmission radio wave Sa at a plurality of carrier frequencies, and through communication for returning a reply radio wave Sb having a plurality of carrier frequencies according to the radio waves to the terminal 24 (electronic key 2). The delay time Tx is measured. Therefore, for example, it is more advantageous to detect unauthorized communication more correctly than when the carrier frequency is one.

  The carrier parameter setting is executed on the terminal 24 (electronic key 2) side. Therefore, since it is not necessary to provide the communication master 23 (verification ECU 4) with a function for changing the carrier wave parameter, the configuration of the communication master 23 does not have to be complicated.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. In addition, 2nd Embodiment is an Example which changed the carrier wave pattern of 1st Embodiment. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different parts are described in detail.

  As shown in FIG. 4, the carrier parameter of this example is the transmission order of the carrier frequency of the return radio wave Sb. That is, in the communication process of delay time estimation, the carrier frequency transmission order is changed at irregular timings. The timing information St of this example designates the carrier frequency of the return radio wave Sb in the first cycle as “f1, f2, f3”, and sets the carrier frequency of the return radio wave Sb in the second cycle as “f1, f3, f2”. It is an information group to specify.

  In this example, since it is instructed to transmit the reply radio wave Sb at the carrier frequency “f1, f2, f3” in the first period, the electronic key 2 sends the reply radio wave Sb to the carrier frequency “f1, f2, f3”. The data is sequentially transmitted at “f3”. That is, the reply radio wave Sb is initially transmitted with the carrier frequency “f1”, the carrier frequency is switched to “f2” in the middle, and the carrier frequency is switched to “f3”. Subsequently, the electronic key 2 appropriately transmits the return radio wave Sb to the vehicle 1 in the subsequent transmission cycles in the carrier frequency according to the timing information St in each cycle.

  Here, if the smart collation is a valid communication, the transmission order of the carrier wave frequencies matches a predetermined pattern, so that establishment of the smart collation is permitted. On the other hand, in the case of unauthorized communication using the repeater 29, the transmission order of the carrier frequency of the return radio wave Sb does not match the determined pattern, and the establishment of smart verification is not permitted. Therefore, after the data from the vehicle 1 is relayed to the electronic key 2 and authentication is established, the act of returning the radio wave received from the vehicle 1 to the vehicle 1 as it is when the delay time is estimated (FIGS. 2A and 2B). It is possible to determine that this communication uses the repeater 29 against the attack pattern indicated by ().

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. Also in this example, only different portions from the first and second embodiments will be described in detail.

  As shown in FIG. 5, the carrier parameter in this example is a combination of carrier frequencies transmitted simultaneously. That is, in the communication process of delay time estimation, a method of changing the combination of simultaneously transmitted carrier frequencies at irregular timing. In this example, selectable carrier frequencies are f1 to f4, and two frequencies are selected and combined. In the timing information St of this example, the combination of the carrier frequencies of the reply radio wave Sb in the first cycle is designated as “f1, f2”, and the combination of the carrier frequencies of the reply radio waves Sb in the second cycle is designated as “f1, f4”. It becomes information group to do.

  After transmitting the timing information St, the verification ECU 4 LF-transmits a transmission radio wave Sa for estimating the delay time from the outdoor transmitter 11 to the electronic key 2. The transmission radio wave Sa in the first cycle in this example is a radio wave having carrier frequencies “f1, f2”. When the electronic key 2 receives the transmission radio wave Sa in the first cycle, the electronic key 2 transmits a reply radio wave Sb according to the timing information St from the transmission unit 19 to the vehicle 1 as a response to the transmission radio wave Sa.

  In this example, since it is instructed to transmit the reply radio wave Sb at the carrier frequency “f1, f2” in the first period, the electronic key 2 sequentially sends the reply radio wave Sb at the carrier frequency “f1, f2”. Send. That is, the reply radio wave Sb is initially transmitted with the carrier frequency “f1”, and the carrier frequency is switched to “f2” during transmission.

  Subsequently, the verification ECU 4 transmits again the transmission radio wave Sa for estimating the delay time in the second period. The transmission radio wave Sa in the second period of this example has a carrier frequency of “f3, f4”. This is to notify the electronic key 2 that the values of the carrier frequency that are the options at the time of radio wave reply are “f3” and “f4”. However, if the electronic key 2 knows the values of f3 and f4 in advance, the carrier wave frequency of the transmission radio wave Sa may be “f1, f2”.

  In the case of this example, since the reply radio wave Sb in the second cycle is instructed to be transmitted with the combination of carrier frequencies “f1, f4”, the electronic key 2 sends the reply radio wave Sb to the transmission frequency “f1, f4”. ”In combination. That is, the reply radio wave Sb is initially transmitted with the carrier frequency “f1”, and the carrier frequency is switched to “f4” during transmission. Then, the electronic key 2 appropriately transmits the return radio wave Sb to the vehicle 1 with the combination pattern of the carrier frequency in accordance with the timing information St in each subsequent period.

  Here, if the smart collation is valid communication, the combination of carrier frequencies matches a predetermined pattern, so that smart collation is permitted. On the other hand, in the case of unauthorized communication using the repeater 29, the combination of the carrier wave frequencies of the return radio wave Sb does not match a predetermined pattern, and establishment of smart verification is not permitted. Therefore, it is possible to determine that this communication uses the repeater 29 against the attack patterns shown in FIGS.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG. In this example, only different parts from the first to third embodiments will be described in detail.

  As shown in FIG. 6, the carrier parameter in this example is an amplitude ratio between carrier frequencies. That is, in the communication process of delay time estimation, the amplitude ratio between carrier frequencies is changed at irregular timing. The timing information St of this example designates the amplitude ratio between the carrier frequencies of the reply radio wave Sb in the first cycle as “1: 1: 2”, and sets the amplitude ratio between the carrier waves of the reply radio wave Sb in the second cycle as “ The information group is designated as “1: 2: 1”.

  In the case of this example, the electronic key 2 sends the return radio wave Sb to the vehicle 1 with the amplitude ratio of the carrier frequencies f1, f2, and f3 set to “1: 1: 2” in the first period during communication for delay time estimation. Send. In addition, the electronic key 2 transmits a reply radio wave Sb to the vehicle 1 with the amplitude ratio of the carrier frequencies f1, f2, and f3 set to “1: 2: 1” in the second period during communication for delay time estimation. That is, in the second period, the amplitude ratio between carrier frequencies is switched from “1: 1: 2” to “1: 2: 1”. The electronic key 2 appropriately transmits the return radio wave Sb to the vehicle 1 in an amplitude ratio pattern according to the timing information St in each subsequent period.

  Here, if the smart collation is valid communication, the amplitude ratio between the carrier frequencies matches the predetermined pattern, so that establishment of the smart collation is permitted. On the other hand, in the case of unauthorized communication using the repeater 29, the amplitude ratio between the carrier frequencies of the return radio wave Sb does not match a predetermined pattern, and establishment of smart verification is not permitted. Therefore, it is possible to determine that this communication uses the repeater 29 against the attack patterns shown in FIGS.

  By the way, in the case of this example, an amplitude ratio pattern is shared in advance by the timing information St between the vehicle 1 and the electronic key 2, and the electronic key 2 changes the amplitude based on the amplitude ratio pattern and returns a radio wave to the vehicle 1. Sb is sent back. Since the vehicle 1 knows that the return radio wave Sb is transmitted with the shared amplitude ratio pattern, the amplitude ratio obtained from the electronic key 2 is corrected based on the information of the shared amplitude ratio pattern. Thus, the delay time Tx is obtained. At this time, the correct delay time Tx cannot be obtained unless the amplitude is corrected accurately.

  Based on this concept, for example, when the attack pattern shown in FIGS. 2A and 2B is performed, the vehicle 1 assumes that the return radio wave Sb is transmitted from the electronic key 2 with the shared amplitude ratio pattern. Then, correction is performed based on the information of the shared amplitude ratio pattern. However, since the amplitude of the radio wave received by the vehicle 1 does not fluctuate during unauthorized communication, correct correction is not performed and the accurate delay time Tx is not estimated. Therefore, since the obtained delay time Tx is different from the actual distance time, it can be determined that the communication is invalid as a result.

  In the case of this example, the operation of measuring the delay time Tx by changing the amplitude ratio pattern of the carrier frequency may be performed a plurality of times. That is, in addition to performing delay time estimation by changing the amplitude ratio between carrier frequencies from “1: 1: 2” to “1: 2: 1”, the amplitude ratio is further changed to “2: 1: 1”. Alternatively, the delay time may be estimated. In this way, all delay times Tx should be equal in the case of regular communication. On the other hand, when the repeater 29 simply sends back the radio wave from the vehicle 1 as in the attack patterns shown in FIGS. 2A and 2B, the obtained delay times Tx are all different values. Thus, unauthorized communication can be detected.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS. In this example, only different parts from the first to third embodiments will be described in detail.

  As shown in FIGS. 7A and 7B, the carrier parameter in this example is the initial phase of the carrier frequency. Changing the initial phase includes an example of switching the initial phase φ1 in FIG. 7A to the initial phase φ2. This example is a method of changing the initial phase of the carrier frequency of the return radio wave Sb at irregular timings in the communication process of delay time estimation. In the timing information St of this example, the initial phases of the carrier frequencies f1, f2, and f3 in the return radio wave Sb in the first cycle are designated as “φ1, φ1, φ1”, and the carrier frequency f1 in the return radio wave Sb in the second cycle. , F2 and f3 are information groups designating “φ1, φ1, φ2”.

  As shown in FIG. 8, the electronic key 2 sets the initial phases of the carrier frequencies f1, f2, and f3 to “φ1, φ1, φ1” in the first period during communication for delay time estimation, and sends a return radio wave Sb to the vehicle. 1 to send. In addition, the electronic key 2 transmits a reply radio wave Sb to the vehicle 1 with the initial phases of the carrier frequencies f1, f2, and f3 set to “φ1, φ1, φ2” in the second period during delay time estimation communication. That is, the initial phase of the carrier frequency f3 is switched from “φ1” to “φ2” in the second period. Then, the electronic key 2 appropriately transmits a return radio wave Sb to the vehicle 1 with an initial phase pattern in accordance with the timing information St in each subsequent period.

  Here, if the smart verification is valid communication, each initial phase of the carrier wave frequency matches a predetermined pattern, so that establishment of smart verification is permitted. On the other hand, in the case of unauthorized communication using the repeater 29, the initial phase of the carrier wave frequency of the return radio wave Sb does not match a predetermined pattern, and establishment of smart verification is not permitted. Therefore, it is possible to determine that this communication uses the repeater 29 against the attack patterns shown in FIGS.

  When the attack patterns shown in FIGS. 2A and 2B are performed, the vehicle 1 is shared on the assumption that the return radio wave Sb is transmitted from the electronic key 2 with the shared initial phase pattern. Correction is performed based on the information of the initial phase pattern. However, since the initial phase of the radio wave received by the vehicle 1 does not fluctuate during unauthorized communication, correct correction is not performed and the accurate delay time Tx is not estimated. Therefore, since the obtained delay time Tx is different from the actual distance time, it can be determined that the communication is invalid as a result. Further, if the operation of measuring the delay time Tx by changing the initial phase pattern of the carrier frequency is performed a plurality of times, it is advantageous for detecting unauthorized communication more correctly.

(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIGS. In this example, only different parts from the first to third embodiments will be described in detail.

  As shown in FIG. 9, the carrier parameter in this example is a frequency interval Δf of the carrier frequency. The frequency interval Δf of the carrier frequency is, for example, an interval between “f1” and “f2” in the return radio wave Sb and an interval between “f2” and “f3” in the return radio wave Sb, and these are the same value. Is set. The timing information St of this example is an information group in which the frequency interval Δf in the first cycle is designated as Δfa and the frequency interval Δf in the second cycle is designated as Δfb.

  The electronic key 2 transmits a reply radio wave Sb in which the frequency interval Δf of the carrier frequency is “Δfa” to the vehicle 1 in the first period during communication for delay time estimation. Further, the electronic key 2 transmits the reply radio wave Sb to the vehicle 1 by switching the frequency interval Δf of the carrier frequency to “Δfb” in the second period during the communication of the delay time estimation. That is, the frequency interval Δf of the carrier frequency is switched from “Δfa” to “Δfb” in the second period. Then, the electronic key 2 appropriately transmits the return radio wave Sb to the vehicle 1 with a frequency interval pattern of the carrier frequency in accordance with the timing information St in each subsequent period.

  Here, if the smart collation is valid communication, since the frequency interval Δf of the carrier frequency matches a predetermined pattern, establishment of the smart collation is permitted. On the other hand, in the case of unauthorized communication using the repeater 29, the frequency interval Δf of the carrier wave frequency of the return radio wave Sb does not match a predetermined pattern, and establishment of smart verification is not permitted. Therefore, it is possible to determine that this communication uses the repeater 29 against the attack patterns shown in FIGS.

  By the way, as shown in FIG. 10, in the unauthorized communication in which the transmission radio wave Sa from the vehicle 1 is relayed by the repeater 29, there is an act of delaying a time different from the actual delay time Tx and establishing the communication illegally. is assumed. This is an attack that uses the periodicity of delay time estimation (repetition of estimable delay time Tk), and is a characteristic that occurs when a method of calculating based on the phase of the frequency is used when calculating the delay time estimation. It is.

  In the case of this example, when the frequency interval Δf of the carrier frequency changes, the estimated delay time Tx also changes. Therefore, the operation of measuring the delay time Tx by switching the frequency interval Δf of the carrier frequency is executed a plurality of times. At this time, if the smart communication is regular communication, since the distance between the vehicle 1 and the electronic key 2 is short, the same delay time Tx can be obtained even if the carrier frequency changes. On the other hand, in an unauthorized communication using the repeater 29, when an action for estimating a time different from the actual time is performed, the delay time Tx of the calculation result takes a different value, so that it can be determined as an unauthorized communication. .

(Seventh embodiment)
Next, a seventh embodiment will be described with reference to FIGS. In this example, the carrier frequency parameter setting (carrier wave parameter change) of the carrier frequency is switched on the communication master 23 side (vehicle 1 side). Therefore, only the parts different from the first to sixth embodiments will be described in detail.

  As shown in FIG. 11, the parameter setting unit 26 of this example is provided not in the terminal 24 but in the communication master 23 (collation ECU 4). Thus, in this example, the carrier wave parameter of the transmission radio wave Sa is changed. Further, when the electronic key 2 receives the transmission radio wave Sa in which the carrier wave parameter is set on the vehicle 1 side, the electronic key 2 sends it back to the vehicle 1 as a return radio wave Sb as it is. That is, a response radio wave Sb conforming to the transmission radio wave Sa transmitted from the vehicle 1 side is sent back to the electronic key 2 and communication correctness is determined on the vehicle 1 side that changes the carrier parameter.

  When the parameter of the carrier wave (carrier wave of the transmission radio wave Sa) is changed on the vehicle 1 side, a method of changing the frequency interval Δf of the carrier wave frequency (example of the sixth embodiment) may be employed. In this case, even if an attack that delays a time different from the actual delay time Tx as shown in FIG. 10 and establishes communication illegally can be determined as unauthorized communication.

  Moreover, when changing the parameter of the carrier wave (the carrier wave of the transmission radio wave Sa) on the vehicle 1 side, a method of changing the amplitude ratio between the carrier wave frequencies (example of the fourth embodiment) may be employed. By the way, as shown in FIG. 12, in the unauthorized communication in which the transmission radio wave Sa from the vehicle 1 is relayed by the repeater 29, there is an act of delaying a time different from the actual delay time Tx and establishing the communication illegally. Suppose it was done. Here, when the vehicle 1 receives the return radio wave Sb with the carrier parameter “pattern 1” in the second cycle, it is after the transmission radio wave Sa with the carrier parameter “pattern 2” is transmitted, so “pattern 2”. The amplitude is corrected by the carrier wave parameter. However, since the reply radio wave Sb received by the vehicle 1 in the second cycle has an amplitude ratio between the carrier frequencies of “Pattern 1”, the reply is made with the transmission radio wave Sa of “Pattern 2” transmitted in the second cycle. When the amplitude ratio of the radio wave Sb is corrected, the delay time Tx cannot be obtained with an accurate value. Therefore, it can be determined that the communication is illegal.

  Furthermore, when the parameter of the carrier wave (the carrier wave of the transmission radio wave Sa) is changed on the vehicle 1 side, a method of performing the operation of measuring the delay time Tx by changing the amplitude ratio pattern of the carrier wave frequency (fourth implementation) Example of form) may be adopted. Thus, even if an unauthorized communication as shown in FIG. 10 is attempted, the obtained delay time Tx becomes a different value every time, so that it can be determined that the communication is unauthorized.

  Moreover, when changing the parameter of the carrier wave (carrier wave of the transmission radio wave Sa) on the vehicle 1 side, a method of changing the initial phase of the carrier wave frequency (example of the fifth embodiment) may be employed. In this case, the operation of measuring the delay time Tx by changing the initial phase of the carrier frequency may be performed a plurality of times. In any case, when unauthorized communication as shown in FIG. 10 is attempted, this communication can be determined as unauthorized.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
In each embodiment, a part of the response code may be expressed by a combination of “do not change” and “change” the carrier frequency parameter. Specifically, the response code consists of a combination of binary information of “0” and “1”. For example, the response code can be set by setting “do not change” to “0” and “change” to “1”. It is also possible to perform delay time estimation and carrier parameter authentication using a part of the code.

In the sixth embodiment, the frequency interval between f1 and f2 and the frequency interval between f2 and f3 are the same, but they may be different values.
In each embodiment, the reply radio wave Sb preferably has the same data content as the transmission radio wave Sa.

-In each embodiment, the data transmission / reception at the time of delay time estimation may be implemented at any timing at the time of communication of ID collation.
In each embodiment, the determination of whether or not unauthorized communication is performed is not limited to being performed on the vehicle 1 side, and may be performed on the electronic key 2 side. In this case, the correctness determination unit 28 is provided in the electronic key 2.

In each embodiment, the change of the carrier wave parameter may be performed in any cycle among a plurality of cycles.
In each embodiment, the number of carrier frequencies in one cycle is not limited to three as in the embodiment, but may be two or four or more.

-In each embodiment, the electronic key system 3 is not limited to the system which performs smart communication, It is good also as a system using another communication format and frequency.
In each embodiment, the timing information St may be notified from the electronic key 2 to the vehicle 1.

In each embodiment, the terminal 24 can be changed to a terminal other than the electronic key 2 (for example, a high function mobile phone).
-In each embodiment, the communication master 23 can apply controllers other than collation ECU4.

-In each embodiment, the communication fraud establishment prevention system 22 of this example is not limited to being applied to the vehicle 1 but may be applied to other devices and apparatuses.
In each embodiment, the communication fraud prevention system 22 is not limited to the half-duplex method and may perform communication using the full-duplex method.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Electronic key which is an example of terminal, 4 ... Vehicle which is an example of communication master, 22 ... Communication fraud establishment prevention system, 23 ... Communication master, 24 ... Terminal, 26 ... Parameter setting part, 28 ... Correct / incorrect Determining section, Sa: Transmission radio wave, Sb: Reply radio wave, Tx: Delay time, f1-f4: Carrier frequency, f1′-f3 ′: Carrier frequency, φ1, φ2: Initial phase, Δf: Frequency interval.

Claims (12)

By causing the terminal to receive a transmission radio wave from the communication master and returning a reply radio wave from the terminal, a delay time from when the transmission radio wave is transmitted to when the reply radio wave is received is measured. In the communication fraud establishment prevention system that judges whether communication between the parties is correct or not,
A parameter setting unit for setting a parameter of a carrier wave in the reply radio wave or the transmission radio wave;
A communication fraud establishment prevention system comprising: a correct / incorrect determination unit that determines whether communication is correct by confirming the parameter of the carrier wave in the received return radio wave or transmission radio wave. The process of transmitting and receiving radio waves between the communication master and the terminal and measuring the delay time is executed in a plurality of cycles,
The communication fraud prevention system according to claim 1, wherein the parameter setting unit changes a parameter of the carrier wave in a certain period of a plurality of periods. 2. The communication master transmits the transmission radio wave at a plurality of carrier frequencies and measures the delay time through communication for returning the reply radio wave having a plurality of carrier frequencies according to the radio waves to the terminal. Or the communication fraud establishment prevention system of 2 or 2. The said parameter setting part is a communication fraud establishment prevention system of Claim 3 which changes a carrier wave frequency in the carrier wave of a certain period in the setting of a carrier wave parameter. The said parameter setting part is a communication fraud establishment prevention system of Claim 3 which changes the transmission order of the carrier wave frequency within 1 period in the carrier wave of a certain period in the setting of a carrier wave parameter. The said parameter setting part is a communication fraud establishment prevention system of Claim 3 which changes the combination of the carrier frequency within 1 period in the carrier wave of a certain period in the setting of a carrier wave parameter. The said parameter setting part is a communication fraud establishment prevention system of Claim 3 which changes the amplitude ratio of the carrier wave frequencies in 1 period in the carrier wave of a certain period in the setting of a carrier wave parameter. The said parameter setting part is a communication fraud establishment prevention system of Claim 3 which changes the initial phase of a carrier wave frequency in the carrier wave of a certain period in the setting of a carrier wave parameter. The said parameter setting part is a communication fraud establishment prevention system of Claim 3 which changes the frequency interval of the carrier wave frequency in 1 period in the carrier wave of a certain period in the setting of a carrier wave parameter. The communication fraud prevention system according to any one of claims 1 to 9, wherein the process of changing the carrier parameter to determine whether communication is correct or not is executed a plurality of times. The communication fraud prevention system according to any one of claims 1 to 10, wherein the setting of the carrier wave parameter is executed on a terminal side. The communication fraud prevention system according to any one of claims 1 to 10, wherein the setting of the carrier wave parameter is executed on a communication master side.