JP2011111845A - Electronic key system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further improve security in an electronic key system. <P>SOLUTION: An electronic key 10 receives common code signals transmitted from an on-vehicle apparatus 20 when locking. In the next communication, the electronic key 10 extracts part of the common code signals received in the past several communications and includes accumulation codes comprising part of the extracted portion, in a response signal to carry out transmission. The on-vehicle apparatus 20 determines, through accumulation code collation, whether at least part of the common code signals transmitted in the past several communications is included in the received response signal. The on-vehicle apparatus 20 carries out various control with the establishment of accumulation code collation as one of conditions. The identification of the electronic key 10 is thus determined to prevent control of the on-vehicle apparatus 20 by an illegal means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic key system that enables control of a control target through wireless communication.

  Conventionally, in an electronic key system for a vehicle, when an ID code verification and a response code verification are established through transmission / reception of various signals between the electronic key and an in-vehicle device mounted on the vehicle, The engine can be started. Specifically, the same ID code and encryption key are stored in the electronic key and the in-vehicle device. And according to the request signal transmitted from the vehicle-mounted device, the electronic key transmits a response signal including the ID code. The in-vehicle device collates the ID code included in the received response signal with the ID code stored in itself.

  The request signal transmitted from the in-vehicle device includes a challenge code. The electronic key generates a response code by encrypting the challenge code included in the received request signal using the encryption key stored in the electronic key. The electronic key transmits the response code together with the ID code in the response signal. The in-vehicle device transmits a request signal including the challenge code as described above, and generates a response code using the encryption key stored by itself. Then, the in-vehicle device collates the response code included in the received response signal with the response code generated by itself. Thus, the vehicle-mounted device can improve the security of the electronic key system by performing ID code verification and response code verification with the electronic key (see, for example, Patent Document 1).

JP 2008-127894 A

  By the way, with the recent development of communication technology, there is a possibility that the request signal and the response signal are intercepted by a third party and the ID code is illegally acquired. Further, for example, the encryption key may be decrypted due to theft of the encryption key or the like. Thereby, when a response code is illegally generated and a response signal including the response code and the ID code is transmitted to the in-vehicle device, there is a concern that the vehicle door is illegally unlocked. Such a problem may occur not only in a vehicle electronic key system but also in a residential electronic key system, for example. Under such circumstances, it has been desired to further improve the security against the illegal means described above.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an electronic key system with further improved security.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to the first aspect of the present invention, the electronic key carried by the user communicates with the control device by transmitting a response signal in response to a request signal from the control device that controls a specific control target. In the electronic key system in which the control device executes control of the control target when the communication is established, the control device performs the next communication with the electronic key to be communicated this time when communicating with the electronic key. A common code signal for confirming whether or not the electronic key to be communicated is the same is transmitted to the electronic key, and the electronic key is received at the time of the next communication at the time of the previous communication. Transmitting a wireless signal including at least a part of a code signal, and the control device determines that the received wireless signal includes at least a part of the common code signal transmitted in a previous communication. When, the previous and current of the electronic key to determine that the same, and its gist to perform the control of the control target.

  According to this configuration, the electronic key receives the common code signal transmitted from the control device during the previous communication. In the next communication, the electronic key transmits a wireless signal including at least a part of the common code signal received in the previous communication. The control device determines whether or not the received radio signal includes at least a part of the common code signal transmitted during the previous communication. When it is determined that the received radio signal includes at least a part of the common code signal transmitted during the previous communication, the control device executes control of the control target. On the other hand, when the control device determines that the received wireless signal does not include at least a part of the common code signal transmitted during the previous communication, the electronic key used in the previous communication and the next communication is The control target is not executed assuming that they are not the same. Specifically, in this case, there is a possibility that the response signal is transmitted by an unauthorized means in the next communication, not from an authorized electronic key. As described above, the identity of the electronic key used for the previous communication and the current communication is ensured, thereby preventing the control target from being controlled by the unauthorized means. Thereby, the security of the electronic key system can be improved.

  According to a second aspect of the present invention, in the electronic key system according to the first aspect, the electronic key uses at least a part of the common code signals for the past predetermined number of times received before the previous communication as the radio signal. When the control device determines that the received wireless signal includes at least a part of the common code signal for the past predetermined number of times transmitted before the previous communication, the control device The gist is to execute the control of the object.

  According to this configuration, the electronic key transmits a wireless signal including at least part of each common code signal of the past predetermined number of times before the previous communication. Specifically, when it is determined that the wireless signal includes at least a part of each common code signal of the past predetermined times transmitted before the previous communication, the identity of the electronic key is guaranteed. Thereby, even if the common code signal is intercepted during the previous communication, the same signal as the wireless signal cannot be illegally generated. Therefore, the controlled object is not controlled through the control device illegally. As described above, it is possible to guarantee the identity between the electronic key used in the current communication and the electronic key used in the previous communication as well as the previous communication. As a result, the security of the electronic key system can be further improved.

  According to a third aspect of the present invention, in the electronic key system according to the first or second aspect, the control target is a door lock device, and the control device executes a door locking control through the door lock device. In addition, the gist is to transmit the common code signal.

  According to this configuration, a common code signal is transmitted from the control device to the electronic key when the door is locked. In other words, because the standard for judging the identity of the electronic key is updated in preparation for the next communication by sending a common code signal when the door is locked, the updated judgment standard is used for the communication related to unlocking the next door. Thus, the identity of the electronic key is determined. Here, if the identity of the electronic key is guaranteed when the door is unlocked, the possibility of unauthorized communication after that is low before the door is unlocked. This is because, for example, when the control device is a vehicle or a house, unauthorized communication is performed mainly when the user leaves the vehicle or the house, that is, when the door is locked. As described above, by updating the determination criterion at the time of locking, the identity of the electronic key is determined based on the updated determination criterion at the time of communication related to unlocking in which unauthorized communication is easily performed. Therefore, transmission of the common code signal at the time of unlocking the door can be omitted while securing the security of the electronic key system.

  According to the present invention, security can be further improved in an electronic key system.

The block diagram of an electronic key system. Timing chart of various signals. The block diagram of the common code and the accumulation code before and after the update.

Hereinafter, an embodiment embodying an electronic key system according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the electronic key system 1 includes an electronic key 10 possessed by a driver of the vehicle 2 and an in-vehicle device 20 mounted on the vehicle 2. Mutual communication is automatically performed between the electronic key 10 and the vehicle-mounted device 20, and the door lock can be locked and unlocked and the engine can be started on the condition that the mutual communication is established outside and inside the vehicle.

<In-vehicle device>
The in-vehicle device 20 includes a computer unit including a CPU, a ROM, a RAM, and the like. As illustrated in FIG. 1, the in-vehicle device 20 includes an in-vehicle control unit 21 that controls various in-vehicle devices, an in-vehicle transmission unit 22, an in-vehicle transmission unit 23, and an in-vehicle reception unit 24 that are electrically connected to the in-vehicle control unit 21. And.

  As shown in FIG. 1, the in-vehicle control unit 21 includes an engine switch 33 that is operated when the engine is started, a door lock device 34 that automatically locks and unlocks the vehicle door, and an engine that starts the engine of the vehicle 2. A control device 35, a door handle sensor 32 that is provided on an outside door handle (not shown) and detects whether or not the user touches the door handle, and a lock switch 36 that is also provided on the door handle and is operated during locking. And are electrically connected.

  The outside transmission unit 22 is provided, for example, inside the door handle. When the request signal is input from the in-vehicle control unit 21, the vehicle exterior transmission unit 22 modulates the request signal into an LF band radio signal, and the modulated request signal is transmitted to the vehicle exterior transmission antenna 22a at a constant intermittent period. To the outside communication area set around the vehicle 2.

  The in-vehicle transmission unit 23 is provided in the vehicle, and when a request signal is input from the in-vehicle control unit 21, the request signal is modulated into an LF-band radio signal, and the modulated request signal is transmitted at a constant intermittent period. Then, the signal is transmitted to the in-vehicle communication area set in the vehicle via the in-vehicle transmission antenna 23a.

  When receiving the response signal transmitted from the electronic key 10 via the receiving antenna 24 a, the in-vehicle receiving unit 24 demodulates this signal into a pulse signal and outputs the demodulated response signal to the in-vehicle control unit 21.

  The in-vehicle control unit 21 includes, for example, a non-volatile memory 21a composed of an EEPROM or the like, and the same ID code as the ID code set in the corresponding electronic key 10 and a number of common codes to be described later are listed in the memory 21a. A common code group consisting of data to be processed, an encryption key used for calculating a response code, and a storage code updated based on a common code signal to be described later are stored.

  The in-vehicle control unit 21 intermittently outputs request signals to the outside transmission unit 22 and the in-vehicle transmission unit 23 at different timings. The in-vehicle control unit 21 receives the response signal transmitted from the electronic key 10 in response to the request signal through the in-vehicle receiving unit 24.

  This response signal includes an ID code, an accumulation code, and a response code. Here, the storage code is a code updated based on the common code signal Sco transmitted from the in-vehicle device 20 every time the vehicle door is locked. The storage code is updated by the electronic key 10 and the in-vehicle device 20, respectively. The accumulation code and the common code signal Sco will be described later in detail.

  The in-vehicle controller 21 collates the ID code included in the response signal with the ID code stored in the memory 21a, and updates the stored code included in the response signal and the stored code stored in the memory 21a. Perform the verification. When both verifications are established, the in-vehicle control unit 21 determines whether the response signal transmitted from the electronic key 10 is a response to the request signal transmitted from the in-vehicle transmission unit 22 or the in-vehicle transmission unit 23. Then, it is determined whether the outside verification or the in-vehicle verification is established. Note that performing the above-described collation with the electronic key 10 existing outside the vehicle via the vehicle outside transmission unit 22 is called vehicle outside verification, and between the electronic key 10 existing inside the vehicle via the vehicle inside transmission unit 23. Performing both the above verifications is called in-vehicle verification.

  When vehicle exterior verification is established in the locked state of the vehicle door, the in-vehicle control unit 21 sets the vehicle door unlockable state. In this unlockable state, the vehicle-mounted control unit 21 unlocks the vehicle door via the door lock device 34 when detecting that the user has touched the door handle (not shown) through the door handle sensor 32.

  When vehicle exterior verification is established in the unlocked state of the vehicle door, the in-vehicle control unit 21 locks the vehicle door via the door lock device 34 when detecting the operation of the lock switch 36 provided on the door handle. When the locked state is actually detected through the door lock device 34, the in-vehicle control unit 21 selects one of the common code groups stored in the memory 21a at random, and the common code including the selected common code. The signal Sco is transmitted to the outside communication area via the outside transmission unit 22. Moreover, the vehicle-mounted control part 21 updates an accumulation code based on the selected common code. The method for updating the storage code will be described in detail later.

  Further, when the in-vehicle verification is established, the engine is allowed to start. In this state, when the engine switch 33 installed in the vicinity of the driver's seat is operated, the operation signal is output to the in-vehicle control unit 21. The vehicle-mounted control unit 21 outputs a command signal to the engine control device 35 when detecting the operation signal in the engine start permission state. Based on the command signal, the engine control device 35 drives a cell motor (not shown) to start the engine.

<Electronic key>
The electronic key 10 has a wireless communication function, and controls various in-vehicle devices through mutual communication with the in-vehicle device 20. The electronic key 10 includes an electronic key control unit 11 configured by a computer unit including a CPU, a ROM, a RAM, and the like, and an LF reception unit that is electrically connected to the electronic key control unit 11 and receives an LF band radio signal. 12 and a UHF transmitter 13 for transmitting a radio signal in the UHF band.

  When the LF receiver 12 receives the request signal and the common code signal Sco which are LF band radio signals transmitted from the in-vehicle device 20, the LF receiver 12 demodulates the request signal and the common code signal Sco into a pulse signal, and demodulates the signal. A signal is output to the electronic key control unit 11. The electronic key control unit 11 extracts a part of the common code included in the demodulated common code signal Sco, and updates the accumulated code based on the extracted code. In this way, every time the common code signal Sco is received, the accumulated code is updated, and the updated accumulated code is stored in the memory 11a.

  The electronic key control unit 11 is provided with a non-volatile memory 11a made of, for example, an EEPROM. The memory 11a stores the storage code, an ID code unique to the electronic key 10, and an encryption key used for encrypting the challenge code. When the demodulated request signal is input from the LF receiver 12, the electronic key controller 11 reads the received data and sends a response signal including the ID code and storage code registered in the memory 11 a to the UHF transmitter 13. Output. And the electronic key 10 transmits the response signal which is a radio signal of a UHF band to the vehicle 2 side via the UHF transmission part 13. As described above, when vehicle interior verification and vehicle exterior verification based on the response signal are established on the vehicle side, the vehicle door can be locked and unlocked and the engine can be started.

Next, a request signal, a response signal, and a common code signal Sco transmitted / received between the in-vehicle device 20 and the electronic key 10 will be described in detail with an example of locking a vehicle door.
Here, each of the request signal and the response signal is not a single signal but a plurality of signals. That is, as shown in FIG. 2, the request signal includes a wake signal Swk, a vehicle ID signal Svi, and a challenge signal Scc, and the response signal includes an ack signal Sac and a response signal Sre. The request signal described above mainly corresponds to the challenge signal Scc, and the response signal mainly corresponds to the response signal Sre.

  Hereinafter, the case of outside-vehicle verification accompanying getting off will be described. When the vehicle door is unlocked, the in-vehicle control unit 21 sends a wake signal Swk from the outside transmission antenna 22a to check whether the electronic key 10 exists in the outside communication area, as shown in the upper part of FIG. Transmit intermittently. The wake signal Swk is a command signal that activates the electronic key 10 in a standby state, and is repeatedly transmitted from the outside transmission antenna 22a at regular intervals.

  When the electronic key 10 enters the outside communication area and receives the wake signal Swk, the electronic key 10 is switched from the standby state to the activated state in response to the reception. If the electronic key 10 is normally activated at this time, the electronic key 10 returns an ACK signal Sac to the vehicle 2 to notify the fact.

  When receiving the ACK signal Sac, the in-vehicle control unit 21 determines that the electronic key 10 exists in the outside communication area. Then, the in-vehicle control unit 21 transmits a vehicle ID signal Svi so that the electronic key 10 can identify the vehicle 2 via the outside transmission unit 22.

  When receiving the vehicle ID signal Svi, the electronic key 10 determines whether or not the vehicle 2 is a legitimate vehicle corresponding to itself through vehicle ID verification that checks whether or not the vehicle ID signal Svi is a normal code. Make a decision. In this way, by performing vehicle ID verification, even if there are a plurality of vehicles around the electronic key 10 and the wake signal Swk is received from the plurality of vehicles, the key is only a regular vehicle and the vehicle. Communication after ID verification can be performed.

  As shown in FIG. 2, when the electronic key 10 recognizes that the vehicle ID verification has been established, the electronic key 10 returns an ACK signal Sac to the vehicle 2 to notify the fact. When the vehicle-mounted control unit 21 receives the ACK signal Sac normally after transmitting the vehicle ID signal Svi, the vehicle-mounted control unit 21 recognizes that the vehicle ID verification has been established with the electronic key 10, and the electronic key 10 existing in the outside communication area. Recognizes that it is paired with itself.

  Thereafter, the in-vehicle control unit 21 causes the challenge signal Scc to be transmitted from the outside transmission antenna 22a. The challenge signal Scc includes a challenge code used as a random number and a key number of the electronic key 10 registered on the vehicle 2 side.

  When the electronic key 10 receives the challenge signal Scc from the vehicle 2, the electronic key 10 compares the key number received at this time with the key number registered in itself to determine whether or not it is a communication target. To do.

  The electronic key 10 returns a response signal Sre to the vehicle 2 side when it is determined that the electronic key 10 is a communication target through this number verification. The response signal Sre is a signal including an ID code, an accumulation code, and a response code stored in the memory 11a. The response code is a code obtained by encrypting the challenge code using the encryption key. The stored code is updated based on the common code signal Sco transmitted from the in-vehicle device 20 for each lock.

  Specifically, the same storage code is stored in advance in both memories 11a and 21a. Here, as shown in the middle part of FIG. 3, the accumulation code is composed of 8 bits A to H. As shown in the upper part of FIG. 3, the electronic key control unit 11 extracts bits I and J that are part of the common code signal Sco received through the LF receiving unit 12 for each lock. In this example, the bits I and J, which are the fourth and fifth bits of the 8-bit signal, are extracted. As shown in the lower part of FIG. 3, the bits C to H of the accumulation code are shifted to the left by 2 bits. Specifically, bits C to H are written in the first to sixth bits. Further, the extracted bits I and J are set to the seventh and eighth bits of the stored code. That is, bit I is written in the seventh bit, and bit J is written in the eighth bit. As a result, the common code is updated from bits A to H to bits C to J. At the next lock, the fourth and fifth bits of the common code are extracted in the same manner as described above, and the stored code is shifted to the left by two bits, and these extracted bits are converted to the seventh and eighth bits. Set. In this way, the accumulated code is updated for each lock, and the accumulated code is stored in the memory 11a for each update. Incidentally, when unlocking or when in-vehicle verification is established, the accumulated code is not updated, but the accumulated code updated at the previous locking is used for communication.

  When receiving the response signal Sre, the in-vehicle control unit 21 performs ID verification, response code verification, and accumulated code verification. Specifically, the vehicle-mounted control unit 21 compares the ID code included in the response signal Sre with the ID code stored in the memory 21a to perform ID verification. Further, when the in-vehicle control unit 21 transmits the challenge signal Scc, the in-vehicle control unit 21 also updates the response code by encrypting the challenge code with its own encryption key. When the in-vehicle control unit 21 receives the response signal Sre from the electronic key 10 by the in-vehicle receiving unit 24, the in-vehicle control unit 21 compares the response code from the electronic key 10 with the response code calculated by itself, and executes response code verification. To do.

  Furthermore, the vehicle-mounted control unit 21 updates the accumulated code every time the common code signal Sco is transmitted. The method for updating the stored code is the same as that performed by the electronic key control unit 11. That is, as shown in FIG. 3, the in-vehicle control unit 21 extracts the 4th and 5th bits of the code every time the common code signal Sco is transmitted, and shifts the stored code stored in the memory 21a by 2 bits. After that, the extracted bits are written into the 7th and 8th bits of the storage code, and the storage code is updated. The updated accumulation code is stored in the memory 21a. Then, the in-vehicle controller 21 compares the storage code included in the response signal Sre with the storage code that has been updated by itself, and executes storage code collation. In other words, the in-vehicle control unit 21 determines whether or not a part of the common code signal Sco for the past four times is included in the stored code through the stored code verification. That is, when the stored code collation is established, it is possible to determine that the electronic key 10 that has performed communication four times in the past and the electronic key 10 that has performed communication this time are the same.

  And if the vehicle-mounted control part 21 judges that all of response code collation, ID code collation, and accumulation | storage code collation were materialized, it will process as that vehicle exterior collation was materialized by this. As described above, in the vehicle door unlocked state, the vehicle-mounted control unit 21 detects that the lock switch 36 provided on the door handle has been operated when the vehicle exterior verification is established, and thus the vehicle door via the door lock device 34. Lock. The vehicle-mounted control unit 21 transmits the common code signal Sco when the locked state is actually detected through the door lock device 34 (time t1 in FIG. 2). Here, the common code signal Sco is not transmitted when unlocking or in-vehicle verification is established. The common code signal Sco is randomly selected from the common code group stored in the memory 21a. The electronic key control unit 11 receives the common code signal Sco through the LF receiving unit 12. Then, as described above, the electronic key control unit 11 updates the stored code based on the common code.

  As described above, since the stored code is updated for each lock, the security of the electronic key system 1 can be improved. Specifically, since the stored code is not encrypted, it may be analyzed by interception. Furthermore, for example, when the ID code and the encryption key are stolen by unauthorized means, there is a possibility that the response signal Sre is transmitted. However, the accumulation code included in the response signal Sre is updated for each lock. Therefore, even if the response signal Sre is transmitted by unauthorized means, the stored code verification is not established due to the update of the stored code at the time of locking, so that locking and unlocking can be prevented. Therefore, the security of the electronic key system 1 can be improved. In this way, by updating the storage code at the time of locking, the sameness between the electronic key 10 used for communication at the time of locking and the electronic key 10 used for communication at the next unlocking is guaranteed.

  In addition, there is a high possibility that a signal is intercepted during communication between the vehicle 2 and the electronic key 10. The timing at which unauthorized communication is performed based on the intercepted signal is usually when the user is away from the vehicle. Here, before the user leaves the vehicle, in order to lock the vehicle door, the common code signal Sco is transmitted and the accumulated code is updated. Therefore, when the user leaves the vehicle, the storage code is different from the storage code included in the intercepted signal. As described above, the stored code is updated at the time of locking, so that the number of times of updating the stored code can be minimized while maintaining the security of the electronic key system 1.

  In addition to ID code verification and response code verification, stored code verification is performed. Therefore, the encryption level required for response code verification can be lowered while improving the overall security as compared with the case where only conventional ID code verification and response code verification are performed. Thereby, the processing burden of encryption related to response code verification can be reduced. Therefore, the communication processing between the in-vehicle device 20 and the electronic key 10 can be speeded up, and the encryption processing capability required for the electronic key control unit 11 and the in-vehicle control unit 21 can be reduced.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) The electronic key 10 receives the common code signal Sco transmitted from the in-vehicle device 20 at the time of locking. In the next communication, the electronic key 10 extracts a part of the common code signal Sco received during the past several times (four times in this example), and the stored code including the extracted part is used as a response signal. It is included in Sre and transmitted. The in-vehicle device 20 determines whether or not the received response signal Sre includes a part of the common code signal Sco transmitted at the past several times of communication through accumulated code verification. The on-vehicle device 20 is based on the condition that when the stored code verification is established, that is, it is determined that the received response signal Sre includes a part of each common code signal Sco transmitted during the past several communications. Execute control. On the other hand, when the in-vehicle device 20 determines that the stored code verification is not established, that is, when the response signal Sre does not include a part of each common code signal Sco transmitted during the past several times of communication, Since the electronic key 10 provided is not the same as the electronic key 10 used for the past several communications, the control is not executed. Specifically, in this case, there is a possibility that the signal is transmitted by an unauthorized means instead of the regular electronic key 10. In this way, by determining the identity of the electronic key 10, the control of the in-vehicle device 20 by the unauthorized means is prevented. Thereby, the security of the electronic key system 1 can be improved.

  (2) The electronic key 10 transmits a storage code including a part of the common code signal Sco for the past several times in the response signal Sre. Therefore, the common code included in the response signal Sre corresponds to the common code signal Sco for the past several times transmitted from the in-vehicle device 20 before the previous communication. Specifically, when it is determined that the response signal Sre includes a part of each common code signal Sco for a predetermined number of times transmitted before the previous communication, the identity of the electronic key is guaranteed. As a result, even if the common code signal Sco of the previous communication is intercepted, the vehicle door can be unlocked through the vehicle-mounted device 20 by unauthorized means unless the previous common code signal Sco is intercepted. It will never be done. That is, it is possible to determine the identity between the electronic key 10 used in the current communication and the electronic key 10 used in the previous communication as well as the previous communication. Thereby, the security of the electronic key system 1 can be further improved.

  (3) When the common code signal Sco is transmitted from the in-vehicle device 20 to the electronic key 10 when the door is locked, the response signal Sre including a part of the common code signal Sco is transmitted to the in-vehicle device 20 in the next communication. . Specifically, a part of the common code signal Sco is reflected (updated) in the accumulated code, the accumulated code is added to the response signal Sre, and the response signal Sre is transmitted. That is, since the determination criterion (accumulation code) of the electronic key 10 by the in-vehicle device 20 is updated in preparation for the next communication when the door is locked, the determination criterion updated at the time of communication related to the next door unlocking The identity of the electronic key 10 is determined by (accumulation code). Here, if the identity of the electronic key 10 is guaranteed when the door is unlocked, the possibility of unauthorized communication after that is low before the door is locked. This is because the unauthorized communication is mainly performed when the user leaves the vehicle, that is, when the vehicle door is locked. In this way, by updating the determination criterion at the time of locking, the identity of the electronic key 10 is determined based on the updated determination criterion at the time of communication related to unlocking in which unauthorized communication is easily performed. Therefore, while ensuring the security of the electronic key system 1, for example, transmission of the common code signal Sco and update of the stored code at the time of unlocking the door can be omitted.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, the electronic key system 1 using the dedicated electronic key 10 is used, but an electronic key system using a mobile phone may be used. In recent years, for example, introduction of a system capable of transmitting information such as a key ID to a mobile phone by e-mail or the like has been studied. In this system, a signal including the key ID is transmitted between the mobile phone having the key ID information and the vehicle, and the vehicle door can be unlocked. At this time, similar to the above embodiment, the common code signal Sco is transmitted from the vehicle to the mobile phone. Therefore, even when the key ID of the mobile phone is stolen illegally, since the stored code verification based on the common code signal Sco is not established, unauthorized unlocking can be prevented.

  In the above embodiment, 2 bits are extracted from the common code, but the number of extracted bits is not limited to this. For example, 1 bit or 3 bits or more may be extracted and written in the storage code. When writing, the stored code is shifted to the left by the number of extracted bits. When increasing the number of bits to be extracted, it is preferable to increase the number of bits of the stored code. Further, all bits of the common code signal Sco may be included in the accumulated code. In this case, it is preferable to increase the number of bits of the accumulated code or decrease the number of bits of the common code signal Sco.

  In the above embodiment, the fourth bit and the fifth bit of the common code are extracted, but the bit position to be extracted is not limited to this. For example, the first bit and the second bit may be extracted.

  In the above embodiment, the accumulation code is 8 bits, but the number of bits of the accumulation code is not limited to this. As the number of bits of the stored code increases, the bits included in the common code signal Sco at the previous locking time are reflected in the stored code, so that the security can be further improved.

  In the above embodiment, the common code signal Sco for the past four times is reflected in the accumulated code. However, if at least the previous common code signal Sco is reflected in the accumulated code, an illegal vehicle door solution by interception is obtained. Lock can be prevented. This is because the previous common code signal Sco cannot be known retroactively by interception. Specifically, for example, in the common code, all 8 bits are extracted and written as an accumulation code. Thereby, only the common code signal Sco transmitted at the time of locking is used for the next stored code collation.

  In the above embodiment, the accumulated code is configured by arranging the extracted bits A to H in order. However, the arrangement order of the extracted bits is not limited to this. In this case, it is necessary to arrange the arrangement order between the electronic key 10 and the in-vehicle device 20 in advance. Thereby, the security of the electronic key system 1 can be further improved.

  In the above embodiment, the common code signal Sco is transmitted at the time of locking, but the timing of transmission of the common code signal Sco is not limited to the time of locking. For example, the common code signal Sco may be transmitted when the in-vehicle verification and the external verification are established. In this case, since the stored code is updated more frequently, the security of the electronic key system 1 can be further improved. Further, the frequency of updating the accumulation code may be lowered. For example, the storage code may be updated once every two times during locking. In this case, it is necessary to negotiate the update frequency of the stored code between the in-vehicle device 20 and the electronic key 10 in advance.

  In the above-described embodiment, the identity of the electronic key 10 used for communication is determined through the verification of the stored code updated for each lock. However, the identity of the electronic key 10 can be determined without relying on the stored code. For example, the in-vehicle control unit 21 stores the common code signal Sco transmitted by itself in the memory 21a when the common code signal Sco is transmitted. Then, the in-vehicle controller 21 determines whether or not the response signal Sre from the electronic key 10 includes a part of the common code signal Sco transmitted by itself. As a result, the identity of the electronic key 10 used in the previous and current communications can be determined. Moreover, the vehicle-mounted control part 21 memorize | stores the common code signal Sco which self transmitted for past several times in the memory 21a, and a part of each common code signal Sco transmitted in the past is included in the received response signal Sre. It may be determined whether or not This makes it possible to determine the identity between the electronic key 10 that has been communicated over the past several times and the electronic key that is used for the current communication.

  In the above embodiment, the storage code is transmitted by being included in the response signal, specifically the response signal Sre. However, the storage code may be transmitted by being included in a radio signal different from the response signal Sre.

  In the above embodiment, the storage code is transmitted by being included in the response signal Sre without being encrypted. However, the stored code may be transmitted after being encrypted. Thereby, the security of the electronic key system 1 can be further improved.

-In the said embodiment, although response code collation and ID collation were performed, these may be abbreviate | omitted.
In the embodiment described above, the electronic key system 1 for a vehicle is embodied, but may be applied to an electronic key system for a house, for example.

Next, the technical idea that can be grasped from the embodiment will be described together with the effects.
(A) The electronic key system according to any one of claims 1 to 3, wherein the wireless signal is a response signal.

  According to this configuration, at least a part of the common code signal is included in the response signal and transmitted from the electronic key. Therefore, the identity of the electronic key can be guaranteed without transmitting a radio signal different from the response signal.

  (B) In the electronic key system according to (a), the electronic key transmits the response signal including its own identification code, and the control device includes at least the common code signal in the response signal. An electronic key system that executes control of the control target when it is determined that a part is included and it is determined that the identification code included in the response signal is valid.

  According to this configuration, the controller determines not only the identity of the electronic key for each communication but also the validity of the electronic key identification code. Thereby, the security of the electronic key system can be further improved.

  (C) In the electronic key system according to claim 2, the control device stores at least a part of the common code signal in its own memory every time the common code signal is transmitted, updates the accumulated code, and The electronic key stores at least a part of the common code signal in its own memory each time the common code signal is received, updates the same accumulated code as the control device, and transmits the updated accumulated code to the wireless key The control device executes control of the control target when the stored code included in the wireless signal is matched with the stored code stored in its own memory. Electronic key system.

  According to this configuration, the identity of the electronic key can be guaranteed through the verification of the stored code.

  DESCRIPTION OF SYMBOLS 1 ... Electronic key system, 2 ... Vehicle, 10 ... Electronic key, 11 ... Electronic key control part, 11a ... Memory, 12 ... LF receiving part, 13 ... UHF transmission part, 20 ... On-vehicle machine (control apparatus), 21 ... On-vehicle Control part, 21a ... Memory, 22 ... Outside transmission part, 23 ... In-car transmission part, 24 ... In-vehicle receiving part.

Claims (3)

The electronic key carried by the user communicates with the control device by transmitting a response signal in response to a request signal from the control device that controls a specific control target, and when the communication is established, In an electronic key system in which a control device executes control of a control target,
When communicating with the electronic key, the control device transmits a common code signal for confirming whether or not the electronic key to be communicated this time and the electronic key to be communicated next time are the same. Send to the key,
The electronic key transmits a radio signal including at least a part of the common code signal received at the previous communication at the time of the next communication,
When determining that the received wireless signal includes at least a part of the common code signal transmitted in the previous communication, the control device determines that the previous and current electronic keys are the same, An electronic key system that executes control of the control target. The electronic key system according to claim 1.
The electronic key transmits the wireless signal including at least a part of each of the common code signals for the past predetermined number of times received before the previous communication,
When the control device determines that the received radio signal includes at least a part of the common code signals for the past predetermined number of times transmitted before the previous communication, the control device executes the control of the control target. Electronic key system. The electronic key system according to claim 1 or 2,
The control object is a door lock device,
An electronic key system for transmitting the common code signal when the control device performs door locking control through the door lock device.

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