JP2008240315A - Radio key system, its controlling method, and program therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a vehicle from being stolen due to the disguise of field intensity level by a relay. <P>SOLUTION: This radio key system notifies a frequency for transceiving between an on-vehicle radio 2 and a radio key 3 by telegram messages from both sides, dynamically changes it, and transmits it. The on-vehicle radio 2 compares the RSSI value with the threshold of each frequency, and when the RSSI values of the telegram messages of all frequencies exceed the threshold, determines that the disguise of the RSSI values by a relay amplifier 5 is absent. Since the user 4 is considered to come into an area 7 near the vehicle, the preparation for boarding the vehicle 1 such that the door of the vehicle 1 is unlocked is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless key system called smart entry (registered trademark) or smart key (registered trademark) of a vehicle, and in particular, is equipped with vehicle equipment such as unlocking a door when the wireless key approaches the vehicle. It is an invention relating to vehicle security, in which the use of the vehicle is restricted by, for example, locking the door when the wireless key is separated from the vehicle.

  In recent years, as a vehicle wireless key is called Smart Entry (registered trademark), Smart Key (registered trademark), etc. Just by carrying the wireless key and approaching the vehicle, the door lock is unlocked and the key is used as a keyhole. Wireless key devices have been introduced that allow users to open and enter a door simply by touching the door knob or entry switch without having to insert and turn it.

  In such a wireless key system, it is determined that the wireless key has approached when a radio wave reachable range or radio wave intensity level exceeds a threshold for setting a nearby area, and authentication is performed by transmitting / receiving a message including an ID. The method to perform is common.

  However, with the intention of misusing this wireless key system, there is also a fear of the appearance of a crime called a relay attack that creates a radio repeater that amplifies the radio wave between the wireless key and the vehicle. That is, even if the user carrying the wireless key moves away from the vehicle, the radio wave repeater amplifies the radio wave from the wireless key, thereby reducing the distance that the radio wave does not reach or the attenuated low electric field strength level on the vehicle side. The wireless device can be received as a strong radio field intensity level, and the user who apparently carries the wireless key is disguised as if in the vicinity of the vehicle.

  As an example of measures for preventing such relay attacks, a method of detecting a delay time that occurs when a message is once decoded and retransmitted when the message is relayed has been proposed (see Patent Document 1).

  Patent Document 1 is used for a keyless entry device of a vehicle. When a return power transmission message for an identification ID request message transmitted from a vehicle to a wireless key is not returned within a predetermined time, the vehicle door is not unlocked. This algorithm prevents relay attacks.

  In this algorithm, when a signal is decoded and amplified by a radio repeater and then retransmitted, a delay occurs between decoding and retransmission, and it is detected that this delay time makes it impossible to return within a predetermined time. To do.

In addition, a method of changing the frequency between transmission and reception to avoid amplification of the relay amplifier can be considered, but as a similar configuration, the frequency at the time of return is reduced for the purpose of reducing the occurrence of communication errors due to interference and noise. The proposal of the method to change is disclosed (refer patent document 2).
JP 2006-118887 A JP-A-2005-299305

In the communication method using amplitude modulation used as an application for performing communication only in the very close range of the vehicle as in Patent Document 1, when a radio wave repeater is created, the S / N is deteriorated. It is necessary to re-transmit the result of decoding once the radio wave is passed through the detection circuit.

  In this method, the signal pattern, which is a unit of a message, is decoded once by the radio repeater and then retransmitted. This causes a processing delay for these processing times, so the delay time is relatively easy to detect. It was.

  In addition, if a carrier wave having a relatively low frequency such as several hundreds KHz is used, the time required to reach the signal pattern becomes longer, so the delay time when relay processing is performed becomes longer and the message is returned within a predetermined time. It was configured to be unable to.

  However, in a method using frequency modulation that assumes that the vehicle is controlled from a distance of several meters or more, for example, a method using a specific low power frequency band such as 426 MHz or 429 MHz, analog signals are not decoded. Therefore, the delay time required for decoding the signal pattern as in Patent Document 1 hardly occurs.

  Therefore, it is difficult to apply an algorithm that detects that the document is not returned within a predetermined time as in the cited document 1. Still, when a method for detecting a delay time as in Patent Document 1 is to be used, a circuit for detecting a very slight delay that occurs in filter processing during amplification by a radio wave repeater is realized. Is necessary, and there are significant disadvantages in terms of circuit scale and cost.

  Moreover, since the method of changing the frequency of transmission / reception like patent document 2 is a method for avoiding interference and noise originally, the structure which changes a frequency dynamically for every transmission / reception, or the structure which conceals the frequency to change There is no description about such. Therefore, by examining the frequency in advance, relay attack is possible by preparing a relay amplifier that covers the transmission and reception frequency bands and two relay amplifiers corresponding to each frequency of transmission and reception. There is a risk.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to notify a frequency to be changed by a message between a wireless key and a wireless device of a vehicle, for example. Transmission and reception are performed while dynamically changing the frequency used for communication for each communication. Therefore, in order to perform relay attack, the telegram is once decoded and analyzed to understand the changed frequency, and the frequency band that can be amplified by the relay amplifier is switched according to the changed frequency. A configuration or a configuration capable of relaying and amplifying the entire frequency band that can be transmitted and received by the wireless key or the wireless device of the vehicle is required.

  Therefore, with respect to the former method, the use of the relay amplifier can be detected by detecting the delay time when the message is decoded by the method of Patent Document 1. In addition, the latter method is effective in preventing relay attacks in that the technical hurdles for manufacturing a relay amplifier are extremely high and the cost effectiveness for manufacturing is greatly reduced. It's very big.

Therefore, in order to solve the conventional problem, a message is transmitted and received between a device wireless device attached to the protective device and a portable wireless device attached to the portable device, and the electric field intensity level measured by the message is a protective device. When the threshold for determining the neighborhood area is exceeded, it is determined that the area is in the vicinity of the protective device, and the use of the function of the protective device is restricted or released when it is determined to enter or exit the area near the protective device. In the wireless key system, either the device wireless device or the portable wireless device notifies the other wireless device of the frequency change pattern in advance, and then transmits the frequency from the transmitting unit of the device wireless device. A message whose frequency is changed according to the change pattern is transmitted, and the message is received by the receiving means of the portable wireless device to measure the electric field strength level. By returning a message including the field strength level from the portable wireless device to the device wireless device, the field strength level acquired by the device wireless device exceeds the threshold in the messages of the plurality of frequencies. In this case, it is determined that the area is in the vicinity of the protective device.

  As a result, even when a relay amplifier or the like is used, it becomes impossible to amplify the electric field strength level of each message following a plurality of changed frequencies, so the electric field strength level could not be disguised sufficiently. A telegram with a low electric field strength level will be received. Therefore, it can be detected that a message whose electric field intensity level does not exceed the threshold is mixed, and the use of the relay amplifier is determined, thereby preventing unauthorized use of the function of the protection device.

  In this way, in a wireless key system that can be used when a legitimate user is in the vicinity of the protective device due to the electric field strength level, the protective device is illegally used by impersonating the electric field strength level by a relay amplifier or the like. It is possible to provide a wireless key system with more secure security that can be prevented from being performed.

  1st invention transmits and receives a message between the apparatus radio | wireless apparatus attached to the protection apparatus, and the portable radio apparatus attached to the portable apparatus, and the electric field strength level which measured the said message determines a protection apparatus vicinity area In the wireless key system that determines whether the area is in the vicinity of the protective device when the threshold is exceeded, and restricts or cancels the use of the function of the protective device when the access to the protective device vicinity area is determined. Either the device wireless device or the portable wireless device notifies the other wireless device of the frequency change pattern in advance, and then changes the frequency according to the frequency change pattern from the transmission means of the device wireless device The received message is received by the receiving means of the portable wireless device, the electric field strength level is measured, and the electric field strength level is included. By returning a message from the portable wireless device to the device wireless device, when the electric field strength level acquired by the device wireless device exceeds the threshold in the messages of the plurality of frequencies, the protection device vicinity area Judgment is within.

  By this, it is possible to prevent unauthorized use of the function of the protective device by impersonating the wireless key so that it exists in the vicinity of the protective device by receiving a large electric field strength level of the message with a relay amplifier etc. It is.

  According to a second aspect of the present invention, a message is transmitted and received between a device wireless device attached to a protective device and a portable wireless device attached to a portable device, and the electric field intensity level obtained by measuring the message determines a protective device vicinity area. In the wireless key system that determines whether the area is in the vicinity of the protective device when the threshold is exceeded, and restricts or cancels the use of the function of the protective device when the access to the protective device vicinity area is determined. Either the device radio apparatus or the portable radio apparatus notifies the other radio apparatus of the frequency change pattern in advance, and then changes the frequency according to the frequency change pattern from the transmission means of the portable radio apparatus. By transmitting the received electronic message, receiving the electronic message by the receiving means of the device wireless device, and measuring the electric field strength level. The electric field intensity level obtained in location is, it is determined that the protective device near area when exceeds said threshold value in message of the plurality of frequencies.

By this, it is possible to prevent unauthorized use of the function of the protective device by impersonating the wireless key so that it exists in the vicinity of the protective device by receiving a large electric field strength level of the message with a relay amplifier etc. It is.

  According to a third aspect of the present invention, a message is transmitted and received between a device wireless device attached to a protective device and a portable wireless device attached to a portable device, and the electric field intensity level obtained by measuring the message determines a protective device vicinity area. In the wireless key system that determines whether the area is in the vicinity of the protective device when the threshold is exceeded, and restricts or cancels the use of the function of the protective device when the access to the protective device vicinity area is determined. A message whose frequency is changed according to a frequency change pattern stored in advance is transmitted from the transmission unit of the device radio apparatus, the electric message is received by the reception unit of the portable radio apparatus, and the electric field strength level is measured. By returning the contained message from the portable wireless device to the device wireless device, the electric field strength level acquired by the device wireless device is It is determined that the protective device near the area when the message of the plurality of frequencies exceeds said threshold value.

  As a result, the relay amplifier also determines impersonation of a relay amplifier or the like that does not have a mechanism for changing the amplification band according to the target wireless key system in advance, and the function of the protection device is illegally used. It can be prevented.

  According to a fourth aspect of the present invention, a message is transmitted and received between a device wireless device attached to a protective device and a portable wireless device attached to a portable device, and the electric field intensity level obtained by measuring the message determines a protective device vicinity area. In the wireless key system that determines whether the area is in the vicinity of the protective device when the threshold is exceeded, and restricts or cancels the use of the function of the protective device when the access to the protective device vicinity area is determined. By transmitting a message whose frequency is changed according to a frequency change pattern stored in advance from a transmission unit of a portable wireless device, and receiving the message by a receiving unit of the device wireless device, and measuring the field strength level, the device wireless When the electric field strength level acquired by the device exceeds the threshold value in the messages of the plurality of frequencies, It is determined that the internal.

  As a result, the relay amplifier also determines impersonation of a relay amplifier or the like that does not have a mechanism for changing the amplification band according to the target wireless key system in advance, and the function of the protection device is illegally used. It can be prevented.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the electric field strength level is lower than the threshold in the transmitted / received messages of the plurality of frequencies, assuming that the electric field strength level exceeds the threshold at the plurality of frequencies. The number of messages is less than or equal to a predetermined allowable number.

  As a result, for a normal relay amplifier, it is possible to sufficiently determine impersonation, and an effect can be expected even if the frequency change width of the device radio apparatus or the portable radio apparatus is slightly narrow.

  A sixth invention includes any one of the first to fifth inventions, wherein the frequency change pattern includes time interval information until a next message whose frequency is changed from a previous message is transmitted, and the device radio apparatus or The transmitting unit of one of the wireless devices starts transmission of the next message using the time interval information, and the receiving unit of the other wireless device receives a message using the time interval information. Start.

  As a result, even when a relay amplifier having a function of changing the frequency to be amplified by presetting a frequency change time interval in advance appears, the timing for changing the frequency cannot be adjusted and impersonation is determined. It becomes possible.

  7th invention transmits / receives a message between the apparatus radio | wireless apparatus attached to the protection apparatus, and the portable radio apparatus attached to the portable apparatus, and the electric field strength level which measured the said message determines a protection apparatus vicinity area A wireless key system control method for determining whether the area is in the vicinity of the protective device when the threshold is exceeded, and restricting or canceling the use of the function of the protective device when it is determined to enter or leave the area in the vicinity of the protective device And a step of notifying a frequency change pattern in advance from one of the device wireless device or the portable wireless device to the other receiving means, and a frequency changing pattern from the transmitting means of the device wireless device Transmitting the message changed in accordance with the method, and receiving the message by the receiving means of the portable wireless device to measure the electric field strength level A step of returning a message including the electric field strength level from the portable wireless device to the device wireless device, and the protection device when the electric field strength level exceeds the threshold in the messages of the plurality of frequencies. And a step of determining that the area is in the vicinity area.

  By this, it is possible to prevent unauthorized use of the function of the protective device by impersonating the wireless key so that it exists in the vicinity of the protective device by receiving a large electric field strength level of the message with a relay amplifier etc. It is.

  An eighth invention is a program for executing at least a part of the wireless key system according to the first to fourth aspects.

  Since it is a program, it is possible to easily realize at least a part of the wireless key system of the present invention by cooperating hardware resources such as an electric / information device, a computer, and a server. In addition, the program can be distributed / updated and installed easily by recording on a recording medium or distributing the program using a communication line.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments.

(Embodiment 1)
FIG. 1 is a schematic diagram in a case where the first embodiment is applied to a wireless key system called a smart entry (registered trademark) of a vehicle as an example of the wireless key system in the first embodiment. Smart Entry (registered trademark) automatically unlocks the door when the user approaches the vehicle with a wireless key. The door knob or entry switch can be used without inserting the actual key into the keyhole of the door and turning it. The door can be opened simply by touching the push switch.

  In FIG. 1, an in-vehicle wireless device 2 that is a device wireless device attached to a vehicle 1 that is an example of a protective device and a wireless key 3 that integrates them as an example of a portable device and a portable wireless device are carried by a user 4. Approaches the vehicle. When the user 4 enters the protective device vicinity area 7 (hereinafter referred to as the vehicle vicinity area) within the distance Dth range from the in-vehicle wireless device 2 indicated by the one-dot chain line, the in-vehicle wireless device 2 is an ECU (FIG. A signal indicating that the vehicle has entered the vehicle vicinity area 7 is input to the vehicle 4 so that the user 4 enters the vehicle 1 and prepares for driving, such as the ECU unlocking the door lock.

At this time, whether the in-vehicle wireless device 2 is a wireless key 3 associated with the vehicle 1 by transmitting / receiving a message to / from the wireless key 3 and collating the identification code ID encrypted and included in the message. Check if. In addition, when the electric field intensity level (hereinafter abbreviated as RSSI value) when the electronic message is received is compared with a predetermined determination threshold value and the threshold value is exceeded, the wireless key 3 is located in the vehicle vicinity area 7. It is determined that it is inside. This is because the RSSI value decreases in inverse proportion to the square of the distance according to the propagation characteristics, except for a local range such as a point where overlapping in the opposite phase due to reflection of normal radio waves occurs.

  In FIG. 1, the vehicle vicinity area 7 is illustrated in a simplified shape with a substantially circular shape centered on the in-vehicle wireless device 2, but actually, the unevenness is caused by the antenna structure and the housing structure such as the vehicle's pier part. It becomes an area that has it.

  1 includes a power supply means, a control means, a transmission means for transmitting a message set by the control means, an electric field received and inputted to the control means, and an electric field strength of the received message. It comprises receiving means for measuring the level (not shown).

  The control means includes a control unit such as a microcomputer and a memory, and an I / O unit such as an interface circuit with the ECU.

  The transmission means and the reception means are composed of a radio circuit unit including an oscillator, a PLL circuit, a digital filter unit, an amplification circuit, and the like. When the transmission unit and the reception unit are switched by a signal from the control unit, It is also possible to use a configuration in which they are shared.

  Further, the transmission unit and the reception unit are configured to set the frequency of a telegram to be transmitted and received by changing circuit constants such as a PLL circuit and a digital filter in accordance with a signal from the control unit.

  The operation of each of these means is simplified in the following description, and is simply described as the in-vehicle wireless device 2 and the wireless key 3 receiving and transmitting a message.

  Next, an example in which fraud is attempted using a relay amplifier or the like as in a relay attack in FIG. 1 will be described. In FIG. 1, when a suspicious person 6 has a radio wave relay amplifier 5 or the like and is behind a vehicle 1 or the like, a message between the wireless key 3 and the in-vehicle wireless device 1 is indicated by a thick dashed arrow. The RSSI value is higher than that of the radio wave that is amplified by the relay amplifier 5 and reaches directly, and is measured while being camouflaged.

  Therefore, the vehicle vicinity area 7 is also apparently surrounded by a dotted line 8 in FIG. 1 (only a part of the boundary is shown) and is enlarged to a disguise vehicle vicinity area 8 indicated by “distance Dth (disguise)”. The suspicious person 6 can get into the vehicle 1 and steal it. As described above, in the wireless key system, the necessity to disguise the RSSI value by the relay amplifier 5 and prevent the crime of the kind called the relay attack aiming at theft or unauthorized use of the protection device has begun to be proposed.

  Therefore, in the first embodiment, in the communication between the in-vehicle wireless device 2 and the wireless key 3, a frequency change pattern to be transmitted / received is notified in advance by a telegram and negotiated to thereby determine the frequency for measuring the RSSI value. Change dynamically.

  According to this method, in the configuration of the relay amplifier 5 in which the generally expected frequency band that can be amplified is fixed, the gain of amplification increases as the frequency to be communicated departs from the frequency band that can be amplified by the relay amplifier 5. As a result, a message transmitted / received at a frequency at which sufficient amplification cannot be performed cannot disguise the RSSI value to the extent that the threshold value is exceeded.

  For this reason, by changing the frequency in-vehicle and comparing the RSSI value of each frequency with the threshold value, if there is a mixture of frequencies that do not exceed the threshold value, the RSSI value is disguised and there is no locking. is there.

  If the advanced relay amplifier 5 is taken into consideration, it is only necessary to prepare a relay amplifier having sufficient amplification characteristics over the entire frequency range where communication between the in-vehicle wireless device 2 and the wireless key 3 is possible.

  However, in the relay amplifier 5, the frequency change pattern that is dynamically changed sequentially is concealed by encryption between the in-vehicle wireless device 2 and the wireless key 3, and cannot be known. Therefore, unlike the in-vehicle wireless device 2 and the wireless key 3, it is not possible to adopt a configuration in which the setting of the PLL circuit or the peripheral circuit is switched to change the transmission / reception frequency, so that communication between the in-vehicle wireless device 2 and the wireless key 3 is always performed. It is necessary to construct a relay amplifier with an amplification characteristic that covers the entire range of possible frequencies.

  Actually, such a very wide-band relay amplifier or a method of operating a plurality of amplifiers in parallel increases the technical hurdles required, and is also disadvantageous in terms of cost effectiveness. Therefore, it is not realistic to aim at this, and is considered to be very effective as a relay attack prevention effect.

  Hereinafter, communication between the in-vehicle wireless device 2 and the wireless key 3 will be described with reference to the flowchart of FIG.

  First, when the in-vehicle wireless device 2 is energized and activated, the in-vehicle wireless device 2 waits for a timing to transmit a request message to the wireless key 3 at regular intervals (step S13).

  In step S13, when the time to transmit the request message elapses, the in-vehicle wireless device 2 transmits a request message including a designated frequency list in which a plurality of frequencies for returning the answer message are randomly selected. At this time, the request message is transmitted at the fixed frequency decided in the first embodiment.

  Note that the number of specified frequencies may be changed randomly for each request message. In addition, when selecting a frequency at random, it is more effective if conditions such as selecting a frequency from a frequency group separated by a certain frequency are added.

  Next, the in-vehicle wireless device 2 uses the frequency (F (m = 1)) specified at the top of the specified frequency list of the request message, that is, the frequency F (m) of the habit at which the answer message is returned next. A reception wait state is set, and an answer message from the wireless key 3 is waited (step S14).

  While waiting for an answer message, it is determined whether or not a timeout time for answer message waiting has elapsed (step S15). If no answer message can be received even after the timeout time has elapsed, the process returns to step S13 to return to the next request message. Wait for the sending time to elapse.

  If the time-out period has not passed in step S16, it is determined whether an answer message has been received. If not received, the process returns to step S14 to continue waiting for an answer message (step S16).

  If the answer signal can be received in step 16, the field strength level (RSSI value) measured and stored when the answer message is received by the wireless receiving circuit of the in-vehicle wireless device 2 is read (step S17), and the frequency F It is compared with a determination threshold value R (THm) for determining the vehicle vicinity area 7 set in advance corresponding to (m) (step S18).

  If the determination threshold value R (THm) is not exceeded in step S18, it is determined that the user carrying the wireless key 3 is not in the vehicle vicinity area 7, and the process returns to step S13.

  If the determination threshold value R (THm) is exceeded, the process proceeds to step S19, where it is determined whether all of the messages for the specified frequency list agreed with the request message have been received.

  If the process ends in step S19, that is, if the RSSI values of all the frequencies in the specified frequency list of the request message exceed a predetermined determination threshold value, it is determined that the vehicle has entered the vehicle vicinity area 8, and the user is in the vicinity of the vehicle. A signal indicating that the vehicle has entered the area 7 is input, and the ECU controls the vehicle equipment such as releasing the door lock to perform a predetermined preparation operation when the user approaches the vehicle 1 (step S20).

  In the above description, the frequency selected from the specified frequency list of the request message is set in advance from frequencies that can be transmitted by the wireless key 3.

  Further, although only changing the transmission frequency of the answer message has been described, a configuration in which time interval information specifying the return time interval of the answer message whose transmission frequency is changed is included in the request message and transmitted is also effective. Thereby, even if the relay amplifier 5 that can change the frequency band to be amplified by switching such as a PLL circuit is used, the transmission time interval of the answer message changes every time the message is transmitted / received. Obviously, the relay amplifier 5 can be disabled.

  In addition, the example of transmitting the specified frequency list with one request message has been explained, but each time an answer message is received, multiple request messages such as sending a request message specifying the frequency to which the answer message should be returned next are sent. It may be configured to transmit.

  Regarding the determination threshold for each frequency, an example in which all frequencies are individually set has been described, but a method of using the same determination threshold for the frequencies in the frequency section may be used as a frequency section in which close frequencies are collected.

  Regarding the determination with the threshold value, the method for determining whether the RSSI values of all the frequencies to be changed exceed the threshold value has been described. However, in the situation where many vehicles are parked nearby, It is also possible that a place where radio waves are weakened due to multipath due to, for example, if the RSSI value of a 9-frequency telegram out of 10 frequencies exceeds, Even when there is a frequency lower than the RSSI value up to a predetermined allowable number, it may be determined that the vehicle has entered the vehicle vicinity area 7.

  Furthermore, although the case where the RSSI value measurement is performed by the in-vehicle wireless device 2 has been described, the in-vehicle wireless device 2 transmits an RSSI value measurement message according to the frequency and transmission interval specified in the request message, and the wireless key 3 side The RSSI value measured by receiving this may be included in the answer message and returned. Of course, a configuration in which determination is made using RSSI values measured by both the in-vehicle wireless device 2 and the wireless key 3 may be used.

  In addition to this, with regard to the frequency change band, if the frequency band is changed greatly, it becomes necessary to prepare an amplifier with a wider amplification band and to prepare a plurality of amplifiers, which has the effect of increasing the barrier of relay attack. It can be considered more effective if configured in consideration of cost-effectiveness such as the contents of the in-vehicle wireless device 2, the wireless key 3, and the target protective device. In addition, when a simple preventive measure is taken depending on the contents of the protective device, a method may be used in which the frequency is changed according to the frequency change pattern stored in advance in the program without sending the designated frequency list by the request message.

Finally, although the first embodiment has been described as a wireless system for a smart entry (registered trademark) of a vehicle, for example, a mobile phone in which a payment function, an address book display, and a call function are locked when there is no mobile key nearby The system is automatically unlocked when a mobile key is brought close to the electronic lock on the front door, or printing or input is performed if the administrator who owns the mobile key is not in the vicinity of the device. It can be widely applied to devices other than mobile phones, such as unacceptable printers and personal computers.

  Note that the means described in this embodiment causes hardware resources such as a CPU (or microcomputer), a RAM, a ROM, a storage / recording device, an electrical / information device including an I / O, a computer, a server, and the like to cooperate. You may implement with the form of a program. In the form of a program, new functions can be easily distributed / updated and installed by recording them on a recording medium such as magnetic media or optical media or distributing them via a communication line such as the Internet.

  As described above, according to the present invention, without the work of taking out the key, inserting it into the keyhole, and turning it, the restriction function of the protective device is released only when a legitimate user carries and approaches the wireless key, While maintaining the convenience of restricting the use of protection functions if you leave, you can prevent unauthorized actions such as relay attacks that amplify radio waves and disguise legitimate users to be in the vicinity of the protection device, A wireless key system that can be widely applied to devices to be used can be realized.

  Further, the present invention can be used not only for keys but also for wireless authentication systems that perform authentication.

The top view which showed the structure of the wireless key system of the vehicle in Embodiment 1 which becomes an example of this invention The flowchart which shows an example of the communication operation | movement of the radio | wireless key system in Embodiment 1 of this invention.

Explanation of symbols

1 Vehicle (Protective equipment)
2 In-vehicle wireless device (equipment wireless device)
3 Wireless key (mobile device and mobile wireless device)
7 Vehicle vicinity area (Protective equipment vicinity area)

Claims (8)

A message is transmitted / received between the device wireless device attached to the protective device and the portable wireless device attached to the portable device, and the electric field intensity level measured by the message exceeds the threshold for determining the protective device vicinity area. In the wireless key system for determining whether the area is in the vicinity of the protective device, and restricting or canceling the use of the function of the protective device when it is determined to enter or exit the area near the protective device,
After either the device wireless device or the portable wireless device notifies the other wireless device of the frequency change pattern in advance,
Sending a message whose frequency has been changed according to the frequency change pattern from the transmission means of the device wireless device,
Receiving the message by the receiving means of the portable wireless device to measure the electric field strength level,
By returning a message including the electric field strength level from the portable wireless device to the device wireless device,
The wireless key system which judges that it is in the said protection apparatus vicinity area, when the said electric field strength level acquired with the said apparatus radio | wireless apparatus is over the said threshold value in the message | telegram of the said several frequency. A message is transmitted / received between the device radio apparatus attached to the protection device and the portable radio device attached to the portable device, and the electric field intensity level measured by the message exceeds the threshold for determining the area near the protection device. In the wireless key system for determining whether the area is in the vicinity of the protective device, and restricting or canceling the use of the function of the protective device when it is determined to enter or exit the area near the protective device,
After either the device wireless device or the portable wireless device notifies the other wireless device of the frequency change pattern in advance,
Sending a message whose frequency has been changed according to the frequency change pattern from the transmission means of the portable wireless device,
By receiving the message by the receiving means of the device wireless device and measuring the electric field strength level,
The wireless key system which judges that it is in the said protection apparatus vicinity area, when the said electric field strength level acquired with the said apparatus radio | wireless apparatus is over the said threshold value in the message | telegram of the said several frequency. A message is transmitted / received between the device radio apparatus attached to the protection device and the portable radio device attached to the portable device, and the electric field intensity level measured by the message exceeds the threshold for determining the area near the protection device. In the wireless key system for determining whether the area is in the vicinity of the protective device, and restricting or canceling the use of the function of the protective device when it is determined to enter or exit the area near the protective device,
Sending a message whose frequency has been changed according to the frequency change pattern stored in advance from the transmission means of the device wireless device,
Receiving the message by the receiving means of the portable wireless device to measure the electric field strength level,
By returning a message including the electric field strength level from the portable wireless device to the device wireless device,
The wireless key system which judges that it is in the said protection apparatus vicinity area, when the said electric field strength level acquired with the said apparatus radio | wireless apparatus is over the said threshold value in the message | telegram of the said several frequency. A message is transmitted / received between the device radio apparatus attached to the protection device and the portable radio device attached to the portable device, and the electric field intensity level measured by the message exceeds the threshold for determining the area near the protection device. In the wireless key system for determining whether the area is in the vicinity of the protective device, and restricting or canceling the use of the function of the protective device when it is determined to enter or exit the area near the protective device,
Sending a message whose frequency has been changed according to the frequency change pattern stored in advance from the transmission means of the portable wireless device,
By receiving the electronic message by the receiving means of the device wireless device and measuring the electric field strength level,
The wireless key system which judges that it is in the said protection apparatus vicinity area, when the said electric field strength level acquired with the said apparatus radio | wireless apparatus is over the said threshold value in the message | telegram of the said several frequency. Assuming that the field strength level is above the threshold at the plurality of frequencies, the number of messages when the field strength level is below the threshold in the transmitted and received messages at the plurality of frequencies is equal to or less than a predetermined allowable number. The wireless key system according to any one of claims 1 to 4. The frequency change pattern includes time interval information until a next message whose frequency has been changed from the previous message is transmitted, and the transmission unit of either the device radio device or the radio device transmits the time interval. The wireless key according to any one of claims 1 to 5, wherein transmission of the next message is started using information, and reception means of the other wireless device starts receiving message using the time interval information. system. A message is transmitted / received between the device radio apparatus attached to the protection device and the portable radio device attached to the portable device, and the electric field intensity level measured by the message exceeds the threshold for determining the area near the protection device. In the control method of the wireless key system for determining whether the area in the vicinity of the protective device in the case, and restricting or canceling the use of the function of the protective device when the access to the area near the protective device is determined.
From the wireless device of either the device wireless device or the portable wireless device, notifying the frequency change pattern in advance to the other receiving means;
Transmitting a message changed according to the frequency change pattern from the transmission means of the device wireless device;
Receiving the message by the receiving means of the portable wireless device and measuring the electric field strength level;
Returning a message containing the field strength level from the portable wireless device to the device wireless device;
Determining that the field strength level is within the protective device vicinity area when the electric field strength level exceeds the threshold in the plurality of frequency messages;
A method for controlling a wireless key system comprising: The program which performs at least one part of the radio | wireless key system of any one of Claims 1-4.

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