JP7036571B2 - Electronic lock system, electronic lock control device, unlocking method of electronic lock in electronic lock system - Google Patents

Description

The present invention relates to an electronic lock system, an electronic lock control device, and a method for unlocking an electronic lock in an electronic lock system, which is automatically unlocked when the key is brought close to the lock.

Currently, vehicles using a smart entry system that allows the user to automatically unlock the door lock of the vehicle just by approaching the vehicle without having to open the lock have been commercialized.

In the smart entry system, the on-board unit mounted on the vehicle and controlling the opening / closing of the door lock of the vehicle wirelessly transmits an activation signal for activating the electronic key, for example, using the LF band. When the electronic key receives such an activation signal, it wirelessly transmits its own ID (identification) using, for example, the UHF band. When the on-board unit receives such an ID, it generates a tricode consisting of random numbers and the like, and wirelessly transmits this using the LF band. When the electronic key receives this tricode, it wirelessly transmits an encrypted tricode obtained by encrypting the tricode with an encryption key using the UHF band. Upon receiving the cryptographic tricode, the vehicle-mounted device determines whether or not the cryptographic tricode corresponds to the tricode transmitted wirelessly as described above. The on-board unit unlocks the door lock of the vehicle only when it is determined that the received cryptographic tricode corresponds to the wirelessly transmitted tricode.

By the way, a vehicle that adopts such a smart entry system has a so-called relay attack in which an unauthorized person illegally unlocks the in-vehicle device by amplifying and relaying the communication between the in-vehicle device and the electronic key. There is a risk of being subject to a so-called security attack.

In the relay attack, for example, when the user of the vehicle is sufficiently away from the vehicle in a parking lot or the like, a high-output wireless relay prepared by an unauthorized person is used to unlock the vehicle between the in-vehicle device and the electronic key owned by the user. The above-mentioned wireless communication for the purpose is relayed. As a result, the door lock of the vehicle is illegally unlocked without the user of the vehicle knowing.

Therefore, in order to prevent such a relay attack, the time spent for wireless communication between the in-vehicle device and the electronic key is measured, and only when the time is within an appropriate range, the in-vehicle device locks the door of the vehicle. A system for unlocking the door has been proposed (see, for example, Patent Document 1).

In the system described in Patent Document 1, the RF transmission / reception unit mounted on the vehicle-mounted device transmits a challenge signal synchronized with the RF clock in the RF band (10 to several tens of megahertz). The portable device as an electronic key transmits a response signal in response to the reception of the challenge signal. The on-board unit measures the time interval from the time when the challenge signal is transmitted to the time when the response signal is received, and when the time interval is within an appropriate range, the in-vehicle device permits the operation of the vehicle.

In addition, the distance between the in-vehicle device and the electronic key is measured by performing wireless communication using UWB (Ultra Wide Band) radio waves of 3.1 GHz to 10.25 GHz between the in-vehicle device and the electronic key, and the distance is measured. A system has been proposed in which the door lock of the vehicle is unlocked when the value is equal to or less than the threshold value (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2015-131608 Japanese Unexamined Patent Publication No. 2014-227647

By the way, in the above-mentioned Patent Document 1, a radio wave having a relatively long wavelength such as the LF band is used for the wireless communication. Therefore, for example, when the electronic key side receives a challenge signal with its own antenna and captures it with a clock signal generated in the electronic key to detect the challenge signal, the wavelength of the LF band is used for the detection timing of the challenge signal. There will be an error corresponding to.

As a result, the timing at which the electronic key side transmits the response signal also has a time difference corresponding to the error, so even if the vehicle user has the electronic key corresponding to this vehicle and approaches, the door of the vehicle is opened. There was a risk of causing a malfunction that the lock could not be performed.

Further, as in Patent Document 2, when a high frequency radio wave in the 3 GHz band is used in order to measure the distance between the in-vehicle device and the electronic key, it is necessary to newly provide a dedicated transmitter, which increases the cost. The problem of inviting arises.

Therefore, an object of the present invention is to provide an electronic lock system, an electronic lock control device, and a method for unlocking an electronic lock in an electronic lock system, which can suppress a high cost and prevent a relay attack without malfunction. And.

The electronic lock system according to the present invention is an electronic lock system including an electronic lock control unit that controls unlocking of the electronic lock and an electronic key, and the electronic lock control unit receives a clock synchronization signal and receives a clock synchronization signal. The measurement start signal is a clock synchronization unit that performs synchronization processing that synchronizes the first clock signal with the received clock synchronization signal, and a carrier signal having a phase synchronized with the first clock signal after the synchronization processing is completed. The response is performed by receiving a first transmission unit that generates a phase-modulated modulation measurement start signal and wirelessly transmitting the signal, a modulation response signal corresponding to the response signal, and performing phase demodulation processing on the received modulation response signal. When the delay time required from the generation of the first receiving unit for acquiring the signal and the acquisition of the response signal by the first receiving unit after the modulation measurement start signal is generated is equal to or less than a predetermined time. The electronic key includes an unlock command unit for unlocking the electronic lock, a clock synchronization signal generation unit that generates a signal synchronized with the second clock signal as the clock synchronization signal, and a modulation measurement start signal. The clock synchronization signal is wirelessly transmitted to the second receiving unit that receives and acquires the measurement start signal by performing phase demodulation processing on the received modulation measurement start signal, and in response to the acquisition of the measurement start signal. A second transmission unit that generates a response signal and phase-modulates a carrier signal having a phase synchronized with the second clock signal with the response signal to generate the modulation response signal and wirelessly transmit the modulation response signal. including.

The electronic lock control device according to the present invention is an electronic lock control device that controls unlocking of an electronic lock, and is a clock that receives a clock synchronization signal and performs synchronization processing that synchronizes a clock signal with the received clock synchronization signal. Corresponds to a synchronization unit, a transmission unit that generates a modulation measurement start signal in which a carrier signal having a phase synchronized with the clock signal is phase-modulated with a measurement start signal and wirelessly transmits the modulation measurement start signal after the synchronization processing is completed, and a response signal. A receiving unit that receives the phase-modulated response signal and obtains the response signal by performing phase demodulation processing on the received phase-modulated response signal, and a receiving unit after the modulation measurement start signal is generated. It has an unlock command unit for unlocking the electronic lock when the delay time required for acquiring the response signal is not more than a predetermined time.

The method for unlocking an electronic lock in an electronic lock system according to the present invention is a method for unlocking an electronic lock in an electronic lock system including an electronic lock control unit that controls unlocking of the electronic lock and an electronic key. When the electronic lock control unit receives the clock synchronization signal, the electronic lock control unit performs synchronization processing for synchronizing the first clock signal with the clock synchronization signal, and after the synchronization processing is completed, the phase synchronized with the first clock signal. By generating a modulation measurement start signal obtained by phase-modulating a carrier signal having a The electronic lock is released when the delay time from the acquisition of the response signal and the generation of the modulation measurement start signal to the acquisition of the response signal by the first receiving unit is equal to or less than a predetermined time. Locked, the electronic key wirelessly transmits the clock synchronization signal, generates a signal synchronized with the second clock signal as the clock synchronization signal, and receives the modulation measurement start signal, the modulation measurement start signal. By performing phase demodulation processing on the above, the measurement start signal is acquired, a response signal is generated in response to the acquisition of the measurement start signal, and a carrier signal having a phase synchronized with the second clock signal is used as the response signal. The modulation response signal is generated by phase modulation and transmitted wirelessly.

In the present invention, first, the clock signal used in the electronic lock control unit that unlocks the electronic lock and the clock signal used in the electronic key are synchronized. Subsequently, the electronic lock control unit measured and measured the delay time required from the wireless transmission of the measurement start signal to the reception of the response signal wirelessly transmitted by the electronic key in response to the reception of the measurement start signal. The electronic lock is released only when the delay time is within the specified time. That is, the electronic lock is unlocked only when the physical distance (corresponding to the delay time) between the electronic key and the electronic lock control unit is within a predetermined distance.

At this time, when the relay attack is received, the above-mentioned delay time becomes longer than the predetermined time, that is, the physical distance between the electronic key and the electronic lock control unit is longer than the predetermined distance, so that the electronic lock Will not be unlocked.

Therefore, it is possible to prevent unauthorized unlocking of the door by a relay attack.

Further, in the present invention, as a modulation method for performing the above-mentioned wireless communication, phase modulation is adopted in which a carrier signal having a phase synchronized with a clock signal is phase-modulated with a measurement start signal (response signal).

Therefore, the signal received by the electronic lock control unit (or electronic key) is a phase modulation signal in which a carrier signal having a phase synchronized with the clock signal is phase-modulated with a response signal (or measurement start signal). As a result, the demodulation unit of the electronic lock control unit (or electronic key) detects the phase change point in the phase modulation signal as the transition point of the signal level (logic level 0 or 1) of the response signal (or measurement start signal). can do. Therefore, the demodulation unit can always acquire the response signal (or measurement start signal) after a predetermined fixed time has elapsed from the time when the phase modulation signal corresponding to the response signal (or measurement start signal) is received by the antenna. It will be possible.

That is, in the electronic lock control unit (or electronic key), the time required from receiving the phase modulation signal to acquiring the response signal (or measurement start signal) is constant. This makes it possible to accurately measure the distance between the electronic lock control unit and the electronic key in meters even if a carrier signal in a band (for example, UHF) generally used in a smart entry system is used. ..

Therefore, according to the present invention, it is possible to suppress a high cost and prevent a relay attack without malfunction.

It is a block diagram which shows the structure of the electronic lock system 100 which concerns on this invention. It is a communication flow diagram which shows an example of the unlocking process performed by the electronic lock control unit 200 and the electronic key 300. It is a block diagram which shows a part of the internal structure of the electronic lock control unit 200. It is a waveform diagram which shows the example of the measurement start signal DM and the example of the modulation measurement start signal PM generated by the phase modulation unit 24 based on the measurement start signal DM. It is a circuit diagram which shows the internal structure of a phase modulation part 24 and 39. It is a circuit diagram which shows the internal structure of the phase demodulation part 28 and 32. It is a time chart which shows an example of the internal operation of a phase demodulation unit 28. It is a circuit diagram which shows an example of the internal structure of a clock synchronization part 29. It is a waveform diagram which shows an example of a clock synchronization pattern and a clock synchronization signal SYC. It is a block diagram which shows a part of the internal structure of an electronic key 300. It is a communication flow diagram which shows the other example of the unlocking process performed by the electronic lock control unit 200 and the electronic key 300. It is a block diagram which shows the other structure of the electronic lock system 100 which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an electronic lock system 100 according to the present invention. As shown in FIG. 1, the electronic lock system 100 includes an electronic lock control unit 200, an electronic key 300, and an electronic lock 400.

The electronic lock control unit 200 is mounted on a vehicle, for example, and receives an unlock command signal LK for unlocking the electronic lock 400 when unlocking is permitted by bidirectional wireless communication with the electronic key 300. Supply to. The electronic key 300 is a portable wireless communication terminal that functions as a "key" for unlocking the door lock of the vehicle. The electronic lock 400 is a vehicle door lock and is unlocked in response to the unlock command signal LK.

FIG. 2 is a communication flow diagram showing an example of an unlocking process performed between the electronic lock control unit 200 and the electronic key 300.

In FIG. 2, the electronic lock control unit 200 wirelessly transmits an activation signal for activating the electronic key 300 by radio waves in the LF (Low Frequency) band of, for example, 30 kHz to 300 kHz (step S11). After executing step S11, the electronic lock control unit 200 determines whether or not a key ID (identification) signal representing a predetermined key identifier has been received (step S12).

When the electronic lock control unit 200 determines that the key ID signal has been received in step S12, the electronic lock control unit 200 wirelessly transmits a tricode composed of random numbers generated by the random number generator by radio waves in the LF band (step S13). After executing step S13, the electronic lock control unit 200 determines whether or not an appropriate cryptographic tricode corresponding to the tricode transmitted wirelessly in step S13 has been received (step S14).

If the electronic lock control unit 200 determines in step S12 that the key ID signal has not been received, or if it determines in step S14 that it has not received an appropriate encryption tricode, the electronic lock control unit 200 determines in step S11. Go back and perform the above-mentioned series of operations again.

During this time, the electronic key 300 determines whether or not the activation signal has been received (step S21), and if it is determined that the activation signal has been received, the electronic key 300 uses a predetermined key ID signal, for example, a UHF (Ultra High Frequency) of 300 MHz to 3 GHz. ) Radio transmission in the band (step S22). After executing step S22, the electronic key 300 returns to step S21 and performs the above-described operation again.

If it is determined in step S21 that the electronic key 300 has not received the activation signal, the electronic key 300 determines whether or not the tricode has been received (step S23). When it is determined in step S23 that the tricode has been received, the electronic key 300 uses the UHF band radio wave to transmit the encryption tricode obtained by performing an encryption operation on the tricode using a predetermined encryption key. Wireless transmission (step S24). After the execution of step S24, the electronic key 300 returns to step S21 and performs the above-described operation again.

During this time, when the electronic lock control unit 200 determines that the proper cryptographic tricode has been received in step S14, the electronic lock control unit 200 wirelessly transmits the clock synchronization request signal by the radio wave in the LF band (step S15).

Here, when it is determined in step S23 that the electronic key 300 has not received the tricode, the electronic key 300 determines whether or not the clock synchronization request signal has been received (step S25). If it is determined in step S25 that the clock synchronization request signal has not been received, the electronic key 300 returns to step S21 and performs the above-described operation again. On the other hand, if it is determined in step S25 that the clock synchronization request signal has been received, the electronic key 300 wirelessly transmits the clock synchronization signal phase-locked to its own clock signal by radio waves in the UHF band (step S26). After the execution of step S26, the electronic key 300 determines whether or not the measurement start signal has been received (step S27). If it is determined in step S27 that the measurement start signal has not been received, the electronic key 300 returns to step S21 and performs the series of operations described above again.

When the electronic lock control unit 200 receives the clock synchronization signal, it performs synchronization processing for synchronizing its own clock signal with the phase of the clock synchronization signal (step S16). After the execution of step S16, the electronic lock control unit 200 wirelessly transmits the measurement start signal by radio waves in the UHF band (for example, 300 MHz) (step S17). Further, the electronic lock control unit 200 starts time counting from the time when the measurement start signal is wirelessly transmitted. After the execution of step S17, the electronic lock control unit 200 determines whether or not the response signal wirelessly transmitted from the electronic key 300 has been received within a predetermined time from the time when the measurement start signal is wirelessly transmitted (step S18). .. If it is determined in step S18 that the response signal has not been received within the predetermined time, the electronic lock control unit 200 returns to step S11 and executes the series of operations described above again.

Here, when it is determined that the electronic key 300 has received the measurement start signal in step S27, the response signal in response to the measurement start signal is wirelessly transmitted by radio waves in the UHF band (for example, 300 MHz) (step S28). After executing step S28, the electronic key 300 returns to step S21 and performs the series of operations described above again.

When the electronic lock control unit 200 determines in step S18 that the response signal has been received within a predetermined time, the electronic lock control unit 200 supplies the unlock command signal LK to the electronic lock 400 (step S19). The electronic lock 400 unlocks the door of the vehicle in response to the unlock command signal LK. On the other hand, if it is determined in step S18 that the response signal has not been received within the predetermined time, the electronic lock control unit 200 returns to step S11 and executes the series of operations described above again. That is, at this time, the electronic lock 400 is not unlocked.

As described above, in the unlocking process shown in FIG. 2, the electronic lock control unit 200 mounted on the vehicle wirelessly transmits an activation signal for activating the electronic key 300 at predetermined time intervals (S11). Here, when the user possessing the electronic key 300 approaches the vehicle, the electronic key 200 receives the activation signal wirelessly transmitted from the electronic lock control unit 200, and wirelessly transmits the key ID unique to the electronic key (the electronic key 200). S21, S22). Upon receiving this key ID, the electronic lock control unit 200 wirelessly transmits a tricode composed of random numbers (S12, S13). When the electronic key 300 receives the tricode, it wirelessly transmits the encrypted tricode obtained by performing an encryption operation on the tricode using a predetermined encryption key (S23, S24). The electronic lock control unit 200 determines whether or not the received cryptographic tricode is appropriate (S14).

Here, only when an appropriate cryptographic tricode is received, the electronic lock control unit 200 and the electronic key 300 shift to the execution of the relay attack prevention process in steps S15 to S18 and S25 to S28. The relay attack prevention process includes a clock synchronization process according to steps S15, S16, S25 and S26, and a delay time measurement process according to steps S17, S18, S27 and S28.

In the clock synchronization process, first, in response to the clock synchronization request (S15) wirelessly transmitted from the electronic lock control unit 200, the electronic key 300 transmits the clock synchronization signal phase-synchronized with its own clock signal to the electronic lock control unit 200. Send. The electronic lock control unit 200 synchronizes the phase of its own clock signal with the received clock synchronization signal (S16).

Therefore, according to the clock synchronization process (S15, S16, S25 and S26), the phase of the clock signal used inside the electronic lock control unit 200 is synchronized with the clock signal used inside the electronic key 300.

Then, in the delay time measurement process following the clock synchronization process, first, the electronic lock control unit 200 wirelessly transmits the measurement start signal (S17). The electronic key 300 wirelessly transmits a response signal in response to the received measurement start signal (S27, S28). Here, the electronic lock control unit 200 measures the delay time required from the wireless transmission of the measurement start signal to the reception of the response signal wirelessly transmitted by the electronic key 200 in response to the reception of the measurement start signal. It is determined whether or not the response signal is received within the predetermined time (S18). At this time, the unlocking permission is given only when it is determined that the response signal is received within the predetermined time, and the electronic lock 400 is unlocked (S19). That is, if the time required from the wireless transmission of the measurement start signal by the electronic lock control unit 200 to the reception of the response signal exceeds a predetermined time, the electronic lock 400 is not unlocked.

Here, during the above-mentioned predetermined time, when the distance between the electronic lock control unit 200 and the electronic key 300 is, for example, 5 meters, the electronic lock control unit 200 transmits a measurement start signal, and then the electronic key 300 is used. The delay time required to receive the response signal is set. Therefore, when the electronic key 300 is separated from the electronic lock control unit 200 by 5 meters or more, the vehicle door is not unlocked.

That is, the fraudster launches the relay attack as described above after the user holding the electronic key 300 is, for example, 5 meters or more away from the vehicle so that he / she is not confirmed to be the fraudulent person. As a result, the time required from the transmission of the measurement start signal by the electronic lock control unit 200 to the reception of the response signal from the electronic key 300 is always longer than the above-mentioned predetermined time.

Therefore, even if the electronic lock control unit 200 receives an appropriate cryptographic tricode due to the relay attack, the door of the vehicle is not unlocked.

Therefore, according to the unlocking process shown in FIG. 2, it is possible to prevent unauthorized unlocking of the vehicle door by the relay attack.

In order to realize the unlocking process as described above, the time required from the electronic lock control unit 200 transmitting the measurement start signal to receiving the response signal, that is, between the electronic lock control unit 200 and the electronic key 300. It is necessary to measure the physical distance of the lock at least in meters.

Therefore, in the electronic lock system 100 shown in FIG. 1, the following configurations are adopted as the electronic lock control unit 200 and the electronic key 300.

FIG. 3 is a block diagram showing an example of the internal configuration of the electronic lock control unit 200. Note that FIG. 3 shows an excerpt of a configuration required for the electronic lock control unit 200 to perform the relay attack prevention process in steps S15 to S19 and S25 to S28 described above.

In FIG. 3, the clock synchronization request signal generation unit 21 starts from a binary (logical level 0, 1) bit string synchronized with the clock signal CK1 in response to the transmission command X1 supplied from the unlock command generation unit 41. Clock synchronization request signal CRQ is generated and output. The clock synchronization request signal generation unit 21 supplies the clock synchronization request signal CRC to the transmission amplifier 22.

The measurement start signal generation unit 23 starts from a binary bit string synchronized with the clock signal CK1, for example, a bit string [10111001] as shown in FIG. 4, in response to the transmission command X2 supplied from the unlock command generation unit 41. The measurement start signal DM is generated and output. The measurement start signal generation unit 23 supplies the output measurement start signal DM to the phase modulation unit 24 and the delay measurement unit 40.

The phase modulation unit 24 is obtained by two-phase phase modulation (BPSK: binary phase-shift keying) in which a carrier signal of, for example, 300 MHz in the UHF band having a phase synchronized with the clock signal CK1 is phase-modulated with the measurement start signal DM. The modulation measurement start signal PM is supplied to the transmission amplifier 22.

FIG. 5 is a circuit diagram showing an example of the internal configuration of the phase modulation unit 24.

In FIG. 5, the inverter 220 supplies the mixer 221 with a signal in which the phase of the measurement start signal DM is inverted. The VCXO (Voltage-Controlled Crystal Oscillator) 222 as a voltage-controlled crystal oscillator generates, for example, a 300 MHz oscillation signal Vf phase-synchronized with the clock signal CK1 as a carrier signal, which is used in the mixer 221 and the 180-degree phase inversion unit 223. Supply.

The mixer 221 outputs a multiplication result obtained by multiplying the phase-inverted signal of the measurement start signal DM consisting of a binary bit string by the oscillation signal Vf, and supplies this to the adder 224.

The 180-degree phase inversion unit 223 generates an inverted oscillation signal Vfb in which the phase of the oscillation signal Vf is inverted by 180 degrees, and supplies this to the mixer 225.

The mixer 225 outputs a multiplication result obtained by multiplying the above-mentioned measurement start signal DM by the inverting oscillation signal Vfb, and supplies this to the adder 224.

The adder 224 outputs a signal representing an addition result obtained by adding the output of the mixer 221 and the output of the mixer 225 as a modulation measurement start signal PM.

With the above configuration, the phase modulation unit 24 has, for example, the waveform shown in FIG. 4 in which the oscillation signal Vf (carrier signal) shown in FIG. 4 is phase-modulated with the measurement start signal DM composed of the binary bit string [10111001]. The modulation measurement start signal PM is generated.

The transmission amplifier 22 shown in FIG. 3 amplifies the modulation measurement start signal PM or the clock synchronization request signal CRQ described above, and wirelessly transmits this via the antenna 26.

The receiving amplifier 27 supplies the received signal RF, which is an amplified signal received via the antenna 26, to the phase demodulation unit 28 and the clock synchronization unit 29.

The phase demodulation unit 28 generates a demodulation data signal PD composed of a binary bit string by performing a phase demodulation process on the received signal RF using a carrier signal having a phase synchronized with the clock signal CK1.

FIG. 6 is a circuit diagram showing an example of the internal configuration of the phase demodulation unit 28.

In FIG. 6, the VCXO281 as a voltage-controlled crystal oscillator generates an oscillation signal Vf of, for example, 300 MHz as a carrier signal phase-synchronized with the clock signal CK1, and supplies this to the mixer 282 and the 180-degree phase inversion unit 283.

The mixer 282 outputs a multiplication result obtained by multiplying the received signal RF by the oscillation signal Vf, and supplies this to the bit determination unit 284.

The 180-degree phase inversion unit 283 generates an inverted oscillation signal Vfb in which the phase of the oscillation signal Vf is inverted by 180 degrees, and supplies this to the mixer 285.

The mixer 285 outputs a multiplication result obtained by multiplying the received signal RF by the inverting oscillation signal Vfb, and supplies this to the bit determination unit 284.

Based on the output results of the mixers 282 and 285, for example, the bit determination unit 284 determines whether the logic level of the bit represented every two cycles of the oscillation signal Vf is the logic level 0 or the logic level 1. judge. Then, the bit determination unit 284 generates a demodulation data signal PD composed of a binary bit string based on the determination result, and supplies the demodulation data signal PD to the delay measurement unit 40 shown in FIG.

For example, when the received signal RF corresponding to the response signal consisting of the bit string [111001] is supplied to the phase demodulation unit 28, the mixers 282 and 285 are shown in FIG. 7 by the oscillation signal Vf and the inverting oscillation signal Vfb shown in FIG. 7, respectively. Outputs a signal with the indicated waveform. Here, the bit determination unit 284 is logical when the level of the signal output from the mixer 282 is lower than the predetermined amplitude center value Th1 and the level of the signal output from the mixer 285 is equal to or higher than the amplitude center value Th1. Judged as level 0. Further, the bit determination unit 284 has a logic level when the level of the signal output from the mixer 282 is equal to or higher than the predetermined amplitude center value Th1 and the level of the signal output from the mixer 285 is lower than the amplitude center value Th1. Determined to be 1.

Therefore, according to the received signal RF having the waveform shown in FIG. 7, the bit determination unit 284 generates a demodulated data signal PD representing a response signal composed of a binary bit string [111001], and causes the delay measurement unit 40 to generate a demodulated data signal PD. Supply.

The clock synchronization unit 29 shown in FIG. 3 generates a clock signal having the same frequency as the carrier signal, for example, a clock signal of 300 MHz as the clock signal CK1. The clock synchronization unit 29 supplies the clock signal CK1 to the clock synchronization request signal generation unit 21, the phase modulation unit 24, the measurement start signal generation unit 23, the phase demodulation unit 28, and the delay measurement unit 40.

The clock synchronization unit 29 performs synchronization processing for synchronizing the phase of the clock signal CK1 with the clock synchronization signal according to the clock synchronization signal included in the received signal RF.

FIG. 8 is a block diagram showing an example of the internal configuration of the clock synchronization unit 29.

As shown in FIG. 8, the clock synchronization unit 29 is a so-called PLL (phase locked loop) circuit having a phase comparator 291 and a loop filter 292 and VCXO293 as a voltage controlled crystal oscillator.

The phase comparator 291 supplies a phase error signal representing the phase difference between the clock synchronization signal included in the received signal RF and the clock signal CK1 to the VCXO293 via the loop filter 292. The VCXO293 outputs a clock signal CK1 whose frequency is changed based on the phase error signal.

FIG. 9 is a waveform diagram showing an example of the format of the clock synchronization signal included in the received signal RF. As shown in FIG. 9, the clock synchronization signal includes a header portion consisting of a binary bit string [1101], a synchronization signal portion in which 16 bits of logic level 0 are continuous, and a bit string [11] representing the end of the synchronization signal. ] Corresponds to the clock synchronization pattern including the end part. That is, the clock synchronization signal is the above-mentioned carrier wave signal phase-modulated with the clock synchronization pattern [1101000000000000000011].

The delay measurement unit 40 shown in FIG. 3 includes a count start unit 401, a counter 402, a response determination unit 403, and a count stop unit 404.

When the measurement start signal DM is output from the measurement start signal generation unit 23, the count start unit 401 supplies the count start signal STA instructing the start of the count operation to the counter 402.

The response determination unit 403 determines whether or not the demodulated data signal PD supplied from the phase demodulation unit 28 represents a response signal. That is, the response determination unit 403 supplies the response detection signal RPD indicating that the response signal has been detected to the counter stop unit 404 when the demodulated data signal PD includes, for example, a binary bit string [111001].

The counter stop unit 404 supplies the counter 402 with a count stop signal STP instructing the stop of the count operation according to the response detection signal RPD.

The counter 402 starts counting the number of pulses of the clock signal CK1 from, for example, the initial value "0" according to the count start signal STA. Further, the counter 402 stops the counting operation of the number of pulses of the clock signal CK1 in response to the count stop signal STP, and supplies the count value at the time of the stop to the unlock command generation unit 41 as the count value CNV. The count value CNV is the delay time required from the wireless transmission of the measurement start signal by the electronic lock control unit 200 to the reception of the response signal wirelessly transmitted by the electronic key 300 in response to the reception of the measurement start signal. That is, it corresponds to the distance between the electronic lock control unit 200 and the electronic key 300.

The unlock command generation unit 41 executes the operations shown in steps S15 to S19 shown in FIG. For example, the unlock command generation unit 41 supplies the transmission command X1 to the clock synchronization request signal generation unit 21 in step S15 shown in FIG. 2 to supply the clock synchronization request signal generation unit 21 to the clock synchronization request signal CRC. Prompt the generation of.

Further, in step S17 shown in FIG. 2, the unlock command generation unit 41 supplies the measurement start signal generation unit 23 with the measurement start signal DM by supplying the transmission command X2 to the measurement start signal generation unit 23. prompt.

Further, the unlock command generation unit 41 determines in step S18 whether or not the count value CNV is less than a predetermined threshold value. Here, when it is determined that the count value CNV is less than a predetermined threshold value, the unlock command generation unit 41 supplies the electronic lock 400 with the unlock command signal LK for unlocking the electronic lock 400 in step S19. do.

FIG. 10 is a block diagram showing an example of the internal configuration of the electronic key 300. Note that FIG. 10 shows an excerpt of the internal configuration of the electronic key 300, which is necessary for performing the relay attack prevention processing in steps S15 to S18 and S25 to S28 described above.

In FIG. 10, the receiving amplifier 31 amplifies the signal received via the antenna 30, and supplies the amplified signal as a received signal RFQ to the phase demodulation unit 32.

The phase demodulation unit 32 generates a demodulated data signal PDQ consisting of a binary bit string by performing phase demodulation processing on the received signal RFQ using a carrier signal having a phase synchronized with the clock signal CK2. Is supplied to the measurement start determination unit 33. The internal configuration of the phase demodulation unit 32 is the same as the internal configuration of the phase demodulation unit 28 shown in FIG.

The measurement start determination unit 33 determines whether or not the demodulated data signal PDQ represents the measurement start signal. That is, the measurement start determination unit 33 supplies the counter 34 and the control unit 35 with a delay measurement detection signal DTM indicating that the measurement start signal is detected when the demodulated data signal PDQ includes, for example, a binary bit string [10111001]. do.

The counter 34 counts the number of pulses of the clock signal CK1 from the time when the delay measurement detection signal DTM is supplied, and supplies the count value to the control unit 35 as the count value Tm.

The control unit 35 executes the operations shown in steps S21 to S28 shown in FIG. For example, in step S26 shown in FIG. 2, the control unit 35 supplies the transmission command Y1 to the clock synchronization signal generation unit 36 to prompt the clock synchronization signal generation unit 36 to generate the clock synchronization signal.

The response start control unit included in the control unit 35 transmits at the timing of step S28 shown in FIG. 2 according to the delay measurement detection signal DTM when the tricode encryption operation is completed at this time. The command Y1 is supplied to the clock synchronization signal generation unit 36. On the other hand, when the tricode encryption operation is not completed at this time, the response start control unit counts the count value Tm supplied from the counter 34 corresponding to the time spent in the tricode encryption operation. When it becomes equal to the value, the transmission command Y2 is supplied to the response signal generation unit 37.

The clock synchronization signal generation unit 36 generates a clock synchronization signal SYC in which the above carrier wave signal is phase-modulated with a clock synchronization pattern consisting of a binary bit string [1101000000000000000011] as shown in FIG. 9, for example, in response to the transmission command Y1. do. The clock synchronization signal generation unit 36 supplies the clock synchronization signal SYC to the transmission amplifier 38.

The response signal generation unit 37 generates a response signal RSP composed of, for example, a binary bit string [111001] synchronized with the clock signal CK2 in response to the transmission command Y2 described above, and supplies the response signal RSP to the phase modulation unit 39.

The phase modulation unit 39 generates a modulation response signal PMQ in which a carrier signal having a phase synchronized with the clock signal CK2, for example, a carrier signal of 300 MHz is phase-modulated with a response signal RSP composed of a binary bit string [111001], and transmits the modulation response signal PMQ. It is supplied to the amplifier 38. The internal configuration of the phase modulation unit 39 is the same as the internal configuration of the phase modulation 24 shown in FIG.

The clock generation unit 50 generates a clock signal having the same frequency as the carrier signal, and uses this as the clock signal CK2 described above as the phase demodulation unit 32, the clock synchronization signal generation unit 36, the response signal generation unit 37, and the phase modulation. Supply to unit 39.

The transmission amplifier 38 amplifies the above-mentioned modulation response signal PMQ or clock synchronization signal SYC, and wirelessly transmits this via the antenna 30.

As described above, in the electronic lock control unit 200 and the electronic key 300, the delay time required from the wireless transmission of the measurement start signal by the electronic lock control unit 200 to the reception of the response signal from the electronic key 300 is set by the counter 402. Is measured by counting the number of pulses of the clock signal CK1.

This delay time is mainly the total time of the following (1) to (8).

(1) Processing time in the phase modulation unit 24 of the electronic lock control unit 200 (2) Time for radio waves to propagate in the space between the electronic lock control unit 200 and the electronic key 300 (3) Processing of the phase demodulation unit 32 of the electronic key 300 Time (4) Time required to generate the response signal RSP in the electronic key 300 (5) Processing time of the phase modulation unit 39 of the electronic key 300 (6) Radio waves in the space between the electronic key 300 and the electronic lock control unit 200 (7) Processing time of the phase demodulation unit 28 of the electronic lock control unit 200 (8) Processing time of the response determination unit 403 of the electronic lock control unit 200 By clock synchronization processing (S15, S16, S25 and S26) The phase of the clock signal CK1 of the electronic lock control unit 200 and the phase of the clock signal CK2 of the electronic key 300 are synchronized. As a result, among the above (1) to (8), each processing time in (1), (3) to (5), (7) and (8) becomes a fixed value.

Therefore, the count value CNV obtained by counting the number of pulses of the clock signal by the counter 402 is the time required for the radio wave to make one round trip between the above-mentioned (2) and (6), that is, the electronic lock control unit 200 and the electronic key 300. That is, it changes depending on the physical distance between the electronic lock control unit 200 and the electronic key 300.

At this time, since the speed of the radio wave is 3 × ¹⁰⁸ [m / s], if a clock signal having the same frequency as the carrier signal of, for example, 300 MHz in the UHF band is used, one cycle of this clock signal is 1 meter. .. As a result, the "10" count of the count value CNN represents 10 meters, that is, 5 meters as the physical distance between the electronic lock control unit 200 and the electronic key 300. Therefore, the count value CNV adds "10" to the count value corresponding to the predetermined fixed time obtained by totaling the processing times of (1), (3) to (5), (7) and (8) described above. If it is larger than the value, it can be determined that the distance between the two (200, 300) exceeds 5 meters.

By the way, in the electronic lock system 100, as a modulation method of wireless communication performed between the electronic lock control unit 200 and the electronic key 300 in order to measure the above-mentioned delay time (distance between the electronic lock control unit 200 and the electronic key 300). The phase modulation is adopted.

That is, in the electronic lock system 100, first, the phase modulation unit 24 of the electronic lock control unit 200 phase-modulates this carrier signal with the measurement start signal DM by using the carrier signal (Vf) having a phase synchronized with the clock signal. The modulated measurement start signal PM is wirelessly transmitted to the electronic key 300.

Then, the phase demodulation unit 32 of the electronic key 300 obtains a demodulated data signal PDQ by performing a phase demodulation process on the received modulation measurement start signal. Then, the measurement start determination unit 33 of the electronic key 300 determines whether or not the demodulated data signal PDQ represents the measurement start signal. At this time, the modulation measurement start signal received by the electronic key 300 is a so-called two-phase phase modulation in which a carrier signal phase-synchronized with the clock signal is phase-modulated with the measurement start signal. Therefore, the phase demodulation unit 32 can detect the phase change point in the phase modulation signal as the transition point of the signal level (logic level 0 or 1) of the measurement start signal. As a result, the electronic key 300 can acquire the measurement start signal after a predetermined fixed time has passed from the time when the phase modulation signal corresponding to the measurement start signal is received.

Here, when the demodulated data signal PDQ is determined by the measurement start determination unit 33 of the electronic key 300 to represent the measurement start signal, the phase modulation unit 39 of the electronic key 300 phase-modulates the carrier signal with the response signal RSP. The response signal PMQ is wirelessly transmitted to the electronic lock control unit 200.

Then, the phase demodulation unit 28 of the electronic lock control unit 200 obtains a demodulated data signal PD by performing a phase demodulation process on the received modulation response signal. Then, the response determination unit 403 of the electronic lock control unit 200 determines whether or not the demodulated data signal PD represents a response signal. At this time, the modulation response signal received by the electronic lock control unit 200 is a so-called two-phase phase modulation in which a carrier signal phase-synchronized with the clock signal is phase-modulated with the response signal. Therefore, the phase demodulation unit 28 can detect the phase change point in the phase modulation signal as the transition point of the signal level (logic level 0 or 1) of the response signal. As a result, the electronic lock control unit 200 can acquire the response signal after a predetermined fixed time has passed from the time when the phase modulation signal corresponding to the response signal is received.

Therefore, according to the electronic lock system 100, the demodulated signal (measurement) is performed after a predetermined fixed period has elapsed from the time when the modulated signal is received by the antenna (26, 30) even under the influence of noise, interference waves, and the like. It becomes possible to acquire a start signal and a response signal).

When amplitude modulation is adopted as the modulation method, the envelope detection is performed before the demodulation process, so that the amplitude fluctuates due to the influence of noise and interfering waves. For example, the smaller the amplitude, the more difficult it is to demodulate, and the longer the time spent in the demodulation process. As a result, the time from the time when the modulated signal is received by the antenna to the time when the demodulated signal is acquired will fluctuate significantly. Therefore, when the band of the carrier wave to be used is relatively low such as the LF band or the UHF band, it is difficult to measure the distance between the electronic lock control unit and the electronic key in meters.

On the other hand, in the electronic lock system 100, the distance between the electronic lock control unit 200 and the electronic key 300 is set in meters by using a carrier wave signal of, for example, 300 MHz in the UHF band generally used in the smart entry system. It becomes possible to measure.

Therefore, according to the present invention, it is possible to suppress high cost and prevent relay attack without malfunction.

FIG. 11 is a communication flow diagram showing another example of the unlocking process performed between the electronic lock control unit 200 and the electronic key 300.

In FIG. 11, the electronic lock control unit 200 wirelessly transmits an activation signal for activating the electronic key 300 by radio waves in the LF band (step S101). After the execution of step S101, the electronic lock control unit 200 determines whether or not a predetermined key ID signal has been received (step S102), and if it is determined that the key ID signal has not been received, the process returns to step S101 and the operation described above is performed again. I do.

During this time, the electronic key 300 determines whether or not the activation signal has been received (step S201), and when it is determined that the activation signal has been received, the electronic key 300 transmits a predetermined key ID signal and a clock synchronization signal by radio waves in the UHF band. Wireless transmission (step S202). After executing step S202, the electronic key 300 returns to step S201 and performs the above-described operation again. If it is determined in step S201 that the activation signal has not been received, the electronic key 300 determines whether or not the measurement start signal has been received (step S203).

When the electronic lock control unit 200 determines that the key ID signal has been received in step S102, the electronic lock control unit 200 performs a synchronization process for synchronizing its own clock signal with the phase of the clock synchronization signal received following the key ID signal (step). S103). After the execution of step S103, the electronic lock control unit 200 wirelessly transmits the measurement start signal and the above-mentioned tricode in order by radio waves in the UHF band (step S104). After executing step S104, the electronic lock control unit 200 determines whether or not an appropriate cryptographic tricode corresponding to the tricode wirelessly transmitted in step S104 has been received (step S105).

When the electronic key 300 determines that the measurement start signal has been received in step S203, the electronic key 300 performs an encryption operation using a predetermined encryption key on the tricode received following the measurement start signal to perform an encryption tricode. (Step S204). Next, the electronic key 300 wirelessly transmits the encrypted tricode on the UHF band radio wave (step S205), and subsequently wirelessly transmits the response signal on the UHF band radio wave (step S206). After executing step S206, the electronic key 300 returns to step S201 and performs the series of operations described above again.

Here, if it is determined in step S105 that the proper cryptographic tricode has not been received, the electronic lock control unit 200 returns to step S101 and executes the series of operations described above again.

On the other hand, when it is determined in step S105 that an appropriate cryptographic tricode has been received, the electronic lock control unit 200 wirelessly transmits the response signal from the electronic key 300 within a predetermined time from the time when the measurement start signal is wirelessly transmitted. Is determined (step S106).

If it is determined in step S106 that the response signal has not been received, or that the response signal has been received after a predetermined time has passed, the electronic lock control unit 200 returns to step S101 and again performs the series of operations described above. To execute. If it is determined in step S106 that the response signal has been received within a predetermined time, the unlock command signal LK is supplied to the electronic lock 400 (step S107). The electronic lock 400 unlocks the door of the vehicle in response to the unlock command signal LK.

As described above, in the unlocking process shown in FIG. 11, after the key ID is confirmed (steps S102 and S202) and the clock synchronization process (S202 and S103) is subsequently executed, the electronic lock control unit 200 outputs the measurement start signal. And, both signals are continuously wirelessly transmitted in the order of the tricode (S104). Upon receiving these measurement start signals and tricodes, the electronic key 300 wirelessly transmits an encrypted tricode (S204, S205) in which the received tricode is encrypted using a predetermined encryption key, and immediately wirelessly transmits a response signal. (S206). During this time, the electronic lock control unit 200 determines whether or not the received cryptographic tricode is appropriate (S105), and when the appropriate cryptographic tricode is received, continuously transmits a measurement start signal. It is determined whether or not the response signal is received within a predetermined time from (S106). Here, the electronic lock control unit 200 grants unlocking permission only when it is determined that the response signal has been received within a predetermined time, and unlocks the electronic lock 400 (S107).

Therefore, according to the unlocking process shown in FIG. 11, after the proper cryptographic tricode is acquired by the relay attack, the unauthorized person uses the pseudo electronic key for measuring the delay time (distance) with the electronic lock control unit 200. It is possible to prevent attacks that attempt to unlock the door by communicating at close range. That is, since it takes time to acquire an appropriate cryptographic tricode by the relay attack, the timing at which the electronic lock control unit 200 receives the response signal is delayed by that time. Therefore, since the electronic lock control unit 200 cannot receive the response signal within a predetermined time, the lock is not unlocked, and as a result, unauthorized unlocking of the door is prevented.

If the electronic lock control unit 200 or the electronic key 300 receives a wireless access that continues for a predetermined period of time or an unauthorized wireless access such as a wireless access that exceeds a specified number of times, the electronic lock control unit 200 or the electronic key 300 forcibly performs its own operation. It may be stopped to ensure safety and save power.

For example, when the electronic key 300 continuously receives the modulation measurement start signal for a predetermined number of times or more within a predetermined period, it is determined that the electronic key 300 has been subjected to a relay attack due to unauthorized wireless access, and its operation is stopped. By doing so, the power consumption is suppressed. The electronic lock control unit 200 in the stopped operation state is restarted when, for example, the key ID wirelessly transmitted from the electronic key 300 is received by operating the release switch provided on the electronic key 300.

Further, when the unauthorized wireless access as described above is received, the display indicating that the unauthorized wireless access has been received may be displayed on the display mounted on the vehicle.

FIG. 12 is a block diagram showing another configuration of the electronic lock system 100 made in view of this point. In the electronic lock system 100 shown in FIG. 12, the other configurations except that the display 500 is provided are the same as those shown in FIG.

In FIG. 12, when the electronic lock control unit 200 receives the illegal wireless access as described above, the display 500 displays an image signal and a voice signal for expressing in characters and voice that the illegal wireless access has been received. Supply to.

Further, in the above embodiment, the electronic lock system 100 shown in FIG. 1 is applied to the smart entry system of the vehicle to explain its operation, but the electronic lock system 100 may be applied to the door of a house or the like.

Further, in the above embodiment, the frequencies of the carrier signal and the clock signals CK1 and CK2 are the same, but the frequencies of the clock signals CK1 and CK2 may be 1 / n (n is an integer of 1 or more) of the carrier signal.

Further, during the unlocking process shown in FIG. 2 or FIG. 11, the processes for authenticating the key ID and the cryptographic tricode (S11 to S14, S21 to S24, S101 to S104, S201, S202, S204 and S205). ) Is included, but the processing may be omitted.

In short, the electronic lock system may include an electronic lock control unit and an electronic key that perform the following operations.

That is, the electronic lock control unit (200) includes the following clock synchronization unit, a first transmission unit, a first reception unit, and an unlock control unit. The clock synchronization unit (27, 29) receives the clock synchronization signal and performs synchronization processing for synchronizing the first clock signal (CK1) with the received clock synchronization signal. After the synchronization processing is completed, the first transmission unit (22 to 24, 26) is a modulation measurement start signal (DM) in which a carrier wave signal having a phase synchronized with the first clock signal is phase-modulated with a measurement start signal (DM). PM) is generated and this is transmitted wirelessly. The first receiving unit (26 to 28, 403) receives the modulation response signal corresponding to the response signal, and acquires the response signal by performing phase demodulation processing on the received modulation response signal. Then, the unlock command unit (41) is electronic when the delay time required from the generation of the modulation measurement start signal (DM) to the acquisition of the response signal by the first receiving unit is equal to or less than a predetermined time. Unlock the lock (400).

The electronic key (300) includes the following clock synchronization signal generation unit, a second reception unit, and a second transmission unit. The clock synchronization signal generation unit (36) generates a signal having a phase synchronized with the second clock signal (CK2) as a clock synchronization signal (SYC). The second receiving unit (30 to 33) receives the modulation measurement start signal and acquires the measurement start signal by performing phase demodulation processing on the received modulation measurement start signal. The second transmission unit (30, 37 to 39) wirelessly transmits the clock synchronization signal, generates a response signal in response to the acquisition of the measurement start signal, and has a carrier signal having a phase synchronized with the second clock signal. Is phase-modulated with this response signal to generate a modulation response signal (PMQ), which is transmitted wirelessly.

21 Clock synchronization request signal generation unit 23 Measurement start signal generation unit 24, 39 Phase modulation unit 28, 32 Phase demodulation unit 29 Clock synchronization unit 36 Clock synchronization signal generation unit 37 Response signal generation unit 40 Delay measurement unit 41 Unlocking command generation unit 100 Electronic lock system 200 Electronic lock control unit 300 Electronic key 400 Electronic lock

Claims (7)

An electronic lock system including an electronic lock control unit that controls unlocking of an electronic lock and an electronic key.
The electronic lock control unit is
A clock synchronization unit that receives a clock synchronization signal and performs synchronization processing to synchronize the first clock signal with the received clock synchronization signal.
After the end of the synchronization process, a first transmission unit that generates a modulation measurement start signal in which a carrier wave signal having a phase synchronized with the first clock signal is phase-modulated with a measurement start signal and wirelessly transmits the modulation measurement start signal.
A first receiving unit that receives a modulation response signal corresponding to the response signal and acquires the response signal by performing phase demodulation processing on the received modulation response signal.
An unlocking command unit that unlocks the electronic lock when the delay time from the generation of the modulation measurement start signal to the acquisition of the response signal by the first receiving unit is equal to or less than a predetermined time. , Including
The electronic key is
A clock synchronization signal generation unit that generates a signal synchronized with the second clock signal as the clock synchronization signal, and a clock synchronization signal generation unit.
A second receiving unit that receives the modulation measurement start signal and acquires the measurement start signal by performing phase demodulation processing on the received modulation measurement start signal.
The clock synchronization signal is wirelessly transmitted, the response signal is generated in response to the acquisition of the measurement start signal, and the carrier signal having a phase synchronized with the second clock signal is phase-modulated with the response signal. An electronic clock system comprising a second transmitter that generates a modulated response signal and wirelessly transmits it. The electronic lock control unit is
The activation signal is wirelessly transmitted, and when a predetermined key identifier is received after the activation signal is wirelessly transmitted, a tricode consisting of a random number is wirelessly transmitted, and after the tricode is wirelessly transmitted, an encrypted tricode corresponding to the tricode is transmitted. When received, the clock synchronization request signal is transmitted wirelessly,
The electronic key is
When the activation signal is received, the key identifier is wirelessly transmitted, and when the tricode is received, the encrypted tricode in which the tricode is encrypted with a predetermined encryption key is wirelessly transmitted, and the clock synchronization request signal is transmitted. The electronic lock system according to claim 1, wherein the clock synchronization signal is wirelessly transmitted when the clock is received. The electronic lock control unit is
The activation signal is wirelessly transmitted, and when the predetermined key identifier and the clock synchronization signal are received after the wireless transmission of the activation signal, the synchronization processing is performed and then the tricode consisting of the modulation measurement start signal and the random number is wirelessly transmitted in order. When the signal is transmitted and the encrypted tricode corresponding to the tricode is received, it is determined whether or not the delay time is the predetermined time or less, and when the delay time is the predetermined time or less, the electronic lock is used. Unlock and
The electronic key is
When the activation signal is received, the key identifier and the clock synchronization signal are transmitted wirelessly in order, and when the modulation measurement start signal and the tricode are received, the tricode is encrypted with a predetermined encryption key. The electronic lock system according to claim 1, wherein a cryptographic tricode is wirelessly transmitted, and then the modulation response signal is wirelessly transmitted. The electronic key is characterized in that when it receives the modulation measurement start signal more than a predetermined number of times within a predetermined period, it is determined that it has received an unauthorized radio access and its operation is forcibly stopped. Item 3. The electronic lock system according to any one of Items 1 to 3. The electronic lock system according to claim 4, wherein the electronic lock control unit displays character information indicating that the unauthorized wireless access has been received on the display. An electronic lock control device that controls the unlocking of electronic locks.
A clock synchronization unit that receives a clock synchronization signal and performs synchronization processing to synchronize the clock signal with the received clock synchronization signal.
After the end of the synchronization process, a transmission unit that generates a modulation measurement start signal in which a carrier wave signal having a phase synchronized with the clock signal is phase-modulated with a measurement start signal and wirelessly transmits the modulation measurement start signal.
A receiving unit that receives a phase modulation response signal corresponding to the response signal and acquires the response signal by performing phase demodulation processing on the received phase modulation response signal.
It has an unlocking command unit for unlocking the electronic lock when the delay time from the generation of the modulation measurement start signal to the acquisition of the response signal by the receiving unit is equal to or less than a predetermined time. An electronic lock control device characterized by this. A method for unlocking an electronic lock in an electronic lock system including an electronic lock control unit that controls unlocking of the electronic lock and an electronic key.
The electronic lock control unit is
When a clock synchronization signal is received, a synchronization process for synchronizing the first clock signal with the clock synchronization signal is performed.
After the completion of the synchronization processing, a modulation measurement start signal in which a carrier wave signal having a phase synchronized with the first clock signal is phase-modulated with a measurement start signal is generated and wirelessly transmitted.
When the modulation response signal corresponding to the response signal is received, the response signal is acquired by performing phase demodulation processing on the modulation response signal.
When the delay time from the generation of the modulation measurement start signal to the acquisition of the response signal is equal to or less than a predetermined time, the electronic lock is unlocked.
The electronic key is
The clock synchronization signal is wirelessly transmitted,
A signal synchronized with the second clock signal is generated as the clock synchronization signal, and the signal is generated.
When the modulation measurement start signal is received, the modulation measurement start signal is subjected to phase demodulation processing to acquire the measurement start signal.
The response signal is generated in response to the acquisition of the measurement start signal, and the carrier signal having a phase synchronized with the second clock signal is phase-modulated with the response signal to generate the modulation response signal. A method for unlocking an electronic lock in an electronic lock system characterized by wireless transmission.

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