JP2013142279A - Electronic key system and key id registration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve security in an electronic key system and a key ID registration method.SOLUTION: An encrypted key ID code IDk' is stored in an immobilizer 20a. An ID code IDh1 for conversion which decrypts the encrypted key ID code IDk' is then stored in an electronic key 10. The immobilizer 20a utilizes the ID code IDh1 for conversion included in an ID signal to decrypt the encrypted key ID code IDk' and collates a decrypted key ID code IDk with a key ID code IDk included in the received ID signal. Only the encrypted key ID code IDk' is stored in the immobilizer 20a but the ID code IDh1 for conversion which decrypts the encrypted key is not stored therein. Therefore, even in the case where unauthorized analysis is performed on the immobilizer 20a, the key ID code IDk can be suppressed from being acquired.

Description

  The present invention relates to an electronic key system and a key ID registration method.

  2. Description of the Related Art Conventionally, as an electronic key system, a configuration is known in which an engine start is permitted when a short-range wireless communication is established between an electronic key and a vehicle by holding the electronic key over a specific position of the vehicle (for example, an engine start switch). (For example, refer to Patent Document 1).

  Specifically, as shown in FIG. 5, the electronic key system of the above type includes an electronic key 110 possessed by a user and an immobilizer 120 mounted on the vehicle. The electronic key 110 stores a key ID code unique to the key in advance.

  The immobilizer 120 includes a CPU (Central Processing Unit) 121 that performs the overall control, and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 122 that is a nonvolatile memory.

  A method for registering the electronic key 110 in the immobilizer 120 will be described. When receiving the driving radio wave from the immobilizer 120, the electronic key 110 transmits an ID signal including a key ID code stored in advance. When receiving the ID signal, the CPU 121 of the immobilizer 120 stores the ID code included in the ID signal in the EEPROM 122. Thereby, registration of the electronic key 110 is completed. In the normal mode after registration, when the CPU 121 receives the ID signal from the electronic key 110, the CPU 121 collates the key ID code included in the ID signal with the key ID code stored in the EEPROM 122. When the verification of the key ID code is established, engine start is permitted.

  In order to improve security, the following registration method is also considered. Specifically, when registering the electronic key 110, first, the CPU 121 stores the conversion ID code. When the CPU 121 receives the ID signal from the electronic key 110, the CPU 121 encrypts the key ID code included in the ID signal through the stored conversion ID code, and stores the encrypted key ID code in the EEPROM 122.

  In this configuration, in the normal mode after registration of the electronic key 110, when the CPU 121 receives the ID signal from the electronic key 110, the CPU 121 converts the encrypted key ID code stored in the EEPROM 122 into the conversion key stored in itself. The decryption is performed through the ID code, and the decrypted key ID code is compared with the key ID code included in the received ID signal. When the verification of the key ID code is established, engine start is permitted.

JP 2010-12921 A

  In the configuration in which the encrypted key ID code is stored, the encrypted key ID code and the conversion ID code for decrypting the encrypted key ID code are stored in the same immobilizer 120. The storage of the key ID code and the conversion ID code in the immobilizer 120 in this way is not preferable from the viewpoint of security, especially considering that the vehicle is left for a long time.

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

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to the first aspect of the present invention, a key ID code unique to itself and a first ID code for conversion used for encryption or decryption of the key ID code are stored, and the key ID code and the first ID code are stored. An electronic key for wirelessly transmitting an ID signal including one conversion ID code and an encrypted key ID code encrypted in its first storage means are stored, and when the ID signal is received, the ID Decrypting the encryption key ID code using the first conversion ID code included in the signal, and collating the decrypted key ID code with the key ID code included in the received ID signal And an authentication device for authenticating whether or not the electronic key is genuine.

  According to this configuration, the authentication device stores the encryption key ID code. The first conversion ID code for decrypting the key ID code is stored in the electronic key. The authentication device decrypts the encrypted key ID code by using the first conversion ID code included in the ID signal, the decrypted key ID code, the key ID code included in the received ID signal, Perform the verification. The electronic key is authenticated through verification of the key ID code. Thus, only the encryption key ID code is stored in the authentication device, and the first conversion ID code for decrypting it is not stored. Therefore, even if an unauthorized analysis is performed on the authentication device, it is possible to suppress acquisition of the key ID code. Thereby, security can be improved.

  According to a second aspect of the present invention, in the electronic key system according to the first aspect, a second conversion ID code is stored in the second storage unit of the authentication device, and the first storage unit stores the second conversion ID code. Is stored with an encryption key ID code encrypted using the first conversion ID code and the second conversion ID code, and when the authentication device receives the ID signal, Decrypting the encryption key ID code using the first conversion ID code included in the signal and the second conversion ID code stored in the second storage means; The gist is that the decrypted key ID code is collated with the key ID code included in the received ID signal.

  According to this configuration, the first conversion ID code is stored in the electronic key, the second conversion ID code is stored in the second storage unit of the authentication device, and the first storage unit stores the second conversion ID code. An encryption key ID code encrypted using both conversion ID codes is stored. In this way, by providing both the electronic key and the authentication device with different conversion ID codes, it is possible to prevent the key ID code from being decrypted illegally. Therefore, security can be further improved.

  According to a third aspect of the present invention, a key ID code unique to the electronic key and a first conversion ID code used for encryption or decryption of the key ID code are written in the electronic key. An ID signal including the key ID code and the first conversion ID code is transmitted, and the authentication device uses the first conversion ID code included in the received ID signal and is included in the ID signal. The gist is to encrypt the key ID code to be stored and store the encrypted encryption key ID code in its own first storage means.

  According to this configuration, after the key ID code and the first conversion ID code are written in the electronic key, the encryption key ID code is written in the authentication device by performing communication between the electronic key and the authentication device. It is. In this way, the encryption key ID code can be easily registered in the authentication device. In addition, the security of communication between the electronic key and the authentication device after registration can be improved.

  According to a fourth aspect of the present invention, in the key ID registration method according to the third aspect, the second storage means of the authentication device uses a second ID used for encryption or decryption of the key ID code. A conversion ID code is written, and the authentication device includes the first conversion ID code included in the received ID signal, the second conversion ID code stored in the second storage means, The key is to encrypt the key ID code included in the ID signal and store the encrypted key ID code in the first storage means.

  According to this configuration, after writing the key ID code and the first conversion ID code into the electronic key and writing the second conversion ID code into the second storage means of the authentication device, the electronic key and the authentication device By performing communication between them, the encryption key ID code encrypted through the first and second conversion ID codes is written in the authentication device. Thus, the encryption key ID code encrypted with the two conversion ID codes can be easily registered in the authentication apparatus. In addition, the security of communication between the electronic key and the authentication device after registration can be improved.

  According to the present invention, security can be improved in the electronic key system and the key ID registration method.

The block diagram which shows the structure of the electronic key system in 1st Embodiment. The sequence chart which shows the operation | movement of the electronic key and immobilizer in the registration mode in 1st Embodiment. The sequence chart which shows the operation | movement of the electronic key and immobilizer which concern on key ID code collation in 1st Embodiment. The sequence chart which shows the operation | movement of the electronic key and immobilizer in the registration mode in 2nd Embodiment. The block diagram which shows the structure of the electronic key system in background art.

A first embodiment of an electronic key system according to the present invention will be described below with reference to FIGS.
As shown in FIG. 1, the electronic key system includes a transponder 10 a built in the electronic key 10 and an immobilizer 20 a mounted on the vehicle 20. Hereinafter, the configuration of the transponder 10a and the immobilizer 20a will be described.

  The transponder 10 a includes a transponder control unit 11 and a transponder side transmission / reception unit 12. The transponder control unit 11 has a non-volatile memory 11a, in which a key ID code IDk and a conversion ID code IDh1 are stored. Registration of the key ID code IDk in the memory 11a is performed by wire or wireless through a dedicated tool.

  The transponder 10a is driven by the driving radio wave from the immobilizer 20a. That is, the transponder control unit 11 is activated by the driving radio wave, generates an ID signal including the key ID code IDk and the conversion ID code IDh1 stored in its own memory 11a, and transmits the generated signal to the transponder side transmitting / receiving unit 12 Output to. The transponder side transmitting / receiving unit 12 modulates the ID signal and wirelessly transmits the modulated signal.

  In addition to the normal mode, the operation mode of the transponder control unit 11 includes a registration mode. This registration mode is an operation mode for registering a key ID code in the immobilizer 20a. In the registration mode, when the transponder control unit 11 receives a random number signal from the immobilizer 20a through the transponder side transmitting / receiving unit 12, the random number included in the random number signal is stored in the memory 11a as the conversion ID code IDh1.

The immobilizer 20 a includes a CPU 21, an immobilizer side transmission / reception unit 22, and an EEPROM 23.
The EEPROM 23 stores an encryption key ID code IDk ′ encrypted through the conversion ID code IDh1. A method for registering the encryption key ID code IDk ′ in the EEPROM 23 will be described in detail later. The immobilizer 20a corresponds to an authentication device.

The vehicle 20 includes a body ECU (Electronic Control Unit) 30, an engine switch 31, and an engine device 32 in addition to the immobilizer 20a.
When the body ECU 30 recognizes that the engine is stopped through the engine device 32, for example, when the foot brake of the vehicle is operated, the body ECU 30 outputs a drive radio wave transmission command signal to the CPU 21. When the CPU 21 receives the drive radio wave transmission command signal, the CPU 21 transmits the drive radio wave through the immobilizer-side transmitting / receiving unit 22. This drive radio wave is transmitted to the periphery of the engine switch 31 provided near the driver's seat. Therefore, when the electronic key 10 is held over the engine switch 31, the immobilizer transmission / reception unit 22 receives the ID signal from the electronic key 10. Then, the immobilizer transmitting / receiving unit 22 demodulates the received ID signal and outputs the demodulated signal to the CPU 21. When receiving the ID signal, the CPU 21 decrypts the encryption key ID code IDk ′ stored in the EEPROM 23 by using the conversion ID code IDh1 included in the signal. Then, the CPU 21 collates the decrypted key ID code IDk with the key ID code IDk included in the received ID signal. When CPU 21 determines that the verification of the key ID code has been established, CPU 21 outputs that fact to body ECU 30.

When the body ECU 30 recognizes that the engine switch 31 has been pressed in a state where the verification of the key ID code has been established, the body ECU 30 starts the engine through the engine device 32.
The operation mode of the CPU 21 includes a registration mode in addition to the normal mode. This registration mode is an operation mode when registering a key ID code in the EEPROM 23. In the registration mode, the CPU 21 generates a random number and wirelessly transmits a random number signal including the random number through the immobilizer-side transmission / reception unit 22 as described above.

  Next, operations of the electronic key 10 (transponder control unit 11) and the immobilizer 20a (CPU 21) in the registration mode will be described with reference to the sequence chart of FIG. It is assumed that the electronic key 10 stores a key ID code IDk in advance. This sequence chart starts when the transponder control unit 11 and the CPU 21 shift to the registration mode.

  The CPU 21 of the immobilizer 20a generates a random number and transmits a random number signal including the random number to the electronic key 10 (S101). Upon receiving the random number signal, the transponder control unit 11 of the electronic key 10 writes the random number included in the signal to the memory 11a as the conversion ID code IDh1 (S102). Then, the CPU 21 transmits a driving radio wave (S103). When receiving the driving radio wave, the transponder control unit 11 transmits an ID signal including the key ID code IDk and the conversion ID code IDh1 (S104). Thus, the operation of the registration mode of the transponder control unit 11 is completed and the normal mode is restored.

  The CPU 21 generates an encryption key ID code IDk ′ by encrypting the key ID code IDk included in the received signal using the conversion ID code IDh1 included in the received ID signal (S105). Then, the CPU 21 writes the generated encryption key ID code IDk ′ in the EEPROM 23 (S106). Thus, the operation of the registration mode of the CPU 21 is completed and the normal mode is restored.

  Next, operations in the normal mode of the electronic key 10 (transponder control unit 11) and the immobilizer 20a (CPU 21) related to key ID code verification will be described with reference to the sequence chart of FIG.

  CPU21 transmits a drive electric wave, when satisfy | filling specific conditions, such as the said engine stop, (S201). When receiving the driving radio wave, the transponder control unit 11 transmits an ID signal including the key ID code IDk and the conversion ID code IDh1 (S202). Thus, the process of the transponder control unit 11 is completed.

  The CPU 21 recognizes the key ID code IDk by decrypting the encryption key ID code IDk ′ stored in the EEPROM 23 using the conversion ID code IDh1 included in the received ID signal (S203). Then, the CPU 21 collates the decrypted key ID code IDk with the key ID code IDk included in the received ID signal (S204). When the CPU 21 determines that the verification of the key ID code IDk has been established, the CPU 21 outputs that fact to the body ECU 30. Thus, the processing of the CPU 21 ends. The body ECU 30 starts the engine when it recognizes that the engine switch 31 has been pressed in a state where the verification of the key ID code has been established.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) The encryption key ID code IDk ′ is stored in the immobilizer 20a. A conversion ID code IDh1 for decrypting the encryption key ID code IDk ′ is stored in the electronic key 10. The immobilizer 20a decrypts the encrypted key ID code IDk ′ using the conversion ID code IDh1 included in the ID signal from the electronic key 10, and the decrypted key ID code IDk and the received ID signal Collation with the included key ID code IDk is performed. The electronic key 10 is authenticated through verification of the key ID code IDk. Thus, only the encryption key ID code IDk ′ is stored in the immobilizer 20a, and the conversion ID code IDh1 for decrypting it is not stored. Therefore, even if an improper analysis is performed on the immobilizer 20a, the acquisition of the key ID code IDk can be suppressed. Thereby, security can be improved.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. The electronic key system of this embodiment is different from the first embodiment in that the conversion ID code is stored in both the electronic key and the immobilizer. Hereinafter, a description will be given focusing on differences from the first embodiment. Note that the electronic key system of this embodiment has the same configuration as the electronic key system of the first embodiment shown in FIG.

  As shown by the one-dot chain line in FIG. 1, the CPU 21 has a nonvolatile internal memory 21a, and a conversion ID code IDh2 is stored in the internal memory 21a. This conversion ID code IDh2 is a code different from the conversion ID code IDh1 stored in the electronic key 10 (memory 11a).

  Further, the EEPROM 23 stores an encryption key ID code IDk ″ encrypted with both conversion ID codes IDh1 and h2. The encryption key ID code IDk ″ is generated by further encrypting the encryption key ID code IDk ′ obtained by encrypting the key ID code IDk with the conversion ID code IDh1 using the conversion ID code IDh2.

  In communication related to key ID code verification, the transponder control unit 11 and the CPU 21 perform the same processing except for the processing in step S203 in FIG. That is, in step S203, the CPU 21 uses the conversion ID code IDh1 included in the received ID signal and the conversion ID code IDh2 stored in the internal memory 21a to store the encryption key ID stored in the EEPROM 23. The key ID code IDk is recognized by decrypting the code IDk ″.

  Next, operations of the electronic key 10 (transponder control unit 11) and the immobilizer 20a (CPU 21) in the registration mode will be described with reference to the sequence chart of FIG. It is assumed that the electronic key 10 stores a key ID code IDk in advance. This sequence chart starts when the transponder control unit 11 and the CPU 21 shift to the registration mode.

  The CPU 21 of the immobilizer 20a generates a random number and transmits a random number signal including the random number to the electronic key 10 (S301). Upon receiving the random number signal, the transponder control unit 11 of the electronic key 10 writes the random number included in the signal as the conversion ID code IDh1 in the memory 11a (S302). Further, the CPU 21 writes the random number generated by itself (random number different from the random number of the random number signal) into the internal memory 21a as the conversion ID code IDh2 (S303). Then, short-range wireless communication is executed between the electronic key 10 and the immobilizer 20a. That is, the CPU 21 of the immobilizer 20a transmits driving radio waves (S304). Upon receiving the driving radio wave, the transponder control unit 11 transmits an ID signal including the key ID code IDk and the conversion ID code IDh1 (S305). This completes the registration mode operation of the transponder control unit 11 and returns to the normal mode.

  The CPU 21 encrypts the key ID code IDk included in the signal by using the conversion ID code IDh1 included in the received ID signal and the conversion ID code IDh2 stored in the internal memory 21a. An encryption key ID code IDk ″ is generated (S306). Then, the CPU 21 writes the encryption key ID code IDk ″ into the EEPROM 23 (S307). Thus, the key ID code writing process in the CPU 21 is completed. Thus, the operation of the registration mode of the CPU 21 is completed, and the normal mode is restored.

The EEPROM 23 corresponds to first storage means, and the internal memory 21a of the CPU 21 corresponds to second storage means.
As described above, according to the embodiment described above, the following effects can be obtained.

  (2) The conversion ID code IDh1 is stored in the electronic key 10, the conversion ID code IDh2 is stored in the internal memory 21a of the immobilizer 20a, and encrypted using the conversion ID codes IDh1 and IDh2 in the EEPROM 23. The encryption key ID code IDk ″ is stored. Thus, by providing both the electronic key 10 and the immobilizer 20a with the conversion ID codes IDh1 and IDh2, it is possible to suppress the key ID code IDk from being decrypted illegally. Therefore, security can be further improved.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In both the above embodiments, the random number signal is transmitted from the immobilizer 20a to the electronic key 10. However, the random number signal may be omitted and the transponder control unit 11 of the electronic key 10 may generate a random number.

  In both the above embodiments, the ID signal includes the key ID code IDk and the conversion ID code IDh1, but the key ID code IDk and the conversion ID code IDh1 are included in separate signals and transmitted. Also good.

  In the second embodiment, the conversion ID code IDh2 is stored in the internal memory 21a. However, if the memory other than the EEPROM 23 in the immobilizer 20a is used, the conversion ID code IDh2 is stored in another memory. Also good.

In both the above embodiments, the EEPROM 23 is employed as the first storage means, but other nonvolatile memories may be employed.
In both the above embodiments, the engine can be started through short-range wireless communication between the electronic key 10 and the immobilizer 20a. However, the control content is not limited to this, and for example, the vehicle door can be unlocked and unlocked. Also good. In this case, the immobilizer 20a is provided outside the vehicle. The user attempts near field communication between the electronic key 10 and the immobilizer 20a from outside the vehicle.

In both the above embodiments, the electronic key system for vehicles is used, but this may be applied to other key systems such as an electronic key system for houses.
In both the above embodiments, the engine is permitted to start through communication between the transponder 10a and the immobilizer 20a by holding the electronic key 10 over the engine switch 31. However, the transponder 10a may be built in the grip portion of the mechanical key, and communication may be performed between the transponder 10a and the immobilizer 20a when the mechanical key is inserted into a key cylinder in the vehicle. Also in this configuration, the establishment of collation of the key ID code in the immobilizer 20a is a condition for starting the engine.

  -Another kind of electronic key system may be added to the electronic key system of both the above embodiments. For example, in a wireless key system which is a kind of electronic key system, a lock / unlock switch is provided on the electronic key 10 and a lock / unlock request signal including an ID code is wirelessly transmitted from the electronic key 10 based on a pressing operation of the lock / unlock switch. Is done. When determining that the ID code included in the received locking / unlocking request signal has been verified, the vehicle switches the locking / unlocking state of the vehicle door.

  In a so-called key operation free system, which is a kind of electronic key system, a request signal is transmitted from the vehicle to the vicinity thereof. When receiving the request signal, the electronic key 10 transmits a response signal including the ID code. When the vehicle determines that the ID code included in the received response signal has been verified, the vehicle is permitted to lock and unlock the vehicle door. In this state, when the vehicle recognizes that the lock switch of the outside door handle of the vehicle door has been operated, the vehicle switches the locking / unlocking state of the vehicle door. When the vehicle transmits a request signal to the vehicle interior and determines that ID code verification has been established for the response signal from the electronic key 10 existing in the vehicle interior, the vehicle is allowed to start the engine. In this state, when the vehicle recognizes that the engine switch 31 has been operated, it starts the engine.

  The request signal may be transmitted from the vehicle when the lock switch or the engine switch 31 is operated. In this case, when the ID code verification is established, the locking / unlocking state of the vehicle door is switched or the engine is started.

  -Moreover, the said key operation free system is the same bidirectional | two-way communication as the communication between the immobilizer 20a and the transponder 10a of the said embodiment. Therefore, in the key operation free system, as in the above embodiment, the conversion ID code IDh1 is registered in the electronic key, and the encryption key ID code IDk ′ is registered in the vehicle, thereby improving security. Can do.

  DESCRIPTION OF SYMBOLS 10 ... Electronic key, 10a ... Transponder, 11 ... Transponder control part, 11a ... Memory, 12 ... Transponder side transmission / reception part, 20 ... Vehicle, 20a ... Immobilizer (authentication apparatus), 21 ... CPU, 21a ... Internal memory, 22 ... Immobilizer Side transmission / reception unit, 23 ... EEPROM, 30 ... body ECU, 31 ... engine switch, 32 ... engine device.

Claims (4)

An ID including a key ID code unique to itself and a first conversion ID code used for encryption or decryption of the key ID code and including the key ID code and the first conversion ID code An electronic key for wireless transmission of signals;
The encrypted key ID code encrypted is stored in its first storage means, and when the ID signal is received, the first conversion ID code included in the ID signal is used to An authentication device that decrypts an encrypted key ID code and authenticates whether the electronic key is authentic or not by comparing the decrypted key ID code with a key ID code included in the received ID signal And an electronic key system. The electronic key system according to claim 1.
A second conversion ID code is stored in the second storage means of the authentication device, and
The first storage means stores an encryption key ID code encrypted using the first conversion ID code and the second conversion ID code,
Upon receiving the ID signal, the authentication device uses the first conversion ID code included in the ID signal and the second conversion ID code stored in the second storage means. An electronic key system that decrypts the encrypted key ID code and collates the decrypted key ID code with the key ID code included in the received ID signal. The electronic key is written with a key ID code unique to itself and a first conversion ID code used for encryption or decryption of the key ID code, and the electronic key includes the key ID code and the first ID code. Send an ID signal containing the conversion ID code,
The authentication device encrypts the key ID code included in the ID signal using the first conversion ID code included in the received ID signal, and uses the encrypted encryption key ID code as its first A key ID registration method stored in one storage means. In the key ID registration method according to claim 3,
In the second storage means of the authentication device, a second conversion ID code used for encryption or decryption of the key ID code is written,
The authentication device uses the first conversion ID code included in the received ID signal and the second conversion ID code stored in the second storage means to generate the ID signal. A key ID registration method of encrypting the key ID code included in the first storage means and storing the encrypted key ID code in the first storage means.