Electronic lock device, electronic lock system, locking / unlocking method, and program

Abstract

The present invention comprises: a certificate authority generation unit that has the function of issuing a public key certificate and generates an owner CA, which is a certificate authority that issues the public key certificate as an unlocking certificate used for unlocking or locking an electronic lock, in response to a request from an owner terminal serving as a digital key paired with the electronic lock; and a locking / unlocking control unit that controls unlocking or locking of the electronic lock in response to notification of the unlocking certificate issued from the terminal by the owner CA.

Description

Electronic Locking Device, Electronic Locking System, Locking / Unlocking Method, and Program

[0001] The present invention relates to an electronic locking device, an electronic locking system, a locking / unlocking method, and a program. This application claims priority based on Japanese Patent Application No. 2025-004154 filed in Japan on January 10, 2025, and incorporates the content thereof herein by reference.

[0002] Conventionally, the keys for doors such as those of vehicles and entrances were physical keys, but in recent years, digital keys, which are electronic keys, have begun to spread. A digital key can be used, for example, by executing a dedicated application (key application) installed on a terminal such as a smartphone. For example, Patent Document 1 discloses a system that controls locking and unlocking of a door by communicating between a digital key and an electronic lock provided on the door.

[0003] Japanese Patent Application Laid-Open No. 2017-216596

[0004] However, when using highly secure user authentication using a public key certificate for determining whether to unlock, while the security can be enhanced, it is necessary to exchange messages to obtain a certificate from a certification authority, and the process becomes complicated.

[0005] The present invention has been made in view of such a situation, and an object thereof is to provide an electronic locking device, an electronic locking system, a locking / unlocking method, and a program that can perform locking and unlocking using highly secure user authentication without complicating the process.

[0006] An electronic locking device according to a first aspect of the present invention is a certification authority generation unit that has a function of issuing a public key certificate and generates an owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used for unlocking or locking an electronic lock in response to a request from an owner terminal as a digital key paired with the electronic lock, and an unlocking / locking control unit that controls unlocking or locking of the electronic lock in response to being notified that the unlocking certificate issued by the owner CA has been received from the terminal.

[0007] A second aspect of the present invention is an electronic lock device according to the first aspect, wherein the electronic lock has a mechanism that can be unlocked by a physical key, the electronic lock is unlocked by the physical key, the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the device further comprises an owner authentication unit that authenticates the owner terminal when the electronic lock is unlocked by the physical key and the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the manufacturer CA's public key certificate is stored in the electronic lock device, and the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit.

[0008] In the second embodiment, the owner authentication unit may determine that owner authentication is complete when the electronic lock is unlocked with a physical key, and the certification authority generation unit may generate an owner CA. Also in the second embodiment, the owner authentication unit may determine that owner authentication is complete when it determines that the certificate notified from the terminal is an owner certificate issued by the manufacturer's CA, and the certification authority generation unit may generate an owner CA.

[0009] In a second embodiment, the electronic lock may be unlocked not by a physical key, but by any key such as a card key or key fob.

[0010] In a second embodiment, any conditions relating to the generation of owner CAs may be set. For example, a specific period may be set during which the generation of owner CAs is possible, or the number of times owner CAs are to be generated may be specified.

[0011] A third aspect of the present invention is an electronic lock device according to the first aspect, further comprising an owner authentication unit that authenticates the owner terminal when the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the manufacturer CA's public key certificate is stored in the electronic lock device, wherein the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit.

[0012] A fourth aspect of the present invention is an electronic lock device according to any of the first to third aspects, wherein the certification authority generation unit, in response to a request from the owner terminal, causes the owner CA to issue the unlocking certificate to be used by the owner terminal, and the owner CA issues the public key certificate, which includes an electronic signature obtained by signing the owner terminal's public key with the owner CA's private key, as the unlocking certificate to be used by the owner terminal.

[0013] A fifth aspect of the present invention is an electronic lock device according to any of the first to fourth aspects, wherein the certification authority generation unit, in response to a request from the owner terminal, causes the owner CA to issue the unlocking certificate to be used by a friend terminal different from the owner terminal, and the owner CA issues a public key certificate, which includes an electronic signature obtained by signing the public key of the friend terminal using the private key of the owner CA, as the unlocking certificate to be used by the friend terminal.

[0014] A sixth aspect of the present invention is an electronic lock device according to any of the first to fifth aspects, further comprising an unlocking certificate management unit that invalidates the unlocking certificate issued by the owner CA in response to a request from the owner terminal.

[0015] A seventh aspect of the present invention is an electronic lock device according to any of the first to sixth aspects, further comprising a certification authority management unit that deletes the owner CA generated by the certification authority generation unit in response to a request from the owner terminal.

[0016] An eighth aspect of the present invention is an electronic lock device according to any of the first to sixth aspects, further comprising a certification authority management unit that, in response to a request from the owner terminal, generates a new owner CA, which is a second owner CA, different from the first owner CA, which is the owner CA, generated by the certification authority generation unit.

[0017] An electronic lock device according to a ninth aspect of the present invention comprises: a certification authority generation unit that generates an owner CA, which is a certification authority that issues a public key certificate in response to a request from an owner terminal, which is a digital key paired with the electronic lock, and issues a public key certificate used as an unlocking certificate for unlocking or locking the electronic lock; and a lock / unlock control unit that controls unlocking or locking the electronic lock in response to the terminal notifying the terminal of the unlocking certificate issued by the owner CA, wherein the electronic lock has a mechanism that can be unlocked with a physical key, the electronic lock is unlocked with the physical key, the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the public key certificate of the manufacturer CA is stored in the electronic lock device, and the certification authority generation unit further comprises an unlocking certificate management unit that generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit, and invalidates the unlocking certificate already issued by the owner CA in response to a request from the owner terminal.

[0018] An electronic lock device according to a tenth aspect of the present invention comprises: a certification authority generation unit that generates an owner CA, which is a certification authority that issues a public key certificate in response to a request from an owner terminal, which is a digital key paired with the electronic lock, and issues a public key certificate used to unlock or lock the electronic lock; and a lock / unlock control unit that controls the unlocking or locking of the electronic lock in response to the terminal notifying the terminal of the unlock certificate issued by the owner CA, wherein the electronic lock has a mechanism that can be unlocked with a physical key, the electronic lock is unlocked with the physical key, the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the public key certificate of the manufacturer CA is stored in the electronic lock device, and the certification authority generation unit further comprises a certification authority management unit that generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit, and deletes the owner CA generated by the certification authority generation unit in response to a request from the owner terminal.

[0019] An electronic lock device according to an eleventh aspect of the present invention comprises: a certification authority generation unit that generates an owner CA, which is a certification authority that has the function of issuing a public key certificate and issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock in response to a request from an owner terminal which is a digital key paired with the electronic lock; and a lock / unlock control unit that controls the unlocking or locking of the electronic lock in response to the terminal notifying the unlocking certificate issued by the owner CA, wherein the electronic lock has a mechanism that can be unlocked with a physical key, and when the electronic lock is unlocked with the physical key, the terminal notifies The Certificate Authority Generation Unit further comprises an Owner Authentication Unit that authenticates the owner terminal when the issued certificate is an owner certificate issued by a manufacturer CA and the manufacturer CA's public key certificate is stored in the electronic lock device, and the Certificate Authority Generation Unit further comprises an Unlock Certificate Management Unit that generates the owner CA in response to a request from the owner terminal authenticated by the Owner Authentication Unit, invalidates the unlock certificate already issued by the owner CA in response to a request from the owner terminal, and a Certificate Authority Management Unit that deletes the owner CA generated by the Certificate Authority Generation Unit in response to a request from the owner terminal.

[0020] An electronic lock system according to a twelfth aspect of the present invention comprises an electronic lock device according to any one of the first to eleventh aspects, and an owner terminal that communicates with the electronic lock device, instructs the electronic lock device to generate the owner CA, and obtains the unlocking certificate issued by the owner CA.

[0021] A thirteenth aspect of the present invention is an electronic lock system according to the twelfth aspect, wherein the unlocking certificate issued by the owner CA has an expiration date set, the owner terminal transmits the unlocking certificate along with a timestamp to the electronic lock device, and the lock / unlock control unit of the electronic lock device controls the unlocking or locking of the electronic lock when it determines that the unlocking certificate notified by the owner terminal is valid based on the timestamp notified by the owner terminal.

[0022] In the 13th embodiment, conditions regarding the timestamp notified from the owner terminal may be set, and a limit may be placed on the number of times authentication (determination) that the unlocking certificate is valid may be set, and control may be implemented to prevent authentication from being performed more times than the limit.

[0023] A locking and unlocking method according to a fourteenth aspect of the present invention is a locking and unlocking method executed by a computer which is an electronic lock device, wherein a certification authority generation unit has the function of issuing public key certificates and generates an owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock in response to a request from an owner terminal which is a digital key paired with the electronic lock, and a locking and unlocking control unit controls the unlocking or locking of the electronic lock in response to the terminal notifying the unlocking certificate issued by the owner CA.

[0024] A program according to a 15th aspect of the present invention causes a computer, which is an electronic lock device, to generate an Owner CA, which is a certification authority that issues a public key certificate in response to a request from an Owner terminal, which is a digital key paired with the electronic lock, and to control the unlocking or locking of the electronic lock in response to the notification from the terminal of the unlocking certificate issued by the Owner CA.

[0025] According to the present invention, locking and unlocking can be performed using highly secure user authentication without complicating the process.

[0026] Figure 3 is a diagram illustrating an example configuration of the electronic lock system 1 in an embodiment. Figure 3 is a block diagram illustrating an example configuration of the electronic lock system 1 in an embodiment. Figure 3 is a diagram illustrating an overview of the processes performed by the electronic lock system 1 in an embodiment. Figure 3 is a diagram illustrating the process flow related to the preliminary preparations shown in Figure 3. Figure 3 is a diagram illustrating the process flow related to the authentication of the owner device shown in Figure 3. Figure 3 is a diagram illustrating the process flow related to the generation of a share key shown in Figure 3. Figure 3 is a diagram illustrating the process flow related to unlocking shown in Figure 3. Figure 3 is a diagram illustrating the process related to the invalidation of the unlocking certificate deletion of the owner CA shown in Figure 3. Figure 3 is a diagram illustrating the process related to the generation of multiple owner CAs shown in Figure 3.

[0027] Embodiments of the present invention will be described below with reference to the drawings.

[0028] (About the configuration of the electronic lock system 1) The electronic lock system 1 is a system that manages the locking and unlocking of an electronic lock. Figure 1 is a diagram showing an example of the configuration of the electronic lock system 1 in an embodiment. The electronic lock system 1 includes, for example, an electronic lock device 10, an owner terminal 20, and a friend terminal 30. The electronic lock device 10 is a lock that can be unlocked or locked using a digital key, and is installed, for example, on a door such as a vehicle or entrance door. Here, the digital key in this embodiment is a public key certificate that is authorized to unlock or lock the electronic lock device 10. More specifically, when the public key certificate corresponding to the digital key is notified to the electronic lock device 10, a request is made to unlock or lock the electronic lock device 10, and the electronic lock device 10 is unlocked or locked on the condition that authentication using the notified public key certificate is successfully performed.

[0029] The owner terminal 20 is a computer operated by the owner who purchased the electronic lock device 10. An application (key app) for unlocking or locking the electronic lock device 10 is installed on the owner terminal 20. The owner terminal 20 unlocks or locks the electronic lock device 10 by communicating with it via the key app. The owner terminal 20 may be an electronic device such as a smartphone, tablet, or mobile phone.

[0030] The Friend Terminal 30 is a different terminal from the Owner Terminal 20. It is a computer that can acquire a digital key via the Owner Terminal 20 and use the acquired digital key to unlock or lock the electronic lock device 10. The Friend Terminal 30 has a key application installed, similar to the Owner Terminal 20. The Friend Terminal 30 communicates with the Owner Terminal 20 via the key application to share the digital key held by the Owner Terminal 20 (generating a shared key). The Friend Terminal 30 uses the shared digital key to unlock or lock the electronic lock device 10. The Friend Terminal 30, like the Owner Terminal 20, may be an electronic device such as a smartphone, tablet, or mobile phone.

[0031] In this embodiment, authentication is performed on a terminal (requesting terminal) that requests the unlocking or locking of the electronic lock device 10. If, as a result of authenticating the requesting terminal, it is determined that the requesting terminal is a legitimate terminal and not an unauthorized terminal or a terminal disguised as a legitimate terminal, the system responds to the request notified by the requesting terminal (unlocking or locking the electronic lock device 10). This prevents the electronic lock device 10 from being illegally unlocked or locked by unauthorized terminals or disguised terminals.

[0032] Authentication uses an authentication method based on a Public Key Infrastructure (PKI), such as the authentication protocol RFC 5246 (TLS 1.2), employing public-key cryptography and digital signatures. Specifically, the requesting terminal requests the unlocking or locking of the electronic lock device 10 by sending a public key certificate issued by the certification authority to the electronic lock device 10. The public key certificate is a digital certificate that proves the public key of the requesting terminal's key pair (public key and private key), and includes the requesting terminal's public key and digital signature. The digital signature is generated by performing a signature calculation process based on a signature algorithm (such as FIPS 186-3 or Digital Signature Standard (DSS)) using the private key of the certification authority's key pair (public key and private key). In the following description, the public key certificate notified by the requesting terminal when requesting the unlocking or locking of the electronic lock device 10 may be referred to as the unlocking certificate.

[0033] Authentication involves two processes: signature verification and private key verification. First, let's explain the signature verification process. Signature verification is the process of determining whether the public key contained in the public key certificate notified by the requesting terminal is trustworthy, using the digital signature in the public key certificate. More specifically, in the signature verification process, if the digital signature contained in the public key certificate notified by the requesting terminal was generated using the private key of a trusted certification authority, that is, if signature verification can be performed using the public key of a trusted certification authority, then the requesting terminal's public key is determined to be trustworthy. Here, the authenticating terminal has the public key certificate or the public key itself of a trusted certification authority stored in advance. Using the public key contained in this pre-stored public key certificate (public key certificate of a trusted certification authority) or the pre-stored public key itself, the digital signature contained in the public key certificate notified by the requesting terminal is verified using a signature verification process based on a signature algorithm (FIPS 186-3, Digital Signature Standard (DSS), etc.). If the digital signature of the public key is successfully verified, it is guaranteed that the public key and the corresponding private key that were successfully verified are authenticated by the Certificate Authority. Next, the private key verification process will be described. The private key verification process here is the process of confirming that the requesting terminal actually possesses the private key that corresponds to the public key that was successfully verified in the signature verification process. The private key verification process is performed in response to the successful verification of the digital signature in the public certificate during the signature verification process. Any verification method can be used for the private key verification process, but for example, a verification method consisting of the following steps HS1 to HS5 can be used. Step HS1: The authentication terminal (in this case, the electronic lock device 10) generates a random number and sends the generated random number to the requesting terminal. Step HS2: The requesting terminal receives the random number from the authentication terminal and generates a signature by signing the received random number using the private key held by the requesting terminal. Step HS3: The requesting terminal sends the signature generated in step HS2 to the authentication terminal. Step HS4: The authentication terminal receives the signature from the requesting terminal and verifies the received signature with the public key contained in the requesting terminal's public key certificate.Step HS5: If the authentication terminal succeeds in verification in Step HS4, it determines that the requesting terminal certainly possesses the private key that corresponds to the public key contained in the public key certificate. This allows the authentication terminal to confirm that the requesting terminal certainly possesses the private key that corresponds to the public key that was successfully verified in the signature verification process. In authentication, if the public key notified by the requesting terminal is determined to be trustworthy in the signature verification process, and the subsequent private key verification process confirms that the requesting terminal certainly possesses the predetermined private key (the private key that corresponds to the public key that was successfully verified in the signature verification process), the electronic lock device 10 determines that the requesting terminal is a legitimate terminal and not an unauthorized terminal or an impersonator, and determines that authentication has been successful.

[0034] Thus, authentication using public key certificates requires the authenticating party to obtain a public key certificate from a trusted certificate authority in advance, and the authenticated party to have the certificate authority issue a public key certificate for its own public key. Since the terminal acting as the digital key paired with the electronic lock device 10 may change, management such as invalidating issued public key certificates or issuing new ones is necessary. Furthermore, in order to ensure security, issued public key certificates must be updated periodically. This makes communication with the certificate authority complicated.

[0035] As a countermeasure, in this embodiment, the electronic lock device 10 is made to function as a certification authority. Specifically, the electronic lock device 10 is made capable of issuing public key certificates to terminals that act as digital keys paired with the electronic lock device 10. This allows the electronic lock device 10 to manage terminals that act as digital keys paired with its own electronic lock, eliminating the need for communication with a certification authority.

[0036] More specifically, in this embodiment, the electronic lock device 10 functions as a root certification authority. Here, a root certification authority is a computer that has the function of issuing a public key certificate that proves the public key of another person (for example, the owner terminal 20) using its own private key. In addition, in this embodiment, a manufacturer CA (Certificate Authority, Certification Authority) is established, and the electronic lock device 10 is able to perform owner authentication to verify the owner terminal 20 using a manufacturer CA certificate issued by the manufacturer CA. Specifically, the manufacturer CA is a computer that has the function of issuing a public key certificate that proves the public key of another person (for example, the owner terminal 20) using its own private key, possesses at least its own public key and the private key that is paired with that public key, has a public key certificate (manufacturer CA certificate) that proves its own public key held in the electronic lock device 10, and has the function of issuing a public key certificate that proves the public key of another person (for example, the owner terminal 20) using its own private key. For example, a server managed by a business that manufactures or sells the electronic lock device 10 can be used as the manufacturer's CA. Businesses that manufacture or sell the electronic lock device 10 usually have regulations in place to ensure the secure operation of the electronic lock device 10, and since it is possible to write and read data to and from the electronic lock device 10 by connecting it to a reader / writer via a wired cable, rather than using a general-purpose network such as the internet, during the manufacturing or sale of the electronic lock device 10, it is possible to make it function as a highly secure certification authority.

[0037] (Regarding the configuration of the electronic lock device 10) Figure 2 is a block diagram showing an example of the configuration of the electronic lock system 1 in an embodiment. The electronic lock device 10 comprises a communication unit 11, a storage unit 12, a control unit 13, a user interface unit 14, and a locking / unlocking mechanism 15. The communication unit 11 communicates with the owner terminal 20 and the friend terminal 30. As a means of communication with the owner terminal 20 and the friend terminal 30, the communication unit 11 may use short-range wireless communication, such as NFC (Near Field Communication) and Bluetooth®, or it may use wired communication or other means of communication such as Internet communication.

[0038] The storage unit 12 stores various data. The storage unit 12 is implemented, for example, by flash memory or EEPROM (Electrically Erasable Programmable Read Only Memory). The storage unit 12 stores, for example, manufacturer CA information 120, encryption key information 121, and issued certificate information 122. The manufacturer CA information 120 is information related to certification using the manufacturer CA, and more specifically, it is information indicating the manufacturer CA's public key certificate or the manufacturer CA's public key. The manufacturer CA's public key certificate is an electronic certificate that proves the manufacturer CA's public key. When the manufacturer CA manufactures or sells the electronic lock device 10, the manufacturer CA stores the manufacturer CA's public key certificate or the public key itself in the storage unit 12 as manufacturer CA information 120. The encryption key information 121 is information indicating the encryption key used for issuing or verifying the public key certificate, and for example, it is information indicating a key pair (a pair of a public key and a private key). This key pair is used as the key pair for the Certificate Authority (Owner CA) generated by the Certificate Authority Generation Unit 131, which will be described later. The issued certificate information 122 is information about the public key certificate issued by the Owner CA.

[0039] Here, the private key among the key pair stored as encryption key information 121 should be stored securely without being known to others. For this reason, the electronic lock device 10 may be provided with a tamper-resistant module called a secure element, and the private key may be stored in the memory of the secure element. Alternatively, a functional unit that performs processing using the private key, such as a process that generates an electronic signature by executing a signature calculation process, may be configured to be executed within the secure element. Similarly, in the owner terminal 20 and the friend terminal 30, the private key may be stored in the memory of a secure element provided in the owner terminal 20 or the friend terminal 30.

[0040] The functionality of the secure element may be realized by an IC or IC module mounted on the circuit board of the electronic lock device 10, or by a detachable USIM (Universal Subscriber Identity Module) card or the like being attached to the electronic lock device 10.

[0041] The control unit 13 controls each part of the electronic lock device 10. The control unit 13 includes an owner authentication unit 130, a certification authority generation unit 131, a lock / unlock control unit 132, an unlocking certificate management unit 133, and a certification authority management unit 134.

[0042] The owner authentication unit 130 performs owner device authentication. Owner device authentication is the process of authenticating the terminal (owner device) operated by the owner of the electronic lock device 10, specifically the owner terminal 20. The specific method of performing owner device authentication will be explained in detail later.

[0043] The certification authority generation unit 131 generates a certification authority. Here, the certification authority generated by the certification authority generation unit 131 is a root certification authority (owner CA) that issues a public key certificate as a digital key paired with the electronic lock device 10 to the terminal. The public key certificate issued by this owner CA is notified from the requesting terminal to the electronic lock device 10 when requesting unlocking or locking of the electronic lock device 10, and is used as an unlocking certificate. In addition, the certification authority generation unit 131 may issue a share key in response to a request from the owner terminal 20. The share key is a digital key that can unlock or lock the electronic lock device 10, and the owner terminal 20 is a digital key held by another different terminal. The certification authority generation unit 131 issues a public key certificate as a share key to another terminal (friend terminal 30) different from the owner terminal 20. The public key certificate (unlocking certificate) issued by the certification authority generation unit 131 is stored in the storage unit 12 as issued certificate information 122 together with its attribute information (for example, information such as issue date, expiration date, or valid / invalid flag). In addition, the attribute information stored here may include a Serial number defined in RFC3280, which is a standard regarding the profile of a public key infrastructure (PKI) certificate and a certificate revocation list (CRL), or unique information equivalent to the Serial number, that is, a value unique to each certificate, for example, the value of the public key of the public key certificate itself, etc.

[0044] The unlocking / locking control unit 132 controls unlocking or locking of the electronic lock device 10. When requesting unlocking or locking of the electronic lock device 10, the unlocking / locking control unit 132 authenticates the public key certificate (unlocking certificate) notified from the requesting terminal to the electronic lock device 10, and the unlocking certificate is issued by the owner CA, is not forged, etc., is a valid public key certificate (unlocking certificate), and when it can be confirmed that the requesting terminal holds the secret key corresponding to the public key that has successfully passed the verification, the unlocking / locking control unit 132 unlocks or locks the electronic lock device 10 in response to the request from the requesting terminal.

[0045] The unlocking certificate management unit 133 manages public key certificates (unlocking certificates) issued by the owner CA. Specifically, the unlocking certificate management unit 133 invalidates issued public key certificates (unlocking certificates) in response to a request from the owner terminal 20. When the unlocking certificate management unit 133 invalidates a public key certificate (unlocking certificate), it updates the issued certificate information 122 in the storage unit 12, for example, by rewriting the valid / invalid flag in the attribute information of the invalidated public key certificate (unlocking certificate) to "invalid". The unlocking certificate management unit 133 may also have a function to issue a new public key certificate based on the public key at the same time as invalidating the public key certificate (unlocking certificate) of an existing owner terminal. Here, generally, an invalid certificate list is often used instead of the valid / invalid flag described above. The invalid certificate list is a list that corresponds to the Certificate Revocation List (CRL) defined in RFC 3280, and shows the Serial number (or unique information equivalent to the Serial number) of invalidated certificates. In this case, for example, the unlocking certificate management unit 133 adds the Serial number, or unique information equivalent to the Serial number, of the certificate to be invalidated.

[0046] The Certificate Authority Management Unit 134 manages the owner CAs generated by the Certificate Authority Generation Unit 131. Specifically, the Certificate Authority Management Unit 134 deletes already generated owner CAs in response to requests from the owner terminal 20. For example, the Certificate Authority Management Unit 134 deletes an owner CA by removing the key pair of the deleted owner CA from the encryption key information 121. When the Certificate Authority Management Unit 134 deletes an owner CA, it deletes the issued certificate information 122 corresponding to the public key certificate issued by the deleted owner CA from the issued certificate information 122 stored in the storage unit 12. The Certificate Authority Management Unit 134 also generates an owner CA (second owner CA) that is different from the already generated owner CA (first owner CA). Generally, public key certificates are issued that correspond to the encryption method that the public key or digital signature supports. For example, if a public key is generated using an RSA encryption algorithm, the public key certificate that proves that public key will include the public key and digital signature using the RSA encryption algorithm, and will be generated as a public key certificate corresponding to the RSA encryption algorithm. This embodiment generates a public key certificate corresponding to the encryption method of the public key notified from the owner terminal 20. For example, if a public key generated using a certain encryption method (first encryption method) is notified, the certification authority generation unit 131 generates an owner CA (first owner CA) corresponding to the first encryption method, and issues a public key certificate as an unlocking certificate using the generated first owner CA. On the other hand, if a public key generated using an encryption method different from the first encryption method (second encryption method) is notified, the certification authority generation unit 131 generates an owner CA different from the first owner CA, that is, an owner CA corresponding to the second encryption method (second owner CA), and issues a public key certificate as an unlocking certificate using the generated second owner CA. In this way, one or more owner CAs may exist in the electronic lock device 10. Furthermore, even if the encryption method is the same, multiple owner CAs may be generated based on the purpose of managing the keys (unlock certificates). By enabling the generation of multiple owner CAs, unlock certificates can be grouped and managed for each group. The certification authority management unit 134 manages the generation and deletion of multiple owner CAs.

[0047] The user interface unit 14 is a functional unit that receives operations from the user for the electronic lock device 10 and presents information to the user, and includes, for example, a display device, an operation input device, and a voice input / output device, etc.

[0048] The locking and unlocking mechanism 15 is a mechanism that unlocks and locks the electronic lock of the electronic lock device 10 according to the control of the locking and unlocking control unit 132. For example, the locking and unlocking mechanism 15 may include actuators such as solenoids and motors, and cylinders that generate driving forces, such as hydraulic cylinders, pneumatic cylinders, or hydraulic cylinders. The driving force generated by these cylinders is used to unlock and lock the electronic lock.

[0049] The storage unit (including the storage unit 12) provided in the electronic lock device 10 is composed of a storage medium such as an HDD (Hard Disk Drive), a flash memory, an EEPROM (Electrically Erasable Programmable Read Only Memory), a RAM (Random Access read / write Memory), or a ROM (Read Only Memory), or a combination thereof. The storage unit provided in the electronic lock device 10 stores programs for executing various processes in the electronic lock device 10 and temporary data used when performing various processes.

[0050] The functional units (including the control unit 13) provided in the electronic lock device 10 are realized by causing the CPU (Central Processing Unit) provided as hardware in the electronic lock device 10 to execute the programs stored in the storage unit 12.

[0051] (Configuration of Owner Terminal 20) The Owner Terminal 20 comprises a communication unit 21, a storage unit 22, a control unit 23, and a user interface unit 24. The communication unit 21 communicates with the electronic lock device 10 and the Friend Terminal 30. When communicating with the electronic lock device 10, the communication unit 21 uses, as described above, short-range wireless communication such as NFC or Bluetooth®, wired communication, or other communication means. When communicating with the Friend Terminal 30, the communication unit 21 uses email via the Internet or a messaging application. When communicating with the Friend Terminal 30, the communication unit 21 may also use a portable medium such as a USB (Universal Serial Bus) memory to exchange data, or use other short-range wireless communication or wired connection communication. Communication between the owner terminal 20 and the friend terminal 30 only needs to involve the exchange of CSR data requesting the issuance of an unlocking certificate, as well as data related to the unlocking certificate, as described later. Any communication method can be used as long as it is a P2P (peer-to-peer) method, that is, a means that allows data to be exchanged one-to-one.

[0052] The storage unit 22 stores various types of data. The storage unit 22 is implemented, for example, by flash memory or EEPROM. The storage unit 22 stores, for example, owner information 220, encryption key information 221, and unlocking certificate 222.

[0053] Owner information 220 is information indicating the public key certificate (owner certificate) of the owner terminal (owner terminal 20) or the public key of the owner terminal 20, issued by the manufacturer CA. Cryptographic key information 221 is information indicating the cryptographic key used for issuing or verifying the public key certificate, for example, information indicating a key pair (a pair of a public key and a private key). Cryptographic key information 221 is information of a key pair indicating the public key included in the owner certificate and the private key that is paired with that public key. Cryptographic key information 221 is also information of a key pair indicating the public key included in the unlocking certificate and the private key that is paired with that public key. Note that the public key included in the owner certificate issued by the manufacturer CA and the public key included in the public key certificate issued by the owner CA may be the same or different. Unlocking certificate 222 is a public key certificate issued by the owner CA.

[0054] The control unit 23 controls each part of the owner terminal 20. The control unit 23 includes a digital key generation request unit 230, a digital key operation unit 231, and a digital key management unit 232. The digital key generation request unit 230 requests the electronic lock device 10 to issue an unlocking certificate as a digital key. When requesting the generation of a digital key, the digital key generation request unit 230 first requests the electronic lock device 10 to generate an owner CA. The electronic lock device 10 generates the owner CA in response to the request. Next, the digital key generation request unit 230 generates a key pair (a pair of public and private keys) and sends a CSR (Certificate Signing Request) containing the public key of the generated key pair to the electronic lock device 10. Based on the CSR sent to the electronic lock device 10, the digital key generation request unit 230 requests the owner CA to issue an unlocking certificate. In response to this request, the certification authority generation unit 131 of the electronic lock device 10 issues a public key certificate as an unlocking certificate, which includes the public key of the owner terminal 20 included in the CSR data and an electronic signature generated using the owner CA's private key, and transmits the issued unlocking certificate to the owner terminal 20. The digital key generation request unit 230 obtains the unlocking certificate issued by the owner CA from the electronic lock device 10 in response to the request. The digital key generation request unit 230 stores the obtained unlocking certificate as an unlocking certificate 222 in the storage unit 22. Although the above description illustrates the case where the owner terminal 20 generates the key pair, it is not limited to this. The electronic lock device 10 may generate the key pair. In this case, the digital key generation request unit 230 requests the owner CA of the electronic lock device 10 to generate a key pair (a pair of public and private keys) and issue an unlocking certificate. Upon request, the owner CA of the electronic lock device 10 generates a key pair and issues an unlocking certificate that certifies the public key of the generated key pair. The electronic lock device 10 transmits the key pair generated by the owner CA and the unlocking certificate issued by the owner CA to the owner terminal 20. The digital key operation unit 231 operates the digital key, specifically unlocking or locking the electronic lock device 10.The digital key operation unit 231 notifies the electronic lock device 10 of the unlocking certificate issued by the owner CA and requests the electronic lock device 10 to be unlocked or locked. If the unlocking certificate notified by the digital key operation unit 231 is authenticated by the lock / unlock control unit 132 of the electronic lock device 10, and the signature verification process confirms that the unlocking certificate notified to the electronic lock device 10 is a valid certificate issued by the owner CA, and the private key verification process confirms that the owner terminal 20 possesses the private key that is paired with the public key that successfully underwent signature verification in the signature verification process, then the electronic lock device 10 is unlocked or locked in response to the request from the digital key operation unit 231.

[0055] The digital key management unit 232 manages digital keys, specifically invalidating unlocking certificates issued by the owner CA. The digital key management unit 232 notifies the electronic lock device 10 of the identification number of the unlocking certificate issued by the owner CA and requests that the notified unlocking certificate be invalidated.

[0056] Furthermore, the digital key management unit 232 may delete owner CAs that have already been generated by the electronic lock device 10 as part of its digital key management. The digital key management unit 232 notifies the electronic lock device 10 of the identification information of the owner CA and requests that it delete the notified owner CA. By deleting the owner CA, all unlocking certificates issued by that owner CA can be deleted.

[0057] Furthermore, the digital key management unit 232 may, as part of its digital key management, generate a different owner CA (second owner CA) from the owner CA (first owner CA) already generated by the electronic lock device 10. The digital key management unit 232 requests the electronic lock device 10 to generate a new owner CA.

[0058] The user interface unit 24 is a functional unit that receives and presents user inputs to the owner terminal 20, and includes, for example, a display device, an operation input device, and an audio input / output device.

[0059] (Configuration of Friend Terminal 30) The Friend Terminal 30 comprises a communication unit 31, a storage unit 32, a control unit 33, and a user interface unit 34. The communication unit 31 communicates with the electronic lock device 10 and the owner terminal 20. In communication with the electronic lock device 10, the communication unit 31 communicates using NFC or Bluetooth®, short-range wireless communication, wired communication, or other communication means, similar to the owner terminal 20. In communication with the owner terminal 20, the communication unit 21 communicates via the internet, such as email or messaging apps, using portable media such as USB memory, or other short-range wireless communication or wired connection, as described above.

[0060] The storage unit 32 stores various types of data. The storage unit 32 is implemented, for example, by flash memory or EEPROM. The storage unit 32 stores, for example, encryption key information 321 and unlocking certificate 322. The storage unit 32 differs from the storage unit 22 of the owner terminal 20 in that it does not store owner information 220. This is because the friend terminal 30 is not subject to owner device authentication.

[0061] The control unit 33 controls various parts of the friend terminal 30. The control unit 33 includes a digital key share request unit 330 and a digital key operation unit 331.

[0062] The control unit 33 differs from the control unit 23 of the owner terminal 20 in that it has a digital key share request unit 330 instead of a digital key generation request unit 230. This is because the friend terminal 30 shares keys via the owner terminal 20. The control unit 33 also differs from the control unit 23 in that it does not have a digital key management unit 232. This is because the friend terminal 30 does not perform digital key management such as invalidating unlocking certificates or deleting owner CAs. However, it is not limited to this. In the electronic lock system 1, the friend terminal 30 may be configured to manage digital keys. In this case, the control unit 33 of the friend terminal 30 has a function unit corresponding to the digital key management unit 232.

[0063] The digital key share request unit 330 requests the owner terminal 20 to share a digital key (generate a share key). The digital key to be shared here is a public key certificate used for authentication before unlocking or locking the electronic lock, issued by the owner CA, and is a public key certificate that certifies the public key of the friend terminal 30. The digital key share request unit 330 requests the sharing of the digital key by, for example, generating a key pair (a pair of a public key and a private key) and sending data containing the public key of the generated key pair to the owner terminal 20. The owner terminal 20 transmits the CSR data notified by the friend terminal 30 to the electronic lock device 10 and requests the issuance of an unlocking certificate based on the CSR transmitted to the electronic lock device 10. In response to this request, the certification authority generation unit 131 of the electronic lock device 10 issues a public key certificate as an unlocking certificate, which includes the public key of the friend terminal 30 included in the CSR data and an electronic signature generated using the owner CA's private key, and transmits the issued unlocking certificate to the owner terminal 20. The owner terminal 20 forwards the unlocking certificate received from the electronic lock device 10 to the friend terminal 30. The friend terminal 30 receives the unlocking certificate forwarded by the owner terminal 20 and stores the received unlocking certificate as unlocking certificate 322 in the storage unit 32. Although the above description illustrates the case where the friend terminal 30 generates the key pair, it is not limited to this. The electronic lock device 10 may generate the key pair. In this case, the digital key share request unit 330 requests the owner CA of the electronic lock device 10, via the owner terminal 20, to generate a key pair (a pair of public and private keys) and issue an unlocking certificate. Upon request, the owner CA of the electronic lock device 10 generates a key pair and issues an unlocking certificate that certifies the public key of the generated key pair. The electronic lock device 10 transmits the key pair generated by the owner CA and the unlocking certificate issued by the owner CA to the owner terminal 20. The owner terminal 20 forwards the key pair and unlocking certificate received from the electronic lock device 10 to the friend terminal 30. The friend terminal 30 receives the key pair and unlocking certificate forwarded by the owner terminal 20 and stores the received unlocking certificate as unlocking certificate 322 in the storage unit 32.

[0064] The digital key operation unit 331, like the digital key operation unit 231, operates the digital key, specifically unlocking or locking the electronic lock device 10. The processing performed by the digital key operation unit 331 is the same as that of the digital key operation unit 231, so its explanation is omitted.

[0065] The user interface unit 34 is a functional unit that receives and presents user inputs to the friend terminal 30, and includes, for example, a display device, an operation input device, and an audio input / output device.

[0066] (Regarding the processing performed by the electronic lock system 1) Figure 3 is a diagram illustrating the overview of the processing performed by the electronic lock system 1 in the embodiment. First, as step S1, processing related to preliminary preparation is performed. Preliminary preparation is the preparation to enable owner device authentication in step S2. After the processing related to preliminary preparation in step S1 is completed, as step S2, processing is performed for owner device authentication, generation of owner CA, and issuance of an unlocking certificate to be used by the owner terminal 20. More specifically, when owner device authentication is performed and the owner terminal 20 is authenticated as a legitimate terminal, the electronic lock device 10 generates an owner CA, and the owner CA issues an unlocking certificate to the owner terminal 20. After the processing related to owner device authentication, etc. in step S2 is completed, each of steps S3 to S7 becomes possible. Specifically, when the friend terminal 30 requests the generation of a share key, as step S3, processing related to the generation of a share key is performed. Furthermore, if the owner terminal 20 unlocks the electronic lock device 10, the process related to unlocking by the owner terminal 20 is performed as step S4. If the friend terminal 30 unlocks the electronic lock device 10, the process related to unlocking by the friend terminal 30 is performed as step S4. If the owner terminal 20 invalidates the unlocking certificate issued by the owner CA, the process related to invalidating the unlocking certificate is performed as step S5. If the owner terminal 20 deletes the owner CA, the process related to deleting the owner CA is performed as step S6. If the owner terminal 20 generates multiple owner CAs, the process related to generating a different owner CA (second owner CA) from the already generated owner CA (first owner CA) is performed as step S7.

[0067] Figure 4 is a diagram illustrating the flow of the processing related to the preliminary preparations in Figure 3 (the processing shown in step S1). First, the manufacturer CA 100 stores the manufacturer CA certificate in the electronic lock device 10 (step S10). For example, when the manufacturer CA 100's key pair is generated and the manufacturer CA is generated, the manufacturer CA 100 issues a public key certificate in advance and stores the issued public key certificate. The manufacturer CA 100 writes the manufacturer CA 100's public key certificate to the electronic lock device 10 and stores it, for example, when the electronic lock device 10 is manufactured or sold. The manufacturer CA 100 issues an electronic certificate containing the manufacturer CA's public key and an electronic signature generated using the manufacturer CA 100's private key as the manufacturer CA 100's public key certificate. The manufacturer CA100 notifies the electronic lock device 10 of the issued public key certificate via a reader / writer or the like, and stores it in the storage unit 12 as manufacturer CA information 120.

[0068] The reader / writer includes, for example, a USB (Universal Serial Bus) interface as a connection point for connecting to the manufacturer CA100, and a socket for inserting the electronic lock device 10. For example, when the manufacturer CA100 and the electronic lock device 10 are connected, inserting the electronic lock device 10 into the reader / writer's socket enables the manufacturer CA100 to communicate with the electronic lock device 10. Communication between the manufacturer CA100 and the electronic lock device 10 is performed using, for example, I2C (Inter-Integrated Circuit) or SPI (Serial Peripheral Interface). The reader / writer communicates with the electronic lock device 10 in response to control from the manufacturer CA100, and reads data from or writes data to the electronic lock device 10.

[0069] Here, when writing the manufacturer CA100's public key certificate to the electronic lock device 10, it is only necessary to write the already issued manufacturer CA100's public key certificate, so it is not necessary to perform a writing operation that connects the manufacturer CA100 and the electronic lock device 10 via a reader / writer. For example, the manufacturer CA100's public key certificate can be stored in advance on the hard disk of the manufacturing equipment used to manufacture the electronic lock device 10. Then, when manufacturing the electronic lock device 10, the manufacturer CA100's public key certificate can be read from the manufacturing equipment's hard disk and written to the electronic lock device 10 for storage. This eliminates the need to keep the manufacturer CA100 running at all times for the purpose of writing the public key certificate to the electronic lock device 10, thus reducing the operating time of the manufacturer CA100.

[0070] Next, the manufacturer CA100 stores the owner certificate in the owner terminal 20 (step S11). For example, the owner certificate is an electronic certificate that includes the public key of the key pair of the owner terminal 20 generated by the manufacturer CA100 and an electronic signature generated using the manufacturer CA100's private key. In this case, when the electronic lock device 10 is sold, or when the user registers as a user of the electronic lock device 10, the manufacturer CA100 registers the terminal of the user who purchased the electronic lock device 10 as the owner terminal 20. During such user registration, the manufacturer CA100 generates a key pair (a pair of public and private keys) for the owner terminal 20, and issues a public key certificate as the owner certificate that includes the public key of the generated key pair and an electronic signature generated using the manufacturer CA100's private key. Here, when the manufacturer CA100 generates key pairs or issues owner certificates for the owner terminal 20, for example, it may generate a quantity of key pairs corresponding to the unit of manufacture or sale of the electronic lock device 10 (for example, about 10,000) in advance, and issue owner certificates corresponding to the public keys of the 10,000 generated key pairs. In this case, information linking the key pairs and the corresponding owner certificates is stored on the hard disk of a server device that accepts user registrations. When the server device accepts user registration from the owner terminal 20, it sequentially notifies the owner terminal 20 that accepted the user registration of the information stored on the hard disk (information linking the key pairs and owner certificates). This eliminates the need to keep the manufacturer CA100 running at all times for the purpose of notifying owner terminals 20 that have become digital key users, such as by purchasing the electronic lock device 10, of key pairs and owner certificates, thereby reducing the operating time of the manufacturer CA100. The manufacturer CA transmits the issued owner certificate to the owner terminal 20 via a reader / writer or the like, and stores it in the storage unit 22 as owner information 220. The manufacturer CA also transmits the owner terminal's key pair (public key and private key pair) to the owner terminal 20 via a reader / writer or the like, and stores it in the storage unit 22 as encryption key information 221.Alternatively, the owner certificate may be an electronic certificate that includes the public key of the key pair generated by the owner terminal 20 and an electronic signature generated using the manufacturer CA's private key. In this case, the manufacturer CA 100 may have the owner terminal 20 generate a key pair (a pair of public and private keys) via the key application when selling the electronic lock device 10 or when the owner terminal 20 registers as a user of the electronic lock device 10. In this case, the owner terminal 20 notifies the manufacturer CA of the public key of the generated key pair (a pair of public and private keys). The manufacturer CA issues a public key certificate as the owner certificate that includes the public key notified by the owner terminal 20 and an electronic signature generated using the manufacturer CA's private key. The manufacturer CA transmits the issued owner certificate to the owner terminal 20 via a reader / writer or the like, and stores it in the storage unit 22 as owner information 220. Furthermore, the owner terminal 20 stores the generated key pair (a pair of public and private keys) as encryption key information 221 in the storage unit 22.

[0071] Furthermore, when the electronic lock device 10 is sold, or when a user registers to use the electronic lock device 10, an owner certificate may be distributed to the owner terminal 20, or to the owner who is operating the owner terminal 20, using a two-dimensional barcode or a communication means such as email. Also, the order in which steps S10 and S11 are executed may be reversed, that is, step S11 may be executed first, and then step S11 may be executed again.

[0072] Figure 5 is a diagram illustrating the flow of the owner device authentication process shown in Figure 3 (the process shown in step S2). First, the digital key generation request unit 230 of the owner terminal 20 requests the electronic lock device 10 to perform owner device authentication for the generation of the owner CA (step S20). Owner device authentication for the generation of the owner CA involves sending an owner certificate to the electronic lock device 10 and, on the condition that the owner terminal 20 is authenticated in the device authentication, instructing the electronic lock device 10 to generate the owner CA and issue an unlocking certificate by the owner CA. If the electronic lock device 10 accepts the authentication of the owner terminal 20 using the owner certificate (owner device authentication) and the owner terminal 20 is authenticated as a legitimate terminal in the owner device authentication, the electronic lock device 10 will generate the owner CA and issue an unlocking certificate by the owner CA.

[0073] In this embodiment, owner device authentication is accepted when it is determined that the owner possesses a physical key. A physical key is a key that can physically unlock or lock the electronic lock, for example, a metal key that can be unlocked or locked by being inserted into a keyhole provided on the electronic lock. Specifically, the owner authentication unit 130 of the electronic lock device 10 accepts owner device authentication on the condition that the electronic lock device 10 has been unlocked with a physical key. For example, if the electronic lock device 10 is an electronic lock installed on a vehicle door, the electronic lock device 10 accepts owner device authentication when an owner certificate is notified from the owner terminal 20 while a physical key is inserted into the keyhole for starting the engine located in the driver's seat of the vehicle. Alternatively, the owner authentication unit 130 may accept owner device authentication if the vehicle door is unlocked or a physical key is inserted into the keyhole for starting the engine within a predetermined time after an owner certificate is notified from the owner terminal 20. Alternatively, if the electronic lock device 10 is an electronic lock installed on a door of a structure such as an entrance, the owner authentication unit 130 accepts owner device authentication if an owner certificate is notified from the owner terminal 20 within a predetermined time elapsed after the door is unlocked with a physical key. Or, the owner authentication unit 130 may accept owner device authentication if the door is unlocked with a physical key within a predetermined time elapsed after an owner certificate is notified from the owner terminal 20.

[0074] Furthermore, electronic locks may be unlocked using any type of key, such as a card key or key fob, rather than a physical key like a metal key.

[0075] In step S20, if owner device authentication is accepted, the owner authentication unit 130 performs owner device authentication (step S21). The owner authentication unit 130 obtains the electronic signature contained in the owner certificate notified from the owner terminal 20. The owner authentication unit 130 also reads the manufacturer CA information 120 from the storage unit 12, and if the read manufacturer CA information 120 is the manufacturer CA certificate, it obtains the manufacturer CA's public key from the public key certificate (manufacturer CA certificate). Alternatively, if the manufacturer CA information 120 read from the storage unit 12 is the manufacturer CA's public key, the owner authentication unit 130 obtains the manufacturer CA's public key read from the storage unit 12. The owner authentication unit 130 can verify the digital signature included in the owner certificate using the manufacturer's CA's public key, and if it can confirm that the owner terminal 20 truly possesses the private key (the private key that is paired with the public key that was used to verify the signature), it determines that the owner terminal 20 is a legitimate terminal and not an unauthorized or impersonating terminal.

[0076] In the above explanation, we have used PKI-based authentication as an example for owner device authentication, but this is not the only option. Other authentication methods may be used for owner device authentication. For example, the following authentication methods A and B may be used as other authentication methods.

[0077] Authentication method A is a method of authentication that is equivalent to general Bluetooth® pairing. Specifically, the electronic lock device 10 is provided with an owner device registration button, and when this owner device registration button is pressed (or held down, etc.), the electronic lock device 10 switches to owner device registration mode. When it switches to owner device registration mode, the electronic lock device 10 displays a one-time password on the display device of the user interface unit 14 (for example, an LCD screen provided on the instrument panel of the vehicle). Also, when it switches to owner device registration mode, the electronic lock device 10 communicates with the owner terminal 20 and displays a password input field on the display device of the user interface unit 24. The operator of the owner terminal 20 visually confirms the one-time password displayed on the display device of the user interface unit 14 and manually enters the one-time password into the input field displayed on the owner terminal 20. The owner terminal 20 transmits the password entered into the input field to the electronic lock device 10. The electronic lock device 10 determines that pairing between the owner terminal 20 and the electronic lock device 10 has been successful if the password notified by the owner terminal 20 matches the password displayed by the electronic lock device 10 on the user interface unit 14, and determines that the owner terminal 20, which has been successfully paired, is a legitimate terminal and not an unauthorized terminal or an impersonator.

[0078] Authentication method B is a method of authentication using a symmetric-key cryptography scheme. Specifically, as a preliminary step, the manufacturer CA stores the master key in the storage unit 12 of the electronic lock device 10. The master key is a random number used to generate the symmetric key. Also as a preliminary step, the manufacturer CA stores the owner ID and derived key in the storage unit 22 of the owner terminal 20. The derived key is an encryption key used for encrypted communication, and in this case, it is a value generated by applying a predetermined encryption key generation process to the owner ID and master key. After the preliminary steps are completed, in response to notification of an owner device authentication request from the owner terminal 20, the electronic lock device 10 sends an arbitrary random number (challenge data) to the owner terminal 20. The owner terminal 20 encrypts the random number (challenge data) notified from the electronic lock device 10 with the derived key and sends the random number encrypted with the derived key (challenge response) and the owner ID to the electronic lock device 10. The electronic lock device 10 receives a random number (challenge response) encrypted with a derived key and the owner ID from the owner terminal 20. The electronic lock device 10 calculates a derived key by applying a predetermined encryption key generation process to the owner ID received from the owner terminal 20 and the master key stored in the storage unit 12. The electronic lock device 10 can decrypt the challenge response received from the owner terminal 20 using the calculated derived key, and if the decrypted challenge response matches the challenge data, it determines that the owner terminal 20 is a legitimate terminal and not an unauthorized terminal or an impersonator.

[0079] The certification authority generation unit 131 of the electronic lock device 10 generates an owner CA when the owner terminal 20 is authenticated in the owner device authentication performed by the owner authentication unit 130, that is, when the owner terminal 20 is determined to be a legitimate terminal and not an unauthorized terminal or an impersonator. First, the certification authority generation unit 131 of the electronic lock device 10 generates a key pair (a pair of public and private keys). The key pair generated here is the key pair of the owner CA generated in correspondence with the owner terminal 20. The certification authority generation unit 131 stores the generated key pair in the cryptographic key information 121. Next, the certification authority generation unit 131 issues an unlocking certificate. The certification authority generation unit 131 issues a public key certificate as an unlocking certificate, which includes the public key of the owner terminal 20 and an electronic signature generated using the private key of the owner CA. The certification authority generation unit 131 stores the issued unlocking certificate in the issued certificate information 122. Here, the certification authority generation unit 131 may distinguish between the unlocking certificate (owner unlocking certificate) issued to the owner terminal 20 in step S21 and the unlocking certificate (friend unlocking certificate) issued to the friend terminal 30 in step S32, which will be described later, and may grant the owner unlocking certificate the authority to perform special processing. For example, the certification authority generation unit 131 stores the owner unlocking certificate in the issued certificate information 122 of the storage unit 12 as a special type of unlocking certificate different from the friend unlocking certificate. Then, in owner device authentication performed between the issuance of the owner unlocking certificate and the deletion of the owner CA, authentication may be performed using this "owner unlocking certificate". Owner device authentication performed between the issuance of the owner unlocking certificate and the deletion of the owner CA is, for example, the owner device authentication related to the generation of a share key performed in step S31, which will be described later, the owner device authentication related to the invalidation of the unlocking certificate performed in step S50, or the owner device authentication related to the deletion of the owner CA performed in step S60. The certification authority generation unit 131 transmits the unlocking certificate issued by the owner CA to the owner terminal 20 (step S22). The owner terminal 20 receives the unlocking certificate notified from the electronic lock device 10. The digital key generation request unit 230 of the owner terminal 20 stores the received unlocking certificate as unlocking certificate 222 in the storage unit 22.

[0080] Here, the public key of the owner terminal 20 included in the unlocking certificate may be one generated by the electronic lock device 10, or one notified by the owner terminal 20.

[0081] When the electronic lock device 10 generates a public key for the owner terminal 20, in step S21, the certification authority generation unit 131 generates a key pair (a pair of a public key and a private key) for the owner terminal 20, and issues a public key certificate as an unlocking certificate, which includes the public key from the generated key pair for the owner terminal 20 and an electronic signature generated using the private key of the owner CA. In this case, in step S22, the certification authority generation unit 131 transmits the key pair for the owner terminal 20 to the owner terminal 20 along with the unlocking certificate issued by the owner CA.

[0082] When owner terminal 20 generates its public key, owner terminal 20 generates its key pair (a pair of a public key and a private key) in advance and stores it in the encryption key information 221 of storage unit 22. In step S20, owner terminal 20 transmits the public key from the owner terminal 20's key pair stored in the encryption key information 221 to the electronic lock device 10 along with the owner certificate. Alternatively, in step S20, if owner terminal 20 is authenticated in owner device authentication, owner terminal 20 may transmit the public key from the owner terminal 20's key pair stored in the encryption key information 221 to the electronic lock device 10 and instruct it to generate an owner CA and issue an unlock certificate. In step S21, the certification authority generation unit 131 issues a public key certificate, which includes the public key notified by owner terminal 20 and an electronic signature generated using the owner CA's private key, as an unlock certificate.

[0083] Figure 6 is a diagram illustrating the flow of the process related to the generation of the share key shown in Figure 3 (the process shown in step S3). First, the digital key share request unit 330 of the friend terminal 30 requests the owner terminal 20 to generate a share key (step S30). The friend terminal 30 has previously generated its own key pair (a pair of public and private keys) and stored it in the encryption key information 321 of the storage unit 32. The friend terminal 30 generates CSR (Public Key Certificate Signature Request) data, which includes the public key of the key pair stored in the encryption key information 321. The friend terminal 30 transmits the generated CSR data to the owner terminal 20. The owner terminal 20 receives the CSR data transmitted from the friend terminal 30. In response to receiving the request for share key generation from the friend terminal 30, the owner terminal 20 requests the electronic lock device 10 to perform owner device authentication related to the generation of the share key (step S31). Owner device authentication related to the generation of a share key involves sending an owner certificate to the electronic lock device 10 and instructing it to issue an unlocking certificate for the friend terminal 30, provided that the owner terminal 20 is authenticated in the owner device authentication process. In this case, similar to step S20, the unlocking certificate for the friend terminal 30 is issued only if the owner device authentication is accepted by the electronic lock device 10 and the owner terminal 20 is authenticated as a legitimate terminal in the owner device authentication process. The conditions for accepting owner device authentication in the electronic lock device 10 and the method of owner device authentication are the same as those described in steps S20 to S21, so their explanation is omitted. In step S31, the owner terminal 20 sends the CSR data received from the friend terminal 30 to the electronic lock device 10 along with the owner certificate. Alternatively, in step S20, if the owner terminal 20 is authenticated in owner device authentication, the owner terminal 20 may transmit the CSR data received from the friend terminal 30 to the electronic lock device 10 and instruct the friend terminal 30 to issue an unlocking certificate.

[0084] The certification authority generation unit 131 of the electronic lock device 10 issues an unlocking certificate for the friend terminal 30 by the owner CA when the owner terminal 20 is authenticated in the owner device authentication performed by the owner authentication unit 130, that is, when the owner terminal 20 is determined to be a legitimate terminal and not an unauthorized terminal or an impersonation (step S32). The method for issuing the unlocking certificate for the friend terminal 30 is the same as the method for issuing the unlocking certificate for the owner terminal 20 in step S21, except that the public key of the friend terminal 30 is used instead of the public key of the owner terminal 20. That is, the certification authority generation unit 131 issues a public key certificate that includes the public key of the friend terminal 30 and an electronic signature generated using the private key of the owner CA as the unlocking certificate for the friend terminal 30. The certification authority generation unit 131 stores the issued unlocking certificate in the issued certificate information 122.

[0085] The certification authority generation unit 131 sends the unlocking certificate for the friend terminal 30, issued by the owner CA, to the owner terminal 20 (step S33). The owner terminal 20 receives the unlocking certificate for the friend terminal 30, notified by the electronic lock device 10, and forwards the received unlocking certificate for the friend terminal 30 to the friend terminal 30 (step S34). The digital key share request unit 330 of the friend terminal 30 stores the received unlocking certificate as unlocking certificate 322 in the storage unit 32.

[0086] Here, an expiration date may be set for the unlocking certificate of the friend terminal 30. When issuing an electronic certificate in accordance with X.509, a standard specification that defines the data format of electronic certificates and certificate revocation lists (CRLs) commonly used, as an unlocking certificate, the unlocking certificate itself contains expiration date information. This expiration date information can be used to manage the expiration date of the unlocking certificate. For example, when an unlocking certificate is notified to the electronic lock device 10 from a device (owner terminal 20 or friend terminal 30) in response to an unlocking request, the electronic lock device 10 can check the validity of the unlocking certificate based on the expiration date included in the unlocking certificate received from the device. Similarly, an expiration date may also be set for the unlocking certificate of the owner terminal 20. In this case, in step S20, the owner terminal 20 notifies the electronic lock device 10 of the public key and the expiration date, and instructs it to issue an unlocking certificate. If no expiration date is set, the certification authority generation unit 131 of the electronic lock device 10 stores information indicating that the unlocking certificate issued by the owner CA has no expiration date in the storage unit 12 as issued certificate information 122.

[0087] Figure 7 is a diagram illustrating the flow of the unlocking process shown in Figure 3 (the process shown in step S4). Here, the case where the owner terminal 20 unlocks the device is explained as an example. The same process is performed when the friend terminal 30 unlocks the device. The digital key operation unit 231 of the owner terminal 20 sends an unlocking certificate to the electronic lock device 10 and requests authentication of the unlocking certificate. On the condition that the unlocking certificate is authenticated, the owner terminal 20 requests to unlock or lock the electronic lock device 10 (step S40). The authentication of the unlocking certificate performed here is carried out by confirming through signature verification processing that the unlocking certificate was issued by the owner CA and has not been tampered with, and by confirming through private key verification processing that the owner terminal 20 possesses a private key that is paired with the public key that successfully underwent signature verification. The lock / unlock control unit 132 of the electronic lock device 10 authenticates the unlocking certificate notified by the owner terminal 20, and unlocks or locks the electronic lock device 10 if the unlocking certificate is authenticated (step S41). The lock / unlock control unit 132 verifies the electronic signature contained in the unlocking certificate notified from the owner terminal 20 using the owner CA's public key. If the lock / unlock control unit 132 is able to verify the electronic signature using the owner CA's public key, it determines that the unlocking certificate notified from the owner terminal 20 was indeed issued by the owner CA and has not been tampered with.

[0088] In this case, the unlocking certificate may have an expiration date. If the electronic lock device 10 does not have time information (such as a clock function or a function to obtain internet time), in step S40, the owner terminal 20 sends data including a timestamp to the electronic lock device 10. The lock / unlock control unit 132 determines, based on the time information of the timestamp, whether the current time has passed the expiration date of the unlocking certificate. If the unlocking certificate notified by the owner terminal 20 was indeed issued by the owner CA and its expiration date has not passed, the lock / unlock control unit 132 determines that the unlocking certificate has been authenticated, that is, the unlocking certificate notified by the owner terminal 20 was indeed issued by the owner CA and is a valid unlocking certificate.

[0089] If the unlocking certificate is authenticated, the lock / unlock control unit 132 controls the lock / unlock mechanism 15 to unlock or lock the electronic lock.

[0090] Although it was explained that an authentication method other than PKI-based authentication may be used for owner device authentication, the authentication method performed in steps S40 to S41 can only be authentication using an unlocking certificate, and no other authentication method can be used. This is because unlocking or locking is premised on authentication using the unlocking certificate issued in step S21. However, if authentication data to be used for an authentication method other than authentication using an unlocking certificate is generated in step S21, authentication using the authentication data will be performed in steps S40 to S41. For example, suppose an unlocking password is generated as authentication data in step S21. In this case, in step S40, the owner terminal 20 transmits the unlocking password to the electronic lock device 10. In step S41, if the unlocking password notified by the owner terminal 20 matches the unlocking password generated in step S21, the electronic lock device 10 controls the locking / unlocking mechanism 15 to unlock or lock the electronic lock.

[0091] Figure 8 (Figures 8A and 8B) is a diagram illustrating the process related to the invalidation of the unlocking certificate. Figure 8A is a diagram illustrating the flow of the process related to the invalidation of the unlocking certificate in Figure 3 (the process shown in step S5). Figure 8B is a diagram showing an example of issued certificate information 122 that is referenced in the process related to the invalidation of the unlocking certificate.

[0092] As shown in Figure 8A, the digital key management unit 232 of the owner terminal 20 requests the electronic lock device 10 to perform owner device authentication for invalidating the unlocking certificate (step S50). Owner device authentication for invalidating the unlocking certificate means sending the owner certificate to the electronic lock device 10 and instructing it to invalidate the unlocking certificate, on the condition that the owner terminal 20 is authenticated in the device authentication. In this case, similar to step S20, the unlocking certificate is invalidated if the electronic lock device 10 accepts the owner device authentication and authenticates the owner terminal 20 as a legitimate terminal in the owner device authentication. The conditions for accepting owner device authentication in the electronic lock device 10 and the method of owner device authentication are the same as those described in steps S20 to S21, so their explanation is omitted.

[0093] The digital key management unit 232 transmits unique information (e.g., a serial number) that can identify the unlocking certificate to be invalidated to the electronic lock device 10 (step S51). For example, when the owner terminal 20 is authenticated in owner device authentication, the digital key management unit 232 transmits the unique information of the unlocking certificate to be invalidated to the electronic lock device 10 and instructs it to invalidate the unlocking certificate.

[0094] Here, in step S51, the digital key management unit 232 may notify the owner certificate and request the electronic lock device 10 to provide a list of unlocking certificates issued by the owner CA. In this case, if the electronic lock device 10 authenticates the owner terminal 20 in owner device authentication, it will present the owner terminal 20 with a list of unlocking certificates issued by the owner CA in response to a request from the digital key management unit 232. For example, if the electronic lock device 10 unlocks or locks the doors of a vehicle, the electronic lock device 10 will display a list (a list of unlocking certificates issued by the owner CA) on an LCD screen or the like provided on the instrument panel of the vehicle. The operator of the owner terminal 20 will perform an operation to select an unlocking certificate from the displayed list by operating the touch panel on the LCD screen provided on the instrument panel of the vehicle. In response to the operator's selection operation, the user interface unit 14 (operation input device) of the electronic lock device 10 will acquire the unique information of the selected unlocking certificate. Alternatively, the electronic lock device 10 may send a list (a list of unlocking certificates issued by the owner CA) to the owner terminal 20. In this case, the owner terminal 20 receives the list from the electronic lock device 10 and displays the received list on the display device in the user interface unit 14 of the owner terminal 20. The operator of the owner terminal 20 selects an unlocking certificate to invalidate from the displayed list. In response to the operator's selection, the owner terminal 20 obtains the unique information of the unlocking certificate selected by the operator, sends the obtained unique information to the electronic lock device 10, and instructs the electronic lock device 10 to invalidate the unlocking certificate corresponding to the unique information.

[0095] The unlocking certificate management unit 133 of the electronic lock device 10 invalidates the instructed unlocking certificate if, in the owner device authentication performed by the owner authentication unit 130, the owner terminal 20 is authenticated in the owner device authentication, that is, if the owner terminal 20 is determined to be a legitimate terminal and not an unauthorized terminal or an impersonator (step S32). The unlocking certificate management unit 133 stores in the storage unit 12 information indicating that the instructed unlocking certificate is invalid in the issued certificate information 122.

[0096] Figure 8B shows an example of issued certificate information 122. Issued certificate information 122 is generated for each owner CA. Issued certificate information 122 includes information corresponding to each of the following items, for example: certificate ID, name, target terminal, issue date, expiration date, valid / invalid flag, and reason for invalidation. The certificate ID is the unique information of the unlocking certificate issued by the owner CA. The name is the name of the unlocking certificate, and is set by the owner (operator of owner terminal 20) to be a name that allows recognition of which terminal the digital key (unlocking certificate) is used for, for example, "Mr. A's digital key". The target terminal is the terminal to which the unlocking certificate will be used. The issue date and expiration date are the issue date and expiration date of the unlocking certificate, respectively. The valid / invalid flag is information indicating whether the issued unlocking certificate is valid or invalid. The reason for invalidation is information indicating the reason why the unlocking certificate became invalid if it is invalid. In this diagram, the unlocking certificate identified by certificate ID (0002) is named "B's Digital Key," issued to a friend's terminal, has an expiration date of (2024 / 10 / 18), and is shown to have been invalidated due to its expiration. Similarly, the unlocking certificate identified by certificate ID (0003) is named "C's Digital Key," issued to a friend's terminal, has an expiration date of (2025 / 1 / 10), and is shown to have been invalidated by instruction from the owner (owner terminal 20). In this way, the unlocking certificate management unit 133 invalidates the instructed unlocking certificate by setting the valid / invalid flag in the issued certificate information 122 to invalid and writing information such as "owner instruction" as the reason for invalidation.

[0097] The above example illustrates a case where the owner terminal 20 instructs the electronic lock device 10 to invalidate the unlocking certificate, but the explanation is not limited to this. The friend terminal 30 may also be able to instruct the electronic lock device 10 to invalidate the unlocking certificate. In this case, in step S50, the friend terminal 30 requests authentication of the unlocking certificate related to the invalidation of the unlocking certificate, instead of the owner device authentication related to the invalidation of the unlocking certificate. Authentication of the unlocking certificate related to the invalidation of the unlocking certificate means sending the unlocking certificate to the electronic lock device 10 and, on the condition that the authentication of the unlocking certificate is successful, instructing the invalidation of the unlocking certificate. In this case, the lock / unlock control unit 132 authenticates the unlocking certificate notified by the owner terminal 20 and outputs the authentication result to the unlocking certificate management unit 133. In step S52, the unlocking certificate management unit 133 of the electronic lock device 10, if it determines that the authentication of the unlocking certificate performed by the lock / unlock control unit 132 was successful, that is, that the unlocking certificate notified from the owner terminal 20 was indeed issued by the owner CA and has not been tampered with, invalidates the instructed unlocking certificate. This allows even a friend terminal 30 that does not possess an owner certificate to invalidate the unlocking certificate it owns.

[0098] Figure 9 is a diagram illustrating the flow of the process related to the deletion of the owner CA in Figure 3 (the process shown in step S6). The digital key management unit 232 of the owner terminal 20 requests owner device authentication related to the deletion of the owner CA from the electronic lock device 10 (step S50). Owner device authentication related to the deletion of the owner CA means sending an owner certificate to the electronic lock device 10 and instructing the deletion of the owner CA on the condition that the owner terminal 20 is authenticated in the device authentication. In this case, similar to step S20, the deletion of the owner CA is performed when the owner device authentication is accepted in the electronic lock device 10 and the owner terminal 20 is authenticated as a legitimate terminal in the owner device authentication. The conditions for accepting owner device authentication in the electronic lock device 10 and the method of owner device authentication are the same as those described in steps S20 to S21, so their explanation is omitted.

[0099] The digital key management unit 232 transmits information that identifies the owner CA to be deleted to the electronic lock device 10 (step S61). For example, when the owner terminal 20 is authenticated in owner device authentication, the digital key management unit 232 transmits information that identifies the owner CA to be deleted to the electronic lock device 10 and instructs the deletion of the owner CA. As information that identifies the owner CA, for example, the list number of the owner CA selected from the list of owner CAs displayed on the display device of the user interface unit 14, or the serial number of the owner CA certificate can be used. Here, the method for displaying the list of owner CAs on the display device of the user interface unit 14 can be the same as the method for displaying the list of issued unlocking certificates in step S51.

[0100] The certification authority management unit 134 of the electronic lock device 10 deletes the instructed owner CA (step S62) if, in the owner device authentication performed by the owner authentication unit 130, the owner terminal 20 is determined to have been authenticated in the owner device authentication, that is, the owner terminal 20 is determined to be a legitimate terminal and not an unauthorized terminal or an impersonator. For example, the certification authority management unit 134 deletes the owner CA's key pair in the cryptographic key information 121. This makes it impossible to generate an electronic signature using the owner CA's private key and to perform signature verification using the owner CA's public key, effectively deleting the owner CA. Alternatively, the unlocking certificate management unit 133 deletes the issued certificate information 122 corresponding to the owner CA to be deleted. Or, the unlocking certificate management unit 133 stores in the storage unit 12 information invalidating all unlocking certificates indicated in the issued certificate information 122 corresponding to the owner CA to be deleted. This allows the unlocking certificate management unit 133 to delete the owner CA.

[0101] Figure 10 is a diagram illustrating the flow of the process related to the generation of multiple owner CAs in Figure 3 (the process shown in step S7). The electronic lock device 10 transmits the unlocking certificate issued by the first owner CA to the owner terminal 20 (step S70). Similar to step S20 described above, the digital key generation request unit 230 of the owner terminal 20 requests the electronic lock device 10 to perform owner device authentication related to the generation of the first owner CA. If the electronic lock device 10 accepts the authentication of the owner terminal 20 using the owner certificate (owner device authentication), and the owner terminal 20 is authenticated as a legitimate terminal in the owner device authentication, the electronic lock device 10 performs the generation of the first owner CA and the issuance of an unlocking certificate by the first owner CA. Once the generation of the first owner CA and the issuance of an unlocking certificate by the first owner CA are performed, the electronic lock device 10 transmits the unlocking certificate issued by the first owner CA to the owner terminal 20.

[0102] The electronic lock device 10 transmits the unlocking certificate issued by the second owner CA to the owner terminal 20 (step S71). Similar to step S20 described above, the digital key generation request unit 230 of the owner terminal 20 requests the electronic lock device 10 to perform owner device authentication related to the generation of the second owner CA. If the electronic lock device 10 accepts the authentication of the owner terminal 20 using the owner certificate (owner device authentication), and the owner terminal 20 is authenticated as a legitimate terminal in the owner device authentication, the electronic lock device 10 performs the generation of the second owner CA and the issuance of the unlocking certificate by the second owner CA. Once the generation of the second owner CA and the issuance of the unlocking certificate by the second owner CA are performed, the electronic lock device 10 transmits the unlocking certificate issued by the second owner CA to the owner terminal 20.

[0103] Encryption methods are constantly evolving, and in order to maintain and improve security, it is desirable to switch from existing encryption methods to new encryption algorithms. However, switching encryption methods cannot always be done immediately. Therefore, it is desirable to set a transition period and make it possible to support both the old and new encryption methods during that period. If, on a certain date, the existing encryption method becomes unsupported and only the new encryption method is supported, all unlocking certificates issued by the Owner CA (First Owner CA) that supported the existing encryption method will become invalid, and all unlocking certificates issued by the First Owner CA must be updated simultaneously, which is not practical. To address this, in this embodiment, the electronic lock device 10 is designed to allow the existence of multiple Owner CAs. For example, at least one of the multiple Owner CAs is a certification authority that supports the existing encryption method, and at least one of the remaining Owner CAs is a certification authority that supports the new encryption method. This makes it possible to support both the old and new encryption methods simultaneously. For example, during the period when the owner terminal 20 does not support the new encryption method (first period), it generates a first owner CA in the electronic lock device 10 as a certification authority that supports the existing encryption method, and uses the unlocking certificate issued by the first owner CA to unlock or lock the electronic lock device 10. For a friend terminal 30 that requested the generation of a share key during the first period, the owner terminal 20 has the first owner CA issue a public key certificate proving the public key of the friend terminal 30 as an unlocking certificate, and then forwards the unlocking certificate issued by the first owner CA to the friend terminal 30, so that the friend terminal 30 uses the unlocking certificate issued by the first owner CA to unlock or lock the electronic lock device 10. Subsequently, during the period when the owner terminal 20 becomes capable of supporting the new encryption method (second period), it generates a second owner CA in the electronic lock device 10 as a certification authority that supports the new encryption method. At this time, the owner terminal 20 does not delete the first owner CA, but keeps it active. During the second period, the owner terminal 20 uses the unlocking certificate issued by the second owner CA to unlock or lock the electronic lock device 10.On the other hand, Friend terminals 30 that requested the generation of a share key in the first period but did not request the generation of a new share key in the second period will continue to unlock or lock the electronic lock device 10 using the unlocking certificate issued by the first owner CA. For Friend terminals 30 that requested the generation of a share key in the second period, the second owner CA will issue a public key certificate proving the public key of Friend terminal 30 as an unlocking certificate, and the unlocking certificate issued by the second owner CA will be transferred to Friend terminal 30 so that Friend terminal 30 can unlock or lock the electronic lock device 10 using the unlocking certificate issued by the second owner CA. In this way, it is possible to support both the old and new encryption methods simultaneously.

[0104] As described above, the electronic lock device 10 of this embodiment comprises a certification authority generation unit 131 and a lock / unlock control unit 132. The certification authority generation unit 131 generates an owner CA. The owner CA has the function of issuing public key certificates. The owner CA is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock in response to a request from the owner terminal, which is a digital key paired with the electronic lock. The lock / unlock control unit 132 controls the unlocking or locking of the electronic lock in response to notification from the terminal of the unlocking certificate issued by the owner CA. As a result, the electronic lock device 10 of this embodiment can function as a certification authority, eliminating the need for the electronic lock device 10 to obtain a public key certificate from a trusted certification authority or to have the owner terminal 20 issue a public key certificate for the owner terminal 20 from that trusted certification authority. Therefore, it is possible to suppress the use of highly secure user authentication for locking and unlocking without complicating the process.

[0105] Furthermore, the electronic lock device 10 of this embodiment further includes an owner authentication unit 130. The electronic lock of the electronic lock device 10 also has a mechanism that allows it to be unlocked with a physical key. The owner authentication unit 130 authenticates the owner terminal 20 and determines that the owner terminal 20 is a legitimate terminal device when the electronic lock is unlocked with a physical key, the certificate notified from the terminal is an owner certificate issued by the manufacturer's CA, and the manufacturer's CA's public key certificate is stored in the electronic lock device 10. The certification authority generation unit 131 generates an owner CA in response to a request from the owner terminal 20 authenticated by the owner authentication unit 130. As a result, the electronic lock device 10 of this embodiment can perform owner device authentication and issue an unlocking certificate to a legitimate terminal (a terminal owned by an owner who possesses a physical key and has an owner certificate issued in advance by a trusted manufacturer's CA stored in it).

[0106] The electronic lock system 1 and electronic lock device 10 in the above-described embodiment may be implemented in whole or in part by a computer. In that case, the program for implementing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into the computer system and executed. The term "computer system" here includes hardware such as the OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and storage devices such as hard disks built into the computer system. Furthermore, the term "computer-readable recording medium" may also include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside the computer system that acts as a server or client in that case. The program may be for implementing a part of the functions described above, or it may be a program that can implement the functions described above in combination with a program already recorded in the computer system, or it may be implemented using a programmable logic device such as an FPGA. Furthermore, the locking and unlocking method may be implemented by realizing all or part of the electronic lock system 1 and electronic lock device 10 in the above-described embodiment using a computer.

[0107] Although embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0108] The present invention can be used in an electronic lock device comprising: a certification authority generation unit that generates an owner CA, which is a certification authority that has the function of issuing public key certificates and issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock in response to a request from an owner terminal, which is a digital key paired with the electronic lock; and a lock / unlock control unit that controls the unlocking or locking of the electronic lock in response to the terminal being notified of the unlocking certificate issued by the owner CA.

[0109] 1...Electronic lock system 10...Electronic lock device 12...Storage unit 120...Manufacturer CA information 121...Encryption key information 122...Issued certificate information 13...Control unit 130...Owner authentication unit 131...Certification authority generation unit 132...Locking / unlocking control unit 133...Unlocking certificate management unit 134...Certification authority management unit 20...Owner terminal 220...Owner information 230...Digital key generation request unit 231...Digital key operation unit 232...Digital key management unit 30...Friend terminal 330...Digital key share request unit 331...Digital key operation unit

Claims

1. An electronic lock device comprising: a certification authority generation unit that has the function of issuing public key certificates and generates an owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock in response to a request from an owner terminal, which is a digital key paired with the electronic lock; and a lock / unlock control unit that controls the unlocking or locking of the electronic lock in response to notification from the terminal of the unlocking certificate issued by the owner CA.

2. The electronic lock device according to claim 1, wherein the electronic lock has a mechanism that can be unlocked with a physical key, and further comprises an owner authentication unit that authenticates the owner terminal when the electronic lock is unlocked with the physical key, the certificate notified from the terminal is an owner certificate issued by the manufacturer's CA, and the manufacturer's CA's public key certificate is stored in the electronic lock device, and the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit.

3. The electronic lock device according to claim 1, further comprising an owner authentication unit that authenticates the owner terminal when the certificate notified from the terminal is an owner certificate issued by a manufacturer CA and the manufacturer CA's public key certificate is stored in the electronic lock device, wherein the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit.

4. The electronic lock device according to claim 1, wherein the certification authority generation unit, in response to a request from the owner terminal, causes the owner CA to issue the unlocking certificate to be used by the owner terminal, and the owner CA issues the public key certificate, which includes an electronic signature obtained by signing the owner terminal's public key with the owner CA's private key, as the unlocking certificate to be used by the owner terminal.

5. The electronic lock device according to claim 1, wherein the certification authority generation unit, in response to a request from the owner terminal, causes the owner CA to issue the unlocking certificate to be used by a friend terminal different from the owner terminal, and the owner CA issues a public key certificate including an electronic signature obtained by signing the public key of the friend terminal using the private key of the owner CA, as the unlocking certificate to be used by the friend terminal.

6. The electronic lock device according to claim 1, further comprising an unlocking certificate management unit that invalidates the unlocking certificate issued by the owner CA in response to a request from the owner terminal.

7. The electronic lock device according to claim 1, further comprising a certification authority management unit that deletes the owner CA generated by the certification authority generation unit in response to a request from the owner terminal.

8. The electronic lock device according to claim 1, further comprising a certification authority management unit that generates a new owner CA, a second owner CA, which is different from the first owner CA, which is the owner CA, generated by the certification authority generation unit, in response to a request from the owner terminal.

9. An electronic lock device comprising: a certification authority generation unit that has the function of issuing public key certificates and generates an owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock an electronic lock in response to a request from an owner terminal which is a digital key paired with an electronic lock; and a lock / unlock control unit that controls the unlocking or locking of an electronic lock in response to the terminal being notified of the unlocking certificate issued by the owner CA, wherein the electronic lock has a mechanism that can be unlocked with a physical key, and further comprises an owner authentication unit that authenticates the owner terminal when the electronic lock is unlocked with the physical key, the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the public key certificate of the manufacturer CA is stored in the electronic lock device, and the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit, and further comprises an unlocking certificate management unit that invalidates the unlocking certificate already issued by the owner CA in response to a request from the owner terminal.

10. An electronic lock device comprising: a certification authority generation unit that has the function of issuing public key certificates and generates an owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock an electronic lock in response to a request from an owner terminal which is a digital key paired with an electronic lock; and a lock / unlock control unit that controls the unlocking or locking of an electronic lock in response to the terminal notifying it of the unlocking certificate issued by the owner CA, wherein the electronic lock has a mechanism that can be unlocked with a physical key, and further comprises an owner authentication unit that authenticates the owner terminal when the electronic lock is unlocked with the physical key, the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the public key certificate of the manufacturer CA is stored in the electronic lock device, and the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit, and further comprises a certification authority management unit that deletes the owner CA generated by the certification authority generation unit in response to a request from the owner terminal.

11. An electronic lock device comprising: a certification authority generation unit that has the function of issuing public key certificates and generates an owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock an electronic lock in response to a request from an owner terminal which is a digital key paired with an electronic lock; and a lock / unlock control unit that controls the unlocking or locking of the electronic lock in response to the terminal notifying the unlocking certificate issued by the owner CA, wherein the electronic lock has a mechanism that can be unlocked with a physical key, and further comprises an owner authentication unit that authenticates the owner terminal when the electronic lock is unlocked with the physical key, the certificate notified from the terminal is an owner certificate issued by a manufacturer CA, and the public key certificate of the manufacturer CA is stored in the electronic lock device, and the certification authority generation unit generates the owner CA in response to a request from the owner terminal authenticated by the owner authentication unit, and an unlocking certificate management unit that invalidates the unlocking certificate already issued by the owner CA in response to a request from the owner terminal, An electronic lock device further comprising: a certification authority management unit that deletes the owner CA generated by the certification authority generation unit in response to a request from the owner terminal.

12. An electronic lock system comprising: the electronic lock device according to claim 1; and the owner terminal that communicates with the electronic lock device, instructs the electronic lock device to generate the owner CA, and obtains the unlocking certificate issued by the owner CA.

13. The unlocking certificate issued by the owner CA has an expiration date set, the owner terminal transmits the unlocking certificate along with a timestamp to the electronic lock device, and the lock / unlock control unit of the electronic lock device controls the unlocking or locking of the electronic lock when it determines that the unlocking certificate notified by the owner terminal is valid based on the timestamp notified by the owner terminal.

14. A locking and unlocking method performed by a computer which is an electronic lock device, wherein a certification authority generation unit has the function of issuing public key certificates and generates an owner CA which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock in response to a request from an owner terminal which is a digital key paired with the electronic lock, and a locking and unlocking control unit controls the unlocking or locking of the electronic lock in response to the terminal notifying the unlocking certificate issued by the owner CA.

15. A program for a computer that is an electronic lock device, which has the function of issuing public key certificates, and which generates an Owner CA, which is a certification authority that issues a public key certificate as an unlocking certificate used to unlock or lock the electronic lock, in response to a request from an Owner terminal which is a digital key paired with the electronic lock, and controls the unlocking or locking of the electronic lock in response to the terminal being notified of the unlocking certificate issued by the Owner CA.

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