JP7658574B2 - Device control device, management device, device management system, device control method, and program - Google Patents

Description

The present invention relates to a device control device, a management device, a device management system, a device control method, and a program.

In recent years, technology has been developed that controls operations such as door locks, device activation, and engine start, triggered by the exchange of electronic signals from electronic keys, etc. For example, Patent Document 1 discloses technology for controlling locks by receiving a processing request from one of multiple communication terminals (see, for example, Patent Document 1).

JP 2016-223212 A

By using the above technology, it becomes possible to adaptively set the authority to control the lock for each communication terminal. Here, the authority set for the communication terminal is set according to the attributes of the owner of that communication terminal. For example, the owner authority is set in advance for the communication terminal of the owner of a guest house with a lock, and only the authority to unlock the door is set in advance for the communication terminal of the user of the guest house.

The lock performs operations according to the permissions preset in the communications device, but these operations are not based on the latest attributes of the communications device's owner. Therefore, even if the attributes of the communications device's owner change, the lock will continue to operate according to the permissions still set in the communications device until the permissions set in the communications device are changed.

The inventors of this application recognized the possibility of increasing the flexibility of device operation control by making the conditions for device operation the attributes of the communication terminal's owner, rather than the permissions set in the communication terminal.

The present invention was made in consideration of these points, and aims to provide technology that increases the flexibility of device operational control.

A first aspect of the present invention is a device control device that is connected to a management device that manages a certificate that certifies information about a user of a controlled device in a manner that allows encrypted communication, and controls the operation of the controlled device. This device includes a user information acquisition unit that reads user information from a user terminal of a user of the controlled device, the user identifier for identifying the user, tag information for identifying a tag that indicates a type of a certificate that certifies information about the user, a signature of the management device generated using a management device private key that is a private key of the management device, and a signature of the user generated using a user private key that is a private key of the user terminal, a device identifier for identifying the device control device, an issuer public key that is a public key of the issuer of the certificate, a management device public key that is a public key of the management device, and a storage unit that stores operating conditions that define operating conditions of the controlled device, and the management device public key that is a public key of the management device. The device control device includes a signature verification unit that uses a public key to verify the authenticity of the signature of the management device included in the user information read from the user terminal, an encryption unit that generates user information for transmission by encrypting information including the user identifier, the tag information, and the device identifier with the management device public key on condition that the signature is authentic, and a communication unit that transmits the user information for transmission to the management device via encrypted communication and receives proof information from the management device that includes a certificate certifying information about the user and a user public key corresponding to the user private key, the proof information including the signature of the issuer generated using an issuer private key that is the private key of the issuer of the certificate. The signature verification unit of the device control device verifies the authenticity of the signature of the issuer included in the proof information using the issuer public key, and verifies the authenticity of the signature of the user included in the user information using the user public key. The device control device further includes an operating condition determination unit that determines whether the certificate included in the certification information satisfies the operating condition, on the condition that both the issuer's signature and the user's signature are valid, and a device control unit that permits operation of the controlled device, on the condition that the certificate included in the certification information satisfies the operating condition.

The tag information may be a hash value of a tag indicating the type of the certificate.

The second aspect of the present invention is the management device that is connected to the above-mentioned device control device via a communication network in a manner that allows encrypted communication. This device includes a communication unit that receives the sending user information from the device control device, and a decryption unit that decrypts the sending user information using a management device private key that is a private key corresponding to the management device public key to obtain the user identifier, the tag information, and the device identifier. The communication unit refers to the user identifier and the tag information obtained by the decryption unit, and transmits to the device control device certification information that includes a certificate that certifies information about the user and a user public key that corresponds to the user private key, and that includes the signature of the issuer that was generated using an issuer private key that is the private key of the issuer of the certificate.

The management device may further include a list checking unit that refers to a permission list that is pre-listed as device identifiers of device control devices that are permitted to control the controlled device, and checks whether the device identifier acquired by the decryption unit is included in the permission list, and the communication unit may transmit the certification information to the device control device on the condition that the device identifier acquired by the decryption unit is included in the permission list.

A third aspect of the present invention is an equipment management system including an equipment control device that controls the operation of a controlled device, and a management device that connects to the equipment control device via a communication network in a manner that enables encrypted communication. In this system, the device control device includes a user information acquisition unit that reads user information from a user terminal of a user of the controlled device, the user information including a user identifier for identifying the user, tag information for identifying a tag indicating a type of certificate certifying information about the user, the signature of the management device generated using a management device private key that is the private key of the management device, and the signature of the user generated using a user private key that is the private key of the user terminal; a memory unit that stores a device identifier for identifying the device control device, an issuer public key that is the public key of the issuer of the certificate, a management device public key that is the public key of the management device, and operating conditions that define the conditions for operation of the controlled device; a signature verification unit that uses the management device public key to verify the validity of the signature of the management device included in the user information read from the user terminal; an encryption unit that encrypts information including the user identifier, the tag information, and the device identifier with the management device public key, provided that the signature is valid, to generate user information for transmission; and a communication unit that transmits the user information for transmission to the management device. The management device includes a communication unit that receives the sending user information from the device control device, and a decryption unit that decrypts the sending user information using a management device private key that is a private key corresponding to the management device public key to obtain the user identifier, the tag information, and the device identifier. The communication unit of the management device refers to the user identifier and the tag information acquired by the decryption unit, and transmits to the device control device proof information including a certificate that certifies information about the user and a user public key that corresponds to the user private key, the proof information including a signature of the issuer generated using an issuer private key that is a private key of the issuer of the certificate, the communication unit of the device control device receives the proof information from the management device, and the signature verification unit of the device control device verifies the authenticity of the signature of the issuer included in the proof information using the issuer public key, and verifies the authenticity of the signature of the user included in the user information using the user public key. The device control device further includes an operating condition determination unit that determines whether the certificate included in the certification information satisfies the operating condition, on the condition that both the issuer's signature and the user's signature are valid, and a device control unit that permits operation of the controlled device, on the condition that the certificate included in the certification information satisfies the operating condition.

The device management system may further include a storage device that stores a permission list that is pre-listed as device identifiers of device control devices that are permitted to control the controlled device, and a certificate database that links and manages the user identifier, the user public key, the user signature, the certificate, the tag information, and the issuer signature, and the management device may further include a storage device management unit that reads out the permission list and the certification information from the storage device.

A fourth aspect of the present invention is a device control method. In this method, a processor of a device control device that is connected to a management device that manages a certificate that certifies information about a user of a controlled device in a manner that allows encrypted communication and controls the operation of the controlled device, reads user information from a user terminal of a user of the controlled device, including a user identifier for identifying the user, tag information for identifying a tag indicating a type of a certificate that certifies information about the user, a signature of the management device generated using a management device private key that is a private key of the management device, and a signature of the user generated using a user private key that is a private key of the user terminal, a step of verifying the validity of the signature of the management device included in the user information read from the user terminal, using a management device public key that is a public key stored in a storage unit of the device control device and is a public key of the management device, and a step of generating user information for transmission in which information including the user identifier, the tag information, and a device identifier for identifying the device control device is encrypted with the management device public key, provided that the signature is valid. a step of verifying the validity of the issuer's signature included in the certification information, a step of transmitting the sending user information to the management device via encrypted communication, a step of receiving from the management device, via encrypted communication, information including a certificate verifying information about the user and a user public key corresponding to the user private key, the certificate including a signature of the issuer generated using an issuer private key that is the private key of the issuer of the certificate, a step of verifying the validity of the issuer's signature included in the certification information using an issuer public key that is the public key of the issuer of the certificate and is a public key stored in a storage unit of the device control device, a step of verifying the validity of the user's signature included in the user information using the user public key, a step of determining whether the certificate included in the certification information satisfies an operating condition that defines the operating condition of the controlled device, on the condition that both the issuer's signature and the user's signature are valid, and a step of permitting the operation of the controlled device, on the condition that the certificate included in the certification information satisfies the operating condition.

A fifth aspect of the present invention is a program. This program is connected to a management device that manages a certificate that certifies information about a user of a controlled device in a manner that allows encrypted communication, and provides a device control device that controls the operation of the controlled device with a function of reading user information from a user terminal of the user of the controlled device, the user information including a user identifier for identifying the user, tag information for identifying a tag indicating a type of a certificate that certifies information about the user, the management device signature generated using a management device private key that is a private key of the management device, and the user signature generated using a user private key that is a private key of the user terminal, a function of verifying the validity of the management device signature included in the user information read from the user terminal, using a management device public key that is a public key stored in a storage unit of the device control device and is a public key of the management device, and a function of generating user information for transmission in which information including the user identifier, the tag information, and a device identifier for identifying the device control device is encrypted with the management device public key, provided that the signature is valid. a function to generate a certificate for the user, a function to transmit the sending user information to the management device via encrypted communication, a function to receive from the management device via encrypted communication, information including a certificate attesting to information about the user and a user public key corresponding to the user private key, and including a signature of the issuer generated using an issuer private key that is the private key of the issuer of the certificate, a function to verify the validity of the signature of the issuer included in the certification information using an issuer public key that is a public key stored in the storage unit of the device control device and is the public key of the issuer of the certificate, a function to verify the validity of the signature of the user included in the user information using the user public key, a function to determine whether the certificate included in the certification information satisfies an operating condition that defines the operating condition of the controlled device, on the condition that both the signature of the issuer and the signature of the user are valid, and a function to permit the operation of the controlled device, on the condition that the certificate included in the certification information satisfies the operating condition.

To provide this program or to update a portion of the program, a computer-readable recording medium having this program recorded thereon may be provided, or this program may be transmitted over a communication line.

In addition, any combination of the above components, and any conversion of the present invention into a method, device, system, computer program, data structure, recording medium, etc., are also valid aspects of the present invention.

The present invention makes it possible to increase the flexibility of device operation control.

FIG. 1 is a diagram for explaining an overview of a device management system according to an embodiment. 2 is a diagram illustrating a schematic functional configuration of a device control device and a management device according to an embodiment; FIG. 2 is a diagram illustrating information stored in a storage unit of a device control device according to an embodiment. FIG. FIG. 2 is a diagram illustrating an example of a data structure of user information according to an embodiment. FIG. 4 is a diagram illustrating a data structure of a certificate database according to the embodiment. FIG. 4 is a diagram illustrating an example of a data structure of a permission list according to an embodiment. 4 is a sequence diagram illustrating the flow of device control processing executed in the device management system according to the embodiment. FIG.

<Overview of the embodiment>
Fig. 1 is a diagram for explaining an overview of a device management system S according to an embodiment. The overview of the embodiment will be described below with reference to Fig. 1.

The device management system S according to the embodiment includes a controlled device D, a device control device 1 that controls the operation of the controlled device D, a management device 2 that manages a certificate that certifies information about a user U of the controlled device D, and a storage device 3. Here, the device control device 1 and the management device 2 are connected in a manner that allows encrypted communication.

In the example of the device management system S shown in FIG. 1, the controlled device D is an electronic lock that uses motor power to unlock and lock. The device control device 1 can obtain information from the user terminal T by reading a code displayed on the display unit of the user terminal T held by the user U.

The following describes an overview of the processes executed by the device management system S according to the embodiment in the order of (1) to (6), with the numbers corresponding to (1) to (6) in FIG. 1.

(1) The device control device 1 reads user information about a user U stored in the user terminal T from the user terminal T. Specifically, the device control device 1 may access the URI (Uniform Resource Identifier) read from the user terminal T and obtain the user information from the accessed destination.

The user information read by the device control device 1 from the user terminal T includes tag information for identifying a tag indicating the type of certificate that certifies information about the user U. Although not limited thereto, a certificate that certifies information about the user U may be, for example, a license for the user U to operate a specific device or heavy machinery, proof that the user U belongs to a specific organization, proof that the user U or a pet owned by the user U has resistance or antibodies against a specific disease, or has been vaccinated, etc.

(2) The device control device 1 encrypts a part of the user information with the management device public key and transmits the encrypted information to the management device 2 .
(3) The management device 2 acquires a certificate from the storage device 3 that stores the certificate that certifies information about the user U, based on the tag information included in the user information received from the device control device 1 .
(4) The management device 2 transmits certificate information including the certificate acquired from the storage device 3 to the device control device 1 .

(5) The device control device 1 determines whether or not the contents of the certificate received from the management device 2 satisfy the conditions for operating the controlled device D.
(6) The device control device 1 permits the operation of the controlled device D on the condition that the contents of the certificate satisfy the conditions for operating the controlled device D.

This allows the device control device 1 to directly reference the attributes of the user U to determine whether or not to operate the controlled device D, thereby increasing the flexibility of the operational control of the controlled device D.

<Functional configuration of device control device 1 and management device 2 according to embodiment>
2 is a diagram illustrating a schematic functional configuration of each of the device control device 1 and the management device 2 according to the embodiment. The device control device 1 includes a communication unit 10, a storage unit 11, and a control unit 12. The management device 2 includes a communication unit 20, a storage unit 21, and a control unit 22.

In FIG. 2, the arrows indicate the main data flows, and there may be data flows not shown in FIG. 2. In FIG. 2, each functional block indicates a functional configuration, not a hardware (device) configuration. Therefore, the functional blocks shown in FIG. 2 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between functional blocks via any means, such as a data bus, a network, or a portable storage medium.

The communication unit 10 is a communication interface that enables the device control device 1 to communicate with external devices such as the management device 2, and is realized, for example, by a mobile communication module or a Wi-Fi (registered trademark) module.

The storage unit 11 is a large-capacity storage device such as a ROM (Read Only Memory) that stores the BIOS (Basic Input Output System) of the computer that realizes the device control device 1, a RAM (Random Access Memory) that serves as the working area of the device control device 1, an HDD (Hard Disk Drive) or SSD (Solid State Drive) that stores the OS (Operating System), application programs, and various information referenced when the application programs are executed.

The control unit 12 is a processor such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit) of the device control device 1, and functions as a user information acquisition unit 120, a signature verification unit 121, an encryption unit 122, an operating condition determination unit 123, and a device control unit 124 by executing programs stored in the memory unit 11.

The communication unit 20 is a communication interface that enables the management device 2 to communicate with external devices such as the device control device 1, and is realized, for example, by a LAN (Local Area Network) module.

The storage unit 21 is a large-capacity storage device such as a ROM that stores the BIOS of the computer that realizes the management device 2, a RAM that serves as the working area of the management device 2, an OS, application programs, and a variety of information referenced when the application programs are executed, such as an HDD or SSD.

The control unit 22 is a processor such as a CPU or GPU of the management device 2, and functions as a decryption unit 220, a storage device management unit 221, and a list confirmation unit 222 by executing the programs stored in the memory unit 21.

Note that FIG. 2 shows an example in which the management device 2 is configured as a single device. However, the management device 2 may be realized by multiple processors, memory, and other computing resources, such as a cloud computing system. In this case, each part constituting the control unit 22 is realized by at least one of multiple different processors executing a program.

The user information acquisition unit 120 reads user information from the user terminal T of the user U. Here, the user information includes a user identifier for identifying the user U, tag information for identifying a tag indicating the type of certificate that certifies information about the user U, a signature of the management device generated using the management device private key, which is the private key of the management device 2, and a signature of the user U generated using the user private key, which is the private key of the user terminal T.

FIG. 3 is a diagram showing information stored in the memory unit 11 of the device control device 1 according to the embodiment. As shown in FIG. 3, the memory unit 11 stores various information referenced during execution of an application program, such as a device identifier for identifying the device control device 1, an issuer public key that is the public key of the issuer of the certificate, a management device public key that is the public key of the management device 2, and operating conditions that define the conditions for the operation of the controlled device D. The information stored in the memory unit 11 is stored in the memory unit 11 by the manufacturer of the device control device 1 when the device control device 1 is manufactured, for example. As shown in FIG. 3, the memory unit 11 may include one or more issuer public keys. Examples of operating conditions that define the conditions for the operation of the controlled device D include that the user U has a specific certificate and that the validity period of the certificate has not expired.

The signature verification unit 121 reads out the management device public key from the storage unit 11. The signature verification unit 121 uses the management device public key to verify the validity of the signature of the management device 2 included in the user information read from the user terminal T. The encryption unit 122 generates user information for transmission by encrypting information including a user identifier, tag information, and device identifier with the management device public key, on the condition that the signature verified by the signature verification unit 121 is valid. Note that the user identifier and tag information are included in the user information acquired from the user terminal T by the user information acquisition unit 120, and the device identifier is stored in the storage unit 11.

The communication unit 20 transmits the sending user information generated by the encryption unit 122 to the management device 2 via encrypted communication. The communication unit 20 receives proof information from the management device 2, including a certificate that certifies information about the user U and a user public key that corresponds to the user private key. This proof information includes the signature of the issuer that was generated using the issuer private key, which is the private key of the certificate issuer. The processing executed in the management device 2 will be described later.

The signature verification unit 121 reads the issuer public key from the memory unit 11. The signature verification unit 121 uses the issuer public key to verify the validity of the issuer signature included in the certification information received by the communication unit 20. The signature verification unit 121 also uses the user public key included in the certification information received by the communication unit 20 to verify the validity of the signature of user U included in the user information acquired by the user information acquisition unit 120.

The operation condition determination unit 123 determines whether the certificate included in the certification information satisfies the operation conditions, provided that both the issuer's signature and the user's signature are valid as a result of the verification by the signature verification unit 121. The device control unit 124 permits the operation of the controlled device D, provided that the certificate included in the certification information satisfies the operation conditions. For example, if the controlled device D is an autolock door, the certificate is a permit for user U to enter, and the device control unit 124 permits the controlled device D to unlock it. As another example, if the controlled device D is a special vehicle that requires a license to operate, the certificate is a special vehicle license issued to user U, and the device control unit 124 permits the controlled device D to start.

The user U can download tag information for identifying a tag indicating the type of certificate to the user terminal T via the communication network N. Therefore, when the user U acquires a new certificate or updates a certificate, the user U can quickly store the tag information in the user terminal T. The device control unit 124 controls the operation of the controlled device D based on the user information read from the user terminal T by the user information acquisition unit 120, and can quickly respond to the acquisition or updating of a new certificate for the user U. As a result, the device control device 1 can increase the flexibility of the operation control of the controlled device D based on the user U's certificate.

Here, the "tag" is information indicating the type of certificate, and examples of such information include a "license for a special vehicle," a "certificate that a specific vaccine has been administered," and an "employee ID card for a specific company." The tag information included in the user information read by the user information acquisition unit 120 from the user terminal T need only be information capable of identifying a tag indicating the type of certificate that certifies information about the user U, and does not necessarily have to be the tag itself. As a specific example, the tag information may be a hash value of the tag, which is information indicating the type of certificate.

Figure 4 is a diagram showing a schematic example of a data structure of user information according to an embodiment. As shown in Figure 4, the data structure includes a user identifier, tag information, the signature of the management device 2, and the signature of the user. In the example shown in Figure 4, a hash value of a tag, which is information indicating the type of certificate, is stored as the tag information. In addition, since the memory unit 11 includes one or more issuer public keys, the user information also includes multiple pieces of tag information.

By its very nature, a hash value has a one-to-one relationship with a tag, and it is considered extremely difficult to restore the original tag from a hash value. For this reason, even if tag information is leaked to a third party, the third party will be virtually unable to restore the tag from the tag information. On the other hand, since the management device 2 already possesses the tag, it is also able to generate tag information corresponding to the tag. Therefore, the management device 2 can identify the corresponding tag by acquiring the tag information from the device control device 1. In this way, the user information held by the user terminal T is tag information rather than the tag itself, and thus the device management system S can reduce the risk of information leakage.

(Processing Executed by Management Device 2)
Next, a process executed by the management device 2 that receives the sending user information from the equipment control device 1 will be described.

The communication unit 20 of the management device 2 receives the sending user information from the device control device 1. The decryption unit 220 decrypts the sending user information using the management device private key, which is a private key corresponding to the management device public key, and obtains the user identifier, tag information, and device identifier.

The communication unit 20 transmits to the device control device 1 certificate information including a certificate that certifies information about the user U and a user public key that corresponds to the user private key. This certificate information includes the issuer's signature that was generated using the issuer private key, which is the private key of the certificate issuer.

Figure 5 is a diagram showing a schematic data structure of the certificate database 30 according to the embodiment. The certificate database 30 is stored in the storage device 3 and is managed by the storage device management unit 221 of the management device 2.

In the example shown in FIG. 5, the certificate database 30 manages a user identifier, a user public key, a user signature, a certificate, tag information, and an issuer signature by linking them together for each user identifier. Specifically, the certificate database 30 stores the user identifier and user public key with the user signature, the certificate, tag information, a hash value of the tag information, and information indicating the certificate expiration date, with the signature of the certificate issuer attached. The signature verification unit 121 refers to the user identifier and tag information acquired by the decryption unit 220, and reads and acquires the certification information from the certificate database 30.

In this way, the management device 2 can transmit the certification information of the user U, who is the owner of the user terminal T, to the device control device 1 based on the information received from the device control device 1, which reads the user information from the user terminal T.

Here, since the device control device 1 may be installed in a place beyond the reach of the management device 2, there is a possibility that it may not be possible to completely prevent the device control device 1 from being stolen or tampered with by a malicious third party. Therefore, the list confirmation unit 222 of the management device 2 refers to a permission list that is pre-listed as device identifiers of the device control devices 1 that are permitted to control the controlled device D, and confirms whether the device identifier acquired by the decryption unit 220 is included in the permission list.

FIG. 6 is a diagram showing an example of the data structure of the permission list 31 according to the embodiment. As shown in FIG. 6, the permission list 31 is stored in the storage device 3 in a pre-listed state of device identifiers of device control devices 1 that are permitted to control the control target device D, and is managed by the list confirmation unit 222 of the management device 2. The permission list 31 is read from the storage device 3 by the storage device management unit 221 of the management device 2.

The communication unit 20 of the management device 2 transmits the certificate information to the device control device 1 on the condition that the device identifier acquired by the decryption unit 220 is present in the permission list 31. For example, if the administrator of the device control device 1 finds any abnormality in the device control device 1, the administrator notifies the administrator of the management device 2. The administrator of the management device 2 deletes the device identifier of the notified device control device 1 from the permission list 31. This allows the management device 2 to refrain from transmitting the certificate information of the user U to the device control device 1 if the theft or tampering of the device control device 1 is found.

<Process flow of device control method executed in device management system S>
FIG. 7 is a sequence diagram for explaining the flow of device control processing executed in the device management system S according to the embodiment.

The user information acquisition unit 120 of the device control device 1 reads user information from the user terminal T of the user U (S2). The signature verification unit 121 reads the management device public key from the storage unit 11 (S4). The signature verification unit 121 uses the management device public key to verify the validity of the signature of the management device 2 included in the user information read by the user information acquisition unit 120 (S6).

If the signature of the management device 2 is valid (Yes in S8), the encryption unit 122 encrypts information including the user identifier, tag information, and device identifier with the management device public key to generate user information for transmission (S10).

The communication unit 10 transmits the sending user information generated by the encryption unit 122 to the management device 2 (S12). The communication unit 20 of the management device 2 receives the sending user information from the device control device 1 (S14). The decryption unit 220 decrypts the sending user information received by the communication unit 20 (S16).

The storage device management unit 221 acquires certification information from the storage device 3 by referring to the user identifier and tag information acquired by the decryption unit 220 by decrypting the sending user information (S18). The communication unit 20 transmits the certification information acquired by the storage device management unit 221 to the device control device 1 (S20).

The communication unit 10 of the device control device 1 receives the certification information from the management device 2 (S22). The signature verification unit 121 uses the issuer public key to verify the validity of the issuer's signature included in the certification information received by the communication unit 10 (S24). If the issuer's signature is valid (Yes in S26), the signature verification unit 121 uses the user public key included in the certification information received by the communication unit 10 to verify the validity of the signature of user U included in the user information acquired by the user information acquisition unit 120 (S28).

If the signature of user U is valid (Yes in S30), the operating condition determination unit 123 determines whether the certificate included in the certification information satisfies the operating conditions (S32). If the certificate included in the certification information satisfies the operating conditions (Yes in S34), the device control unit 124 permits the operation of the controlled device D (S36).

If the signature of the management device 2 is invalid (No in S8), if the signature of the issuer is invalid (No in S26), if the signature of the user U is invalid (No in S30), or if the certificate included in the certification information does not satisfy the operating conditions (No in S34), the device control device 1 does not perform any special processing.

<Effects of the device control device 1 according to the embodiment>
As described above, the device control device 1 according to the embodiment can increase the flexibility of device operation control.

Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination also has the effect of the original embodiment.

<First Modification>
In the above, a case has been described in which the device control device 1 acquires user information from the user terminal T by reading a code displayed on the display unit of the user terminal T. Alternatively or in addition to this, the device control device 1 may read out user information from the user terminal T via short-range wireless communication such as NFC (Near Field Communication). In this case, the device control device 1 may include an NFC reader (not shown) and read information from an NFC tag included in the user terminal T.

<Second Modification>
In the above, it is assumed that the storage device 3 is a normal single storage device, but the storage device 3 may be a distributed storage device. In particular, the storage device 3 may be realized using a known distributed ledger technology such as a blockchain.

1...Device control device 10...Communication unit 11...Memory unit 12...Control unit 120...User information acquisition unit 121...Signature verification unit 122...Encryption unit 123...Operation condition determination unit 124...Device control unit 2...Management device 20...Communication unit 21...Memory unit 22...Control unit 220...Decryption unit 221...Storage device management unit 222...List confirmation unit 3...Storage device 30...Certificate database 31...Permission list N...Communication network S...Device management system

Claims (8)

A device control device that is connected to a management device that manages a certificate that certifies information about a user of a controlled device in a manner that enables encrypted communication and controls an operation of the controlled device,
a user information acquisition unit that reads user information from a user terminal of a user of the controlled device, the user information including a user identifier for identifying the user, tag information for identifying a tag indicating a type of a certificate that certifies information about the user, a signature of the management device generated using a management device private key that is a private key of the management device, and a signature of the user generated using a user private key that is a private key of the user terminal;
a storage unit that stores a device identifier for identifying the device control device, an issuer public key that is a public key of an issuer of the certificate, a management device public key that is a public key of the management device, and operating conditions that define conditions for the operation of the controlled device;
a signature verification unit that uses the management device public key to verify the validity of the signature of the management device included in the user information read from the user terminal;
an encryption unit that encrypts information including the user identifier, the tag information, and the device identifier with the management device public key to generate transmission user information, on condition that the signature is valid;
a communication unit that transmits the sending user information to the management device via encrypted communication, and receives from the management device certification information including a certificate certifying information about the user and a user public key corresponding to the user private key, the certification information including a signature of the issuer generated using an issuer private key that is a private key of the issuer of the certificate,
the signature verification unit of the device control device verifies the authenticity of the signature of the issuer included in the certification information by using the issuer public key, and verifies the authenticity of the signature of the user included in the user information by using the user public key;
The device control device further comprises:
an operating condition determination unit that determines whether the certificate included in the certification information satisfies the operating condition, on the condition that both the signature of the issuer and the signature of the user are valid;
a device control unit that permits operation of the controlled device on condition that the certificate included in the certification information satisfies the operating condition.
Equipment control device. the tag information is a hash value of a tag indicating the type of the certificate;
The device control device according to claim 1 . 3. The management device connected to the device control device according to claim 1 or 2 in a manner enabling encrypted communication via a communication network,
a communication unit that receives the transmission user information from the device control device;
a decryption unit that decrypts the sending user information using a management device private key that is a private key corresponding to the management device public key to obtain the user identifier, the tag information, and the device identifier;
the communication unit, by referring to the user identifier and the tag information acquired by the decryption unit, transmits to the device control device certification information including a certificate certifying information about the user and a user public key corresponding to the user private key, the certification information including a signature of the issuer generated using an issuer private key that is a private key of the issuer of the certificate.
Management device. The management device includes:
a list checking unit that checks whether or not the device identifier acquired by the decryption unit is included in an authorization list that is previously listed as device identifiers of device control devices that are permitted to control the control target device,
the communication unit transmits the certification information to the device control device on condition that the device identifier acquired by the decryption unit is included in the permission list.
The management device according to claim 3 . 1. An equipment management system including: an equipment control device that controls an operation of a control target equipment; and a management device that is connected to the equipment control device via a communication network in a manner that enables encrypted communication,
The device control device includes:
a user information acquisition unit that reads user information from a user terminal of a user of the controlled device, the user information including a user identifier for identifying the user, tag information for identifying a tag indicating a type of a certificate that certifies information about the user, a signature of the management device generated using a management device private key that is a private key of the management device, and a signature of the user generated using a user private key that is a private key of the user terminal;
a storage unit that stores a device identifier for identifying the device control device, an issuer public key that is a public key of an issuer of the certificate, a management device public key that is a public key of the management device, and operating conditions that define conditions for the operation of the controlled device;
a signature verification unit that uses the management device public key to verify the validity of the signature of the management device included in the user information read from the user terminal;
an encryption unit that encrypts information including the user identifier, the tag information, and the device identifier with the management device public key to generate transmission user information, on condition that the signature is valid;
a communication unit that transmits the transmission user information to the management device,
The management device includes:
a communication unit that receives the transmission user information from the device control device;
a decryption unit that decrypts the sending user information using a management device private key that is a private key corresponding to the management device public key to obtain the user identifier, the tag information, and the device identifier;
the communication unit of the management device refers to the user identifier and the tag information acquired by the decryption unit, and transmits to the device control device certification information including a certificate certifying information about the user and a user public key corresponding to the user private key, the certification information including a signature of the issuer generated using an issuer private key that is a private key of the issuer of the certificate;
The communication unit of the device control device receives the certification information from the management device,
the signature verification unit of the device control device verifies the authenticity of the signature of the issuer included in the certification information by using the issuer public key, and verifies the authenticity of the signature of the user included in the user information by using the user public key;
The device control device further comprises:
an operating condition determination unit that determines whether the certificate included in the certification information satisfies the operating condition, on the condition that both the signature of the issuer and the signature of the user are valid;
a device control unit that permits operation of the controlled device on condition that the certificate included in the certification information satisfies the operating condition.
Equipment management system. The device management system includes:
an authorization list in which device identifiers of device control devices that are permitted to control the control target device are listed in advance;
a storage device that stores the user identifier, the user public key, the signature of the user, the certificate, the tag information, and a certificate database that associates and manages the user identifier, the user public key, the signature of the user, the certificate, the tag information, and the signature of the issuer,
The management device includes:
a storage device manager that reads the permission list and the certification information from the storage device;
The device management system according to claim 5 . A processor of a device control device that is connected to a management device that manages a certificate that certifies information about a user of the controlled device in a manner that enables encrypted communication and controls the operation of the controlled device,
reading user information from a user terminal of a user of the controlled device, the user information including a user identifier for identifying the user, tag information for identifying a tag indicating a type of a certificate certifying information about the user, a signature of the management device generated using a management device private key that is a private key of the management device, and a signature of the user generated using a user private key that is a private key of the user terminal;
verifying the authenticity of the signature of the management device included in the user information read from the user terminal by using a management device public key that is a public key stored in a storage unit of the device control device and is a public key of the management device;
generating user information for transmission by encrypting information including the user identifier, the tag information, and a device identifier for identifying the device control device with the management device public key, on condition that the signature is valid;
transmitting the transmission user information to the management device via encrypted communication;
receiving, via encrypted communication, from the management device, certification information including a certificate attesting to information regarding the user and a user public key corresponding to the user private key, the certification information including a signature of the issuer generated using an issuer private key that is a private key of the issuer of the certificate;
verifying the authenticity of the signature of the issuer included in the certification information by using an issuer public key that is a public key stored in a storage unit of the device control device and is a public key of the issuer of the certificate;
verifying the authenticity of the user's signature included in the user information by using the user's public key;
determining whether the certificate included in the certification information satisfies an operating condition that defines an operating condition of the controlled device, provided that both the signature of the issuer and the signature of the user are valid;
permitting operation of the controlled device on condition that the certificate included in the certification information satisfies the operating condition.
Device control method. A device control device that is connected to a management device that manages a certificate that certifies information about a user of a controlled device in a manner that enables encrypted communication and controls the operation of the controlled device,
a function of reading user information from a user terminal of a user of the controlled device, the user information including a user identifier for identifying the user, tag information for identifying a tag indicating a type of a certificate certifying information about the user, a signature of the management device generated using a management device private key that is a private key of the management device, and a signature of the user generated using a user private key that is a private key of the user terminal;
a function of verifying the authenticity of the signature of the management device included in the user information read from the user terminal by using a management device public key that is a public key stored in a storage unit of the device control device and is a public key of the management device;
a function of generating transmission user information by encrypting information including the user identifier, the tag information, and a device identifier for identifying the device control device with the management device public key, on condition that the signature is valid;
a function of transmitting the transmission user information to the management device via encrypted communication;
a function of receiving, via encrypted communication, from the management device, certification information including a certificate attesting to information regarding the user and a user public key corresponding to the user private key, the certification information including a signature of the issuer generated using an issuer private key that is a private key of the issuer of the certificate;
a function of verifying the authenticity of the signature of the issuer included in the certification information by using an issuer public key that is a public key stored in a storage unit of the device control device and is a public key of the issuer of the certificate;
a function of verifying the authenticity of the user's signature included in the user information by using the user public key;
a function of determining whether or not the certificate included in the certification information satisfies an operating condition that defines an operating condition of the controlled device, provided that both the signature of the issuer and the signature of the user are valid;
a function of permitting operation of the controlled device on condition that the certificate included in the certification information satisfies the operating conditions;
program.

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