Communication device, control terminal, communication system, information processing method, and program

Abstract

To provide a communication apparatus or the like capable of taking measures against a replay attack without sharing time information in a mesh network.SOLUTION: Each of the communication devices 20 belonging to the mesh network 40 includes an acquisition unit 221 that acquires a control signal transmitted by the control terminal 30 to at least a part of the plurality of communication devices 20, a storage unit 23 that stores, as reference information, control count information indicating a cumulative count of control execution instructions included in the control signal acquired by the acquisition unit 221, a determination unit 223 that determines whether or not a first control signal is a past signal based on first control count information included in the first control signal acquired by the acquisition unit 221 after the control signal and the reference information, and a control unit 222 that executes control based on the first control signal when it is determined that the first control signal is not a past signal and does not execute control based on the first control signal when it is determined that the first control signal is a past signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a communication device, a control terminal, a communication system, an information processing method, and a program. [Background technology]

[0002] Patent Document 1 discloses a technique for synchronizing the time held by each of a plurality of communication devices belonging to a mesh network. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-042838 Summary of the Invention [Problem to be solved by the invention]

[0004] As with the technology disclosed in Patent Document 1, by sharing time information among multiple communication devices belonging to a mesh network, it is possible to confirm the reliability of a received signal based on the shared time information.

[0005] More specifically, one method of unauthorized access to a mesh network is a replay attack (also known as a reflection attack), in which an unauthorized third party eavesdrops on legitimate control signals transmitted and received over the mesh network and then retransmits the intercepted control signals in an attempt to control communication devices belonging to the mesh network.As a countermeasure against replay attacks, time information shared within the mesh network can be included in control signals, making it possible to prevent a third party from accepting control signals that they have previously intercepted.

[0006] To save power, there is a demand for communication devices to be powered off when they are not in operation. However, this poses a problem in that time information cannot be shared because time information cannot be retained while the power is off.

[0007] Therefore, an object of the present disclosure is to provide a communication device, a control terminal, a communication system, an information processing method, and a program that can counter replay attacks without sharing time information in a mesh network. [Means for solving the problem]

[0008] One aspect of a communication device according to the present disclosure is one of a plurality of communication devices belonging to a mesh network, the communication device comprising: an acquisition unit that acquires a control signal transmitted by a control terminal belonging to the mesh network to instruct at least some of the plurality of communication devices to execute a control; a memory unit that stores control count information, which is included in the control signal acquired by the acquisition unit and indicates the cumulative number of times the instruction to execute the control, as reference information; a determination unit that determines whether the first control signal is a past signal based on first control count information and the reference information included in a first control signal acquired by the acquisition unit after the control signal; and a control unit that executes control based on the first control signal if the determination unit determines that the first control signal is not a past signal, and does not execute control based on the first control signal if the determination unit determines that the first control signal is a past signal.

[0009] Furthermore, one aspect of a control terminal according to the present disclosure is a control terminal belonging to a mesh network, to which a plurality of communication devices belong in addition to the control terminal, and the control terminal includes: a memory unit that stores a cumulative number of times that control execution instructions have been given to at least some of the plurality of communication devices in the past; and an output unit that outputs a control signal including control count information that indicates the cumulative number of times that control execution instructions have been given stored in the memory unit, and after outputting the control signal, the output unit updates the cumulative number stored in the memory unit.

[0010] Furthermore, one aspect of a communication system according to the present disclosure includes a plurality of the above communication devices and one or more of the above control terminals.

[0011] Furthermore, one aspect of the information processing method according to the present disclosure is an information processing method executed by each of a plurality of communication devices constituting a mesh network, and includes an acquisition step of acquiring a control signal from a control terminal, the control signal including control count information indicating the number of times the control has been performed by the control terminal; a control step of executing control based on the control signal acquired by the acquisition step; and a determination step of determining whether the first control signal is a past signal based on the first control count information included in the acquired first control signal and the control count information included in the control signal acquired in the past, wherein in the control step, if it is determined in the determination step that the first control signal is a past signal, control based on the first control signal is not executed.

[0012] Furthermore, one aspect of the information processing method according to the present disclosure is an information processing method executed by a control terminal belonging to a mesh network, wherein in addition to the control terminal, a plurality of communication devices belong to the mesh network, and the information processing method includes an output step of outputting a control signal including control count information indicating a cumulative number of times that control execution has been instructed to at least some of the plurality of communication devices in the past, and an update step of updating the cumulative number.

[0013] The present disclosure can be realized not only as the information processing method, but also as a program for causing a computer to execute the information processing method, and further as a computer-readable recording medium storing the program. [Effects of the Invention]

[0014] The communication device, control terminal, communication system, information processing method, and program according to the present disclosure can counter replay attacks without sharing time information in a mesh network. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram illustrating a functional configuration of a communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a network configuration of a mesh network according to an embodiment. [Figure 3] FIG. 3 is a flowchart illustrating the operation of the control terminal according to the embodiment. [Figure 4] FIG. 4 is a flowchart illustrating the operation of the first operation example of the communication device according to the embodiment. [Figure 5] FIG. 5 is a flowchart illustrating the operation of the second operation example of the communication device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Embodiment) Hereinafter, embodiments of a communication device, a control terminal, a communication system, an information processing method, and a program according to the present disclosure will be described in detail with reference to the accompanying drawings. Each of the embodiments described below represents a preferred specific example of the present disclosure. The numerical values, components, the layout and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components constituting a preferred embodiment.

[0017] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

[0018] Furthermore, unless otherwise specified, ordinal numbers such as "first" and "second" in this disclosure do not refer to the number or order of components, etc., but are used for the purpose of avoiding confusion and distinguishing between components, etc. of the same type.

[0019] [composition] 1 is a block diagram showing the functional configuration of a communication system 10 according to an embodiment. The communication system 10 includes a plurality of communication devices 20 and a plurality of control terminals 30.

[0020] In the communication system 10, each of the multiple communication devices 20 and one or more control terminals 30 has a wireless communication function, and the multiple communication devices 20 and one or more control terminals 30 form a mesh network 40. The mesh network 40 is an example of a wireless network.

[0021] The mesh network 40 may include devices other than the plurality of communication devices 20 and the plurality of control terminals 30. For example, the mesh network 40 may include devices such as an environmental sensor or a projector (not shown).

[0022] For example, if the communication device 20 is a lighting device, the information transmitted through the mesh network 40 is control information for controlling the on / off or dimming of the communication device 20. Furthermore, if the communication device 20 is an environmental sensor, the measurement value (sensing information) of the environmental sensor is transmitted.

[0023] FIG. 2 is a diagram illustrating an example of a network configuration of a mesh network 40 according to an embodiment. Each circle in FIG. 2 corresponds to one communication device 20 or control terminal 30 (in other words, a communication node). In the example illustrated in FIG. 2, communication devices 20a to 20e are included as the multiple communication devices 20, and three control terminals 30a to 30c are included as the multiple control terminals 30, belonging to the mesh network 40. A dashed-dotted circle centered on the control terminal 30a indicates the wireless communication range of the control terminal 30a, i.e., the range within which a control signal transmitted by the control terminal 30a can reach. The communication devices 20a and 20b receive the control signal transmitted by the control terminal 30a via direct wireless communication and communication via the mesh network 40. The communication devices 20c to 20e and the control terminals 30b and 30c receive the control signal transmitted by the control terminal 30a via communication via the mesh network 40.

[0024] Here, we will explain the transmission of information in communication via the mesh network 40. In the mesh network 40, when information is transmitted from one communication node (also referred to as a first communication node) to another communication node (also referred to as a second communication node), the information is transmitted by, for example, a routing method, but may also be transmitted by other methods such as a flooding method.

[0025] In the mesh network 40, a communication path is set in advance that allows information to be distributed to the communication nodes belonging to the mesh network 40. When the first communication node unicasts information including the address information (destination information) of the second communication node based on the set communication path, other communication nodes belonging to the same mesh network 40 as the first communication node that receive the information further unicast the received information based on the set communication path. In other words, the other communication nodes relay the information. By repeating this relay of information within the same mesh network 40, the second communication node can receive the information transmitted by the first communication node.

[0026] In the mesh network 40, a communication path is set in advance that allows information to be distributed to the communication nodes belonging to the mesh network 40, but the communication path may be changed as appropriate depending on the radio wave strength of the communication node.

[0027] The first communication node may broadcast information including the address information (destination information) of the second communication node, and other communication nodes that receive the information and belong to the same mesh network 40 as the first communication node may relay the received information and further broadcast it. By repeating this relay of information within the same mesh network 40, the information transmitted by the first communication node reaches all communication nodes that belong to the same mesh network 40 as the first communication node. Therefore, the second communication node can receive the information transmitted by the first communication node.

[0028] Returning to Fig. 1, the communication device 20 will be described. The communication device 20 has a wireless communication function, and a plurality of communication devices 20, together with one or more control terminals 30, form a mesh network 40. The communication device 20 has a function of relaying an acquired control signal to another communication device 20 via the mesh network 40.

[0029] The communication device 20 is, for example, a lighting-related device. When the communication device 20 is a lighting device, for example, the communication device 20 is a base light installed on the ceiling of an indoor space to illuminate the indoor space. The communication device 20 has a function of irradiating light into the indoor space based on a control signal acquired via the mesh network 40. The form of the communication device 20 is not particularly limited, and may be a ceiling light, a downlight, a spotlight, or the like. When the communication device 20 is a scheduler, the communication device 20 controls the communication device 20, which is a lighting device, to a predetermined dimming state at a predetermined time based on a predetermined schedule. Furthermore, the communication device 20 may be, for example, another lighting-related device such as an environmental sensor or a camera.

[0030] Specifically, the communication device 20 includes a communication unit 21, an information processing unit 22, a storage unit 23, and a function unit 24.

[0031] The communication unit 21 is a wireless communication circuit that enables the communication device 20 to perform wireless communication (more specifically, radio wave communication) with the control terminal 30 and other communication devices 20. The communication unit 21 performs communication through a mesh network 40 that is configured by a plurality of communication devices 20 and one or a plurality of control terminals 30. Specifically, the communication unit 21 performs wireless communication in accordance with a communication standard such as BLE (Bluetooth (registered trademark) Low Energy) or Bluetooth (registered trademark) mesh.

[0032] The information processing unit 22 executes information processing and the like for the operation of the communication device 20. The information processing unit 22 operates the communication device 20 by, for example, controlling the function unit 24. The information processing unit 22 is realized by, for example, a microcomputer, but may also be realized by a processor or a dedicated circuit. The functions of the information processing unit 22 are realized by hardware such as a microcomputer or processor constituting the information processing unit 22 executing a computer program (software) stored in the storage unit 23. Specifically, the information processing unit 22 includes an acquisition unit 221, a control unit 222, a determination unit 223, and an output unit 224.

[0033] The acquisition unit 221 acquires a control signal.

[0034] The control unit 222 executes control based on the acquired control signal.

[0035] The determination unit 223 determines whether the acquired control signal is a past signal. A control signal being a past signal means that the control signal is not a control signal currently being transmitted. Here, "present" in the present disclosure has a predetermined width, and the predetermined width is, for example, 1 minute, but may also be 5 minutes or 10 minutes.

[0036] The output unit 224 transmits the acquired control signal to the other communication device 20.

[0037] The memory unit 23 is a storage device that stores time information indicating the time shared among the multiple communication devices 20 belonging to the mesh network 40, reference information, and various information necessary for the operation of the communication devices 20. The reference information is control count information included in a control signal previously acquired. The reference information may be information in which the individual identification number of each control terminal 30 is associated with the control count information. The memory unit 23 is realized by, for example, a semiconductor memory or the like.

[0038] The time information stored in the storage unit 23 is shared, for example, by at least one of the communication devices 20 belonging to the mesh network 40 acquiring time information from an external NTP (Network Time Protocol) server and transmitting a signal for sharing the time information. The time information shared among the communication devices 20 does not need to be exactly the same time, and may have an error of about several minutes.

[0039] The functional unit 24 is a device for realizing the functions of the communication device 20 during operation of the communication device 20. The functional unit 24 is controlled by the information processing unit 22. When the communication device 20 is a lighting device, the functional unit 24 is, for example, a light source that irradiates white light into an indoor space to illuminate the indoor space. The functional unit 24 is realized by, for example, an LED element, but may also be realized by other light-emitting elements such as a semiconductor laser, an organic EL element, or an inorganic EL element.

[0040] Next, the control terminal 30 will be described. The control terminal 30 has a wireless communication function and configures a mesh network 40 together with a plurality of communication devices 20 and other control terminals 30. The control terminal 30 is, for example, a remote controller for controlling the communication devices 20. The control terminal 30 may be portable. Specifically, the control terminal 30 includes a communication unit 31, an information processing unit 32, a storage unit 33, and an operation receiving unit 34.

[0041] The communication unit 31 is a wireless communication circuit that enables the control terminal 30 to perform wireless communication (more specifically, radio wave communication) with the communication devices 20 and other control terminals 30. The communication unit 31 performs communication through a mesh network 40 that is configured by multiple communication devices 20 and one or multiple control terminals 30. Specifically, the communication unit 31 performs wireless communication in accordance with a communication standard such as BLE or Bluetooth (registered trademark) mesh.

[0042] The information processing unit 32 executes information processing and the like for the control terminal 30 to transmit a control signal for controlling the communication device 20. The information processing unit 32 is realized, for example, by a microcomputer, but may also be realized by a processor or a dedicated circuit. The functions of the information processing unit 32 are realized by hardware such as a microcomputer or processor constituting the information processing unit 32 executing a computer program (software) stored in the storage unit 33. Specifically, the information processing unit 32 includes an acquisition unit 321, a control unit 322, and an output unit 323.

[0043] The acquisition unit 321 acquires the operation accepted by the operation acceptance unit 34 .

[0044] The control unit 322 generates a control signal to be transmitted based on the information acquired by the acquisition unit 321 .

[0045] The output unit 323 outputs a control signal for controlling the communication device 20 and the like.

[0046] The storage unit 33 is a storage device that stores information necessary for information processing, such as control count information indicating the cumulative number of times that the control terminal 30 has issued control execution instructions in the past, an individual identification number, setting information set in the control terminal 30, and computer programs executed by the information processing unit 32. The storage unit 33 is realized by, for example, a semiconductor memory. The computer programs stored in the storage unit 33 include dedicated application programs for operating the control terminal 30 as a control terminal for the communication device 20.

[0047] The operation accepting unit 34 accepts user operations and is realized by, for example, a push button or the like.

[0048] Here, a description will be given of a case where a user configures the control terminal 30. Using a configuration terminal (not shown), the user configures the control target and control content of the control signal that is transmitted when, for example, the operation acceptance unit 34 of each of the multiple control terminals 30 is operated.

[0049] The setting terminal is, for example, a mobile terminal such as a smartphone, a tablet terminal, a PDA (Personal Digital Assistant), etc. The setting terminal may also be a dedicated remote controller used in the communication system 10.

[0050] The setting terminal communicates with one of the devices that make up the mesh network 40 using, for example, a communication protocol different from that of the mesh network 40. By transmitting this communication via the mesh network 40, any control terminal 30 can be set.

[0051] Furthermore, the user can use the setting terminal to set the configuration of the mesh network 40. In other words, the user can use the setting terminal to make the communication device 20 or the control terminal 30 join the mesh network 40 and make the communication device 20 or the control terminal 30 belonging to the mesh network 40 leave the mesh network 40.

[0052] [Operation] Next, an operation of the communication system 10 according to the embodiment will be described. The communication system 10 includes a plurality of communication devices 20 and one or more control terminals 30 that belong to a mesh network 40. The plurality of communication devices 20 included in the communication system 10 share time information.

[0053] As a countermeasure against replay attacks, the communication system 10 includes time information shared within the mesh network 40 in the control signal, thereby preventing the communication device 20 from accepting control using a control signal that has been previously intercepted by a third party.

[0054] Here, in order to save power, the control terminal 30 is powered off (or in a sleep state) while the control terminal 30 is not operating. Since the control terminal 30 cannot retain time information while the power is off, the control terminal 30 cannot share the time information shared among multiple communication devices 20.

[0055] Therefore, the control terminal 30 keeps track of the cumulative number of times that it has instructed at least some of the multiple communication devices 20 to execute control in the past, and by adding information indicating the cumulative number of times to the control signal, it is possible to prevent the communication device 20 from accepting control by a control signal sent by a control terminal 30 that has been eavesdropped on by a third party in the past.

[0056] The operations of the communication device 20 and the control terminal 30 in such a communication system 10 will be described below.

[0057] [Control terminal operation] The following describes the operation of the control terminal 30. Fig. 3 is a flowchart illustrating the operation of the control terminal 30 according to the embodiment.

[0058] First, the operation acceptance unit 34 of the control terminal 30 accepts an operation from the user (S11). For example, the user presses a button on the operation acceptance unit 34. Pressing a button is an example of a predetermined operation.

[0059] When the operation receiving unit 34 receives a predetermined operation, the acquiring unit 321 acquires control count information stored in the storage unit 33 (S12). The control count information is information indicating the cumulative number of times that the control terminal 30 has instructed at least some of the multiple communication devices 20 to execute control in the past.

[0060] Next, the control unit 322 determines whether the control count information has been initialized (S13). The initialization of the control count information stored in the storage unit 33 is performed, for example, by the user using a setting terminal. For example, when the user wants to change the content of an instruction set in the control terminal 30 or when the user wants to erase an error log or the like stored in the control terminal 30, the user can initialize the control count information stored in the storage unit 33 using the setting terminal.

[0061] If it is determined that the control count information has been initialized (Yes in S13), the control unit 322 adds reset information to the control signal (S14). That is, the control signal transmitted by the control terminal 30 includes reset information. The reset information is information indicating that the number of control execution instructions has been initialized.

[0062] If it is determined that the control count information has not been initialized (No in S13), or after adding the reset information to the control signal, the control unit 322 adds the control count information to the control signal (S15). That is, the control signal transmitted by the control terminal 30 includes the control count information.

[0063] After assigning the control count information to the control signal, the control unit 322 assigns an individual identification number to the control signal (S16). That is, the control signal transmitted by the control terminal 30 includes the individual identification number. The individual identification number is stored in the storage unit 33. The individual identification number is information for distinguishing the control terminals 30 when multiple control terminals 30 belong to the mesh network 40. In the example shown in FIG. 2, different individual identification numbers are set for the control terminals 30a to 30c. The individual identification number may be, for example, the manufacturing number of each control terminal 30.

[0064] It should be noted that the process of step S16 does not need to be executed if the mesh network 40 has only one control terminal 30.

[0065] It should be noted that there is no restriction on the order in which the processes of steps S13, S14, S15, and S16 are executed, and there is no particular restriction on the order in which the various information is added to the control signal.

[0066] Next, the control terminal 30 transmits a control signal (S17). Specifically, the output unit 323 of the control terminal 30 transmits the control signal using the communication unit 31. The control signal includes information indicating the content of the control to be executed by the communication device 20 that received the control signal, and destination information that identifies at least some of the multiple communication devices 20 that belong to the mesh network 40. The user sets the information indicating the content of the control and the destination information included in the control signal in advance, using the setting terminal, in association with the operation accepted in step S11.

[0067] In addition, when the control signal includes reset information, the control signal includes destination information to be transmitted to all communication devices 20 belonging to the mesh network 40, regardless of the content of the instruction to execute the control.

[0068] Finally, the control unit 322 updates the control count information stored in the storage unit 33 (S18). For example, the control unit 322 updates the control count information by incrementing the control count information stored in the storage unit 33. The control unit 322 may decrement the control count information or may add 2 to the control count information. There is no particular limitation on the method for updating the control count information.

[0069] Such a control terminal 30 can transmit a control signal including information on the number of times of control. Therefore, together with the communication device 20 that receives the control signal (described later), it is possible to take measures against replay attacks in the mesh network 40 without sharing time information.

[0070] In step S17, the control terminal 30 may transmit a control signal using two communication methods. The control terminal 30 transmits a control signal for directly communicating with and controlling the communication devices 20 within the wireless communication range. This control signal is an example of a fourth control signal. The control terminal 30 transmits a control signal for controlling the communication devices 20 via the mesh network 40. This control signal is an example of a fifth control signal. Here, the control count information indicates the cumulative number of times that the control terminal 30 has previously instructed at least some of the multiple communication devices 20 to execute control. Therefore, the control count information included in the control signal for directly communicating with and controlling the communication devices 20 within the wireless communication range and the control count information included in the control signal for controlling the communication devices 20 via the mesh network 40 are different values. In this case, the control count information stored in the storage unit 33 in step S18 is updated twice.

[0071] [Operation of communication devices] [Example 1] 2 acquires a control signal from the control terminal 30a without going through the mesh network 40. The control signal acquired by the communication device 20a and the communication device 20b from the control terminal 30a without going through the mesh network 40 does not include time information. This control signal is an example of a first control signal.

[0072] Hereinafter, a first example of operation of communication device 20 when a control signal not including such time information is received will be described. Fig. 4 is a flowchart illustrating the operation of communication device 20 according to the embodiment in the first example of operation.

[0073] First, the communication device 20 receives a control signal (S21). Specifically, the acquisition unit 221 of the communication device 20 acquires the control signal received by the communication unit 21.

[0074] When the acquisition unit 221 acquires a control signal, the determination unit 223 determines whether or not the acquired control signal includes time information. The determination unit 223 determines that the acquired control signal does not include time information (S22).

[0075] If it is determined that the acquired control signal does not include time information, the determination unit 223 determines whether or not the control count information included in the control signal is past control count information (S23). The determination unit 223 determines whether or not the control count information is past control count information based on reference information stored in the storage unit 23. The reference information is control count information included in the control signal last received by the communication device 20. The control count information being past control count information means that the control count information is control count information that was included in a control signal transmitted through the mesh network 40 in the past, not the present.

[0076] For example, if the control count information is set to increase by increment or the like, the judgment unit 223 judges that the control count information included in the control signal is past control count information when the number indicated by the control count information is equal to or less than the number indicated by the reference information.

[0077] If the control signal includes an individual identification number, the determining unit 223 determines whether the control signal is past control count information based on the reference information associated with the individual identification number stored in the storage unit 23.

[0078] When the control signal includes reset information, the determination unit 223 determines that the information is not past control count information regardless of the number indicated by the reference information. Note that when the reset information includes information indicating the time of the last initialization, the determination unit 223 determines that the information is not past control count information when it determines that the information stored in the reference information does not match the reset information included in the control signal.

[0079] If it is determined that the control signal is not past control count information (No in S23), the control unit 222 accepts the control signal (S24). If the destination information included in the control signal includes the communication device 20, the control unit 222 executes control based on the control signal. If the destination information included in the control signal includes another communication device 20, the output unit 224 adds time information stored in the storage unit 23 to the acquired control signal and then transmits the control signal to the other communication device 20 using the communication unit 21. The control signal output by the output unit 224 includes the time information. The control signal is an example of a second control signal.

[0080] Finally, the control unit 222 updates the control count information (S25). The control unit 222 updates the control count information (reference information) stored in the storage unit 23 to the control count information included in the control signal received in step S24.

[0081] If it is determined that the control count information is past (Yes in S23), the control unit 222 discards the control signal (S26). If the control count information included in the acquired control signal is past control count information, the control signal can be determined to be a past signal. In other words, it can be estimated that the acquired control signal is a control signal that has been repeatedly transmitted as is, a control signal that was previously intercepted by a third party.

[0082] Such a communication device 20 can determine whether an acquired control signal is a control signal acquired previously based on the control count information included in the acquired control signal. Therefore, such a communication device 20 can take measures against replay attacks without sharing time information in the mesh network 40.

[0083] In step S17, when the control terminal 30 transmits a control signal using two communication methods, the communication device 20 within the wireless communication range receives a control signal for controlling the communication device 20 through direct communication and a control signal for controlling the communication device 20 through the mesh network 40. Since the control count information included in these two control signals has different values, it is determined in step S23 that the control count is not a past control count, and both of these two control signals are accepted. In such a case, the control unit 222 does not execute control based on the control signal for controlling the communication device 20 through the mesh network 40, and the output unit 224 executes transmission of the control signal through the mesh network 40. Such a communication device 20 can prevent the communication device 20 from executing overlapping control.

[0084] [Example 2] As described in step S24 of the first operational example, at least one of the communication device 20a and the communication device 20b shown in Fig. 2 transmits a control signal including time information via the mesh network 40. This control signal is an example of a second control signal.

[0085] 2 receives a control signal including time information transmitted by at least one of communication device 20a and communication device 20b via mesh network 40. This control signal is an example of a third control signal.

[0086] Hereinafter, a second example of operation of communication device 20 when receiving a control signal including such time information will be described. Fig. 5 is a flowchart illustrating the operation of communication device 20 according to the embodiment in the second example of operation.

[0087] First, the communication device 20 receives a control signal (S31). The acquisition unit 221 of the communication device 20 acquires the control signal received by the communication unit 21.

[0088] When the acquisition unit 221 acquires a control signal, the determination unit 223 determines whether or not the acquired control signal includes time information. The determination unit 223 determines that the acquired control signal includes time information (S32).

[0089] If it is determined that the acquired control signal includes time information, the determination unit 223 determines whether the time information included in the control signal is past time information or not (S33). The determination unit 223 determines whether the time information included in the control signal is past time information or not based on the time information stored in the storage unit 23.

[0090] If it is determined that the time information is not in the past (No in S33), the control unit 222 accepts the control signal (S34). If the destination information included in the control signal includes the communication device 20, the control unit 222 executes control based on the control signal. If the destination information included in the control signal includes another communication device 20, the output unit 224 transmits the control signal to the other communication device 20 using the communication unit 21.

[0091] Finally, the control unit 222 updates the control count information (S35). The control unit 222 updates the control count information (reference information) stored in the storage unit 23 to the control count information included in the control signal received in step S34.

[0092] If it is determined that the time information is from the past (Yes in S33), the control unit 222 discards the control signal (S36). If the time information included in the acquired control signal is from the past, the control signal can be determined to be a past signal. In other words, it can be assumed that the acquired control signal is a control signal that has been repeatedly transmitted as is, a control signal that was previously intercepted by a third party.

[0093] Such a communication device 20 can determine whether an acquired control signal is a control signal acquired in the past based on the time information included in the acquired control signal. Therefore, such a communication device 20 can take measures against replay attacks by using the time information shared among the communication devices 20 belonging to the mesh network 40.

[0094] Furthermore, in the second operational example, the communication device 20 does not make a determination based on the control count information, but only makes a determination based on the time information. The determination based on the time information requires simpler processing than the determination based on the control count information, and therefore requires less time for processing. Therefore, the communication device 20 in the second operational example can suppress a decrease in processing speed caused by countermeasures against replay attacks.

[0095] [Other actions] The communication device 20 can join an already configured mesh network 40. The user causes the communication device 20 to join the mesh network 40 using a setting terminal.

[0096] In this case, communication device 20 does not execute the determination of step S23 in operation example 1. In other words, in communication device 20, when acquisition unit 221 acquires a control signal that does not include time information in a case where reference information is not stored in storage unit 23, determination unit 223 does not determine whether the control signal is a past signal or not. Control unit 222 executes control based on the control signal acquired by acquisition unit 221, and stores control count information included in the control signal in storage unit 23.

[0097] Such a communication device 20 can perform control based on a control signal transmitted by the control terminal 30 when no reference information is stored in the memory unit 23, i.e., when no control signal has been received from the control terminal 30 since joining the mesh network 40.

[0098] [Effects, etc.] The technologies derived from the disclosure of this specification are, for example, the following technologies. Below, the technologies derived from the disclosure of this specification will be described together with the effects and the like obtained by the technologies.

[0099] Technique 1 relates to a communication device 20, which is one of a plurality of communication devices 20 belonging to a mesh network 40, and which includes: an acquisition unit 221 that acquires a control signal transmitted by a control terminal 30 belonging to the mesh network 40 to instruct at least some of the plurality of communication devices 20 to execute control; a memory unit 23 that stores, as reference information, control count information that indicates the cumulative number of control execution instructions and is included in the control signal acquired by the acquisition unit 221; a determination unit 223 that determines whether the first control signal is a past signal based on the first control count information and the reference information included in a first control signal acquired by the acquisition unit 221 after the control signal; and a control unit 222 that executes control based on the first control signal when the determination unit 223 determines that the first control signal is not a past signal, and does not execute control based on the first control signal when the determination unit 223 determines that the first control signal is a past signal.

[0100] Such a communication device 20 can determine whether an acquired control signal is a control signal acquired previously based on the control count information included in the acquired control signal. Therefore, such a communication device 20 can take measures against replay attacks without sharing time information in the mesh network 40.

[0101] Technique 2 is the communication device 20 of Technique 1, in which the determination unit 223 determines that the first control signal is a past signal when the number indicated by the first control count information is equal to or less than the number indicated by the reference information stored in the memory unit 23.

[0102] When the control count information is set to increase by increment or the like, such a communication device 20 can determine whether or not the acquired control signal is a control signal that has been acquired in the past.

[0103] Technique 3 is a communication device 20 of Technique 1 or 2, in which time information is stored in the memory unit 23, and the communication device 20 further includes an output unit 224 that outputs a second control signal, in which the time information is added to the acquired first control signal, to other communication devices 20 belonging to the mesh network 40.

[0104] Such a communication device 20 can determine whether or not an acquired control signal is a control signal acquired in the past, based on time information included in the acquired control signal.

[0105] Technology 4 is the communication device 20 of Technology 3, in which the acquisition unit 221 adds time information to the first control signal acquired by another communication device 20 and acquires a third control signal transmitted to the mesh network 40, the determination unit 223 determines whether the third control signal is a past signal based on the time information included in the third control signal acquired by the acquisition unit 221 and the time information stored in the memory unit 23, and the control unit 222 does not execute control based on the third control signal when the determination unit 223 determines that the second control signal is a past signal.

[0106] Such a communication device 20 can determine whether an acquired control signal is a control signal acquired in the past based on the time information included in the acquired control signal. Therefore, such a communication device 20 can take measures against replay attacks by using the time information shared among the communication devices 20 belonging to the mesh network 40.

[0107] Furthermore, such a communication device 20 only performs determination based on time information, which requires less time for processing than determination based on control count information, and therefore can suppress a decrease in processing speed caused by countermeasures against replay attacks.

[0108] Technique 5 is a communication device 20 according to any one of techniques 1 to 4, in which, when reference information is not stored in memory unit 23 and acquisition unit 221 acquires a control signal that does not include time information, determination unit 223 does not determine whether the control signal is a past signal or not.

[0109] Such a communication device 20 can perform control based on a control signal transmitted by the control terminal 30 when no reference information is stored in the memory unit 23, i.e., when no control signal has been received from the control terminal 30 since joining the mesh network 40.

[0110] Technique 6 is a control terminal 30 that belongs to a mesh network 40, to which a plurality of communication devices 20 belong in addition to the control terminal 30, and the control terminal 30 is equipped with a memory unit 33 that stores the cumulative number of times that control execution instructions have been given to at least some of the plurality of communication devices 20 in the past, and an output unit 323 that outputs a control signal including control count information that indicates the cumulative number of control execution instructions stored in the memory unit 33, and the output unit 323 is a control terminal 30 that updates the cumulative number stored in the memory unit 33 after outputting the control signal.

[0111] Such a control terminal 30 can transmit a control signal containing control count information, which is the cumulative number of times that control execution has been instructed in the past, thereby making it possible to take measures against replay attacks without sharing time information in the mesh network 40.

[0112] Furthermore, since such a control terminal 30 does not need to retain time information, it can be turned off (or put into sleep mode) when not in operation, which can contribute to power saving in the communication system 10.

[0113] Technique 7 is the control terminal 30 of technique 6, in which, when the control terminal 30 receives a predetermined operation, the number of instructions to execute control stored in the memory unit 33 is initialized, and the control signal output by the output unit 323 after the number of instructions to execute control has been initialized further includes information indicating that the number of instructions to execute control has been initialized.

[0114] Such a control terminal 30 can make it possible to take measures against replay attacks without sharing time information in the mesh network 40, even if a user initializes the control count information stored in the memory unit 33 using a setting terminal.

[0115] Technique 8 is the control terminal 30 of Technique 6 or 7, in which the individual identification number of the control terminal 30 is stored in the storage unit 33, and the control signal further includes information indicating the individual identification number.

[0116] Such a control terminal 30 can determine whether an acquired control signal is a control signal acquired in the past based on the control count information contained in the acquired control signal, even if there are multiple control terminals belonging to the mesh network 40.

[0117] Technique 9 is a communication system 10 including a plurality of communication devices 20 according to any one of techniques 1 to 5 and one or more control terminals 30 according to any one of techniques 6 to 8.

[0118] Such a communication system 10 can take measures against replay attacks without sharing time information in the mesh network 40.

[0119] Technology 10 is a communication system 10 of Technology 9, in which, when a predetermined operation is received, the control terminal 30 transmits a fourth control signal for directly communicating with and controlling a communication device 20 within the wireless communication range of the control terminal 30, and a fifth control signal for controlling the communication device 20 via a mesh network 40, and when the communication device 20 receives the fifth control signal that is not a past signal, if it has acquired a fourth control signal corresponding to the received fifth control signal, it does not perform control based on the fifth control signal and transmits the fifth control signal to the mesh network 40, and if it has not acquired a fourth control signal corresponding to the received fourth control signal, it performs control based on the fifth control signal and transmits the fifth control signal to the mesh network 40.

[0120] Such a communication system 10 can prevent the communication device 20 from performing overlapping control when the control terminal 30 transmits control signals using two communication methods: a control signal for directly communicating with and controlling the communication device 20 within the wireless communication range, and a control signal for controlling the communication device 20 via the mesh network 40.

[0121] Technique 11 is the communication system 10 of technique 9 or 10, in which the communication device 20 is a lighting-related device.

[0122] Such a communication system 10 can provide countermeasures against replay attacks without sharing time information among the lighting systems that make up the mesh network 40.

[0123] Technique 12 is an information processing method executed by each of a plurality of communication devices 20 constituting a mesh network 40, and includes an acquisition step of acquiring a control signal from a control terminal 30, the control signal including control count information indicating the number of times control has been performed by the control terminal 30; a control step of executing control based on the control signal acquired by the acquisition step; and a determination step of determining whether the first control signal is a past signal based on the first control count information included in the acquired first control signal and the control count information included in a control signal acquired in the past, wherein in the control step, if it is determined in the determination step that the first control signal is a past signal, the control based on the first control signal is not executed.

[0124] Such an information processing method can determine whether or not an acquired control signal is a control signal acquired in the past, based on control count information included in the acquired control signal.

[0125] The thirteenth aspect is a program for causing each of a plurality of communication devices 20 to execute the information processing method of the twelfth aspect.

[0126] Such a program can assist in determining whether an acquired control signal is a control signal acquired in the past, based on control count information included in the acquired control signal.

[0127] Technique 14 is an information processing method executed by a control terminal 30 belonging to a mesh network 40, in which a plurality of communication devices 20 belong in addition to the control terminal 30, and the information processing method includes an output step of outputting a control signal including control count information indicating the cumulative number of times that control execution has been instructed to at least some of the plurality of communication devices 20 in the past, and an update step of updating the cumulative number.

[0128] Such an information processing method can transmit a control signal including control count information, which is the cumulative number of times that control execution has been instructed in the past.

[0129] Technique 15 is a program for causing the control terminal 30 to execute the information processing method of technique 14.

[0130] Such a program can transmit a control signal including control count information, which is the cumulative number of times that control execution has been instructed in the past.

[0131] (Other embodiments) Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments.

[0132] In the above embodiment, the control terminal 30 cannot retain time information while the power is off, and therefore does not share time information among the communication devices 20. However, the control terminal 30 may store time information included in a response signal sent by the communication device 20 in response to a control signal sent by the control terminal 30, thereby adding the time information to a control signal to be sent subsequently. Such a control terminal 30 can transmit a control signal including time information.

[0133] Furthermore, the fourth control signal and the fifth control signal in the above-described embodiment may be repeatedly transmitted multiple times. For example, when a predetermined user operation is received, the output unit 323 of the control terminal 30 may transmit the same fourth control signal 20 times in succession at intervals of several milliseconds, and then transmit the same fifth control signal 20 times in succession at intervals of several milliseconds. By repeatedly transmitting the same control signal multiple times, the control terminal 30 can more reliably cause the communication device 20 to receive the control signal.

[0134] For example, in the above embodiment, the communication system is realized by a plurality of devices. When the communication system is realized by a plurality of devices in this way, the components (particularly functional components) of the communication system may be allocated in any manner among the plurality of devices.

[0135] Furthermore, the method of communication between the devices in the above-described embodiments is not particularly limited. Furthermore, a relay device (such as a gateway device) (not shown) may be involved in the communication between the devices.

[0136] In the above-described embodiment, the processing performed by a specific processing unit may be performed by another processing unit. The order of multiple processing operations may be changed, or multiple processing operations may be performed in parallel.

[0137] In the above-described embodiments, each component may be realized by executing a software program suitable for that component, or by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0138] Furthermore, each component may be realized by hardware. For example, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or each may be a separate circuit. Furthermore, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0139] Furthermore, the general or specific aspects of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0140] For example, the present disclosure may be realized as an information processing method executed by a computer such as the communication system of the above-described embodiments, or as a program for causing a computer to execute the information processing method (in other words, a computer program product).Furthermore, the present disclosure may be realized as a computer-readable non-transitory recording medium on which such a program is recorded.

[0141] In addition, this disclosure also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, or forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the intent of this disclosure. [Explanation of symbols]

[0142] 10. Communication Systems 20, 20a~20e Communication equipment 221 Acquisition Department 222 Control Unit 223 Judgment section 224 Output Section 23 Memory section 30, 30a to 30c Control terminal 31 Communications Department 323 Output Section 33 Storage section 40 Mesh Network

Claims

1. One communication device among a plurality of communication devices belonging to a mesh network, an acquisition unit that acquires a control signal transmitted by a control terminal belonging to the mesh network to instruct at least some of the plurality of communication devices to execute control; a storage unit that stores, as reference information, control count information indicating a cumulative number of times an instruction to execute the control, which is included in the control signal acquired by the acquisition unit; a determination unit that determines whether the first control signal is a past signal based on first control count information and the reference information included in a first control signal acquired by the acquisition unit after the control signal; a control unit that executes control based on the first control signal when the determination unit determines that the first control signal is not a past signal, and that does not execute control based on the first control signal when the determination unit determines that the first control signal is a past signal. Communication equipment.

2. the determination unit determines that the first control signal is a past signal when the number indicated by the first control count information is equal to or less than the number indicated by the reference information stored in the storage unit. The communication device according to claim 1 .

3. The storage unit stores time information, The communication device further includes an output unit that outputs a second control signal obtained by adding the time information to the acquired first control signal to another communication device that belongs to the mesh network.

3. A communication device according to claim 1 or 2.

4. the acquisition unit adds the time information to the first control signal acquired by another communication device and acquires a third control signal transmitted to the mesh network; the determination unit determines whether the third control signal is a past signal based on the time information included in the third control signal acquired by the acquisition unit and the time information stored in the storage unit; the control unit does not execute control based on the third control signal when the determination unit determines that the second control signal is a past signal. The communication device according to claim 3 .

5. When the reference information is not stored in the storage unit, and the acquisition unit acquires a control signal that does not include time information, the determination unit does not determine whether the control signal is a past signal.

3. A communication device according to claim 1 or 2.

6. A control terminal belonging to a mesh network, In addition to the control terminal, a plurality of communication devices belong to the mesh network, The control terminal a storage unit that stores a cumulative number of times that control execution has been instructed to at least some of the plurality of communication devices in the past; an output unit that outputs a control signal including control count information that indicates a cumulative number of control execution instructions stored in the storage unit, the output unit updates the cumulative number stored in the storage unit after outputting the control signal. Control terminal.

7. When the control terminal receives a predetermined operation, the number of times of instructions to execute control stored in the storage unit is initialized; the control signal output by the output unit after the number of times of instructions to execute the control has been initialized further includes information indicating that the number of times of instructions to execute the control has been initialized.

7. The control terminal according to claim 6.

8. The storage unit stores an individual identification number of the control terminal, The control signal further includes information indicating the individual identification number.

8. The control terminal according to claim 6 or 7.

9. a plurality of communication devices according to claim 1 or 2; and one or more control terminals according to claim 6 or 7. Communication system.

10. when the control terminal receives a predetermined operation, the control terminal transmits a fourth control signal for directly communicating with and controlling a communication device within a wireless communication range of the control terminal, and a fifth control signal for controlling the communication device via a mesh network; When the communication device receives the fifth control signal that is not a past signal, When the fourth control signal corresponding to the received fifth control signal has been acquired, the fifth control signal is transmitted to the mesh network without performing control based on the fifth control signal; When the fourth control signal corresponding to the received fourth control signal has not been acquired, the fifth control signal is executed, and the fifth control signal is transmitted to the mesh network.

10. The communication system of claim 9.

11. The communication device is a lighting-related device.

11. A communication system according to claim 9 or 10.

12. An information processing method executed by each of a plurality of communication devices constituting a mesh network, comprising: an acquisition step of acquiring a control signal including control count information indicating the number of times of control by the control terminal from the control terminal; a control step of executing control based on the control signal acquired in the acquisition step; a determination step of determining whether the first control signal is a past signal based on first control count information included in the acquired first control signal and the control count information included in the previously acquired control signal, In the control step, when it is determined in the determination step that the first control signal is a past signal, control based on the first control signal is not executed. Information processing methods.

13. A program for causing each of the plurality of communication devices to execute the information processing method according to claim 12.

14. An information processing method executed by a control terminal belonging to a mesh network, wherein a plurality of communication devices belong to the mesh network in addition to the control terminal, The information processing method includes: an output step of outputting a control signal including control count information indicating a cumulative number of times that control execution has been instructed to at least some of the plurality of communication devices in the past; an updating step of updating the cumulative number of times; Information processing methods.

15. A program for causing the control terminal to execute the information processing method according to claim 14.

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