JP2011172278A - Communication apparatus and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication parameter efficiently and simply even in an ad-hoc mode. <P>SOLUTION: Identification information of a provision apparatus to provide the communication parameter is acquired and is transmitted by adding the identification information of the provision apparatus in response to a search signal from other communication apparatus. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication device and a communication method.

Compared with wired communication, wireless communication has a danger of being executed without knowing an act such as wiretapping, and thus security functions such as authentication and encryption are important.
In the wireless LAN communication of the IEEE 802.11 standard, communication security is ensured by setting communication parameters such as an SSID that is a network identifier, a frequency channel, an authentication method, an encryption method, and an encryption key.
These communication parameters are highly specialized and difficult to be set by general users. For this reason, in wireless LAN communication based on the IEEE 802.11 standard, various companies have developed a technology that enables easy initial setting. In addition, WPS (Wi-Fi Protected Setup) compiled as a standard has been announced.
In WPS, a function that provides communication parameters is called a registrar, and a function that receives and sets communication parameters from a registrar device is called an enrollee. The access point may have a registrar function, or a device different from the access point may exist as a registrar while connected to the access point. In WPS, there are two communication parameter setting methods between a registrar device and an enrollee device. One is a PIN system in which the same 8-digit number (PIN) is input between the registrar device or access point and the enrollee device. The other is a push button method (PB method) in which the setting buttons of the registry device and the enrollee device are pressed for a certain period.

JP 2005-223745 A

However, the simple setting method and WPS of each company specify communication through an access point called an infrastructure mode, and there is no sufficient specification for the ad hoc mode. Currently, the infrastructure mode via an access point occupies most of the use forms of the wireless LAN, but there is a possibility that the wireless LAN will be installed in portable devices such as games and cameras in the future. In these devices, even if there is no fixedly installed access point, it is expected that the use mode of the ad hoc mode in which a device freely constitutes a network will increase.
In this case, what is important is to secure a safe communication path as in the infrastructure mode, and a technology that can easily set a safe communication path. In particular, many devices used in the ad hoc mode have user interface (UI) restrictions, and it takes time to input a PIN or the like. For this reason, the setting method by the push button method can be an important use case.
Here, when considering application of WPS defined in the infrastructure mode to the ad hoc mode, there is a technical problem due to the characteristics unique to the ad hoc mode. In the infrastructure mode, an access point transmits a beacon that is a notification signal. The access point also returns a response to the Probe request signal that is a network search request.
There are important parameters related to WPS in the response of a beacon or Probe request. For example, it is a parameter such as whether to select a PIN method or a push button method as a method for exchanging communication parameters.
On the other hand, in the ad hoc mode, a terminal that transmits a beacon is not uniquely determined. A beacon is transmitted with an algorithm according to the probability that one of the devices is distributed among the devices constituting the network. That is, when there are two terminals, beacons are transmitted with 50% establishment. Further, in the ad hoc mode, it is defined that the response to the Probe request signal is performed by the device that transmitted the beacon.
In the ad hoc mode, the registrar device does not always transmit a beacon. Also, the registrar device does not know which device will play the next beacon. Therefore, the intention of the registrar device cannot be reliably notified to other devices. Only when the registrar device transmits a beacon, the intention of the registrar device can be notified. In this method, a device that newly joins the network cannot acquire information about the registrar device except when the registrar device transmits a beacon.

The present invention makes it possible to easily find a providing apparatus even when a communication apparatus other than the providing apparatus that provides communication parameters responds to the search signal.
For this purpose, the present invention is a communication device, and based on a signal from a providing device that provides communication parameters, an acquisition unit that acquires identification information of the providing device, and a response to a search signal from another communication device Transmitting means for transmitting a signal to the other communication apparatus, wherein the transmitting means transmits the response signal to which the identification information of the providing apparatus acquired by the acquiring means is added. .
Moreover, the control method and program for implement | achieving the said communication apparatus are provided.

  ADVANTAGE OF THE INVENTION According to this invention, even if communication apparatuses other than the provision apparatus which provides a communication parameter respond to a search signal, a provision apparatus can be easily discovered now.

Configuration of wireless network of embodiment Configuration diagram of cameras 101 and 102 of the embodiment Configuration diagram of the printer 103 according to the embodiment Operation flowchart of the printer 103 according to the first embodiment. Operation flowchart of the camera 101 of the first embodiment. Operation flowchart of the camera 102 of the first embodiment. Operation flowchart of the printer 103 and the camera 101 according to the first embodiment. Sequence diagram of the first embodiment Operation flowchart of the camera 102 of the second embodiment. Operation Flowchart of Printer 103 of Third Embodiment Operation flowchart of the camera 101 of the third embodiment. Operation flowchart of the camera 102 of the second embodiment. Sequence diagram of the third embodiment

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of a wireless communication system that enables data transmission by wireless communication. In FIG. 1, the digital cameras (101 to 102) have a wireless communication function. If appropriate settings are made, wireless cameras can be used to connect digital cameras or printers (103). Data transmission can be performed. A communication mode in which terminals communicate directly with each other without using a base station is called an ad hoc mode. In the present embodiment, an example in which WPS (Wi-Fi Protected Setup) is applied to the ad hoc mode will be described. Accordingly, for the sake of convenience in this description as well, a device for providing and managing various communication parameters (SSID as a network identifier, frequency channel, authentication method, encryption method, encryption key, etc.) defined in the IEEE 802.11 standard to other devices. A registry device. The device to be set upon receiving communication parameters from the registry device is an enrollee device. The SSID is an abbreviation for Service Set Identifier.

  FIG. 2 shows a functional block diagram of the digital camera. Here, the digital camera 101 and the digital camera 102 have the same functional blocks.

  The operation unit 210 is connected to the CPU 215 via the system controller 211, and includes a shutter switch and various operation keys of the digital camera. The imaging unit 202 is a block that captures an image when the shutter is pressed, and the captured image is processed by the imaging processing unit 203. The display unit 206 is a block that displays information for the user, such as LCD display, LED display, audio display, and the like. Further, an operation such as selecting from information displayed on the display unit 206 is performed in conjunction with the operation unit 210. That is, the display unit 206 and the operation unit 210 constitute a user interface. The memory card I / F 208 is an interface for connecting the memory card 209. The USB I / F 212 is an interface for connecting to an external device using a USB. The audio I / F 214 is an interface for connecting a sound signal to an external device.

  The functional parts shown in these block diagrams are processed by control from the CPU 215, and a program controlled by the CPU 215 is stored in the ROM 216 or the flash ROM 213. Data processed by the CPU 215 is written to and read from the RAM 217 or the flash ROM 213.

  The wireless communication function unit 204 is a block that performs wireless communication, and the RF unit 205 transmits and receives wireless signals to and from other wireless communication devices. The RF unit 205 and the wireless communication function unit 204 may be realized as one block, but are illustrated separately here. The functions of the wireless communication function unit 204 are implemented with packet framing, data response processing, data encryption / decryption processing, and the like, which are wireless standards. A program for operating the wireless communication function unit 204 and the RF unit 205 is normally placed on the ROM 216 and operates on the CPU 215. The flash ROM 213 is a non-volatile storage area that stores setting information for wireless communication. In the present embodiment, the wireless communication function unit 204 and the RF unit 205 perform wireless LAN communication represented by the IEEE 802.11 standard.

  The RF unit 205 wireless communication function unit 204 controls beacon transmission in the ad hoc mode. The beacon signal is a kind of broadcast signal and is broadcast to the network. The beacon is transmitted by determining a random number in a range called a beacon contention window (0 to CWmax), and decrementing the random value at regular intervals to transmit the beacon when it becomes zero. Some beacon contention windows can be changed by a program operating on the CPU 215, and some beacon contention windows have fixed values in the wireless communication function unit 204. Information to be added to the beacon is stored in a frame that is actually transmitted by the wireless communication unit 204 and transmitted via the RF unit 205 by performing a predetermined setting from a program operating on the CPU 215. Similarly, when the added information is deleted, it can be deleted by making a predetermined setting from a program operating on the CPU 215.

  FIG. 3 shows functional blocks of the printer 103. The operation unit 310 is connected to the CPU 315 via the system controller 311. The print engine 302 is a functional block that actually prints an image on paper, and the print processing unit 303 processes the image to be printed. The display unit 306 is a block that displays information for the user, such as an LCD display, an LED display, and a voice display, and is processed by the display processing unit 307. Further, an operation such as selecting from information displayed on the display unit 306 is performed via the operation unit 310. The memory card I / F 308 is an interface for connecting the memory card 309. The USB I / F 312 is an interface for connecting to an external device using a USB. The parallel I / F 314 is an interface for connecting to an external device using parallel communication.

  The functional parts shown in these block diagrams are processed by control from the CPU 315, and programs controlled by the CPU are stored in the ROM 315 or the flash ROM 313. Data processed by the CPU 315 is written to and read from the RAM 317 or the flash ROM 313.

  The wireless communication function unit 304 is a block that performs wireless communication, and the RF unit 305 transmits and receives wireless signals to and from other wireless communication devices. The RF unit 305 and the wireless communication function unit 304 may be realized as one block, but are illustrated separately here. The functions of the wireless communication function unit 304 are implemented with wireless packet framing, data response processing, data encryption / decryption processing, and the like. A program that causes the wireless communication function unit 304 and the RF unit 305 to operate according to an application instruction is normally placed on the ROM 316 and operates on the CPU 315. The flash ROM 313 is a non-volatile storage area in which setting information for wireless communication is stored. In the present embodiment, the wireless communication function unit 204 and the RF unit 205 perform wireless LAN communication represented by the IEEE 802.11 standard.

  Control of beacon transmission in the ad hoc mode is performed by the RF unit 305 wireless communication function unit 304. The beacon is transmitted by determining a random number in a range called a beacon contention window (0 to CWmax), and decrementing the random value at regular intervals to transmit the beacon when it becomes zero. Some of the beacon contention windows can be changed by a program operating on the CPU 315, and some of the beacon contention windows have fixed values in the wireless communication function unit 304. Information to be added to the beacon is stored in a frame that is actually transmitted by the wireless communication function unit 304 and transmitted via the RF unit 305 by performing a predetermined setting from a program operating on the CPU 315. Similarly, when the added information is deleted, it can be deleted by making a predetermined setting from a program operating on the CPU 315.

  The configurations of the digital cameras 101 and 102 and the printer 103 in the embodiment have been described above. Note that although an antenna is provided in the RF unit, the antenna does not necessarily have a form protruding outward. In particular, in the case of a digital camera, since portability is an important factor, it is desirable that the antenna be built in or mounted on the surface rather than protruding outside.

  In this embodiment, it is assumed that the printer 103 becomes a communication parameter provider (registrar device) for constructing a network. In addition, the camera 101 has already acquired communication parameters, completed desired settings, and can perform wireless communication with the printer 103. The camera 102 is about to acquire a new communication parameter from the parameter provider. That is, the camera 102 functions as an enrollee device.

The printer 103 and the camera 102 can share the same communication parameter by pressing the buttons almost simultaneously (corresponding to the WPS PB method).
First, the operation of the printer 103 will be described with reference to the flowchart of FIG. The operation of FIG. 4 is performed by the CPU 315 executing a program stored in the ROM 316 or the flash ROM 313 and controlling each unit. The printer 103 performs beacon transmission according to a certain algorithm with the camera 101. According to this algorithm, when the printer 103 assumes the role of beacon transmission, the printer 103 transmits a beacon. When the camera 101 assumes the role of beacon transmission, the camera 101 transmits a beacon. Accordingly, there are various cases such as when the printer 103 and the camera 101 configure a network while alternately transmitting beacons, when only one device transmits a beacon, and when beacons are transmitted at random. The present embodiment also supports these various cases.

  First, the CPU 315 sets a printer as a communication parameter provider (registrar) according to a user instruction (S401). In this embodiment, all devices can be communication parameter providers, but the default setting (initial setting) is the communication parameter acquirer. Therefore, in the present embodiment, the registrar is selected after agreement between the users, and the user designates and sets it via the operation unit 310. These do not particularly limit the present embodiment, and the procedure for determining the registrar may be determined manually or a mechanism for automatically determining it may be devised.

  Next, when the CPU 315 of the printer 103 detects a button operation for exchanging communication parameters of the operation unit 310 by the user (S402), the registrar information is added to the beacon as additional information and transmitted (S403). The button operation for exchanging communication parameters may be a soft button displayed as a result of a plurality of operations such as selecting a desired function while changing the menu on the display unit 306.

  The registrar information includes information that the parameter providing service is currently being executed, information related to authentication using the push button method, and the like, and these information is stored in a specific format in the beacon. Further, the registrar information includes information including a MAC address (identification information) indicating a destination of the registrar in addition to the same contents as WPSIE (WPS Information Element) defined by WPS. When the printer 103 as the registrar device transmits a beacon, the MAC address of the printer 103 is included.

Since this description is an operation in the ad hoc mode, beacon transmission is performed when the printer 103 is in a role of transmitting a beacon.
The communication parameter provision period in the push button method is within a certain period (set period) after starting the parameter provision service in consideration of safety, and the printer 103 adds registrar information during the period. The beacon is transmitted (S404). When this period expires, the CPU 315 deletes the registrar information from the transmitted beacon (S405).

  The CPU 315 monitors whether a parameter acquisition request is sent from the enrollee device until the set period expires (S406). When receiving the parameter acquisition request from the enrollee device, the CPU 315 provides communication parameters managed by itself to the enrollee device that has transmitted the request (S407).

  When the communication parameters have been provided, the process returns to S403, and communication parameter providing processing for other enrollee devices is performed until the set period expires. In this description, the communication parameter provision processing for other enrollee devices is performed until the set period expires, but the processing may be terminated when the communication parameters are provided to the enrollee device. In this way, it is possible to prevent communication parameters from being provided to unintended devices.

Next, the operation of the camera 101 whose communication parameters have already been exchanged with the printer 103 (provided) will be described with reference to the flowchart of FIG. 5 is performed by the CPU 215 executing a program stored in the ROM 216 or the flash ROM 213 and controlling each unit.
The CPU 215 of the camera 101 monitors the beacon from the printer 103 and, when receiving the beacon from the printer 103, determines whether the content has changed from the beacon received from the printer 103 previously received (S501). Note that the camera 101 transmits a beacon when the camera 101 plays a role of beacon transmission while monitoring the beacon from the printer 103. In order to determine whether there is a change in information in the received beacon, the CPU 215 of the camera 101 stores the information included in the beacon in the RAM 217 when receiving the beacon. Since this information includes the address information of the beacon transmission source device, the contents of the beacon from the device with the same address are compared to determine whether the beacon information from the same device has changed (S501). ).
If there is a change in the beacon information as a result of this determination, it is determined whether the change is that the registrar information has been added to the beacon or has been deleted (S502, S505).

  When the registrar information is added, the CPU 215 confirms the content, and confirms that there is a WPSIE information element and the MAC address of the communication parameter provider (S503). Then, the received registrar information (WPSIE added by the printer 103 and the MAC address of the printer 103) is added to the beacon transmitted by the camera 101 (S504). When the camera 101 plays a role of transmitting a beacon, it transmits a beacon to which the received registrar information (WPSIE added by the printer 103 and the MAC address of the printer 103) is added. Thus, a device that shares the same communication parameters as a network in which a registrar device already exists and is in a communicable state on the same network adds the registrar information from the registrar device to its beacon and transmits it. By doing in this way, the apparatus (enrollee) which received this beacon (beacon from apparatuses other than a registrar) can recognize the information of a registrar apparatus. Therefore, even in an ad hoc mode in which the registrar device does not always transmit a beacon, the intention of the registrar device (registrar information) can be efficiently notified to other devices.

  If the received change in the beacon information is a change in which the registrar information is deleted (S505), the registrar information is deleted from the beacon transmitted by the camera 101 (S506). Accordingly, the registrar information is deleted from the beacon transmitted by the camera 101 thereafter.

  The communication parameter providing period of the printer 103 ends in a limited time. Therefore, the registrar information added to the beacon from the printer 103 is deleted when this period expires. When the registrar information is deleted from the beacon of the printer 103, the registrar information from the beacon transmitted by the camera 101 is deleted. Therefore, it is possible to prevent information related to the registrar device from being announced by a device other than the registrar device even though the registrar device has ended the parameter providing service. Therefore, security outside the parameter providing service period is also improved.

  Next, operations when the printer 103 and the camera 101 receive a search request (Probe request signal, search signal) will be described with reference to the flowchart of FIG. Note that the operation of FIG. 7 is performed in parallel with the operations of FIGS. When the printer 103 executes the operation shown in FIG. 7, the operation shown in FIG. 7 is performed by the CPU 315 executing a program stored in the ROM 316 or the flash ROM 313 and controlling each unit. When the camera 101 executes the operation shown in FIG. 7, the operation shown in FIG. 7 is performed by the CPU 215 executing a program stored in the ROM 216 or the flash ROM 213 and controlling each unit.

  When a network search request is received (S701), the CPUs 215 and 315 determine whether to respond to the search request (S702). In the ad hoc mode, it is defined that a device that has transmitted a beacon immediately before a search request is transmitted responds to the search request. Therefore, the CPUs 215 and 315 determine whether or not a beacon has been transmitted immediately before receiving the search request, and if the device itself is a device that has transmitted the beacon immediately before, the CPU 215 or 315 is a device (response device) that responds to the search request. It is determined that there is (S702). If another device transmits a beacon immediately before and does not transmit a beacon (S702), it determines that it does not respond to the search request, and ends the process.

When the CPUs 215 and 315 determine that they are responding devices, the CPUs 215 and 315 determine whether or not the parameter providing service is being performed (S703). In the case of the CPU 315, if the button operation is detected in S402 and the state is shifted to the parameter providing service state, it is determined that the parameter providing service is being performed. In the case of the CPU 215, if there is a change in the beacon information received in S501 and this change is a change in which the registrar information is added to the received beacon, it is determined that the parameter providing service is being performed. In other words, when the device (registrar device) that transmitted the beacon is in the parameter providing service and the device itself is in the state of transmitting the registrar information from the registrar device to the beacon, it is determined that the device is in the parameter providing service.
When determining that the parameter providing service is being performed, the CPUs 215 and 315 add the registrar information (WPSIE and the MAC address of the communication parameter provider) to the response to the search request and transmit it (S704). If the CPUs 215 and 315 determine that the parameter providing service is not being performed, the CPUs 215 and 315 transmit the response to the search request without adding registrar information (WPSIE and the MAC address of the communication parameter provider) (S705). The CPUs 215 and 315 unicast the response to the search request to the device that has transmitted the search request.

  Next, the operation of the camera 102 attempting to acquire communication parameters will be described with reference to the flowchart of FIG. 6 is performed by the CPU 215 executing a program stored in the ROM 216 or the flash ROM 213 and controlling each unit.

  When the CPU 215 of the camera 102 detects a button operation for exchanging communication parameters of the operation unit 210 by the user (S601), the CPU 215 transmits a network search request via the wireless communication unit 204 and the RF unit 205 (S602). Then, it is monitored whether a response to the search request is received (S603). If a response is received from the detection of the button operation in S601 until the set period expires, the process proceeds to S604. If no response is received, a network search request is periodically transmitted until the set period expires (S607).

  In S604, it is determined whether there is registrar information in the received response. If there is no registrar information, the process proceeds to S607, and a network search request is periodically transmitted until the set period expires. When the set period expires without receiving a response including registrar information (S607), the process ends. When the registrar information is included in the received response (S604), a parameter acquisition request is transmitted to the MAC address of the communication parameter provider included in the registrar information to request provision of communication parameters (S605). . Then, the communication parameter is provided from the communication parameter provider, and the communication parameter is acquired (S606). As a specific procedure of the communication parameter providing process, communication parameters including a key are securely exchanged using a public key such as Diffie-Hellman or RSA.

  When the acquisition of communication parameters ends normally (S607), the acquired parameters are stored in a memory such as the flash ROM 213 or RAM 217 (S608). If acquisition of communication parameters does not end normally, the process ends. The communication parameters stored in the memory are set in the wireless communication function unit 204 according to an instruction from the CPU 215, and the camera 102 performs wireless communication according to the set communication parameters. This setting may be performed automatically when the acquisition of communication parameters is successful, or may be performed by the operation of the operation unit 210 by the user. In this embodiment, since the camera 102 performs communication parameter acquisition in order to perform wireless communication with the printer 103, the CPU 215 automatically acquires the acquired communication parameter to the wireless communication function unit 204 when the communication parameter acquisition is successful. Shall be set.

  Since the enrollee device transmits a parameter acquisition request to the registrar device address included in the registrar information, the enrollee device receives communication parameters from the registrar device even if a device other than the registrar device transmits a search response. be able to.

FIG. 8 is an overall sequence diagram of the camera 101, the camera 102, and the printer 103.
The camera 101 and the printer 103 operate on a network created by both devices. In step S801, the printer 103 transmits a beacon. The user operates the operation unit 310 of the printer 103, sets the printer 103 as a registrar device, and operates buttons for communication parameter provision processing (S802). In response to this, the printer 103 adds the registrar information (WPSIE and the MAC address of the printer 103) to the beacon and transmits it (S803).
The camera 101 that has received this beacon adds this information to the beacon and transmits it (S804).

Next, the user of the camera 102 newly joining the network operates a button for communication parameter provision processing (S805). When the camera 102 detects the above operation, it transmits a network search request (Prob Req) (S807). In FIG. 8, this request is transmitted to the camera 101 that transmitted the beacon immediately before, but may be broadcast to all devices.
The camera 101 that has received this search request returns a response (Prob Res) to the search request (S808). This response includes registrar information of the printer 103.

When receiving a response to the search request, the camera 102 acquires WPSIE information and a MAC address in the response. Accordingly, the camera 102 confirms that the registrar device is the printer 103. Thereafter, the camera 102 requests communication parameters from the printer 103 as a registrar and receives provision of communication parameters (exchange of communication parameters) (S809).
When the camera 102 receives communication parameters from the printer 103, the camera 102 sets the communication parameters and participates in the same network as the printer 103 and the camera 101. If the camera 102 participates in the same network, the camera 102 is also a terminal constituting the network, so beacon transmission is performed based on the flowchart shown in FIG. 5 (S810). When the setting time ends, the registrar information is deleted from the beacon transmitted from the printer 103 (S811). Thereafter, the registrar information is also deleted from the beacons transmitted by other devices.

In addition to the operation of the camera 102, a process of comparing the registrar information included in the search response and the registrar information included in the beacon may be added after S604. If the registrar information matches as a result of the comparison, the process proceeds to S605, and a parameter acquisition request is transmitted. If the registrar information does not match, there are a plurality of registrars in the parameter providing service, and there is a possibility that an undesired communication parameter is provided, or a malicious device is trying to provide an unauthorized communication parameter.
Therefore, if the search response and the beacon registrar information do not match, the processing may be terminated. By doing so, security can be improved.

  Until now, in ad hoc communication, there has not been considered a mechanism in which specific information transmitted by another communication terminal is taken over and delivered by the next different terminal. By providing this mechanism, it becomes possible to quickly detect which terminal is a registrar from a beacon or search response information for a newly participating terminal.

  As described above, even in an ad hoc mode in which no access point exists, communication parameters can be provided and received efficiently, and communication parameters can be easily set.

(Second embodiment)
In this embodiment, the enrollee device requests communication parameters using registrar information included in the received beacon.

  Since the configuration of the network and the configuration of each device are the same as those in the first embodiment, description thereof will be omitted. Since the operations of the camera 101 and the printer 103 are the same as those in the first embodiment, description thereof is omitted.

  The operation of the camera 102 attempting to acquire the communication parameter will be described below with reference to FIG. The operation of FIG. 9 is performed by the CPU 215 executing a program stored in the ROM 216 or the flash ROM 213 and controlling each unit.

When the CPU 215 of the camera 102 detects a button operation for exchanging communication parameters on the operation unit 210 by the user (S901), it monitors reception of a beacon (S902). When the beacon is received, it is determined whether or not the received beacon has registrar information (S903). If there is no registrar information, the process returns to S902 to monitor reception of a beacon. If a beacon including registrar information is not received from the detection of the button operation in S901 until the set period expires, the process ends (S908).
When the received beacon includes registrar information (S903), a parameter acquisition request is transmitted to the MAC address of the communication parameter provider included in the registrar information to request provision of communication parameters (S904). . Then, the communication parameter is provided from the communication parameter provider, and the communication parameter is acquired (S905). As a specific procedure of the communication parameter providing process, communication parameters including a key are securely exchanged using a public key such as Diffie-Hellman or RSA.

When the acquisition of communication parameters is completed normally (S906), the acquired parameters are stored in a memory such as the flash ROM 213 or RAM 217 (S907). If acquisition of communication parameters does not end normally, the process ends. The communication parameters stored in the memory are set in the wireless communication function unit 204 according to an instruction from the CPU 215, and the camera 102 performs wireless communication according to the set communication parameters. This setting may be performed automatically when the acquisition of communication parameters is successful, or may be performed by the operation of the operation unit 210 by the user. In this embodiment, since the camera 102 performs communication parameter acquisition in order to perform wireless communication with the printer 103, the CPU 215 automatically acquires the acquired communication parameter to the wireless communication function unit 204 when the communication parameter acquisition is successful. Shall be set.
According to this embodiment, it is possible to obtain registrar information from a beacon and receive communication parameters without transmitting a network search request.

(Third embodiment)
In the present embodiment, a countermeasure when the beacon information is falsified will be described.

  A malicious third party enters between the two terminals that have correctly pressed the button and eavesdrops, impersonates a registrar, exchanges communication parameters, and then prevents important data from being stolen.

Since the configuration of the network and the configuration of each device are the same as those in the first embodiment, description thereof will be omitted. Also in this embodiment, the printer 103 becomes a communication parameter provider for constructing a network. In addition, the camera 101 has already acquired communication parameters, completed desired settings, and is performing wireless communication. The camera 102 is about to acquire a new communication parameter. The printer 103 and the camera 102 can share the same communication parameter by pressing the button almost simultaneously (corresponding to the WPS PB method).
The operation of the printer 103 will be described with reference to the flowchart of FIG. The operation of FIG. 10 is performed by the CPU 315 executing a program stored in the ROM 316 or the flash ROM 313 and controlling each unit. The printer 103 performs beacon transmission according to a certain algorithm with the camera 101. According to this algorithm, when the printer 103 assumes the role of beacon transmission, the printer 103 transmits a beacon. When the camera 101 assumes the role of beacon transmission, the camera 101 transmits a beacon. Accordingly, there are various cases such as when the printer 103 and the camera 101 configure a network while alternately transmitting beacons, when only one device transmits a beacon, and when beacons are transmitted at random. The present embodiment also supports these various cases.

  First, the CPU 315 sets a printer as a communication parameter provider (registrar) in accordance with a user instruction (S1001). In this embodiment, all devices can be communication parameter providers, but the default setting (initial setting) is the communication parameter acquirer. Therefore, in the present embodiment, the registrar is selected after agreement between the users, and the user designates and sets it via the operation unit 310. These do not particularly limit the present embodiment, and the procedure for determining the registrar may be determined manually or a mechanism for automatically determining it may be devised.

Next, when the CPU 315 of the printer 103 detects a button operation for exchanging communication parameters of the operation unit 310 by the user (S1002), the registrar information is added to the beacon and transmitted (S1003). The button operation for exchanging communication parameters may be a soft button displayed as a result of a plurality of operations such as selecting a desired function while changing the menu on the display unit 306.
The registrar information includes information indicating that the parameter providing service is currently being executed, information related to authentication using the push button method, and the like, and stores such information in a specific format in the beacon. The registrar information is information including a MAC address indicating the destination of the registrar in addition to the same contents as WPSIE (WPS Information Element) defined by WPS.
Since this description is an operation in the ad hoc mode, beacon transmission is performed when the printer 103 is in a role of transmitting a beacon.

  When the CPU 315 receives a beacon of another terminal (S1004), the CPU 315 confirms whether or not the same registrar information as the registrar information added by the terminal itself is added (S1005). That is, it is confirmed that the registrar information added by the terminal itself has not been corrected or deleted. In other words, it is confirmed that registrar information different from the registrar information added by the terminal is added or not deleted. In order to confirm this, the registrar information (WPSIE and MAC address) added by the terminal is directly compared with the registrar information (WPSIE and MAC address) in the received beacon. Alternatively, when adding registrar information to a beacon in S1003, the hash value of the information element is calculated and stored, and the hash value is compared with the hash value of the received information to confirm whether it has been deleted or modified. May be.

As a result of the determination in S1005, if the compared registrar information is not the same (corrected or deleted), a warning message is transmitted using a broadcast frame that can be received by all terminals on the same network (S1008). This warning message notifies the communication parameter providing service processing interruption warning (S1008). Thus, if the compared registrar information is not the same (if modified or deleted), there is a possibility that someone has changed the beacon information in an attempt to falsify. Therefore, the other terminal is warned and the process is interrupted. The broadcast frame may be a management frame of IEEE 802.11 or a data packet that flows specially for authentication including an EAP header. When a warning is given in S1008, a warning message may be displayed on the display unit 306 to notify the user that the processing of the communication parameter providing service is interrupted.
If the registrar information is the same, it is checked whether the setting period for providing communication parameters has expired (S1006), and if it has not expired, the process returns to S1003. The communication parameter provision period in the push button method is within a certain period (set period) after starting the parameter provision service in consideration of safety, and the printer 103 adds registrar information during the period. Then, transmission of a beacon is attempted (S1003).
When the set period expires (S1006), the registrar information (WPSIE and MAC address) is deleted from the beacon (S1007).

If the beacon is not received, the CPU 315 monitors whether a parameter acquisition request is sent from the enrollee device (S1009). When receiving the parameter acquisition request from the enrollee device, the CPU 315 provides communication parameters managed by itself to the enrollee device that has transmitted the request (S1010).
When the communication parameters have been provided, the process returns to S1003, and communication parameter provision processing for other enrollee devices is performed until the set period expires. In this description, the communication parameter provision processing for other enrollee devices is performed until the set period expires, but the processing may be terminated when the communication parameters are provided to the enrollee device. In this way, it is possible to prevent communication parameters from being provided to unintended devices.

Next, the operation of the camera 101 that already exists in the same network as the printer 103 and whose communication parameters have been exchanged with the printer 103 will be described with reference to the flowchart of FIG. The operation in FIG. 11 is performed by the CPU 215 executing a program stored in the ROM 216 or the flash ROM 213 and controlling each unit.
The CPU 215 of the camera 101 monitors the beacon and, when receiving the beacon, determines whether or not the content of the beacon from the printer 103 received last time has changed (S1101). The camera 101 transmits a beacon when the camera 101 is in a role of beacon transmission even while monitoring the beacon from the printer 103. In order to determine whether there is a change in information in the received beacon, the CPU 215 of the camera 101 stores the information included in the beacon in the RAM 217 when receiving the beacon. Since this information includes the address information of the beacon transmission source device, the contents of the beacon from the device with the same address are compared to determine whether the beacon information from the same device has changed (S1101). ).

If there is a change in the received beacon information, it is determined whether or not the change is made by adding registrar information to the beacon (S1102). If it is not a change to which the registrar information is added, the process returns to S1101.
When the registrar information is added, the CPU 215 confirms the contents, and confirms that there is a WPSIE information element and the MAC address of the communication parameter provider (S1103). The registrar information (WPSIE and MAC address) is stored in the memory (flash ROM 213 or RAM 217) (S1104). As a method for saving, the registrar information may be saved as it is, or the WPSIE and the hash value of the MAC address may be saved. Then, the received registrar information (WPSIE added by the printer 103 and the MAC address of the printer 103) is added to the beacon transmitted by the camera 101 (S1105). When the camera 101 plays a role of transmitting a beacon, it transmits a beacon to which the received registrar information (WPSIE added by the printer 103 and the MAC address of the printer 103) is added. Thus, a device that shares the same communication parameters as a network in which a registrar device already exists and is in a communicable state on the same network adds the registrar information from the registrar device to its beacon and transmits it. A device (enrollee) that has received this beacon (a beacon from a device other than the registrar) can recognize information on the registrar device. Therefore, even in an ad hoc mode in which the registrar device does not always transmit a beacon, the intention of the registrar device (registrar information) can be efficiently notified to other devices.

Next, the CPU 215 of the camera 101 monitors reception of a beacon (S1106). When the beacon is received, it is confirmed whether the registrar information stored in S1104 has been deleted or modified (S1107). If it has not been deleted or modified, the process returns to S1106 to monitor reception of a beacon.
When the registrar information added to the received beacon has been deleted or modified, the registrar information (WPSIE added by the printer 103 and the MAC address of the printer 103) is deleted from the beacon transmitted by the camera 101. (S1109). Accordingly, the registrar information is deleted from the beacon transmitted by the camera 101 thereafter.

  When the registrar information added to the beacon is deleted or corrected in this way, the registrar information may be falsified by a third party. Therefore, the registrar information is deleted from the beacon transmitted by the camera 101 to prevent damage caused by tampering. Also, when the registrar device (printer 103) selected by the user transmits registrar information and transmits a beacon, that is, when the communication parameter providing service is stopped, the registrar information of the beacon received by the camera 101 is deleted or Will be corrected. Also in this case, since the registrar information is deleted from the beacon transmitted by the camera 101, the information about the registrar device is announced from a device other than the registrar device even though the registrar device has ended the parameter providing service. Can be prevented.

  The operations when the printer 103 and the camera 101 receive a search request (Probe request signal) are the same as those in the first embodiment and operate as shown in FIG.

  Next, the operation of the camera 102 attempting to acquire communication parameters will be described with reference to the flowchart of FIG. The operation in FIG. 12 is performed by the CPU 215 executing a program stored in the ROM 216 or the flash ROM 213 and controlling each unit.

  When the CPU 215 of the camera 102 detects a button operation for exchanging communication parameters of the operation unit 210 by the user (S1201), the CPU 215 transmits a network search request via the wireless communication unit 204 and the RF unit 205 (S1202). Then, it is monitored whether a response to the search request is received (S1203). When a response is received from the detection of the button operation in S1201 until the set period expires, the process proceeds to S1204. If no response is received, a network search request is periodically transmitted until the set period expires (S1211).

  In S1204, it is checked whether or not the received response includes registrar information (WPSIE and the MAC address of the communication parameter provider) (S1204). If it does not exist, a network search request is periodically transmitted until the set period expires (S1211). When the set period expires without receiving a response including the registrar information (S1211), the process ends. If the registrar information is included in the received response (S1204), a parameter acquisition request is transmitted to the MAC address of the communication parameter provider included in the registrar information to request provision of communication parameters (S1205). . Then, the communication parameter is provided from the communication parameter provider, and the communication parameter is acquired (S1206). As a specific procedure of the communication parameter providing process, communication parameters including a key are securely exchanged using a public key such as Diffie-Hellman or RSA.

  If acquisition of communication parameters does not end normally (S1207), the process ends. When the acquisition of the communication parameters is completed normally (S607), a warning message arrives and whether or not there is a warning notification is confirmed for a certain period (S1208). If the warning message does not arrive, the acquired parameters are stored in a memory such as the flash ROM 213 or the RAM 217 (S1209). When the warning message arrives, the acquired parameter is discarded (S1210). The communication parameters stored in the memory are set in the wireless communication function unit 204 according to an instruction from the CPU 215, and the camera 102 performs wireless communication according to the set communication parameters. This setting may be performed automatically when the acquisition of communication parameters is successful, or may be performed by the operation of the operation unit 210 by the user. In this embodiment, since the camera 102 performs communication parameter acquisition in order to perform wireless communication with the printer 103, the CPU 215 automatically acquires the acquired communication parameter to the wireless communication function unit 204 when the communication parameter acquisition is successful. Shall be set.

  If the communication parameter is discarded, the display unit 206 displays a failure to acquire the communication parameter and notifies the user. The user who has confirmed this notification can start the communication parameter setting process again. Further, when the user notification is made, it may be displayed that the communication parameter is discarded by a warning notification from the registrar device (printer 103). By doing so, the user can recognize the presence of a malicious third party, and can cancel the communication parameter setting process.

FIG. 13 is an overall sequence diagram of the camera 101, the camera 102, and the printer 103.
The sequence is the same as that shown in FIG. However, in the example of FIG. 13, the camera 101 transmits the beacon with different registrar information added in S1310. In response to this, a warning message is transmitted from the printer 103 in S1311. The camera 102 that has received this warning message discards the parameters (S1312).

As described above, when the registrar information added to the beacon is falsified, it is possible to prevent communication parameters from being set based on the falsified information, and it is possible to safely exchange communication parameters. .
In the above description, the enrollee device transmits the parameter acquisition request using information included in the registrar information added to the response to the search request. However, as in the second embodiment, the communication parameter may be requested using the registrar information included in the received beacon.

  As described above, in the above description, the communication device determines a change in the content of the notification signal transmitted by another communication device. Based on this determination, the specific additional information included in the notification signal received by the communication device is added to the notification signal transmitted by the communication device, or the specific additional information is added from the notification signal transmitted by the communication device. Deleted and sent.

  Here, the above configuration may be the following configuration. That is, the communication device transmits a notification signal with another communication device according to a predetermined algorithm. Further, the content of the notification signal is changed by determining whether additional information is added to the received notification signal, deleted, or modified. The additional information includes information indicating that the communication parameter providing service is being executed, identification information of a device that executes the communication parameter providing service, or information related to authentication. In addition, when a search signal from another communication device is received, a response determination is performed to determine whether or not to respond to the search signal, and it is determined whether or not the other communication device is executing a communication parameter providing service. Make a service decision. Then, depending on the response determination and the service determination, the response signal for the search signal is transmitted with or without adding the specific additional information included in the received notification signal.

  Further, in the above description, the communication device adds specific additional information to the notification signal and transmits it based on a user operation, and adds the additional information added to the transmitted notification signal to the notification signal transmitted by another communication device. Whether or not is added is determined. In response to this determination, a warning notification is made.

  Here, the above configuration may be the following configuration. That is, the warning notifies the processing interruption of the communication parameter providing service. Further, the warning notifies the other communication device or the user of the warning. Further, the additional information added to the transmitted notification signal is deleted from the notification signal transmitted by the other communication device, or the additional information added to the transmitted notification signal is added to the notification signal transmitted by the other communication device. It is determined whether additional information different from that is added.

In the above description, it is confirmed whether the received signal includes identification information of a device that is executing the communication parameter providing service, and the communication parameter providing service is based on the identification information included in the received signal. Get communication parameters from the device executing Then, the acquired communication parameters are discarded based on the warning message transmitted from the device executing the communication parameter providing service.
Therefore, even in an ad hoc mode in which no access point exists, communication parameters can be efficiently provided and accepted, and communication parameters can be easily set.
In other words, even if the same device does not always transmit a beacon, and even if the same device does not always respond to a search request, communication parameters can be provided and received efficiently and communication parameters can be set easily. Will be able to.

101 Camera 102 Camera 103 Printer

Claims (10)

A communication device,
An obtaining unit for obtaining identification information of the providing device based on a signal from the providing device that provides the communication parameter;
Transmitting means for transmitting a response signal to the search signal from the other communication device to the other communication device;
Have
The communication device transmits the response signal to which the identification information of the providing device acquired by the acquiring device is added.   The transmission means transmits the response signal to which the identification information of the providing device is added during a period when the providing device provides the communication parameter providing service, and the providing device provides the communication parameter providing service. The communication apparatus according to claim 1, wherein a response signal to which identification information of the providing apparatus is not added is transmitted during a period when the providing apparatus is not used. A determination means for determining whether or not to respond to the search signal when the search signal is received;
The communication apparatus according to claim 1, wherein the transmission unit transmits the response signal when the determination unit determines to respond to the search signal.   The determination means determines whether or not to respond to the search signal based on whether or not the device that transmitted the beacon signal before the search signal is transmitted is the communication device. The communication apparatus according to any one of claims 1 to 3.   5. The information according to claim 1, wherein information related to authentication of the communication parameter providing service is also added to the response signal to which the identification information of the providing device is added. Communication device.   6. The response signal to which identification information of the providing device is added is also added with information indicating that the communication parameter providing service is being executed. Item 1. The communication device according to item 1.   The communication apparatus according to claim 1, further comprising a notification unit that transmits a notification signal to which the identification information of the providing device acquired by the acquisition unit is added.   The communication device according to claim 1, wherein the acquisition unit and the transmission unit perform the processing in a communication mode in which communication devices directly communicate with each other without using a base station. . A communication device control method comprising:
An acquisition step of acquiring identification information of the providing device based on a signal from the providing device that provides communication parameters;
A transmission step of transmitting a response signal to a search signal from another communication device to the other communication device;
Have
In the transmission step, the response signal to which the identification information of the providing device acquired in the acquisition step is added is transmitted. A program executed in a communication device,
An acquisition step of acquiring identification information of the providing device based on a signal from the providing device that provides communication parameters;
A step of transmitting a response signal to a search signal from another communication device to the other communication device, and a step of transmitting the response signal to which the identification information of the providing device acquired in the acquisition step is added. A program for causing the communication device to execute.

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