COMMUNICATION DEVICE AND COMPUTER PROGRAM FOR THE COMMUNICATION DEVICE

Abstract

To disclose a technique for suppressing the establishment of a wireless connection between a communication device and a second external device by a third party using a first external device.SOLUTION: A communication device accepts an input of user authentication information for authenticating a user, cause an output unit to output specific information obtained by using a public key when the authentication using the input user authentication information is successful, receives the authentication request using the public key from the first external device after the specific information is output, transmits an authentication response to the first external device, transmits the first connection information from the first external device, and receives and uses the first connection information from the first external device to establish a first wireless connection between the communication device and the second external device via a wireless interface.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] This specification discloses a technique related to a communication device capable of establishing a wireless connection with an external device. [Background technology]

[0002] Patent Document 1 discloses a technique for establishing a wireless connection between a camera and an AP using a smartphone. In response to receiving an operation from a user, the camera displays a QR code (registered trademark) including information for setting communication parameters, and starts monitoring the reception of a search signal. The smartphone acquires information for setting communication parameters by reading the QR code displayed on the camera, and transmits a search signal to the camera. When the camera receives a search signal from the smartphone, the camera transmits a response to the search signal to the smartphone. When a response is received from the camera, the smartphone sets communication parameters using the acquired information, and transmits the set communication parameters to the camera. The smartphone also executes a similar process with the AP and transmits the communication parameters to the AP. This allows the camera to establish a wireless connection with the AP using the received communication parameters. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-28454 A [Patent Document 2] JP 2018-6983 A [Patent Document 3] JP 2018-37978 A [Non-patent literature]

[0004] [Non-Patent Document 1] “Device Provisioning Protocol Technical Specification Version 1.1” Wi-Fi Alliance, 2018 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above technology, a third party other than the camera user may use a smartphone to establish a wireless connection between the camera and the AP.

[0006] This specification discloses a technique for preventing a wireless connection from being established between a communication device and a second external device by a third party using a first external device. [Means for solving the problem]

[0007] A first aspect of a communication device disclosed in this specification includes an output unit, a wireless interface, a determination unit that determines whether the state of the communication device is a first state in which use of the communication device is not restricted, or a second state in which use of the communication device is restricted, a reception unit that receives input of user authentication information for authenticating a user of the communication device when it is determined that the state of the communication device is the second state, and a first output control unit that causes the output unit to output specific information obtained using a public key when it is determined that the state of the communication device is the second state and authentication using the inputted user authentication information is successful, and when authentication using the inputted user authentication information fails, the specific information is not output by the output unit, and the public key is acquired by a first external device by outputting the specific information, and when it is determined that the state of the communication device is the first state, the specific information is output without accepting input of the user authentication information. the first output control unit causing the output unit to output public key information to the output unit; an authentication request receiving unit receiving an authentication request using the public key from the first external device via the wireless interface after the specific information has been output; an authentication response transmitting unit transmitting an authentication response that is a response to the authentication request to the first external device via the wireless interface when the authentication request is received from the first external device; a connection information receiving unit receiving first connection information from the first external device via the wireless interface after the authentication response has been transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and the second external device via the wireless interface; and an establishment unit establishing the first wireless connection between the communication device and the second external device via the wireless interface using the first connection information when the first connection information is received from the first external device. Communication device disclosed herein The second aspectthe first output control unit causes the output unit to output specific information obtained by using a public key when authentication using the input user authentication information is successful, and when authentication using the input user authentication information is unsuccessful, the specific information is not output by the output unit, and the public key is acquired by a first external device as a result of the specific information being output; an authentication request receiving unit receives an authentication request using the public key from the first external device via the wireless interface after the specific information is output; the first external device via the wireless interface after the authentication response has been transmitted to the first external device, the connection information receiving unit receiving first connection information from the first external device via the wireless interface after the authentication response has been transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and the second external device via the wireless interface; and an establishment unit establishing the first wireless connection between the communication device and the second external device via the wireless interface using the first connection information when the first connection information is received from the first external device.

[0008] According to the above configuration, when authentication using the input user authentication information is successful, the communication device outputs specific information obtained using the public key, but when authentication using the input user authentication information is unsuccessful, the communication device does not output the specific information. As a result, each process corresponding to the output of the specific information is not executed. This makes it possible to prevent a third party other than the user from using the first external device and establishing a wireless connection between the communication device and the second external device.

[0009] Furthermore, a third aspect of a communication device disclosed in this specification includes a wireless interface, a determination unit that determines whether a state of the communication device is a first state in which use of the communication device is not restricted, or a second state in which use of the communication device is restricted, a reception unit that receives input of user authentication information for authenticating a user of the communication device when it is determined that the state of the communication device is the second state, and a first state transition unit that transitions the state of the communication device from an impossible state to a possible state when it is determined that the state of the communication device is the second state and authentication using the input user authentication information is successful, wherein when authentication using the input user authentication information fails, the state of the communication device is maintained in the impossible state, the impossible state is a state in which an authentication response that is a response to an authentication request is not transmitted, and the possible state is a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from a first external device, and when it is determined that the state of the communication device is the first state, the first state transition unit transitioning the state of the communication device from the impossible state to the possible state without accepting input of the user authentication information; an authentication request receiving unit receiving the authentication request from the first external device via the wireless interface; an authentication response transmitting unit transmitting the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device has transitioned to the possible state; a connection information receiving unit receiving first connection information from the first external device via the wireless interface after the authentication response has been transmitted to the first external device, wherein the first connection information is information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; and an establishment unit establishing the first wireless connection between the communication device and the second external device via the wireless interface using the first connection information when the first connection information is received from the first external device. Also, the present specification discloses a communication device Fourth aspectthe first state transition unit transitions a state of the communication device from an impossible state to a possible state when authentication using the input user authentication information is successful, and when authentication using the input user authentication information is unsuccessful, the state of the communication device is maintained in the impossible state, the impossible state being a state in which an authentication response that is a response to an authentication request is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from a first external device; an authentication request receiving unit receiving the authentication request from the first external device via the wireless interface; the communication device includes an authentication response transmitting unit that transmits the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the communication device has transitioned to the possible state; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; and an establishment unit that uses the first connection information to establish the first wireless connection between the communication device and the second external device via the wireless interface when the first connection information is received from the first external device.

[0010] According to the above configuration, when authentication using the input user authentication information is successful, the communication device transitions the state of the communication device to an enabled state, whereas when authentication using the input user authentication information is unsuccessful, the communication device maintains the state of the communication device in an disabled state. As a result, when authentication fails, an authentication response to an authentication request from the first external device is not transmitted, and a wireless connection is not established between the communication device and the second external device. This makes it possible to prevent a third party other than the user from using the first external device and thus establishing a wireless connection between the communication device and the second external device.

[0011] A computer program for implementing the above communication device and a computer-readable recording medium storing the computer program are also novel and useful. A method executed by the above communication device is also novel and useful. A communication system including the above communication device and other devices (e.g., a first external device, a second external device) is also novel and useful. [Brief description of the drawings]

[0012] [Figure 1] 1 shows the configuration of a communication system. [Diagram 2] FIG. 1 is an explanatory diagram for explaining an outline of an embodiment; [Diagram 3] A sequence diagram of Bootstrapping overview is shown below. [Figure 4] A sequence diagram of authentication process is shown below. [Diagram 5] A sequence diagram of Configuration processing is shown below. [Figure 6] A sequence diagram of the Network Access process is shown below. [Figure 7] Details of Bootstrapping are shown below. [Figure 8] A sequence diagram for the case where the QR code is not photographed is shown below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Configuration of communication system 2; Figure 1) 1, the communication system 2 includes two APs (abbreviation of Access Point) 6 and 7, a terminal 10, and a printer 100. In this embodiment, it is assumed that a user uses the terminal 10 to establish a wireless connection between the printer 100 and the AP 6 according to the Wi-Fi method (hereinafter, referred to as "Wi-Fi connection").

[0014] (Terminal 10 Configuration) The terminal 10 is a portable terminal device such as a mobile phone (e.g., a smartphone), a PDA, or a tablet PC. In a modified example, the terminal 10 may be a stationary PC, a notebook PC, or the like. The terminal 10 includes a camera 15 and a Wi-Fi interface 16. Hereinafter, the interface is simply referred to as "I / F". The camera 15 is a device for photographing an object, and in this embodiment, it is used to photograph QR codes for the APs 6 and 7 and the printer 100 in particular. The terminal 10 also stores a connection application 40 (hereinafter, simply referred to as "app 40"). The app 40 is a program for establishing a Wi-Fi connection between the printer 100 and an AP (e.g., AP 6), and is installed in the terminal 10 from a server on the Internet provided by the vendor of the printer 100, for example.

[0015] The Wi-Fi I / F 16 is a wireless interface for performing Wi-Fi communication according to the Wi-Fi method. The Wi-Fi method is a wireless communication method for performing wireless communication according to, for example, the IEEE (The Institute of Electrical and Electronics Engineers, Inc.) 802.11 standard and standards equivalent thereto (for example, 802.11a, 11b, 11g, 11n, 11ac, etc.). In particular, the Wi-Fi I / F 16 supports the DPP (abbreviation of Device Provisioning Protocol) method that is to be formulated by the Wi-Fi Alliance. The DPP method is described in "Device Provisioning Protocol Technical Specification Version 1.1," a specification created by the Wi-Fi Alliance, and is a wireless communication method for easily establishing a Wi-Fi connection between a pair of devices (for example, the printer 100 and the AP 6) using the terminal 10.

[0016] (Configuration of Printer 100) The printer 100 is a peripheral device (for example, a peripheral device of the terminal 10) capable of executing a printing function. The printer 100 includes an operation unit 112, a display unit 114, a Wi-Fi I / F 116, a print execution unit 118, and a control unit 130. Each unit 112 to 130 is connected to a bus line (reference numerals omitted).

[0017] The operation unit 112 has a plurality of keys. A user can input various instructions to the printer 100 by operating the operation unit 112. The display unit 114 is a display for displaying various information. The Wi-Fi I / F 116 is the same as the Wi-Fi I / F 16 of the terminal 10. That is, the Wi-Fi I / F 116 supports the DPP method. In addition, the Wi-Fi I / F 116 has a MAC address "abc". The print execution unit 118 has a printing mechanism such as an inkjet method or a laser method.

[0018] The control unit 130 includes a CPU 132 and a memory 134. The CPU 132 executes various processes in accordance with a program 136 stored in the memory 134. The memory 134 is configured by a volatile memory, a non-volatile memory, or the like.

[0019] (Outline of this embodiment; Figure 2) Next, an overview of this embodiment will be described with reference to Fig. 2. As described above, the terminal 10 and the printer 100 support the DPP method, and the AP 6 also supports the DPP method. In this embodiment, the devices 6, 10, and 100 execute communication according to the DPP method to establish a Wi-Fi connection between the printer 100 and the AP 6. In the following, for ease of understanding, the operations executed by the CPU of each device (e.g., CPU 132, etc.) will be described with the device (e.g., printer 100) as the subject, rather than the CPU as the subject.

[0020] At T5, the terminal 10 executes DPP-based Bootstrapping (hereinafter simply referred to as "BS") with the AP 6. The BS is a process in which the AP 6 provides the terminal 10 with information used in Authentication (hereinafter simply referred to as "Auth") at T10, which will be described later, in response to the terminal 10 photographing a QR code attached to the AP 6.

[0021] At T10, the terminal 10 uses the information already acquired at the BS at T5 to execute DPP-based Auth with the AP 6. This Auth is processing by which each of the terminal 10 and the AP 6 authenticates the other party of communication.

[0022] At T15, the terminal 10 executes a DPP-based Configuration (hereinafter, simply referred to as "Config") with the AP 6. The Config is a process for transmitting information for establishing a Wi-Fi connection between the printer 100 and the AP 6 to the AP 6. Specifically, the terminal 10 generates a first Configuration Object (hereinafter, the Configuration Object is simply referred to as "CO") for establishing a Wi-Fi connection between the printer 100 and the AP 6 in the Config, and transmits the first CO to the AP 6. As a result, the first CO is stored in the AP 6.

[0023] Next, in T20, the terminal 10 executes BS of the DPP method with the printer 100. The BS is a process in which, in response to the terminal 10 capturing an image of a QR code displayed on the printer 100, the printer 100 provides the terminal 10 with information used in Auth in T25, which will be described later.

[0024] In T25, the terminal 10 uses the information already acquired in the BS of T20 to execute DPP-based Auth with the printer 100. The Auth is a process in which the terminal 10 and the printer 100 each authenticate the other party in communication.

[0025] At T30, the terminal 10 executes a DPP-based Config with the printer 100. The Config is a process for transmitting information for establishing a Wi-Fi connection between the printer 100 and the AP 6 to the printer 100. In the Config, the terminal 10 generates a second CO for establishing a Wi-Fi connection between the printer 100 and the AP 6, and transmits the second CO to the printer 100. As a result, the second CO is stored in the printer 100.

[0026] At T35, the printer 100 and the AP 6 execute DPP-based Network Access (hereinafter, simply referred to as "NA") using the stored first and second COs. NA is a process for sharing a connection key for establishing a Wi-Fi connection between the printer 100 and the AP 6.

[0027] In T40, the printer 100 and the AP 6 execute 4way-handshake communication. In at least a part of the process of the 4way-handshake communication, the printer 100 and the AP 6 communicate encrypted information encrypted by the connection key shared in the NA of T35. If the encrypted information is successfully decrypted, a Wi-Fi connection is established between the printer 100 and the AP 6. This allows the printer 100 to participate as a slave station in the wireless network formed by the AP 6, and as a result, the printer 100 can communicate with other devices participating in the wireless network via the AP 6. In a modified example, the printer 100 and the AP 6 may execute SAE (short for Simultaneous Authentication of Equals, commonly known as "Dragonfly") communication instead of the 4way-handshake communication.

[0028] In the DPP method, in order to establish a Wi-Fi connection between the printer 100 and the AP 6, the user does not need to input information (such as SSID (short for Service Set Identifier), password, etc.) of the wireless network in which the AP 6 operates as a master station into the printer 100. Therefore, the user can easily establish a Wi-Fi connection between the printer 100 and the AP 6.

[0029] (Explanation of each process: Figures 3 to 9) Next, the details of each process executed at T20 to T35 in Fig. 2 will be described with reference to Figs. 3 to 9. Note that the processes at T5 to T15 are similar to the processes at T20 to T30 except that AP6 is used instead of printer 100, and detailed description thereof will be omitted. Also, an overview of BS is shown in Fig. 3, and its details are shown in Fig. 7. Fig. 8 also shows the case of BS executed between terminal 10 and printer 100. Figs. 3, 7, and 8 show the processes executed in one embodiment.

[0030] (Outline of Bootstrapping (BS); Fig. 3) First, an overview of the BS process at T20 in Fig. 2 will be described with reference to Fig. 3. In the initial state in Fig. 3, the memory 134 of the printer 100 prestores the public key PPK1 and private key psk1 of the printer 100. Furthermore, when the power of the printer 100 is turned on, the printer 100 starts operating in an impossible state, which will be described later.

[0031] In response to receiving an operation to start the application 40 from the user, the terminal 10 starts the application 40 in T100, and further starts the camera 15. Each of the subsequent processes executed by the terminal 10 is realized by the application 40. When the application 40 is started, the terminal 10 and the printer 100 execute processes of T102 to T112 in FIG. 7, which will be described later.

[0032] When the process of T112 ends, the printer 100 transitions from the impossible state to the possible state in T122. The impossible state is a state in which the Wi-Fi I / F 116 does not transmit a DPP Authentication Response (hereinafter simply referred to as "ARes") (see T210 described later) even if it receives a DPP Authentication Request (hereinafter simply referred to as "AReq") (see T200 in FIG. 4 described later) from the terminal 10. That is, the impossible state is a state in which ARes, which is a response to AReq, is not transmitted. The possible state is a state in which the Wi-Fi I / F 116 transmits ARes to the terminal 10 in response to receiving AReq from the terminal 10. That is, the printer 100 transitions from the impossible state to the possible state, thereby becoming a state in which Auth (see T25 in FIG. 2) can be executed. Specifically, in this embodiment, the impossible state is a state in which the Wi-Fi I / F 116 does not supply the signal to the CPU 132 even if it receives the signal from the outside. Moreover, the possible state is a state in which the Wi-Fi I / F 116 supplies the signal to the CPU 132 in response to receiving a signal from the outside and transmits a response to the signal. The possible state is a state in which the CPU 132 processes a signal received from the outside, and therefore has a higher processing load than the impossible state. Note that, in a modified example, the impossible state may be a state in which the Wi-Fi I / F 116 is not energized, and the possible state may be a state in which the Wi-Fi I / F 116 is energized. In another modified example, the impossible state may be a state in which the Wi-Fi I / F 116 does not supply a notification indicating that the AReq has been received to the CPU 132 even if the Wi-Fi I / F 116 receives an AReq from the outside, and the possible state may be a state in which the Wi-Fi I / F 116 supplies a notification indicating that the AReq has been received to the CPU 132 in response to receiving an AReq from the outside.

[0033] Next, in T124, the printer 100 displays a QR code on the display unit 114. The QR code is a code image obtained by encoding the public key PPK1 pre-stored in the memory 134, the channel list pre-stored in the memory 134, and the MAC address "abc" of the Wi-Fi I / F 116. The channel list is a list of values ​​of a plurality of communication channels to be used in Auth (see T25 in FIG. 2). The QR code may be generated by the printer 100 when the process of T124 is executed, or may be pre-stored in the memory 134 at the time of shipment of the printer 100.

[0034] In T132, the terminal 10 uses the camera 15 to capture an image of the QR code displayed on the printer 100. Then, in T134, the terminal 10 decodes the captured QR code and acquires the public key PPK1, the channel list, and the MAC address "abc."

[0035] (Authentication (Auth); Figure 4) Next, the Auth process at T25 in Fig. 2 will be described with reference to Fig. 4. In response to acquiring the public key PPK1 etc. at T134 in Fig. 3, the terminal 10 generates the public key TPK1 and secret key tsk1 of the terminal 10 at T141. Next, the terminal 10 generates a shared key SK1 using the generated secret key tsk1 and the acquired public key PPK1 according to ECDH (short for Elliptic curve Diffie-Hellman key exchange) at T142. Then, the terminal 10 encrypts a random value RV1 using the generated shared key SK1 at T144 to generate encrypted data ED1.

[0036] In T200, the terminal 10 transmits AReq to the printer 100 via the Wi-Fi I / F 16, with the MAC address "abc" acquired in T134 of FIG. 3 as the destination. AReq is a signal requesting the printer 100 to execute authentication. Here, the terminal 10 repeatedly transmits AReq to the printer 100 by sequentially using a plurality of communication channels in the channel list acquired in T134. The AReq includes the public key TPK1 of the terminal 10 generated in T141, the encrypted data ED1 generated in T144, and the capability of the terminal 10.

[0037] Capability is information that is specified in advance in a device that supports the DPP method, and includes one of the following values: a value indicating that the device can operate only as a Configurator in the DPP method; a value indicating that the device can operate only as an Enrollee in the DPP method; and a value indicating that the device can operate both as a Configurator and an Enrollee. Note that the Configurator refers to a device that transmits a CO to be used in the NA (T35 in FIG. 2) to the Enrollee in the Config (T30 in FIG. 2). On the other hand, the Enrollee refers to a device that receives a CO to be used in the NA from the Configurator in the Config. As described above, in this embodiment, the terminal 10 generates the first or second CO and transmits it to the AP 6 or the printer 100. Therefore, the capability of the terminal 10 includes a value indicating that the terminal 10 can operate only as a Configurator.

[0038] At T200, the printer 100 receives the AReq from the terminal 10 via the Wi-Fi I / F 116. As described above, the AReq is transmitted to the MAC address “abc” of the printer 100 as the transmission destination. Therefore, the printer 100 can appropriately receive the AReq from the terminal 10.

[0039] 3, the printer 100 monitors whether one of the communication channels in the channel list receives the AReq used. As described above, the AReq of T200 is transmitted by sequentially using the communication channels in the channel list. Therefore, the printer 100 can properly receive the AReq from the terminal 10.

[0040] Next, the printer 100 executes the following process to authenticate the sender of the AReq (i.e., the terminal 10). Specifically, first, in T202, the printer 100 generates a shared key SK1 according to ECDH using the public key TPK1 of the terminal 10 in the AReq and the private key psk1 of the printer 100 pre-stored in the memory 134. Here, the shared key SK1 generated by the terminal 10 in T142 is the same as the shared key SK1 generated by the printer 100 in T204. Therefore, in T204, the printer 100 can appropriately decrypt the encrypted data ED1 in the AReq using the generated shared key SK1, and as a result, can obtain the random value RV1. If the decryption of the encrypted data ED1 is successful, the printer 100 determines that the sender of the AReq is the device that captured the QR code displayed by the printer 100, that is, determines that the authentication has been successful, and executes the process from T206 onwards. On the other hand, if the printer 100 is not successful in decrypting the encrypted data ED1, it determines that the sender of the AReq is not the device that captured the image of the QR code displayed on the printer 100, i.e., it determines that authentication has failed, and does not execute the processing from T206 onwards.

[0041] In T206, the printer 100 generates a new public key PPK2 and a new private key psk2 of the printer 100. In a modified example, the public key PPK2 and the private key psk2 may be stored in advance in the memory 134. Next, in T207, the printer 100 generates a shared key SK2 using the public key TPK1 of the terminal 10 in the AReq of T200 and the private key psk2 of the printer 100 that has already been generated, according to ECDH. Then, in T208, the printer 100 encrypts the acquired random value RV1 and the new random value RV2 using the generated shared key SK2 to generate encrypted data ED2.

[0042] In T210, the printer 100 transmits an ARes to the terminal 10 via the Wi-Fi I / F 116. The ARes includes the public key PPK2 of the printer 100 generated in T206, the encrypted data ED2 generated in T208, and the capability of the printer 100. The capability includes a value indicating that the printer 100 can operate only as an Enrollee.

[0043] In response to receiving an ARes from the printer 100 via the Wi-Fi I / F 16 in T210, the terminal 10 executes the following process for authenticating the sender of the ARes (i.e., the printer 100). Specifically, first, in T212, the terminal 10 generates a shared key SK2 according to ECDH using the private key tsk1 of the terminal 10 generated in T141 and the public key PPK2 of the printer 100 in the ARes. Here, the shared key SK2 generated by the printer 100 in T207 is the same as the shared key SK2 generated by the terminal 10 in T212. Therefore, in T214, the terminal 10 can appropriately decrypt the encrypted data ED2 in the ARes using the generated shared key SK2, and as a result, can obtain the random values ​​RV1 and RV2. If the decryption of the encrypted data ED2 is successful, the terminal 10 determines that the sender of the ARes is a device that has displayed a photographed QR code, that is, determines that authentication has been successful, and executes the processes from T220 onward. On the other hand, if the decryption of the encrypted data ED2 is not successful, the terminal 10 determines that the sender of the ARes is not a device that has displayed a photographed QR code, that is, determines that authentication has failed, and does not execute the processes from T220 onward.

[0044] In T220, the terminal 10 transmits a Confirm to the printer 100 via the Wi-Fi I / F 16. The Confirm includes information indicating that the terminal 10 operates as a Configurator and the printer 100 operates as an Enrollee. As a result, in T222, the terminal 10 decides to operate as a Configurator, and in T224, the printer 100 decides to operate as an Enrollee. When the process of T224 ends, the process of FIG. 4 ends.

[0045] (Configuration(Config); Figure 5) Next, the Config process of T30 in Fig. 2 will be described with reference to Fig. 5. In T300, the printer 100 transmits a DPP Configuration Request (hereinafter, simply referred to as "CReq") to the terminal 10 via the Wi-Fi I / F 116. The CReq is a signal requesting the transmission of a CO (i.e., information for establishing a Wi-Fi connection between the printer 100 and the AP 6).

[0046] In T300, the terminal 10 receives CReq from the printer 100 via the Wi-Fi I / F 16. In this case, in T301, the terminal 10 acquires the group ID "Group1", the public key TPK2, and the private key tsk2 from the memory (not shown) of the terminal 10. As described above, the terminal 10 has already executed the Config of T15 in FIG. 2 with the AP 6, and at this time, the terminal 10 generates the group ID "Group1", the public key TPK2, and the private key tsk2 and stores them in the memory. The group ID "Group1" is information for identifying a wireless network formed by establishing a Wi-Fi connection between the printer 100 and the AP 6. In addition, in a modified example, a character string designated by a user may be used as the group ID. That is, in T301, the terminal 10 acquires each piece of information stored in T15 in FIG. 2. Next, in T302, the terminal 10 generates a second CO (see T30 in FIG. 2). Specifically, the terminal 10 executes the following processes.

[0047] The terminal 10 generates a hash value HV by hashing the public key TPK2 of the terminal 10. The terminal 10 also generates a specific value by hashing a combination of the hash value HV, the group ID "Group1", and the public key PPK2 of the printer 100 in the ARes of T210 in FIG. 4. The terminal 10 then generates an electronic signature DS1 by encrypting the generated specific value using the private key tsk2 of the terminal 10 according to ECDSA (short for Elliptic Curve Digital Signature Algorithm). As a result, the terminal 10 can generate a Signed-Connector for the printer (hereinafter, the Signed-Connector will be simply referred to as "SCont") including the hash value HV, the group ID "Group1", the public key PPK2 of the printer 100, and the electronic signature DS1. The terminal 10 then generates a second CO including the SCont for the printer and the public key TPK2 of the terminal 10.

[0048] At T310, the terminal 10 transmits a DPP Configuration Response (hereinafter simply referred to as “CRes”) including the second CO to the printer 100 via the Wi-Fi I / F 16.

[0049] In T310, the printer 100 receives CRes from the terminal 10 via the Wi-Fi I / F 116. In this case, in T312, the printer 100 stores the second CO in the CRes in the memory 134. When the process of T312 ends, the process of FIG. 5 ends.

[0050] (Network Access (NA); Figure 6) Next, referring to FIG. 6, the process of NA at T35 in FIG. 2 executed between the printer 100 and the AP6 will be described. As described above, the processes at T5 to T15 in FIG. 2 have been executed between the terminal 10 and the AP6, similar to T20 to T30 in FIG. 2. However, the AP6 does not execute the processes at T102 to T124 in FIG. 7, which will be described later. The AP6 stores the public key APK1 and the secret key ask1 of the AP6 in advance. A QR code obtained by encoding the public key APK1 of the AP6, the channel list of the AP6, and the MAC address of the AP6 is attached to the housing of the AP6. The terminal 10 photographs the QR code, and the processes similar to the processes after T134 are executed between the terminal 10 and the AP6. As a result, the AP6 stores the public key APK2 and the secret key ask2 of the AP6 (see T206 in FIG. 4), and further stores the first CO received from the terminal 10 (see T312 in FIG. 5). The first CO includes the AP SCont and the public key TPK2 of the terminal 10. The public key TPK2 is the same as the public key TPK2 included in the second CO. The AP SCont also includes a hash value HV, a group ID "Group1", a public key APK2 of the AP6, and an electronic signature DS2. The hash value HV and the group ID "Group1" are the same as the hash value HV and the group ID "Group1" included in the second CO, respectively. The electronic signature DS2 is information obtained by hashing a combination of the hash value HV, the group ID "Group1", and the public key APK2, and encrypting the specific value with the private key tsk2 of the terminal 10, and is a value different from the electronic signature DS1 included in the second CO.

[0051] In T400, the printer 100 transmits a DPP Peer Discovery Request (hereinafter, simply referred to as "DReq") including the SCont for the printer to the AP 6 via the Wi-Fi I / F 116. The DReq is a signal requesting the AP 6 to perform authentication and transmit the SCont for the AP.

[0052] In response to receiving the DReq from the printer 100 in T400, the AP 6 executes a process for authenticating the sender of the DReq (i.e., the printer 100) and each piece of information in the DReq (i.e., the hash value HV, "Group1", and the public key PPK2). Specifically, in T402, the AP 6 first executes a first AP determination process as to whether or not the hash value HV and the group ID "Group1" in the received printer-specific SCont match the hash value HV and the group ID "Group1" in the AP-specific SCont included in the stored first CO. In the case of FIG. 6, the AP 6 determines that they "match" in the first AP determination process, and therefore determines that the authentication of the sender of the DReq (i.e., the printer 100) has been successful. Incidentally, the fact that the hash value HV in the received SCont for the printer matches the hash value HV in the SCont for the AP included in the stored first CO means that the SCont for the printer and the SCont for the AP are generated by the same device (i.e., the terminal 10). Therefore, the AP 6 also judges that the authentication of the generator (i.e., the terminal 10) of the received SCont for the printer has been successful. Furthermore, the AP 6 decrypts the electronic signature DS1 in the received SCont for the printer using the public key TPK2 of the terminal 10 included in the stored first CO. In the case of FIG. 6, since the decryption of the electronic signature DS1 is successful, the AP 6 executes the second AP judgment process regarding whether or not the specific value obtained by decrypting the electronic signature DS1 matches the value obtained by hashing each piece of information in the received SCont for the printer (i.e., the hash value HV, "Group1", and the public key PPK2). 6, since the AP6 judges that the second AP judgment process "matches," it judges that the authentication of each piece of information in the DReq was successful and executes the processes from T404 onward. The judgment that the second AP judgment process "matches" means that the information in the received printer-SCont (i.e., the hash value HV, "Group1," and the public key PPK2) has not been tampered with by a third party after the second CO was stored in the printer 100.On the other hand, if the first AP judgment process determines that there is no match, if decryption of electronic signature DS1 fails, or if the second AP judgment process determines that there is no match, AP6 determines that authentication has failed and does not execute processing after T404.

[0053] Next, in T404, the AP6 generates a connection key (ie, a shared key) CK using the acquired public key PPK2 of the printer 100 and the stored private key ask2 of the AP6 according to ECDH.

[0054] At T410, the AP 6 transmits a DPP Peer Discovery Response (hereinafter simply referred to as “DRes”) including the SCont for the AP to the printer 100.

[0055] In response to receiving the DRes from the AP6 via the Wi-Fi I / F 116 in T410, the printer 100 executes a process for authenticating the sender of the DRes (i.e., the AP6) and each piece of information in the DRes (i.e., the hash value HV, “Group1”, and the public key APK2). Specifically, in T412, the printer 100 first executes a first PR determination process regarding whether or not the hash value HV and the group ID “Group1” in the received AP-SCont match the hash value HV and the group ID “Group1” in the printer-SCont included in the stored second CO. In the case of FIG. 6, the printer 100 determines that they “match” in the first PR determination process, and therefore determines that the authentication of the sender of the DRes (i.e., the AP6) has been successful. In addition, if the hash value HV in the received SCont for AP and the hash value HV in the SCont for printer included in the stored second CO match, it means that the SCont for printer and the SCont for AP are generated by the same device (i.e., the terminal 10). Therefore, the printer 100 also determines that the authentication of the generator (i.e., the terminal 10) of the received SCont for AP is successful. Furthermore, the printer 100 decrypts the electronic signature DS2 in the received SCont for AP using the public key TPK2 of the terminal 10 included in the stored second CO. In the case of FIG. 6, since the decryption of the electronic signature DS2 is successful, the printer 100 executes the second PR determination process regarding whether or not the specific value obtained by decrypting the electronic signature DS2 matches the value obtained by hashing each piece of information in the received SCont for AP (i.e., the hash value HV, "Group1", and the public key APK2). 6, the printer 100 judges that there is a "match" in the second PR judgment process, and therefore judges that the authentication of each piece of information in the DRes has been successful, and executes the processes from T414 onward. The fact that there is a "match" in the second PR judgment process means that the information in the AP SCont (i.e., the hash value HV, "Group1", and the public key APK2) has not been tampered with by a third party after the first CO was stored in the AP6.On the other hand, if the first PR judgment process determines that there is no match, if the decryption of the electronic signature DS2 fails, or if the second PR judgment process determines that there is no match, the printer 100 determines that the authentication has failed and does not execute the processing after T414.

[0056] In T414, the printer 100 generates a connection key CK according to ECDH using the stored private key psk2 of the printer 100 and the public key APK2 of the AP 6 in the received SCont for AP. Here, the connection key CK generated by the AP 6 in T404 is the same as the connection key CK generated by the printer 100 in T414. As a result, the connection key CK for establishing a Wi-Fi connection is shared between the printer 100 and the AP 6. When T414 ends, the process of FIG. 6 ends.

[0057] As described above, after the connection key CK is shared between the printer 100 and the AP 6, in T40 of FIG. 2, the printer 100 and the AP 6 execute 4-way-handshake communication using the connection key CK. As a result, a Wi-Fi connection is established between the printer 100 and the AP 6. As described above, the printer 100 receives the AReq of T200 of FIG. 4 from the terminal 10 using one of the communication channels included in the channel list of the printer 100. That is, the printer 100 receives the AReq of T200 from the terminal 10 using a communication channel available to both the printer 100 and the terminal 10. On the other hand, in T40 of FIG. 2, the printer 100 establishes a Wi-Fi connection with the AP 6 using a communication channel available to both the printer 100 and the AP 6. Here, the communication channel available to the terminal 10 and the communication channel available to the AP 6 may be different. In this embodiment, the communication channel through which the printer 100 receives the AReq from the terminal 10 at T200 in Fig. 4 is different from the communication channel through which the printer 100 establishes a Wi-Fi connection with the AP 6 at T40 in Fig. 2. However, in a modified example, the former communication channel and the latter communication channel may be the same.

[0058] (Details of Bootstrapping (BS); Figure 7) Next, the BS in Fig. 3 will be described in detail with reference to Fig. 7. In particular, the processes of T102 to T112 will be described.

[0059] When the terminal 10 starts the application 40 in T100, the terminal 10 broadcasts a PReq via the Wi-Fi I / F 16 in T102. The PReq includes the SSID "DISPLAY" that is predetermined in the application 40. Note that the character string of the SSID in the PReq is not limited to "DISPLAY" and may be any character string that can be interpreted by the printer 100.

[0060] When the printer 100 receives the PReq from the terminal 10 via the Wi-Fi I / F 116 in T102, the printer 100 acquires the SSID "DISPLAY" from the Wi-Fi I / F 116. In this case, the printer 100 executes the process from T104 onwards, since the SSID included in the received PReq contains the predetermined character string "DISPLAY". If the SSID does not contain the predetermined character string "DISPLAY", the printer 100 skips the process from T104 onwards and ends the process in FIG. 7.

[0061] In T104, the printer 100 judges whether the second CO is stored in the memory 134. As described above, when the Config process with the terminal 10 is executed, the printer 100 stores the second CO in the memory 134 (see T312 in FIG. 5) and executes NA with the AP using the second CO (see FIG. 6). That is, the fact that the second CO is stored in the memory 134 means that NA is executed between the printer 100 and the AP (for example, AP7 different from AP6) and a Wi-Fi connection has already been established between the printer 100 and the AP. When the printer 100 judges that the second CO is stored in the memory 134, that is, that a Wi-Fi connection has already been established between the printer 100 and the AP (YES in T104), the printer 100 proceeds to T108. On the other hand, if the second CO is not stored in the memory 134, that is, if the printer 100 has not established a Wi-Fi connection with any AP (NO in T104), the printer 100 proceeds to T106.

[0062] In T106, the printer 100 judges whether the state of the printer 100 is the default state. The default state is a state in which a default password is stored in the memory 134 as a password for authenticating a user. The default password is stored in advance in the memory 134 at the time of shipment of the printer 100, and is described, for example, in the instruction manual of the printer 100. The default password is used to log in to the printer 100. Specifically, the printer 100 operates as a server on a wired LAN (abbreviation of Local Area Network). When the printer 100 receives a login request from a terminal (e.g., 10) via the wired LAN, the printer 100 causes the terminal to display a password input screen. When the password entered in the password input screen matches the default password, the terminal completes the login to the printer 100. In the login state, the terminal can access the printer 100 and display a change screen for changing the settings of the printer 100 (e.g., the default password, values ​​related to network settings, etc.). For example, when a new password is entered on the change screen, the terminal transmits the new password to the printer 100. This causes the printer 100 to store the new password in memory 134 instead of the default password. When the new password is stored in memory 134, only users who know the new password can change the settings of the printer 100.

[0063] When the printer 100 determines that the state of the printer 100 is the default state (YES in T106), it skips the processes of T108 to T112, which will be described later, and executes the process of T122. On the other hand, when the printer 100 determines that the state of the printer 100 is not the default state, that is, that the new password is stored in the memory 134 (NO in T106), it proceeds to T108.

[0064] In T108, the printer 100 displays on the display unit 114 a notification screen that notifies the user that the printer 100 is ready to accept the input of a password.

[0065] In T110, the printer 100 accepts input of a password by the user operating a plurality of keys on the operation unit 112.

[0066] In T112, the printer 100 performs authentication using the password entered in T110. If the entered password matches the password in the memory 134, the printer 100 determines that the authentication has been successful (YES in T112) and proceeds to T122. As a result, as described above, the printer 100 becomes ready (T122), the QR code is displayed (T124), and BS with the terminal 10 is executed. On the other hand, if the entered password does not match the password in the memory 134, the printer 100 determines that the authentication has failed (NO in T112), skips the processing from T122 onwards, and the processing in FIG. 7 ends. In other words, BS with the terminal 10 is not executed.

[0067] According to this configuration, if authentication using the entered password is successful (YES in T112), the printer 100 displays a QR code obtained by encoding the public key PPK1 (T124). On the other hand, if authentication using the entered password is unsuccessful (NO in T112), the printer 100 does not display a QR code. As a result, the processes after BS are not executed. This makes it possible to prevent a Wi-Fi connection from being established between the printer 100 and the AP 6 when a third party other than the user of the printer 100 (i.e., a user who does not know the password) uses the terminal 10.

[0068] Furthermore, according to this configuration, if authentication using the entered password is successful (YES in T112), the printer 100 transitions the state of the printer 100 to the available state (T122). On the other hand, if authentication using the entered password fails (NO in T112), the printer 100 maintains the state of the printer 100 in the unavailable state. That is, if password authentication fails, the ARes in response to the AReq from the terminal 10 is not transmitted, and the Auth process is not completed. As a result, a Wi-Fi connection is not established between the printer 100 and the AP 6. This makes it possible to prevent a third party other than the user of the printer 100 (i.e., a user who does not know the password) from using the terminal 10 from establishing a Wi-Fi connection between the printer 100 and the AP 6.

[0069] Furthermore, when the second CO is stored in memory 134 and authentication using the entered password is successful (YES in T104 and YES in T112), printer 100 transitions to a possible state and displays a QR code (T122, T124). That is, in a situation where a Wi-Fi connection has already been established between printer 100 and an AP (particularly another AP), the user needs to input a password to transition to the possible state and display the QR code. This makes it possible to prevent a Wi-Fi connection with another AP 6 from being established without permission, for example, in a situation where a Wi-Fi connection has already been established between printer 100 and AP 7.

[0070] Furthermore, if the state of the printer 100 is not the default state and authentication using the entered password is successful (YES in T106 and YES in T112), the printer 100 transitions to an available state and displays a QR code (T122, T124). The fact that a new password is stored in the memory 134 means that use of the printer 100 is restricted by the user who entered the new password. In a situation where use of the printer 100 is restricted, it is possible to prevent a Wi-Fi connection to an AP (e.g. AP6) from being established without permission.

[0071] Furthermore, if the second CO is not stored in the memory 134 and the printer 100 is in the default state (NO in T104 and NO in T106), the printer 100 does not accept password input, transitions to a possible state, and displays a QR code (T122, T124). This means that the printer 100 has not established a Wi-Fi connection with any AP, and furthermore, a default password is stored in the memory 134. In other words, it is highly likely that the printer 100 is in the shipping state. In this case, eliminating the need to input a password can improve user convenience.

[0072] Furthermore, when the printer 100 receives a PReq including the SSID "DISPLAY" from the terminal 10 (T102 in FIG. 7), the printer 100 displays a notification screen (T108). With this configuration, the user can know that he or she must enter a password just by starting the application 40 of the terminal 10 without operating the printer 100.

[0073] (When the QR code is not photographed: Figure 8) Next, processing of another case of BS will be described with reference to Fig. 8. In this case, it is assumed that the QR code displayed on the printer 100 is not photographed by the terminal 10. This case is a continuation of Fig. 6. That is, a second CO is stored in the memory 134 of the printer 100.

[0074] T500 and T502 are the same as T100 and T102 in FIG. 7. In T504, the printer 100 determines that the second CO is stored in the memory 134 (YES in T104 in FIG. 7). T508 and T510 are the same as T108 and T110 in FIG. 7. In T512, the printer 100 determines that the authentication of the password entered in T510 has been successful (YES in T112). T522 and T524 are the same as T122 and T124 in FIG. 7. In this case, the AReq (see T200 in FIG. 4) is not transmitted from the terminal 10 to the printer 100 because the QR code displayed on the printer 100 is not photographed by the terminal 10. In this case, the printer 100 determines in T526 that it has not received AReq within a predetermined time after transitioning to the possible state in T522, and transitions from the possible state to the impossible state in T528. This can prevent the printer 100 from remaining in the available state for a long period of time. That is, it can prevent the state in which the Wi-Fi I / F 116 supplies a signal received from the outside to the CPU 132, that is, the state in which the CPU 132 processes a signal received from the outside, from continuing. This can reduce the processing load of the printer 100. Then, in T530, the printer 100 displays an error screen on the display unit 114 indicating that AReq was not received from the terminal 10. When the processing of T530 ends, the processing of FIG. 8 ends.

[0075] (Correspondence) The printer 100, the terminal 10, and the AP 6 are examples of a "communication device," a "first external device," and a "second external device," respectively. The display unit 114 and the Wi-Fi I / F 116 are examples of an "output unit" and a "wireless interface," respectively. The password is an example of "user authentication information." The public key PPK1 and the QR code of the printer 100 are examples of a "public key" and "specific information," respectively. The AReq, ARes, and the second CO of T310 in FIG. 5 are examples of an "authentication request," an "authentication response," and a "first connection information," respectively. The Wi-Fi connection established at T40 in FIG. 2 is an example of a "first wireless connection."

[0076] The AP7, the second CO stored in the memory 134 in the Config with the AP7, and the Wi-Fi connection with the AP7 are examples of the "third external device", the "second connection information", and the "second wireless connection", respectively. The default state and the state in which a new password is stored in the memory 134 are examples of the "first state" and the "second state", respectively. The channel list, the communication channel used in T200 in FIG. 4, and the communication channel used in T40 in FIG. 2 are examples of the "communication channel information", the "first communication channel", and the "second communication channel", respectively. The passage of a predetermined time in T526 in FIG. 8 is an example of the "specific condition". The SCont for the AP and the hash value HV in the second CO are examples of the "reception information" and the "authentication information", respectively.

[0077] T110 and T124 in FIG. 7, T200 and T210 in FIG. 4, T310 in FIG. 5, and T40 in FIG. 2 are examples of processing executed by the "reception unit," the "first output control unit," the "authentication request receiving unit," the "authentication response transmitting unit," the "connection information receiving unit," and the "establishment unit," respectively.

[0078] T110 and T122 in FIG. 7, T200 and T210 in FIG. 4, T310 in FIG. 5, and T40 in FIG. 2 are examples of processing executed by the “reception unit”, the “first state transition unit”, the “authentication request reception unit”, the “authentication response transmission unit”, the “connection information reception unit”, and the “establishment unit”, respectively.

[0079] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. Modifications of the above-mentioned embodiments are listed below.

[0080] (Variation 1) For example, the QR code displayed on the printer 100 at T124 in Fig. 7 does not have to be an encoded version of the channel list and the MAC address "abc". That is, the QR code only needs to be a code image obtained by encoding at least the public key PPK1. In this case, in response to the transition from the impossible state to the possible state at T122, the printer 100 monitors whether one of all wireless channels available to the printer 100 receives the used AReq. Also, in T200 in Fig. 4, the terminal 10 sequentially transmits the AReq by broadcast, sequentially using all wireless channels available to the terminal 10. That is, the "specific information" only needs to be information obtained using at least the public key.

[0081] (Variation 2) The process (e.g., T142, T202 in FIG. 4) for generating a shared key (e.g., SK1) is not limited to the process according to ECDH in the above embodiment, but may be other processes according to ECDH. Also, the process for generating a shared key is not limited to the process according to ECDH, but may be processes according to other methods (e.g., DH (abbreviation of Diffie-Hellman key exchange) etc.). Also, in the above embodiment, the digital signatures DS1 and DS2 were generated according to ECDSA, but may be generated according to other methods (e.g., DSA (abbreviation of Digital Signature Algorithm), RAS (abbreviation of Rivest-Shamir-Adleman cryptosystem), etc.).

[0082] (Variation 3) For example, in T102 of FIG. 7, the terminal 10 may transmit a Service Discovery Request of the WFD method to the printer 100 instead of the PReq. The request includes information for inquiring whether the printer 100 is capable of displaying a QR code. In this variation, the Service Discovery Request is an example of a "specific signal." In another variation, the terminal 10 may transmit a signal using a method other than the Wi-Fi method (for example, an NFC (short for Near Field Communication) method, a Bluetooth (registered trademark) method, etc.) to the printer 100 instead of the PReq. In this variation, the signal using the other method is an example of a "specific signal."

[0083] (Variation 4) In the above embodiment, when the printer 100 receives a PReq from the terminal 10, the printer 100 displays a notification screen (T108 in FIG. 7). Alternatively, the printer 100 may display a notification screen when a predetermined operation is performed on the operation unit 112. In this variation, the "specific signal receiving unit" can be omitted. In another variation, instead of the notification screen, the printer 100 may output a sound notifying the user that password input is acceptable, or may turn on a light indicating the notification. In this variation, outputting a sound and turning on a light are examples of processing realized by the "notification unit."

[0084] (Variation 5) In the above embodiment, the printer 100 determines whether or not the second CO is stored in the memory 134 (T104 in FIG. 7). Alternatively, the printer 100 may determine whether or not the SSID and password used to establish a Wi-Fi connection with the AP 7 are stored in the memory 134. In this variation, the SSID and password are an example of the "second connection information."

[0085] (Variation 6) The process of T104 in Fig. 7 does not have to be executed. In this variation, the "second connection information" can be omitted.

[0086] (Variation 7) In the above embodiment, the printer 100 judges whether the state of the printer 100 is the default state (T106 in FIG. 7). Alternatively, for example, at the shipping stage of the printer 100, the password may not be stored in the memory 134. The printer 100 may not display the notification screen when the password is not stored in the memory 134, and may display the notification screen when the password is stored in the memory 134. In this variation, the state where the password is not stored and the state where the password is stored are examples of the "first state" and the "second state", respectively. In another variation, the printer 100 may store either of the setting "ON" that restricts the use of the print function by a specific user and the setting "OFF" that does not restrict the use of the print function by a specific user. The printer 100 may not display the notification screen when the setting "OFF" is stored, and may display the notification screen when the setting "ON" is stored. In this modified example, the state in which the setting "OFF" is stored and the state in which the setting "ON" is stored are examples of the "first state" and the "second state", respectively.

[0087] (Modification 8) The process of T106 in Fig. 7 does not have to be executed. In this modification, the "first state" and the "second state" can be omitted.

[0088] (Modification 9) In the above embodiment, the printer 100 starts operation in the impossible state when the printer 100 is powered on. Then, when the printer 100 receives a PReq from the terminal 10 and determines that the second CO is stored in the memory 134 (YES in T104), the printer 100 transitions from the impossible state to the possible state (T122). Alternatively, the printer 100 may determine whether to operate in the impossible state or the possible state when the printer 100 is powered on. For example, the printer 100 may start operation in the possible state when it determines that the second CO is not stored in the memory 134, and start operation in the impossible state when it determines that the second CO is stored in the memory 134. Then, when the printer 100 receives a PReq from the terminal 10 and the second CO is not stored in the memory 134, the printer 100 may maintain operation in the possible state without displaying a notification screen, and when the printer 100 receives a PReq from the terminal 10 and the second CO is stored in the memory 134, the printer 100 may display a notification screen and transition from the impossible state to the possible state depending on the subsequent authentication success. Note that whether the printer 100 operates in the impossible state or the possible state may be determined based on whether the printer 100 is in the default state. In this modified example, maintaining operation in the possible state is an example of an "operation control unit."

[0089] (Modification 10) For example, in T124 of FIG. 7, the printer 100 may cause the print execution unit 118 to print the QR code on a print medium instead of displaying the QR code on the display unit 114. According to this modification, even in a situation where the printer 100 does not have the display unit 114, for example, it is possible to execute communication according to the DPP method and establish a Wi-Fi connection between the printer 100 and the AP 6. In this modification, the print execution unit 118 is an example of an "output unit". In another modification, the printer 100 may have a wireless interface (e.g., NFC I / F, Bluetooth I / F) different from the Wi-Fi I / F 116. Note that the Bluetooth I / F includes a wireless interface for executing communication according to Bluetooth version 4.0 or higher. In this case, the printer 100 may transmit the public key PPK1, the channel list, and the MAC address "abc" to the terminal 10 via the wireless interface in T124. In this modification, the wireless interface different from the Wi-Fi I / F 116 is an example of an "output unit". In this modified example, the "specific information" does not have to be a "code image."

[0090] (Variation 11) The standard "Device Provisioning Protocol Technical Specification Version 1.1" created by the Wi-Fi Alliance states that a shared code, key, phrase, and word are called a "code." Therefore, in T124, printer 100 may display on display unit 114, instead of the QR code, an image including a shared code, key, phrase, and word obtained by encoding public key PPK1, a channel list, and MAC address "abc."

[0091] 2, NA processing may be executed between the terminal 10 and the printer 100, and a Wi-Fi connection may be established between the terminal 10 and the printer 100. In other words, the "second external device" may be the same device as the "first external device."

[0092] (Variation 13) The process of FIG. 8 does not need to be executed. That is, printer 100 does not need to transition from the possible state to the impossible state when a predetermined time has elapsed since transitioning to the possible state. In this variation, the "second state transition unit" can be omitted. Also, in another variation, in T526 of FIG. 8, printer 100 may monitor for receipt of an instruction from the user indicating a transition to the impossible state, instead of monitoring for the passage of a predetermined time. In this variation, receipt of an instruction from the user is an example of a "specific condition."

[0093] (Modification 14) In the above embodiment, a Wi-Fi connection is established between the printer 100 and the AP 6 using the terminal 10. Instead of this, for example, a Wi-Fi connection may be established between the printer 100 operating as a G / O (abbreviation for Group Owner) in the WFD system (i.e., a device operating as a parent station) and another device (i.e., a device operating as a child station) using the terminal 10. In other words, the "second external device" does not have to be a "parent station device."

[0094] (Variation 15) The "communication device" does not have to be a printer, but may be other devices such as a scanner, a multi-function device, a mobile terminal, a PC, or a server.

[0095] (Variation 16) The processes of T102 and T122 in FIG. 7 do not need to be executed. In this variation, printer 100 may always operate in a possible state. Printer 100 may display a notification screen when a predetermined operation (e.g., an operation for logging in) is performed on operation unit 112, and may display a QR code if authentication is successful. In this variation, the process realized by the "reception unit" may be executed in response to a predetermined operation being performed on printer 100, and the "first state transition unit" may be omitted.

[0096] (Variation 17) The processes of T102 and T124 in FIG. 7 do not need to be executed. In this variation, printer 100 may display a notification screen when a predetermined operation (e.g., an operation for logging in) is performed on operation unit 112. After printer 100 becomes ready due to successful authentication, terminal 10 may photograph a QR code affixed to the housing of printer 100 and acquire public key PPK1, etc. In this variation, the process realized by the "reception unit" may be executed in response to a predetermined operation being performed on printer 100, and the "first display control unit" may be omitted.

[0097] (Variation 18) The process realized by the "reception unit" is not limited to the process of inputting a password to the operation unit 112 of the printer 100 (T110 in FIG. 7). For example, the password may be stored in an IC card, and the password may be input to the printer 100 by a card reader of the printer 100 reading the password from the IC card. Also, the password may be stored in a terminal, and the printer 100 may receive the password from the terminal, and the password may be input to the printer 100. Here, the password may be received using a wireless connection according to various communication methods such as the NFC method, the Bluetooth method, or the WFD (short for Wi-Fi Direct (registered trademark)) method.

[0098] (Modification 19) In the above embodiments, the processes in FIGS. 2 to 8 are implemented by software (i.e., program 136), but at least one of these processes may be implemented by hardware such as a logic circuit.

[0099] In addition, the technical elements described in this specification or drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies exemplified in this specification or drawings achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful. The features of the technology disclosed in this specification are listed below. (Item 1) 1. A communication device, comprising: An output unit; A wireless interface; a reception unit that receives an input of user authentication information for authenticating a user of the communication device; a first output control unit that causes the output unit to output specific information obtained by using a public key when authentication using the input user authentication information is successful, and when authentication using the input user authentication information is unsuccessful, the specific information is not output by the output unit, and the public key is acquired by a first external device by outputting the specific information; and an authentication request receiving unit that receives an authentication request using the public key from the first external device via the wireless interface after the specific information is output; an authentication response transmission unit that, when the authentication request is received from the first external device, transmits an authentication response, which is a response to the authentication request, to the first external device via the wireless interface; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A communication device comprising: (Item 2) the reception unit receives an input of the user authentication information when second connection information for establishing a second wireless connection between the communication device and a third external device via the wireless interface is stored in a memory of the communication device; The first output control unit is when the second connection information is stored in the memory and authentication using the user authentication information is successful, outputting the specific information to the output unit; 2. The communication device according to claim 1, wherein, if the second connection information is not stored in the memory, the output unit is caused to output the specific information without accepting input of the user authentication information. (Item 3) the receiving unit receives an input of the user authentication information when a state of the communication device is a second state of a first state in which use of the communication device is not restricted and a second state in which use of the communication device is restricted; The first output control unit is when the state of the communication device is the second state and authentication using the user authentication information is successful, causing the output unit to output the specific information; 3. The communication device according to claim 1, wherein when the communication device is in the first state, the communication device causes the output unit to output the specific information without accepting an input of the user authentication information. (Item 4) 4. The communication device according to any one of claims 1 to 3, wherein the specific information is a code image obtained by encoding the public key. (Item 5) The code image is a QR code (registered trademark), 5. The communication device according to item 4, wherein the public key is obtained by the first external device in response to the QR code being photographed by the first external device. (Item 6) the output unit is a display unit for displaying an image, 6. The communication device according to any one of items 1 to 5, wherein the first output control unit causes the specific information to be displayed on the output unit, which is the display unit. (Item 7) The communication device further comprises: a first state transition unit that transitions a state of the communication device from an impossible state to a possible state when authentication using the input user authentication information is successful, and when authentication using the input user authentication information is unsuccessful, the state of the communication device is maintained in the impossible state, the impossible state being a state in which the authentication response is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from the first external device; The communication device according to any one of items 1 to 6, wherein the authentication response sending unit sends the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device is transitioned to the possible state. (Item 8) the specific information is information obtained by using the public key and communication channel information indicating a first communication channel that is predetermined in the communication device, The identification information is output, whereby the communication channel information is acquired by the first external device; the possible state is a state in which the authentication device monitors whether the authentication request is received from the first external device using the first communication channel, and transmits the authentication response to the first external device in response to receiving the authentication request from the first external device; The communication device described in item 7, wherein the authentication response sending unit sends the authentication response to the first external device via the wireless interface when the authentication request using the first communication channel is received from the first external device after the state of the communication device is transitioned to the possible state. (Item 9) 1. A communication device, comprising: A wireless interface; a reception unit that receives an input of user authentication information for authenticating a user of the communication device; a first state transition unit that transitions a state of the communication device from an impossible state to a possible state when authentication using the input user authentication information is successful, and when authentication using the input user authentication information fails, the state of the communication device is maintained in the impossible state, the impossible state being a state in which an authentication response that is a response to an authentication request is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from the first external device; an authentication request receiving unit that receives the authentication request from the first external device via the wireless interface; an authentication response transmission unit that transmits the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device is transitioned to the available state; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A communication device comprising: (Item 10) the reception unit receives an input of the user authentication information when second connection information for establishing a second wireless connection between the communication device and a third external device via the wireless interface is stored in a memory of the communication device; The first state transition unit is transitioning a state of the communication device from the unavailable state to the available state when the second connection information is stored in the memory and authentication using the user authentication information is successful; The communication device further comprises: 10. The communication device according to item 9, further comprising an operation control unit that, when the second connection information is not stored in the memory, operates the communication device in the possible state without accepting input of the user authentication information. (Item 11) the receiving unit receives an input of the user authentication information when a state of the communication device is a second state of a first state in which use of the communication device is not restricted and a second state in which use of the communication device is restricted; The first state transition unit is when the state of the communication device is the second state and authentication using the user authentication information is successful, transitioning the state of the communication device from the impossible state to the possible state; The communication device further comprises: 11. The communication device according to item 9 or 10, further comprising an operation control unit that, when the state of the communication device is the first state, operates the communication device in the possible state without accepting input of the user authentication information. (Item 12) the possible state is a state in which the communication device monitors whether the authentication request is received from the first external device using a first communication channel that is predetermined in the communication device, and transmits the authentication response to the first external device in response to receiving the authentication request from the first external device; The communication device according to any one of items 9 to 11, wherein the authentication response sending unit sends the authentication response to the first external device via the wireless interface when the authentication request using the first communication channel is received from the first external device after the state of the communication device is transitioned to the possible state. (Item 13) The communication device according to item 8 or 12, wherein the establishment unit establishes the first wireless connection between the communication device and the second external device via the wireless interface by using a second communication channel different from the first communication channel. (Item 14) The communication device further comprises: A communication device according to any one of claims 7 to 13, further comprising a second state transition unit that transitions the state of the communication device from the possible state to the impossible state when a specific condition is satisfied after the state of the communication device is transitioned to the possible state. (Item 15) The communication device further comprises: a specific signal receiving unit that receives a specific signal from the first external device; 15. The communication device according to any one of claims 1 to 14, further comprising: a notification unit that notifies the user that input of the user authentication information is available when the specific signal is received from the first external device. (Item 16) Item 16. The communication device according to item 15, wherein the notification unit causes a notification screen to be displayed on a display unit of the communication device to notify the user that input of the user authentication information is available. (Item 17) the second external device is a device different from the first external device and is a master station device that should operate as a master station of a wireless network; 17. The communication device according to any one of claims 1 to 16, wherein the establishment unit establishes the first wireless connection between the communication device and the second external device via the wireless interface, and causes the communication device to participate in the wireless network as a child station. (Item 18) 18. The communication device according to any one of claims 1 to 17, wherein the first connection information includes authentication information for authenticating received information received from the second external device. (Item 19) The communication device further comprises: A communication device described in any one of items 1 to 18, comprising an operation control unit that causes the communication device to operate as an Enrollee according to the Wi-Fi standard after the authentication response is sent to the first external device, and the first external device operates as a Configurator according to the Wi-Fi standard. (Item 20) A computer program for a communication device, comprising: The communication device includes: An output unit; A wireless interface; A computer, Equipped with The computer program causes the computer to operate in the following manner: a reception unit that receives an input of user authentication information for authenticating a user of the communication device; a first output control unit that causes the output unit to output specific information obtained by using a public key when authentication using the input user authentication information is successful, and when authentication using the input user authentication information is unsuccessful, the specific information is not output by the output unit, and the public key is acquired by a first external device by outputting the specific information; and an authentication request receiving unit that receives an authentication request using the public key from the first external device via the wireless interface after the specific information is output; an authentication response transmission unit that, when the authentication request is received from the first external device, transmits an authentication response, which is a response to the authentication request, to the first external device via the wireless interface; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A computer program that functions as a (Item 21) A computer program for a communication device, comprising: The communication device includes: A wireless interface; A computer, Equipped with The computer program causes the computer to operate in the following manner: a reception unit that receives an input of user authentication information for authenticating a user of the communication device; a first state transition unit that transitions a state of the communication device from an impossible state to a possible state when authentication using the input user authentication information is successful, and when authentication using the input user authentication information fails, the state of the communication device is maintained in the impossible state, the impossible state being a state in which an authentication response that is a response to an authentication request is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from the first external device; an authentication request receiving unit that receives the authentication request from the first external device via the wireless interface; an authentication response transmission unit that transmits the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device is transitioned to the available state; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A computer program that functions as a [Explanation of symbols]

[0100] 2: communication system, 6, 7: AP, 10: terminal, 15: camera, 16, 116: Wi-Fi I / F, 40: connection application, 100: printer, 112: operation unit, 114: display unit, 118: print execution unit, 130: control unit, 132: CPU, 134: memory, 136: program

Claims

1. A communication device, comprising: An output unit; A wireless interface; a determination unit that determines whether the state of the communication device is a first state in which use of the communication device is not restricted, or a second state in which use of the communication device is restricted; a reception unit that receives an input of user authentication information for authenticating a user of the communication device when the state of the communication device is determined to be the second state; a first output control unit that causes the output unit to output specific information obtained by using a public key when it is determined that the state of the communication device is the second state and authentication using the input user authentication information is successful, and when authentication using the input user authentication information fails, the specific information is not output by the output unit, and when the public key is acquired by a first external device by outputting the specific information and it is determined that the state of the communication device is the first state, causes the output unit to output the specific information without accepting input of the user authentication information; an authentication request receiving unit that receives an authentication request using the public key from the first external device via the wireless interface after the specific information is output; an authentication response transmission unit that, when the authentication request is received from the first external device, transmits an authentication response that is a response to the authentication request to the first external device via the wireless interface; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A communication device comprising:

2. The first state is a state in which default information is stored in a memory of the communication device as the user authentication information, The communication device according to claim 1 , wherein the second state is a state in which information updated from the default information is stored in the memory as the user authentication information.

3. The first state is a state in which the user authentication information is not stored in a memory of the communication device, The communication device according to claim 1 , wherein the second state is a state in which the user authentication information is stored in the memory.

4. The communication device has a printing function, The communication device further comprises: a memory for storing a setting value indicating either a first value indicating that a specific user is not restricted from using the print function or a second value indicating that the specific user is restricted from using the print function; the first state is a state in which the setting value in the memory indicates the first value; The communication device according to claim 1 , wherein the second state is a state in which the setting value in the memory indicates the second value.

5. A communication device as described in any one of claims 1 to 4, wherein the user authentication information is a password.

6. The communication device according to claim 1 , wherein the specific information is a code image obtained by encoding the public key.

7. the code image is a QR code (registered trademark), The communication device according to claim 6 , wherein the public key is obtained by the first external device in response to the QR code being photographed by the first external device.

8. the output unit is a display unit for displaying an image, The communication device according to claim 1 , wherein the first output control unit causes the specific information to be displayed on the output unit which is the display unit.

9. The communication device further comprises: a first state transition unit that transitions a state of the communication device from an impossible state to a possible state when authentication using the input user authentication information is successful, and when authentication using the input user authentication information is unsuccessful, the state of the communication device is maintained in the impossible state, the impossible state being a state in which the authentication response is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from the first external device; 9. The communication device according to claim 1, wherein the authentication response transmission unit transmits the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device is transitioned to the possible state.

10. the specific information is information obtained by using the public key and communication channel information indicating a first communication channel that is predetermined in the communication device, The communication channel information is acquired by the first external device by outputting the specific information, the possible state is a state in which the authentication device monitors whether the authentication request is received from the first external device using the first communication channel, and transmits the authentication response to the first external device in response to receiving the authentication request from the first external device; 10. The communication device according to claim 9, wherein the authentication response transmission unit transmits the authentication response to the first external device via the wireless interface when the authentication request using the first communication channel is received from the first external device after the state of the communication device is transitioned to the possible state.

11. A communication device, comprising: A wireless interface; a determination unit that determines whether the state of the communication device is a first state in which use of the communication device is not restricted, or a second state in which use of the communication device is restricted; a reception unit that receives an input of user authentication information for authenticating a user of the communication device when the state of the communication device is determined to be the second state; a first state transition unit that transitions a state of the communication device from an impossible state to a possible state when it is determined that the state of the communication device is the second state and authentication using the input user authentication information is successful, wherein when authentication using the input user authentication information fails, the state of the communication device is maintained in the impossible state, the impossible state being a state in which an authentication response that is a response to an authentication request is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from a first external device, and when it is determined that the state of the communication device is the first state, transitions the state of the communication device from the impossible state to the possible state without accepting input of the user authentication information; an authentication request receiving unit that receives the authentication request from the first external device via the wireless interface; an authentication response transmission unit that transmits the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device is transitioned to the enabled state; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A communication device comprising:

12. the possible state is a state in which the communication device monitors whether the authentication request is received from the first external device using a first communication channel that is predetermined in the communication device, and transmits the authentication response to the first external device in response to receiving the authentication request from the first external device; 12. The communication device according to claim 11, wherein the authentication response transmission unit transmits the authentication response to the first external device via the wireless interface when the authentication request using the first communication channel is received from the first external device after the state of the communication device is transitioned to the possible state.

13. 13. The communication device according to claim 10, wherein the establishment unit establishes the first wireless connection between the communication device and the second external device via the wireless interface by using a second communication channel different from the first communication channel.

14. The communication device further comprises: The communication device according to claim 9 , further comprising a second state transition unit that transitions the state of the communication device from the possible state to the impossible state when a specific condition is satisfied after the state of the communication device is transitioned to the possible state.

15. The communication device further comprises: a specific signal receiving unit that receives a specific signal from the first external device; 15. The communication device according to claim 1, further comprising: a notification unit that notifies the user that input of the user authentication information is available when the specific signal is received from the first external device.

16. The communication device according to claim 15 , wherein the notification unit causes a display unit of the communication device to display a notification screen notifying the user that input of the user authentication information is available.

17. the second external device is a master station device that is different from the first external device and that is to operate as a master station of a wireless network; 17. The communication device according to claim 1, wherein the establishment unit establishes the first wireless connection between the communication device and the second external device via the wireless interface, and causes the communication device to participate in the wireless network as a child station.

18. The communication device according to claim 1 , wherein the first connection information includes authentication information for authenticating received information received from the second external device.

19. The communication device further comprises: The communication device according to any one of claims 1 to 18, further comprising an operation control unit that causes the communication device to operate as an Enrollee in accordance with the Wi-Fi standard after the authentication response is transmitted to the first external device, and the first external device operates as a Configurator in accordance with the Wi-Fi standard.

20. A computer program for a communication device, comprising: The communication device includes: An output unit; A wireless interface; A computer, Equipped with The computer program causes the computer to operate in the following manner: a determination unit that determines whether the state of the communication device is a first state in which use of the communication device is not restricted, or a second state in which use of the communication device is restricted; a reception unit that receives an input of user authentication information for authenticating a user of the communication device when the state of the communication device is determined to be the second state; a first output control unit that causes the output unit to output specific information obtained by using a public key when it is determined that the state of the communication device is the second state and authentication using the input user authentication information is successful, and when authentication using the input user authentication information fails, the specific information is not output by the output unit, and when the public key is acquired by a first external device by outputting the specific information and it is determined that the state of the communication device is the first state, causes the output unit to output the specific information without accepting input of the user authentication information; an authentication request receiving unit that receives an authentication request using the public key from the first external device via the wireless interface after the specific information is output; an authentication response transmission unit that, when the authentication request is received from the first external device, transmits an authentication response that is a response to the authentication request to the first external device via the wireless interface; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A computer program that functions as a

21. A computer program for a communication device, comprising: The communication device includes: A wireless interface; A computer, Equipped with The computer program causes the computer to operate in the following manner: a determination unit that determines whether the state of the communication device is a first state in which use of the communication device is not restricted, or a second state in which use of the communication device is restricted; a reception unit that receives an input of user authentication information for authenticating a user of the communication device when the state of the communication device is determined to be the second state; a first state transition unit that transitions a state of the communication device from an impossible state to a possible state when it is determined that the state of the communication device is the second state and authentication using the input user authentication information is successful, wherein when authentication using the input user authentication information fails, the state of the communication device is maintained in the impossible state, the impossible state being a state in which an authentication response that is a response to an authentication request is not transmitted, and the possible state being a state in which the authentication response is transmitted to the first external device in response to receiving the authentication request from a first external device, and when it is determined that the state of the communication device is the first state, transitions the state of the communication device from the impossible state to the possible state without accepting input of the user authentication information; an authentication request receiving unit that receives the authentication request from the first external device via the wireless interface; an authentication response transmission unit that transmits the authentication response to the first external device via the wireless interface when the authentication request is received from the first external device after the state of the communication device is transitioned to the enabled state; a connection information receiving unit that receives first connection information from the first external device via the wireless interface after the authentication response is transmitted to the first external device, the first connection information being information for establishing a first wireless connection between the communication device and a second external device via the wireless interface; an establishment unit that, when the first connection information is received from the first external device, establishes the first wireless connection between the communication device and the second external device via the wireless interface by using the first connection information; A computer program that functions as a

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