Communication device, computer program for communication device, and method executed by communication device

Abstract

To provide a new technique for reducing a load on a memory of a first communication device.SOLUTION: The first communication apparatus includes: a first storage control unit configured to, when variable first communication information for establishing a first wireless connection between the first communication apparatus and a second communication apparatus is acquired and the invariable identification information of the second communication apparatus is received from the second communication apparatus, store the first communication information and the identification information in association with each other in a memory; and a second storage control unit configured to, after the first wireless connection is disconnected, when variable second communication information for establishing a second wireless connection between the first communication apparatus and the second communication apparatus is acquired and the identification information is received from the second communication apparatus, delete the first communication information associated with the identification information from the memory and store the second communication information in association with the identification information in the memory.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This specification discloses techniques related to establishing wireless connections. [Background technology]

[0002] The wireless communication device in Patent Document 1 stores, as a history, the connection IDs of mobile communication terminals that have previously established connections with the wireless communication device, and determines the mobile communication terminal to connect to using the connection IDs. The connection IDs are deleted after a predetermined time has elapsed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-233195 Summary of the Invention [Problem to be solved by the invention]

[0004] The present specification provides novel techniques for reducing the memory load of a first communication device. [Means for solving the problem]

[0005] A first communication device disclosed in this specification includes a memory, a first acquisition unit that acquires variable first communication information for establishing a first wireless connection between the first communication device and a second communication device, a first reception unit that receives unchanging identification information of the second communication device from the second communication device, a first storage control unit that, when the first communication information is acquired and the identification information is received, associates the first communication information with the identification information and stores them in the memory, and a first storage control unit that, when the first wireless connection is disconnected, disconnects the first communication device from the second communication device. a second acquiring unit that acquires variable second communication information for establishing a second wireless connection between the second communication device and the second communication device, the second communication information being different from the first communication information; a second receiving unit that receives the identification information from the second communication device after the first wireless connection is disconnected; and a second storage control unit that, when the second communication information is acquired and the identification information is received, deletes the first communication information associated with the identification information from the memory and stores the second communication information in the memory in association with the identification information.

[0006] According to the above configuration, the first communication device acquires variable first communication information for establishing a first wireless connection between the first communication device and the second communication device, receives unchanging identification information from the second communication device, and stores the variable first communication information in association with the second communication device. After the first wireless connection is terminated, the first communication device acquires variable second communication information for establishing a second wireless connection between the first communication device and the second communication device, and receives the identification information from the second communication device. In this case, the first communication device deletes the first communication information associated with the identification information and stores the second communication information in association with the identification information. Since the first communication information is not continuously stored in memory, the memory load is reduced.

[0007] The computer program for the above-mentioned first communication device, a computer-readable recording medium storing the computer program, and a method executed by the first communication device are also novel and useful. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of a communication system. [Figure 2] FIG. 10 is a sequence diagram of processing executed between devices. [Figure 3] This is a continuation of the sequence diagram of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Communication system configuration; Figure 1) 1, the communication system 2 includes a printer 10 and a terminal 100. In this embodiment, a situation is assumed in which a wireless connection in accordance with the Wi-Fi Aware method of the Wi-Fi standard (hereinafter referred to as "Wi-Fi Aware connection") is established between the printer 10 and the terminal 100.

[0010] (Printer 10 configuration) The printer 10 is a peripheral device capable of executing a printing function, such as a peripheral device for a terminal 100. In a modified example, the printer 10 may be a multi-function device capable of executing a scanning function, a facsimile function, etc. in addition to a printing function. The printer 10 includes an operation unit 12, a display unit 14, a Wi-Fi interface 16, a print execution unit 18, and a control unit 30. Each unit 12 to 30 is connected to a bus line. In the following, the interface will be referred to as "I / F."

[0011] The operation unit 12 is an I / F that allows the user to input various information to the printer 10, and includes, for example, a touch screen and buttons. The user can input various information to the printer 10 via the operation unit 12. The display unit 14 is a display for displaying various information. The print execution unit 18 includes, for example, an inkjet, laser, or thermal printing mechanism.

[0012] The Wi-Fi I / F 16 is a wireless I / F for performing Wi-Fi communication in accordance with the Wi-Fi standard. The Wi-Fi standard is a wireless communication standard for performing wireless communication in accordance with, for example, the 802.11 standard of the Institute of Electrical and Electronics Engineers, Inc. (IEEE) and its equivalent standards, such as 802.11a, 11b, 11n, and 11ac. In particular, the Wi-Fi I / F 16 supports the Wi-Fi Aware method established by the Wi-Fi Alliance. Details of the Wi-Fi Aware method are described in the standard document "Wi-Fi Aware Specification Version 4.0" created by the Wi-Fi Alliance. Wi-Fi Aware is also called a Wi-Fi Neighbor Awareness Network (NAN).

[0013] As will be described in detail later, each device (printer 10, terminal 100) can participate in a Wi-Fi Aware Neighbor Awareness Network (NAN) cluster. The discovery windows, which are the periods during which signals are sent and received, are synchronized among devices participating in the same NAN class.

[0014] Each device participating in a NAN cluster is assigned one of three roles: Master, Anchor Master, or Non-Master. A Master can share timer information, search for services, and invite devices to the NAN cluster. An Anchor Master can set timer information for synchronization in addition to the functions that a Master can perform. A Non-Master can share timer information and search for services, but cannot invite devices to the cluster.

[0015] Each device participating in a NAN cluster can search for other devices in the NAN cluster (more specifically, for services provided by those other devices). The signal for searching for services is called Subscribe. A device that receives Subscribe transmits a response signal called Publish. As will be described in detail later, in this embodiment, the terminal 100 transmits Subscribe to search for other devices that can provide connection services related to Wi-Fi Aware connections. Since the printer 10 can provide a connection service, it transmits a Publish to the terminal 100 indicating that it can provide the connection service. As a result, when processing for establishing a Wi-Fi Aware connection between the printer 10 and the terminal 100 is executed, a Wi-Fi Aware connection is established between the printer 10 and the terminal 100.

[0016] The control unit 30 includes a CPU 32 and a memory 34. The memory 34 includes a main storage device and an auxiliary storage device. The main storage device includes, for example, RAM and cache memory. The auxiliary storage device may be, for example, a flash memory, a solid state drive (SSD), or a ROM, or a combination thereof. A program 36 is stored in the auxiliary storage device. The CPU 32 performs various processes in accordance with the program 36 loaded from the auxiliary storage device to the main storage device.

[0017] The memory 34 also stores a device table 40. The device table 40 is a table for storing information about devices that have established a Wi-Fi Aware connection with the printer 10 (i.e., paired devices). The device table 40 stores the serial number of a device that has established a Wi-Fi Aware connection with the printer 10, the NAN Identity Key (NIK) of the device, and the NAN Pairing Key (NPK) shared with the device, in association with each other. The serial number is information assigned by the device vendor and is immutable. On the other hand, the NIK and NPK are variable information used to establish a Wi-Fi Aware connection between the printer 10 and the device. More specifically, the NIK is device identification information in the Wi-Fi Aware system. The NIK has an expiration date, and the NIK is changed when the expiration date expires. The NPK is key information used for encryption in a Wi-Fi Aware connection. The NPK is changed each time a Wi-Fi Aware connection is established.

[0018] (Configuration of terminal 100) The terminal 100 is a portable terminal device such as a mobile phone, a smartphone, a PDA, or a tablet PC. In a modified example, the terminal 100 may be a desktop PC, a laptop PC, or the like. The terminal 100 includes an operation unit 112, a display unit 114, a Wi-Fi I / F 116, and a control unit 130. The units 112 to 130 are connected to a bus line.

[0019] The operation unit 112 is an I / F that allows the user to input various information to the terminal 100, and includes, for example, a touch screen and buttons. The user can input various information to the terminal 100 via 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 printer 10. That is, the Wi-Fi I / F 116 supports the Wi-Fi Aware system.

[0020] The control unit 130 includes a CPU 132 and a memory 134. The memory 134 includes a main storage device and an auxiliary storage device. The main storage device includes, for example, a RAM and a cache memory. The auxiliary storage device may be, for example, a flash memory, a solid state drive (SSD), or a ROM, or a combination thereof. An OS program 136 and an application program 138 are stored in the auxiliary storage device. The CPU 132 performs various processes in accordance with the programs 136 and 138 loaded from the auxiliary storage device to the main storage device. Hereinafter, the OS program will be referred to as "OS." Furthermore, an application program will be referred to as "app."

[0021] OS 136 controls the basic operations of terminal 100. App 138 can establish a Wi-Fi Aware connection between printer 10 and terminal 100 by causing OS 136 to execute processing in accordance with the Wi-Fi Aware standard. App 138 can also use the Wi-Fi Aware connection to send print data representing an image to be printed to printer 10. App 138 is, for example, downloaded from a server on the Internet and installed on terminal 100.

[0022] The memory 134 further stores a device table 140. Similar to the device table 40 stored in the memory 34 of the printer 10, the device table 140 stores the serial number of a device that has established a Wi-Fi Aware connection with the terminal 100, the NIK of the device, and the NPK shared with the device, in association with each other.

[0023] (Processing performed between each device; Figure 2) Next, the processing executed between each device will be described with reference to Figure 2. Note that, in the following, for ease of understanding, the processing executed by the CPU (e.g., 32, 132) of each device (e.g., printer 10, terminal 100) will be described as the processing subject, rather than each CPU being described as the processing subject. Also, communication between each device is performed via a Wi-Fi I / F (e.g., 16, 116). Therefore, in the following description, when describing communication, the phrase "via a Wi-Fi I / F" will be omitted.

[0024] 2, the printer 10 belongs to a NAN cluster and operates as an Anchor Master. In particular, the printer 10 stores its own NIK, "SSS."

[0025] When terminal 100 receives a NAN activation operation from the user at T10, it transitions to a state in which it can receive signals conforming to the Wi-Fi Aware method, and generates the NIK "AAA" of terminal 100. Here, "a state in which it can receive signals conforming to the Wi-Fi Aware method" means a state in which Wi-Fi I / F 116 receives signals conforming to the Wi-Fi Aware method from the outside, and CPU 132 can execute processing conforming to the signals.

[0026] At T12, the printer 10 broadcasts a NAN Discovery Beacon frame (hereinafter referred to as "Discovery"). Discovery is a signal conforming to the Wi-Fi Aware method, and is a signal for notifying the outside world of information about the NAN cluster to which the printer 10 belongs. A device that does not belong to the NAN cluster can join the NAN cluster in response to receiving Discovery. In other words, Discovery can be said to be a signal for inviting devices that do not belong to the NAN cluster to join the NAN cluster. The printer 10 periodically transmits Discovery.

[0027] At stage T12, terminal 100 is operating in a state in which it can receive signals conforming to the Wi-Fi Aware method. Therefore, terminal 100 receives a Discovery from printer 10 at T12. In this case, terminal 100 joins the NAN cluster at T14. As a result, printer 10 and terminal 100 belong to the same NAN cluster. Although not shown, once terminal 100 joins the NAN cluster, it communicates with printer 10 to determine its role within the NAN cluster. In this case, terminal 100 operates as a Non-Master.

[0028] At T20, the terminal 100 broadcasts a Subscribe to the NAN cluster. The Subscribe is sent when a predetermined trigger occurs (for example, new membership in the NAN cluster, the arrival of a predetermined timing, or receipt of a predetermined operation). In this case, the Subscribe is sent to the printer 10 in the NAN cluster. The Subscribe in this case is a signal for searching for devices that provide connection services, i.e., a signal for searching for devices that can establish a Wi-Fi Aware connection. The Subscribe includes a NAN Identity Resolution Attribute (NIRA). The NIRA also includes Tag information. The Tag information includes a hash value of the NIK "AAA" of the terminal 100. Although not specifically described in this embodiment, the printer 10 may also send a Subscribe.

[0029] When the printer 10 receives a Subscribe from the terminal 100 in T20, the printer 10 determines whether it has already been paired with the terminal 100 that sent the Subscribe. Specifically, the printer 10 first identifies one NIK included in the device table 40. Then, the printer 10 calculates a hash value for the identified NIK. If the calculated hash value matches the hash value received in T20, the printer 10 determines that it has already been paired with the terminal 100. On the other hand, if the calculated hash value does not match the hash value received in T20, the printer 10 identifies another NIK included in the device table 40 and performs the same process as described above for that other NIK. If the hash value of the NIK does not match the hash value received in T20 for each of the NIKs included in the device table 40, the printer 10 determines that it has not already been paired with the terminal 100. If the device table 40 does not contain even one NIK, the printer 10 also determines that it has not been paired with the terminal 100.

[0030] In this case, at the stage of T20, not a single NIK is stored in the device table 40. Therefore, the printer 10 determines that it is not paired with the terminal 100, and at T22, it sends a Publish including a NAN Pairing Bootstrapping Attribute (NPBA) to the terminal 100. The NPBA includes information indicating the bootstrapping method supported by the printer 10. In this case, the printer 10 supports at least QR code, Near Field Communication (NFC), and Bluetooth (BT) as bootstrapping methods. Therefore, the Publish sent at T22 includes information indicating the QR code, information indicating NFC, and information indicating BT. Here, QR code is a registered trademark of Denso Wave Inc. Furthermore, Bluetooth is a registered trademark of Bluetooth SIG.

[0031] At T22, the terminal 100 receives a Publish including an NPBA from the printer 10. In this case, the terminal 100 identifies the bootstrapping method supported by the terminal 100 from among the bootstrapping methods indicated by the received NPBA. In this case, the terminal 100 is equipped with a camera (not shown) and does not have either NFC I / F or BTI / F. That is, the terminal 100 in this case supports bootstrapping by photographing a QR code, but does not support bootstrapping by NFC or BT. Therefore, at T24, the terminal 100 transmits a Follow-up including an NPBA to the printer 10. The Follow-up includes information indicating that the terminal 100 supports QR codes. The Follow-up is a signal defined by the Wi-Fi Aware system.

[0032] When the printer 10 receives a Follow-up from the terminal 100 at T24, the printer 10 transmits the Follow-up including an NPBA to the terminal 100 at T26. The NPBA includes information indicating that bootstrapping using a QR code will be performed. Then, at T30, the printer 10 displays the QR code on the display unit 14. The QR code is obtained by encoding a Service Set Identifier (SSID) and a password (hereinafter referred to as "PW"). The SSID and PW are authentication information used to perform Pre-Association Security Negotiation (PASN). PASN is a process for exchanging key information such as a public key between the printer 10 and the terminal 100, and is performed using a method similar to WPA3-SAE, for example.

[0033] At T26, the terminal 100 receives a Follow-up from the printer 10. In this case, although not shown, the terminal 100 may display on the display unit 114 a message informing the user that they should photograph the QR code displayed on the printer 10. At T32, the user of the terminal 100 uses the camera of the terminal 100 to photograph the QR code displayed on the printer 10. In this case, the terminal 100 decodes the photographed QR code and acquires the SSID and PW. The terminal 100 can execute PASN with the printer 10 by using the acquired SSID and PW.

[0034] Then, in T34, the terminal 100 generates a public key TPK1 and a private key tpk1 of the terminal 100. The public key TPK1 and the private key tpk1 are information used to generate the NPK. After generating the public key TPK1 and the private key tpk1, the terminal 100 transmits the public key TPK1 to the printer 10 in T36.

[0035] When the printer 10 receives the public key TPK1 from the terminal 100 in T36, the printer 10 generates the public key PPK1 and private key ppk1 of the printer 10 in T38. The public key PPK1 and private key ppk1 are also information used to generate the NPK. After generating the public key PPK1 and private key ppk1, the printer 10 generates the NPK "XXX" in T40 using the public key TPK1 of the terminal 100 that it has received and the private key ppk1 of the printer 10 that it has generated. Then, the printer 10 transmits the public key PPK1 to the terminal 100 in T42.

[0036] When the terminal 100 receives the public key PPK1 from the printer 10 in T42, it generates an NPK "XXX" in T44 using the received public key PPK1 of the printer 10 and the generated private key tpk1 of the terminal 100. The NPK "XXX" generated here is the same as the NKP "XXX" generated by the printer 10 in T40. In other words, the NPK "XXX" is shared between the printer 10 and the terminal 100.

[0037] Next, in T46, the terminal 100 transmits a Follow-up Protected Management Frame (PMF) including the terminal 100's NIK "AAA" to the printer 10. Here, "Follow-up PMF" means that Follow-up communication is performed using a communication path encrypted by the NPK. In other words, the Follow-up in T46 is transmitted from the terminal 100 to the printer 10 using a communication path encrypted by the NPK "XXX."

[0038] In T46, the printer 10 receives a Follow-up PMF including the NIK "AAA" of the terminal 100 from the terminal 100. Then, in T48, the printer 10 transmits a Follow-up PMF including the NIK "SSS" of the printer 10 to the terminal 100.

[0039] At T48, the terminal 100 receives a Follow-up PMF including the NIK "SSS" of the printer 10 from the printer 10. Then, at T50, the terminal 100 transmits a Follow-up PMF including the serial number T1 of the terminal 100 to the printer 10.

[0040] At T50, the printer 10 receives a Follow-up PMF including the serial number T1 of the terminal 100 from the terminal 100. In this way, the printer 10 receives the serial number T1 during a series of processes for establishing a Wi-Fi Aware connection. That is, the printer 10 can receive the serial number T1 of the terminal 100 relatively quickly. Then, at T52, the printer 10 transmits a Follow-up PMF including the serial number P1 of the printer 10 to the terminal 100.

[0041] At T52, the terminal 100 receives a Follow-up PMF including the serial number P1 of the printer 10 from the printer 10.

[0042] Through the above processing, the printer 10 acquires the NPK "XXX" and the NIK "AAA" of the terminal 100. Furthermore, the terminal 100 acquires the NPK "XXX" and the NIK "SSS" of the printer 10. As described above, the NPK and NIK are information for establishing a Wi-Fi Aware connection. Therefore, at T54, various processes using the NPK, NIK, etc. are executed between the printer 10 and the terminal 100, and a Wi-Fi Aware connection is established between the printer 10 and the terminal 100 (i.e., the printer 10 and the terminal 100 are in a paired state).

[0043] Furthermore, in T60, the printer 10 updates the device table 40. Specifically, the printer 10 first determines whether the serial number T1 received in T50 is stored in the device table 40. In this case, the serial number T1 is not stored in the device table 40, so the printer 10 associates the serial number T1 received in T50 with the NIK "AAA" received in T46 and the NPK "XXX" generated in T40 and stores them in the device table 40.

[0044] Furthermore, the terminal 100 updates the device table 140 in T62. Specifically, the terminal 100 first determines whether the serial number P1 received in T52 is stored in the device table 140. In this case, since the serial number P1 is not stored in the device table 140, the terminal 100 associates the serial number P1 received in T52 with the NIK "SSS" received in T48 and the NPK "XXX" generated in T44 and stores them in the device table 140. In this way, various pieces of information for establishing a Wi-Fi Aware connection (see T54) between the printer 10 and the terminal 100 are stored in each of the printer 10 and the terminal 100.

[0045] (Continuation of Figure 2; Figure 3) 3, the terminal 100 receives a print operation from the user to cause the printer 10 to print an image to be printed. The print operation includes, for example, designation of image data representing the image to be printed, designation of the printer to execute printing, and designation of printing conditions (e.g., print paper size, number of copies to be printed, number of colors (color, monochrome, grayscale), etc.). In this case, the terminal 100 transmits a Data Path Request to the printer 10 in T112. The Data Path Request is a signal requesting the printer 10 to establish a communication path (i.e., a Data Path) for communicating print data within the established Wi-Fi Aware connection (see T54 in FIG. 2).

[0046] When the printer 10 receives a Data Path Request from the terminal 100 in T112, it transmits a Data Path Response to the terminal 100 in T114.

[0047] When the terminal 100 receives a Data Path Response from the printer 10 in T114, it sends a Data Path Confirm to the printer 10 in T116. As a result, in T118, a Data Path is established in the Wi-Fi Aware connection between the printer 10 and the terminal 100. Then, in T120, the terminal 100 uses the Data Path to send print data representing an image to be printed to the printer 10. The print data has a data format that can be interpreted by the printer 10.

[0048] When the printer 10 receives the print data from the terminal 100 in T120, the printer 10 causes the print execution unit 18 to execute the image to be printed represented by the print data in T122.

[0049] Furthermore, when the terminal 100 completes sending the print data in T120, it sends a Data Path Termination to the printer 10 in T124. As a result, the Data Path between the printer 10 and the terminal 100 disappears in T126.

[0050] Thereafter, in response to the occurrence of a predetermined trigger, the terminal 100 transmits a Subscribe to the printer 10 in T130. The processing in T130 is the same as the processing in T20 in FIG.

[0051] When the printer 10 receives a Subscribe from the terminal 100 in T130, the printer 10 determines whether or not it has already been paired with the terminal 100 that sent the Subscribe. The specific method has already been described. In this case, at the stage of T130, one NIK "AAA" is stored in the device table 40 (see T60 in FIG. 2). The printer 10 identifies the one NIK "AAA" from the device table 40 and calculates its hash value. The calculated hash value matches the hash value already received in T130. Therefore, the printer 10 determines that it has already been paired with the terminal 100. In this case, the printer 10 sends a Publish to the terminal 100 in T132. The Publish includes an NIRA. The NIRA also includes Tag information that includes the hash value of the printer 10's NIK "SSS."

[0052] When the terminal 100 receives Publish from the printer 10 in T132, it determines whether or not it has already been paired with the printer 10 that sent it. In this case, at the stage of T132, one NIK "SSS" is stored in the device table 140 (see T62 in FIG. 2). The terminal 100 identifies the one NIK "SSS" from the device table 140 and calculates its hash value. The calculated hash value matches the hash value already received in T130. Therefore, the terminal 100 determines that it has already been paired with the printer 10.

[0053] As described above, an expiration date is set for the NIK. Assume that the NIK "AAA" of the terminal 100 expires after a predetermined time has elapsed after the processing of T132. In this case, the terminal 100 generates a new NIK "BBB" for the terminal 100 in T140. As described above, the NIK of the terminal 100 is information used to establish (i.e., maintain) a Wi-Fi Aware connection with the terminal 100, and is stored by the other device (e.g., the printer 10) with which the Wi-Fi Aware connection is established (see T60 in FIG. 2). Therefore, when the NIK of the terminal 100 is changed, the Wi-Fi Aware connection established between the printer 10 and the terminal 100 (see T54 in FIG. 2) is disconnected (i.e., the printer 10 and the terminal 100 are no longer paired). Then, the terminal 100 updates the device table 140 in T144. Specifically, the terminal 100 deletes various pieces of information stored in the device table 140. As described above, when the NIK is changed, the established Wi-Fi Aware connection is disconnected, and the various pieces of information stored in the device table 140 become unnecessary information.

[0054] Thereafter, the terminal 100 transmits a Subscribe to the printer 10 in response to the occurrence of a predetermined trigger (see T20 in FIG. 2). At this stage, a Wi-Fi Aware connection has not been established between the printer 10 and the terminal 100 (i.e., the printer 10 and the terminal 100 have not yet been paired), and therefore, the same processes as T20 to T32 in FIG. 2 are executed. The processes of T154 to T166 are the same as the processes of T34 to T46 in FIG. 2, except that the various types of information used (i.e., the public key, the private key, the NPK, and the NIK) are different. Thereafter, the same processes as T48 to T52 in FIG. 2 are executed, and at T174, a Wi-Fi Aware connection is established between the printer 10 and the terminal 100.

[0055] The printer 10 updates the device table 40 at T180. Specifically, the printer 10 first determines whether the serial number T1 received at T50 in FIG. 2, which is referenced in FIG. 3, is stored in the device table 40. In this case, the serial number T1 is stored in the second row of the device table 40. In this case, the printer 10 deletes the various information stored in the second row of the device table 40 (i.e., the serial number T1, the NIK "AAA", and the NPK "XXX") from the device table 40. Next, the printer 10 associates the serial number T1 received at T50 in FIG. 2, which is referenced in FIG. 3, the NIK "BBB" received at T166, and the NPK "YYY" generated at T160, and stores these in the device table 40 (see the third row of the device table 40 in FIG. 3). In a modified example, in T180, the printer 10 may store NIK "BBB" and NPK "YYY" in place of NIK "AAA" and NPK "XXX" in the second row, respectively, without deleting all of the information in the second row of the device table 40 (i.e., the information in the second row of the device table 40 may be updated).

[0056] Furthermore, the terminal 100 updates the device table 140 in T182. Specifically, the terminal 100 first determines whether the serial number P1 received in T52 of FIG. 2, which is referenced in FIG. 3, is stored in the device table 140. In this case, since the serial number P1 is not stored in the device table 140 (see T144), the terminal 100 associates the serial number P1 received in T52 of FIG. 2, which is referenced in FIG. 3, with the NIK "SSS" received in T48 of FIG. 2, which is referenced in FIG. 3, and the NPK "YYY" generated in T164, and stores these in the device table 140. In this way, various pieces of information for newly establishing a Wi-Fi Aware connection (see T174) between the printer 10 and the terminal 100 are stored in each of the printer 10 and the terminal 100.

[0057] (Effects of the Example) According to the above configuration, the printer 10 acquires the NIK "AAA" and the NPK "XXX" to establish a Wi-Fi Aware connection between the printer 10 and the terminal 100 (T40 and T46 in FIG. 2), receives the serial number T1 from the terminal 100 (T50), and stores these in association with each other in the device table 40 (T60). After that, after the established Wi-Fi Aware connection is disconnected at T54 in FIG. 2 (see T140 in FIG. 3), the printer 10 acquires the NIK "BBB" and the NPK "YYY" to establish a new Wi-Fi Aware connection between the printer 10 and the terminal 100 (T160 and T166 in FIG. 3), and receives the serial number T1 from the terminal 100 (T50 in FIG. 2 cited in FIG. 3). In this case, the printer 10 deletes the NIK "AAA" and NPK "XXX" associated with the serial number T1 from the device table 40 and stores the NIK "BBB" and NPK "YYY" associated with the serial number T1 (T180). When the serial number T1 is stored in the device table 40, if the serial number T1 is received and a NIK and NPK different from the NIK and NPK stored in association with the serial number T1 are acquired, a new Wi-Fi Aware connection is established between the printer 10 and the terminal 100, and the old Wi-Fi Aware connection is disconnected. In other words, in the above situation, the NIK "AAA" and NPK "XXX" are unnecessary information. Since such unnecessary information is not continuously stored in the memory 34, the load on the memory 34 is reduced.

[0058] Furthermore, as described above, when the printer 10 receives a Subscribe containing Tag information from the terminal 100, it identifies one NIK from the device table 40, calculates a hash value for that NIK, and compares it with the hash value contained in the Tag information. If unnecessary information continues to be stored in the device table 40, the above-described comparison process will be performed on the unnecessary information as well, increasing the processing load on the printer 10. In contrast, in this embodiment, unnecessary information in the device table 40 is not continuously stored in the memory 34, thereby reducing the processing load on the printer 10.

[0059] (Correspondence) The printer 10 and the terminal 100 are examples of a "first communication device" and a "second communication device," respectively. The Wi-Fi Aware connection established at T54 in FIG. 2 and the Wi-Fi Aware connection established at T174 in FIG. 3 are examples of a "first wireless connection" and a "second wireless connection," respectively. The NIK "AAA" and the NPK "XXX" are examples of "first communication information." In particular, the NIK "AAA" is an example of "first variable identification information" and a "first NIK." The NPK "XXX" is an example of "first key information" and a "first NPK." The NIK "BBB" and the NPK "YYY" are examples of "second communication information." In particular, the NIK "BBB" is an example of "second variable identification information" and a "second NIK." The NPK "YYY" is an example of "second key information" and a "second NPK." The serial number T1 of the terminal 100 is an example of "identification information."

[0060] The processes of T40 and T46 in FIG. 2 are an example of a process executed by a "first acquisition unit." The process of T50 is an example of a process executed by a "first receiving unit." The process of T60 is an example of a process executed by a "first storage control unit." The processes of T160 and T166 in FIG. 3 are an example of a process executed by a "second acquisition unit." The process of T50 in FIG. 2 cited in FIG. 3 is an example of a process executed by a "second receiving unit." The process of T180 in FIG. 3 is an example of a process executed by a "second storage control unit."

[0061] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications of the above examples are listed below.

[0062] (Variation 1) In the above embodiment, an example was described in which, in response to a change in the NIK of the terminal 100 from NIK "AAA" to NIK "BBB," the NIK "AAA" and NPK "XXX" are deleted from the device table 40 of the printer 10, and new NIK "BBB" and NPK "YYY" are stored. As in the above embodiment, a technique is also useful in which, in response to a change in the NIK of the printer 10, the device table 140 of the terminal 100 is updated. In this variation, the terminal 100 and the printer 10 are examples of a "first communication device" and a "second communication device," respectively.

[0063] (Variation 2) The printer 10 may store, for example, a MAC address in place of the serial number in the device table 40. The MAC address is also unchanging information. In this case, the printer 10 may receive a Follow-up PMF including the MAC address of the terminal 100 at T50 in FIG. 2. In this variation, the MAC address is an example of "identification information." Generally speaking, the "identification information" may be unchanging information of the "second communication device."

[0064] (Variation 3) In the above embodiment, the printer 10 receives the NIK "AAA", serial number T1, etc. from the terminal 100 by Follow-up (T46, T50 in FIG. 2). Alternatively, the printer 10 may, for example, establish a data path with the terminal 100 and then receive the serial number T1, etc. from the terminal 100 using that data path, or may receive the serial number T1, etc. from the terminal 100 by Subscribe or Publish. Generally speaking, the "first (and second) receiving unit" may receive identification information from the second communication device by a method other than Follow-up.

[0065] (Variation 4) In the above embodiment, when the NIK "AAA" expires, the NIK "AAA" is changed to the NIK "BBB". In a variation, for example, when a NAN invalidation operation is received from a user, the NIK "AAA" may be deleted. Thereafter, when a NAN activation operation is received again from the user, a new NIK "BBB" may be generated. In another variation, for example, when an operation to reset the settings of the terminal 100 is received from a user, the NIK "AAA" may be deleted and a new NIK "BBB" may be generated.

[0066] (Variation 5) In the above embodiment, the NIK and NPK are used to establish a Wi-Fi Aware connection. In a variation, at least one of the NIK and NPK may not be used, or information other than the NIK and NPK may also be used. Generally speaking, the "communication information" may not include at least one of the "key information" and the "variable identification information," or may include information other than the "key information" and the "variable identification information."

[0067] (Variation 6) The wireless connection established between the printer 10 and the terminal 100 does not have to be a Wi-Fi Aware connection (that is, a wireless connection conforming to the Wi-Fi Aware standard).

[0068] (Variant 7) In the above embodiment, the processing of each step in Figures 2 and 3 is realized by software (e.g., program 36, OS 136, application 138), but at least one of these processes may be realized by hardware such as a logic circuit.

[0069] The technical elements described in this specification or drawings may exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings may achieve multiple objectives simultaneously, and achieving one of those objectives alone is technically useful.

[0070] In the scope of the claims at the time of filing, even if each claim depends on only some of the claims, it is not limited to the fact that each claim can depend on only those some of the claims. To the extent that there is no technical contradiction, each claim can also depend on other claims that were not dependent at the time of filing. In other words, the technology of each claim can be combined in various ways as follows: (Item 1) a first communication device, Memory and a first acquisition unit that acquires variable first communication information for establishing a first wireless connection between the first communication device and a second communication device; a first receiving unit that receives immutable identification information of the second communication device from the second communication device; a first storage control unit that, when the first communication information is acquired and the identification information is received, stores the first communication information and the identification information in the memory in association with each other; a second acquisition unit that acquires variable second communication information for establishing a second wireless connection between the first communication device and the second communication device after the first wireless connection is disconnected, the second communication information being different from the first communication information; a second receiving unit that receives the identification information from the second communication device after the first wireless connection is disconnected; a second storage control unit that, when the second communication information is acquired and the identification information is received, deletes the first communication information associated with the identification information from the memory and stores the second communication information in the memory in association with the identification information; A first communication device comprising: (Item 2) the first communication information includes variable first key information used for encryption in the first wireless connection; Item 1. The first communication device according to item 1, wherein the second communication information includes variable second key information used for encryption in the second wireless connection. (Item 3) the first communication information includes first variable identification information that is variable identification information of the second communication device; 3. The first communication device according to item 1 or 2, wherein the second communication information includes second variable identification information that is variable identification information of the second communication device. (Item 4) The first communication device according to any one of items 1 to 3, wherein each of the first wireless connection and the second wireless connection is a wireless connection conforming to the Wi-Fi Aware method of the Wi-Fi standard. (Item 5) the first communication information is a NAN Paring Key (NPK) defined in the Wi-Fi Aware system, and includes a variable first NPK used for encryption in the first wireless connection; 5. The first communication device of claim 4, wherein the second communication information includes a variable second NPK used for encryption in the second wireless connection. (Item 6) the first communication information is a NAN Identity Key (NIK) defined in the Wi-Fi Aware system, and includes a first NIK that is variable identification information of the second communication device; 6. The first communication device according to item 4 or 5, wherein the second communication information includes a second NIK, which is variable identification information of the second communication device. (Item 7) the first receiving unit receives the identification information from the second communication device by Follow-up defined in the Wi-Fi Aware method; 7. The first communication device according to any one of items 4 to 6, wherein the second receiving unit receives the identification information from the second communication device by the Follow-up. [Explanation of symbols]

[0071] 2: Communication system, 10: Printer, 12, 112: Operation unit, 14, 114: Display unit, 16, 116: Wi-Fi I / F, 18: Print execution unit, 30, 130: Control unit, 32, 132: CPU, 34, 134: Memory, 36: Program, 40, 140: Device table, 100: Terminal, 136: OS program, 138: Application program

Claims

1. a first communication device, Memory and a first acquisition unit that acquires variable first communication information for establishing a first wireless connection between the first communication device and a second communication device; a first receiving unit that receives immutable identification information of the second communication device from the second communication device; a first storage control unit that, when the first communication information is acquired and the identification information is received, stores the first communication information and the identification information in the memory in association with each other; a second acquisition unit that acquires variable second communication information for establishing a second wireless connection between the first communication device and the second communication device after the first wireless connection is disconnected, the second communication information being different from the first communication information; a second receiving unit that receives the identification information from the second communication device after the first wireless connection is disconnected; a second storage control unit that, when the second communication information is acquired and the identification information is received, deletes the first communication information associated with the identification information from the memory and stores the second communication information in the memory in association with the identification information; A first communication device comprising:

2. the first communication information includes variable first key information used for encryption in the first wireless connection; The first communication device according to claim 1 , wherein the second communication information includes variable second key information used for encryption in the second wireless connection.

3. the first communication information includes first variable identification information that is variable identification information of the second communication device, The first communication device according to claim 1 , wherein the second communication information includes second variable identification information that is variable identification information of the second communication device.

4. The first communication device according to claim 1 , wherein each of the first wireless connection and the second wireless connection is a wireless connection conforming to a Wi-Fi Aware method of the Wi-Fi standard.

5. the first communication information is a NAN Pairing Key (NPK) defined in the Wi-Fi Aware scheme, and includes a variable first NPK used for encryption in the first wireless connection; The first communication device of claim 4 , wherein the second communication information includes a variable second NPK used for encryption in the second wireless connection.

6. the first communication information is a NAN Identity Key (NIK) defined in the Wi-Fi Aware system, and includes a first NIK that is variable identification information of the second communication device; The first communication device according to claim 4 , wherein the second communication information includes a second NIK that is variable identification information of the second communication device.

7. the first receiving unit receives the identification information from the second communication device by Follow-up defined in the Wi-Fi Aware standard; 5. The first communication device according to claim 4, wherein the second receiving unit receives the identification information from the second communication device by the Follow-up.

8. A computer program for a first communication device, comprising: the first communication device, Memory and A computer, Equipped with The computer program controls the computer to operate as follows: a first acquisition unit that acquires variable first communication information for establishing a first wireless connection between the first communication device and a second communication device; a first receiving unit that receives immutable identification information of the second communication device from the second communication device; a first storage control unit that, when the first communication information is acquired and the identification information is received, stores the first communication information and the identification information in the memory in association with each other; a second acquisition unit that acquires variable second communication information for establishing a second wireless connection between the first communication device and the second communication device after the first wireless connection is disconnected, the second communication information being different from the first communication information; a second receiving unit that receives the identification information from the second communication device after the first wireless connection is disconnected; a second storage control unit that, when the second communication information is acquired and the identification information is received, deletes the first communication information associated with the identification information from the memory and stores the second communication information in the memory in association with the identification information; A computer program that functions as a

9. 1. A method performed by a first communication device, comprising: the first communication device comprises a memory; The method comprises: a first obtaining step of obtaining variable first communication information for establishing a first wireless connection between the first communication device and a second communication device; a first receiving step of receiving immutable identification information of the second communication device from the second communication device; a first storage control step of, when the first communication information is acquired and the identification information is received, storing the first communication information and the identification information in the memory in association with each other; a second acquisition step of acquiring variable second communication information for establishing a second wireless connection between the first communication device and the second communication device after the first wireless connection is disconnected, the second communication information being different from the first communication information; a second receiving step of receiving the identification information from the second communication device after the first wireless connection is disconnected; a second storage control step of, when the second communication information is acquired and the identification information is received, deleting the first communication information associated with the identification information from the memory and storing the second communication information in the memory in association with the identification information; A method comprising:

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