Connection method

Abstract

To connect an information terminal to a projector while preventing a PIN code of an output device such as a projector from being leaked due to wiretapping or the like.SOLUTION: An information terminal 20 acquires identification information for identifying an output device 10A and generates a hash value on the basis of the acquired identification information. The information terminal 20 generates a first PIN code on the basis of the generated hash value. The output device 10A acquires a hash value on the basis of its own identification information, and generates and displays a second PIN code on the basis of the hash value. The information terminal 20 accepts a first input operation for inputting the second PIN code displayed by the output device 10A into its own device, and transmits a connection request signal to the output device 10A when the second PIN code input into its own device matches the first PIN code.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a connection method for connecting an information terminal to an output device. [Background technology]

[0002] The projector disclosed in Patent Document 1 displays the projector's identification code on the projection surface in response to a predetermined operation. With the technology disclosed in Patent Document 1, when the projector's identification code is input to an information terminal running an application program for the display system, the information terminal sends a connection request including the identification code to the projector. If the connection request received from the information terminal includes the identification code displayed on the projection surface or the like, the projector disclosed in Patent Document 1 allows connection to the information terminal's communication means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-152663 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 has the risk of the projector's identification code being leaked due to eavesdropping on communications between the information terminal and the projector. [Means for solving the problem]

[0005] One aspect of a connection method of the present disclosure includes a connection method for connecting an output device and an information terminal, the connection method including: the information terminal acquiring identification information for identifying the output device; the information terminal generating a hash value based on the identification information acquired by the information terminal; the information terminal generating a first identification code based on the hash value generated by the information terminal; the output device acquiring the identification information; the output device generating a hash value based on the identification information acquired by the output device; the output device generating a second identification code based on the hash value generated by the output device; the information terminal accepting a first input operation for inputting the second identification code generated by the output device to the information terminal; and, if the second identification code input by the first input operation matches the first identification code, transmitting a connection request signal to the output device. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a diagram illustrating an example of the configuration of an information system 1 according to an embodiment of the present disclosure. [Figure 2] 10 is a diagram showing an example of a standby screen G1 displayed by the output device 10. FIG. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of an information terminal 20. [Figure 4] 10 is a diagram showing an example of a UI screen G2 displayed on a display device 230 of an information terminal 20. FIG. [Figure 5] 10 is a flowchart showing the flow of processing in a connection method according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] The embodiments described below are subject to various technically preferable limitations, but the embodiments of the present disclosure are not limited to the following embodiments. 1. Embodiment Fig. 1 is a diagram illustrating a configuration example of an information system 1 according to an embodiment of the present disclosure. As shown in Fig. 1, the information system 1 includes an output device 10A, an output device 10B, and an information terminal 20. The output device 10 and the information terminal 20 are connected to a network NW such as a wired or wireless LAN (Local Area Network).

[0008] The output device 10A and the output device 10B are both display devices that display images, specifically projectors. When there is no need to distinguish between the output device 10A and the output device 10B, the output device 10A and the output device 10B are referred to as "output device 10." Another device, such as a personal computer, is connected to the output device 10 via a network NW. The output device 10 displays an image represented by image data supplied from the other connected device by projecting the image onto a projection surface, such as a projection screen. An example of another device in this embodiment is an information terminal 20.

[0009] When the power supply (not shown in FIG. 1) of the output device 10 is turned on, the output device 10 displays a standby screen on the projection surface for waiting for connection of other devices. FIG. 2 is a diagram showing an example of a standby screen G1 displayed by the output device 10A. As shown in FIG. 2, the standby screen G1 includes a character string representing the name of the output device 10A and a character string representing a PIN code, which is an identification code used when connecting other devices to the output device 10 via the network NW. As shown in FIG. 2, the identification information of the output device 10A is "EB10000" and the PIN code is "2679."

[0010] In this embodiment, the identification information of the output device 10 is stored in advance in the storage device 250 of the information processing device 20 (the configuration of the information processing device 20 will be described in detail later). The output device 10 acquires the identification information of the output device 10 by reading the identification information from the storage device 250. The output device 10 also generates a PIN code in the following manner. The output device 10 first generates a string (hereinafter referred to as a string to be hashed) by concatenating a specific unique string with the identification information of the output device 10. In this embodiment, "lcp1" is used as the unique string. Therefore, in this embodiment, the output device 10A generates "EB10000lcp1" as the string to be hashed. The unique string is stored in advance in the storage device 250, similar to the identification information. The specific unique string may be a different string each time the output device 10 is powered on. For example, a string representing a date (e.g., 20240330 for March 30, 2024) or the cumulative number of connections between the output device 10 and the information terminal 20 (e.g., 200 if the cumulative number of connections is 200) may be used. Next, the output device 10 generates a hash value by inputting the string to be hashed into a predetermined hash function. Then, the output device 10 picks up a predetermined number of digits (four in this embodiment) from the beginning of the hash value and generates a PIN code by arranging these four digits from left to right in the order in which they were picked. The identification information and unique string of the output device 10 may be stored in a storage device within the output device 10 in addition to the storage device 250. In this case, the output device 10 may read the identification information and unique string from the storage device of the output device 10.

[0011] For example, suppose that the output device 10A inputs the string to be hashed, "EB10000lcp1," into a predetermined hash function to obtain the hash value "abb267b9d8a8ee5b3···0." The output device 10A picks up four numbers, "2," "6," "7," and "9," in order from the beginning of the hash value, and arranges these four numbers from left to right in the order picked up to generate the PIN code "2679." The PIN code generated in this manner is displayed on the standby screen G1. The PIN code generated by the output device 10 is an example of a second identification code in the present disclosure.

[0012] The information terminal 20 is, for example, a personal computer. In this embodiment, when a user of the information terminal 20 desires to connect the information terminal 20 to the output device 10A, the user must start an application program for the information system 1 on the information terminal 20 and input the PIN code displayed on the standby screen G1 displayed by the output device 10A into the information terminal 20. In this respect, this is the same as the technology disclosed in Patent Document 1. In this embodiment, the information terminal 20 can be connected to the output device 10 via the network NW without transmitting the PIN code input into the information terminal 20 to the output device 10A via the network NW, which is a feature of this embodiment. The following description will focus on the information terminal 20, which plays a central role in this embodiment.

[0013] FIG. 3 is a diagram illustrating an example of the configuration of the information terminal 20. As illustrated in FIG. 3, the information terminal 20 includes a processing device 210, a communication device 220, a display device 230, an input device 240, and a storage device 250. The processing device 210 is one or more processors. Specifically, the processing device 210 is a central processing unit (CPU). The processing device 210 functions as the control center of the information terminal 20 by operating in accordance with a program stored in the storage device 250. The communication device 220 is a device that performs wireless or wired communication with other devices and includes, for example, an interface circuit. A specific example of another device that communicates with the communication device 220 is the output device 10. The display device 230 is a device that displays various images under the control of the processing device 210 and includes, for example, a liquid crystal display and its drive circuit. The input device 240 includes, for example, operators such as a numeric keypad, and provides data representing user operations on the operators to the processing device 210.

[0014] The storage device 250 is a recording medium readable by the processing device 210. The storage device 250 includes, for example, a nonvolatile memory and a volatile memory. The nonvolatile memory is, for example, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM). The volatile memory is, for example, a random access memory (RAM). The nonvolatile memory of the storage device 250 stores the unique character string (i.e., "lcp1") and various programs. Examples of the various programs stored in the nonvolatile memory include a kernel program and a program PRA. The kernel program is not shown in FIG. 3. The kernel program is a program that causes the processing device 210 to implement an operating system (OS).

[0015] When power supply to the information terminal 20 is started, the processing device 210 reads a kernel program from nonvolatile memory to volatile memory and begins executing the read kernel program. The processing device 210, operating in accordance with the kernel program, reads a program instructed to be started from nonvolatile memory to volatile memory in response to an operation on the input device 240, and executes the read program. For example, when instructed to start the program PRA, the processing device 210 reads the program PRA from nonvolatile memory to volatile memory and begins executing the program PRA read into the volatile memory. The program PRA is an application program for the information system 1. The processing device 210, operating in accordance with the program PRA, functions as the display control unit 211, acquisition unit 212, generation unit 213, and connection control unit 214 shown in FIG. 3. In other words, the display control unit 211, acquisition unit 212, generation unit 213, and connection control unit 214 shown in FIG. 3 are each software modules realized by operating the processing device 210 in accordance with the program PRA. The roles of the display control unit 211, the acquisition unit 212, the generation unit 213, and the connection control unit 214 shown in FIG. 3 are as follows.

[0016] The display control unit 211 displays on the display device 230 a UI screen G2 that prompts the user to input various information for connecting the information terminal 20 to the output device 10. FIG. 4 is a diagram showing an example of the UI screen G2. As shown in FIG. 4, the UI screen G2 is provided with an input box A1 and an input box A2. The input box A1 is an input area for inputting identification information of a device to which the information terminal 20 is to be connected. When a user of the information terminal 20 wishes to connect the information terminal 20 to the output device 10A, the user inputs the identification information displayed on the standby screen G1 displayed by the output device 10A into the input box A1 by performing an input operation on the input device 240. The input operation of inputting the identification information into the input box A1 is an example of a second input operation in the present disclosure. The input box A2 is an input area for inputting a PIN code of the device to which the information terminal 20 is to be connected. When the user desires to connect the information terminal 20 to the output device 10A, the user inputs the PIN code displayed on the standby screen G1 displayed by the output device 10A into the input box A2 by performing an input operation on the input device 240. The input operation of inputting the PIN code into the input box A2 is an example of a first input operation in the present disclosure.

[0017] The acquisition unit 212 acquires the identification information and PIN code of the device to which the information terminal 20 is connected from the input device 240. In this embodiment, the acquisition unit 212 acquires the identification information input by a user's input operation from the input device 240, but the acquisition unit 212 may acquire the identification information from the output device 10 by communicating with the output device 10 using the communication device 220.

[0018] The generation unit 213 generates a PIN code based on the identification information acquired by the acquisition unit 212 and the unique string described above, using the same procedure as in the output device 10. Specifically, the generation unit 213 first generates a string to be hashed by concatenating the identification information acquired by the acquisition unit 212 with the unique string described above. Next, the generation unit 213 generates a hash value by inputting the generated string to be hashed into the same hash function as in the output device 10. The generation unit 213 then picks up a predetermined number of digits (four in this embodiment) from the beginning of the hash value and generates a PIN code by arranging these four digits from left to right in the order they were picked. The PIN code generated by the generation unit 213 is an example of a first identification code in the present disclosure.

[0019] The connection control unit 214 determines whether the PIN code generated by the generation unit 213 matches the PIN code acquired by the acquisition unit 212. If the PIN code generated by the generation unit 213 does not match the PIN code acquired by the acquisition unit 212, the connection control unit 214 displays an error message on the UI screen G2 prompting the user to re-enter the identification information and the PIN code. On the other hand, if the connection control unit 214 determines that the PIN code generated by the generation unit 213 matches the PIN code acquired by the acquisition unit 212, the connection control unit 214 transmits a connection request, which does not include the PIN code of the output device 10, to the output device 10 indicated by the identification information acquired by the acquisition unit 212. The output device 10 that receives this connection request via the network NW unconditionally replies with a connection response and establishes a communication path with the sender of the connection request. When a communication path is established between the output device 10 and the information terminal 20, the information terminal 20 and the output device 10 are connected. The reason why the output device 10 unconditionally establishes a communication path with the sender of the connection request upon receiving the connection request is because the sender has already performed PIN code authentication. Since authentication using a PIN code is not performed in the output device 10, there is no need to include the PIN code of the output device 10 in the connection request sent from the information terminal 20 to the output device 10. For this reason, in this embodiment, the connection request sent by the connection control unit 214 does not include a PIN code. Because the connection request sent from the information terminal 20 to the output device 10 does not include a PIN code, the PIN code will not be leaked even if the connection request is intercepted or otherwise intercepted. The above is the configuration of the information terminal 20.

[0020] Next, referring to FIG. 5, operations performed by each of the information terminal 20 and the output device 10A in a connection method for connecting the information terminal 20 to the output device 10A will be described, taking the case of connecting the information terminal 20 to the output device 10A as an example. FIG. 5 is a diagram showing the flow of processing in the connection method. As shown in FIG. 5, this connection method includes first display processing SA100, second display processing SA110, acquisition processing SA120, generation processing SA130, connection request processing SA140, and connection response processing SA150. As shown in FIG. 5, the first display processing SA100 and the connection response processing SA150 are processing performed by the output device 10, and the second display processing SA110, acquisition processing SA120, generation processing SA130, and connection request processing SA140 are processing performed by the information terminal 20. The processing contents of each of the first display processing SA100, second display processing SA110, acquisition processing SA120, generation processing SA130, connection request processing SA140, and connection response processing SA150 are as follows.

[0021] The first display process SA100 is executed when the output device 10A is powered on. In the first display process SA100, the output device 10A acquires the identification information of the output device 10A by reading the identification information from the storage device 250, and generates a PIN code based on the acquired identification information and a predetermined unique character string. Then, in the first display process SA100, the output device 10A displays a standby screen G1 including the acquired identification information and the generated PIN code on the projection surface. In this operation example, the identification information included in the standby screen G1 is "EB10000," and the PIN code is "2697." The user of the information terminal 20 visually checks the standby screen G1 to ascertain the identification information and the PIN code.

[0022] The second display process SA110 is executed when an input operation instructing the activation of the program PRA is performed on the input device 240. In the second display process SA110, the processing device 210 functions as the display control unit 211 and displays the UI screen G2 on the display device 230. The user of the information terminal 20 inputs the identification information and PIN code of the output device 10A, which the user has grasped by visually viewing the standby screen G1, into the input box A1 and the input box A2, respectively, by performing an input operation on the input device 240. As described above, the identification information grasped by the user of the information terminal 20 from the standby screen G1 is "EB10000," and the PIN code grasped by the user from the standby screen G1 is "2697," so "EB10000" is input into the input box A1, and "2697" is input into the input box A2.

[0023] In the acquisition process SA120 executed in the information terminal 20 subsequent to the second display process SA110, the processing device 210 functions as the acquisition unit 212. In the acquisition process SA120, the processing device 210 acquires the identification information and PIN code of the device to which the information terminal 20 is connected from the input device 240. In this operation example, since "EB10000" is entered in the input box A1 and "2697" is entered in the input box A2, the processing device 210 acquires "EB10000" as the identification information and "2697" as the PIN code.

[0024] In the generation process SA130 executed in the information terminal 20 following the acquisition process SA120, the processing device 210 functions as the generation unit 213. In the generation process SA130, the processing device 210 generates a string to be hashed by concatenating the above-mentioned unique string with the identification information acquired in the acquisition process SA120. As described above, the identification information acquired in the acquisition process SA120 in this operation example is "EB10000" and the fixed string is "lcp1," so "EB10000lcp1" is generated as the string to be hashed. Next, the processing device 210 generates a hash value by inputting the string to be hashed into the same hash function as in the output device 10. The processing device 210 then picks up a predetermined number of digits (four in this embodiment) from the beginning of the hash value and generates a PIN code by arranging these four digits from left to right in the order in which they were picked. In this example, the string to be hashed, "EB10000lcp1," is input into a specified hash function to obtain the hash value "abb267b9d8a8ee5b3···0." Four numbers, "2," "6," "7," and "9," are then picked from the beginning of the hash value, and the PIN code "2697" is generated by arranging these four numbers from left to right in the order they were picked.

[0025] In connection request processing SA140, which is executed in the information terminal 20 following generation processing SA130, the processing device 210 functions as a connection control unit 214. In connection request processing SA140, it is determined whether the PIN code generated in generation processing SA130 matches the PIN code acquired in acquisition processing SA120. If they do not match, an error message is displayed on the UI screen G2. If they match, a connection request is sent to the device indicated by the identification information acquired in acquisition processing SA120, without including the PIN code of that device. In this operation example, the PIN code acquired in acquisition processing SA120 is "2697," and the PIN code generated in generation processing SA130 is also "2697," so the two PIN codes match. Therefore, in connection request processing SA140 in this operation example, a connection request is sent to the device whose identification information is "EB10000."

[0026] The connection response processing SA150 is processing executed by the output device 10 when a connection request is received via the network NW. In the connection response processing SA150, the output device 10 unconditionally establishes a communication path with the sender of the connection request, and the sender and the output device 10 are connected. Thereafter, the output device 10 displays on the projection surface an image represented by image data sent from the information terminal 20 via the network NW.

[0027] According to this embodiment, the PIN code generated by the output device 10 is not transmitted or received via the network NW, and there is no risk of the PIN code being leaked due to eavesdropping on the network NW. Furthermore, according to this embodiment, unless the identification information of the output device 10, the specific unique character string, and the hash function are all leaked, the PIN code of the output device 10 cannot be correctly generated, thereby preventing the fabrication of a PIN code.

[0028] 2. Transformation The above embodiment can be modified as follows. (1) In the above embodiment, the output device 10 is a projector, but it may be a printer or a scanner. In the above embodiment, the information terminal 20 is a personal computer, but it may be a smartphone or a tablet terminal. In the above embodiment, the PIN code is generated in each of the output device 10 and the information terminal 20 based on the identification information of the output device 10 and a unique string. However, each of the output device 10 and the information terminal 20 may generate a PIN code based only on the identification information of the output device 10, in other words, using the identification information of the output device 10 itself as the string to be hashed. Even in an aspect in which a PIN code is generated based only on the identification information of the output device 10, the PIN code of the output device 10 cannot be correctly generated unless the identification information of the output device 10 and the hash function are all leaked, thereby preventing the fabrication of a PIN code.

[0029] (2) In each of the above embodiments, the display control unit 211, the acquisition unit 212, the generation unit 213, and the connection control unit 214 are software modules. However, any one, any two, any three, or all of the display control unit 211, the acquisition unit 212, the generation unit 213, and the connection control unit 214 may be a hardware module such as an ASIC (Application Specific Integrated Circuit). Even if at least one of the display control unit 211, the acquisition unit 212, the generation unit 213, and the connection control unit 214 is a hardware module, the same effects as those of the above embodiments can be achieved.

[0030] (3) The program PRA may be manufactured as a standalone product or provided free of charge or for a fee. Specific examples of providing the program PRA include providing the program PRA by writing it to a computer-readable recording medium such as a flash ROM, or providing the program PRA by downloading it via a telecommunications line such as the Internet. Operating a general computer in accordance with the program PRA provided in these ways can cause the computer to function as the information terminal 20 of the above-described embodiment.

[0031] 3. Summary of this disclosure The present disclosure is not limited to the above-described embodiments and modifications, and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following forms. The technical features in the above embodiments corresponding to the technical features in each form described below can be replaced or combined as appropriate to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. A summary of this disclosure is provided below.

[0032] (Appendix 1) A connection method disclosed herein is a connection method for connecting an output device and an information terminal, the connection method including the steps of: acquiring identification information for identifying the output device by the information terminal; generating a hash value by the information terminal based on the identification information acquired by the information terminal; generating a first identification code by the information terminal based on the hash value generated by the information terminal; acquiring the identification information by the output device; generating a hash value by the output device based on the identification information acquired by the output device; generating a second identification code by the output device based on the hash value generated by the output device; accepting a first input operation by the information terminal for inputting the second identification code generated by the output device into the information terminal; and transmitting a connection request signal to the output device if the second identification code input by the first input operation matches the first identification code. According to this connection method, the second identification code generated by the output device is not transmitted to the information terminal via a communication network, and there is no risk of the second identification code being leaked due to eavesdropping on the communication network.

[0033] (Appendix 2) A more preferred embodiment of the connection method is the connection method described in (Appendix 1), in which generating a hash value by the information terminal based on identification information acquired by the information terminal includes acquiring a unique string by the information terminal and generating a hash value based on the identification information acquired by the information terminal and the unique string acquired by the information terminal, and generating a hash value by the output device based on identification information acquired by the output device includes acquiring a unique string by the output device and generating a hash value based on the identification information acquired by the output device and the unique string acquired by the output device. This embodiment provides improved security compared to an embodiment in which a hash value is generated based only on identification information.

[0034] (Appendix 3) Another preferred embodiment of the connection method is the connection method described in (Supplementary Note 1) or (Supplementary Note 2), in which the output device is a display device that outputs an image by displaying the image, the output device displays the identification information, and the information terminal receives a second input operation for inputting the identification information displayed by the output device into the information terminal, and the information terminal acquires the identification information for identifying the output device by acquiring the identification information input by the second input operation. According to this embodiment, a user can connect the information terminal to the display device by inputting the two pieces of information displayed on the display device. [Explanation of symbols]

[0035] 1...information system, 10A, 10B, 10...output device, 20...information terminal, NW...network, 210...processing device, 211...display control unit, 212...acquisition unit, 213...generation unit, 214...connection control unit, 220...communication device, 230...display device, 240...input device, 250...storage device, PRA...program, PRA...program.

Claims

1. A connection method for connecting an output device and an information terminal, The information terminal acquires identification information for identifying the output device; generating a hash value by the information terminal based on the identification information acquired by the information terminal; generating a first identification code by the information terminal based on the hash value generated by the information terminal; The output device acquires the identification information; generating a hash value by the output device based on the identification information acquired by the output device; generating a second identification code by the output device based on the hash value generated by the output device; receiving, by the information terminal, a first input operation for inputting a second identification code generated by the output device into the information terminal, and transmitting a connection request signal to the output device when the second identification code input by the first input operation matches the first identification code; How to connect.

2. The information terminal generates a hash value based on the identification information acquired by the information terminal, The information terminal acquires a unique character string; generating a hash value based on the identification information acquired by the information terminal and the unique character string acquired by the information terminal; The output device generates a hash value based on the identification information acquired by the output device, said output device obtaining a unique string; generating a hash value based on the identification information acquired by the output device and the unique string acquired by the output device; The connection method according to claim 1 .

3. the output device is a display device that outputs an image by displaying the image, the output device displays the identification information; receiving, by the information terminal, a second input operation for inputting the identification information displayed by the output device into the information terminal; The information terminal acquires identification information for identifying the output device, acquiring the identification information input by the second input operation; The connection method according to claim 1 .

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