Nodes and programs

Abstract

To improve convenience of a transaction between a service provider and a user.SOLUTION: The service providing apparatus 70 receives a transaction request for a trading object (for example, an electronic book) provided by the service provider from the communication terminal 10, and transmits a change request for the use authority for the trading object to the blockchain 8 that stores the use authority for the trading object provided by the service provider. Then, the service providing device 70 provides the trading object or the accompanying data accompanying the trading object to the communication terminal 10 having the use authority changed in response to the change request.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a service providing device, a service providing system, a network system, a service providing method, a program, a node, and a blockchain. [Background technology]

[0002] In recent years, with the development of electronic commerce, services for buying and selling digital content such as e-books and music files have become widespread. In such services, users can use electronic data distributed by service providers by conducting transactions with the service providers over a network.

[0003] Furthermore, measures to protect copyrights to works such as e-books and music files traded through such services are necessary. For example, Patent Document 1 discloses a technology that allows users to use e-books for secondary purposes in accordance with the use of the e-books that has been permitted in advance by the copyright holder of the e-book. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-95731 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional methods use a dedicated system provided by the service provider, making it difficult to, for example, transfer ownership between the service provider and the user or to confirm the location of ownership. [Means for solving the problem]

[0006] In order to solve the above-mentioned problem, the invention of claim 1 is a service providing device capable of communicating with a blockchain that stores the usage authority of a transaction object provided by a service provider, and is equipped with a receiving means for receiving a transaction request for the transaction object from a communication terminal, a transmitting means for transmitting a request to change the usage authority of the transaction object to the blockchain, and a providing means for providing the transaction object to the communication terminal that has the usage authority changed in accordance with the change request. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the convenience of transactions between service providers and users. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of a network system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of a computer according to an embodiment. [Figure 3] FIG. 2 is a diagram illustrating an example of a software configuration of a communication terminal according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of an outline of processing in the network system according to the first embodiment. [Figure 5] FIG. 1 is a diagram illustrating an example of a functional configuration of a network system according to a first embodiment. [Figure 6A] FIG. 3 is a conceptual diagram illustrating an example of an authentication management table according to the first embodiment. [Figure 6B] FIG. 3 is a conceptual diagram illustrating an example of an owner management table according to the first embodiment. [Figure 7A] FIG. 3 is a conceptual diagram illustrating an example of a data management table according to the first embodiment. [Figure 7B] FIG. 3 is a conceptual diagram illustrating an example of an owner management table according to the first embodiment. [Figure 8]FIG. 4 is a sequence diagram showing an example of a registration process of electronic data provided from a service providing device in the network system according to the first embodiment. [Figure 9] FIG. 4 is a diagram showing an example of a data registration screen displayed on the service providing device according to the first embodiment. [Figure 10] FIG. 2 is a conceptual diagram showing an example of asset information stored in a node according to the first embodiment. [Figure 11A] FIG. 2 is a conceptual diagram illustrating an example of transaction information stored in a node according to the first embodiment. [Figure 11B] FIG. 2 is a conceptual diagram illustrating an example of transaction information stored in a node according to the first embodiment. [Figure 12] FIG. 10 is a conceptual diagram showing another example of transaction information stored in a node according to the first embodiment. [Figure 13] FIG. 3 is a sequence diagram showing an example of a method for trading electronic data between a communication terminal and a service providing device according to the first embodiment. [Figure 14] FIG. 4 is a diagram showing an example of a login screen displayed on the communication terminal according to the first embodiment. [Figure 15] FIG. 4 is a diagram showing an example of a data list screen displayed on the communication terminal according to the first embodiment. [Figure 16] FIG. 3 is a sequence diagram showing an example of a method for trading electronic data between a communication terminal and a service providing device according to the first embodiment. [Figure 17] FIG. 10 is a conceptual diagram showing an example of asset information updated in step S47. [Figure 18] FIG. 10 is a conceptual diagram showing an example of transaction information generated in step S48. [Figure 19] FIG. 1 is a diagram showing an example of an outline of a method for trading electronic data between users in a network system according to a first embodiment. [Figure 20] FIG. 2 is a sequence diagram showing an example of a method for trading electronic data among a plurality of communication terminals according to the first embodiment. [Figure 21]FIG. 4 is a diagram showing an example of a selection screen displayed on the communication terminal according to the first embodiment. [Figure 22] FIG. 10 is a conceptual diagram showing an example of asset information updated in step S70. [Figure 23] FIG. 10 is a conceptual diagram showing an example of transaction information generated in step S71. [Figure 24] FIG. 10 is a sequence diagram showing another example of the method for trading electronic data among a plurality of communication terminals according to the first embodiment. [Figure 25] FIG. 10 is a diagram illustrating an example of an outline of processing in a network system according to a second embodiment. [Figure 26] FIG. 10 is a conceptual diagram illustrating an example of a user management table according to the second embodiment. [Figure 27] FIG. 10 is a conceptual diagram illustrating an example of asset information stored in a node according to the second embodiment. [Figure 28] FIG. 10 is a sequence diagram showing an example of a method for trading electronic data in a network system according to a second embodiment. [Figure 29] FIG. 10 is a diagram showing an example of a data list screen displayed on a communication terminal according to the second embodiment. [Figure 30] FIG. 10 is a conceptual diagram showing an example of asset information updated in step S118. [Figure 31] FIG. 10 is a conceptual diagram showing an example of transaction information generated in step S119. [Figure 32] FIG. 10 is a diagram illustrating an example of an outline of processing in a network system according to an application example of an embodiment. [Figure 33] FIG. 10 is a diagram illustrating an example of an outline of processing in a network system according to an application example of an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0010] ●Embodiment● ●System configuration Fig. 1 is a diagram showing an example of the overall configuration of a network system according to an embodiment. The network system 1 shown in Fig. 1 is a system for conducting transactions between service providers and users by managing transaction objects provided by multiple service providers using a blockchain 8.

[0011] The network system 1 is configured by a communication terminal 10, a service management device 30, and a service providing system 7. The communication terminal 10, the service management device 30, and the service providing system 7 are connected to each other via a communication network 5. The communication network 5 is constructed using a LAN (Local Area Network), a dedicated line, the Internet, a mobile communication network, or the like. Note that the communication network 5 may include not only wired communication networks but also networks using wireless communication networks such as 5G (5th Generation), Wi-Fi (Wireless Fidelity (registered trademark)), WiMAX (Worldwide Interoperability for Microwave Access), or LTE (Long Term Evolution).

[0012] The communication network 5 also includes a blockchain 8 made up of multiple nodes 80. The nodes 80 are, for example, smartphones, tablet devices, mobile phones, or PCs (Personal Computers). The blockchain 8 is a distributed ledger technology (distributed network) that shares information (ledger) among users. The blockchain 8 makes transaction information public and all users check its legitimacy, thereby ensuring that transactions (contracts) are carried out without fraud. The blockchain 8 also includes multiple nodes 80 used by each user. Users use their own nodes 80 to rewrite or check the information managed in the blockchain 8.

[0013] The communication terminal 10 is a terminal device such as a smartphone used by a user. The communication terminal 10 can perform data communication with the service providing device 70 by accessing a communication network 5 such as the Internet. Note that the communication terminal 10 is not limited to a smartphone, and may be a tablet terminal, a mobile phone, a PC, or the like.

[0014] The service management device 30 is a server device that manages the services provided by the service provider via the communication terminal 10 .

[0015] The service providing system 7 is composed of multiple service providing devices 70 (70a, 70b, 70c; hereinafter, when there is no need to distinguish between them, they will be referred to as the service providing devices 70). The service providing devices 70 are server devices that provide services for trading between users and transaction objects issued by service providers. Services provided by service providers include, for example, e-book viewing services, distribution services for videos, still images such as photographs or paintings, music, or audio, document issuance services for contracts or official documents, and electricity trading services in the electricity retail business. The transaction objects include electronic data such as e-books, video data, still image data, music data, audio data, and document data.

[0016] 1, the number of service providing devices 70 constituting the service providing system 7 is not limited to this. Also, the service management device 30 and the service providing device 70 may each be configured to have their functions distributed across multiple computers. Furthermore, although the service management device 30 and the service providing device 70 will be described as server computers existing in a cloud environment, they may also be servers existing in an on-premise environment.

[0017] ●Hardware configuration Next, the hardware configuration of each device constituting the network system 1 will be described with reference to Fig. 2. Note that components may be added or deleted from the hardware configuration shown in Fig. 2 as needed. Each device constituting the network system 1 has the configuration of a general computer. Here, an example of the hardware configuration of a general computer will be described.

[0018] 2 is a diagram showing an example of the hardware configuration of a computer according to an embodiment. The computer includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, a HD (Hard Disk) 504, an HDD (Hard Disk Drive) controller 505, a display 506, an external device connection I / F (Interface) 508, a network I / F 509, a bus line 510, a keyboard 511, a pointing device 512, a DVD-RW (Digital Versatile Disk Rewritable) drive 514, and a media I / F 516.

[0019] Of these, the CPU 501 controls the operation of the entire computer. The ROM 502 stores programs, such as the IPL, used to drive the CPU 501. The RAM 503 is used as a work area for the CPU 501. The HD 504 stores various data, such as programs. The HDD controller 505 controls the reading and writing of various data from and to the HD 504 under the control of the CPU 501. The display 506 displays various information, such as a cursor, menus, windows, characters, or images. The external device connection I / F 508 is an interface for connecting various external devices. In this case, external devices include, for example, USB (Universal Serial Bus) memories and printers. The network I / F 509 is an interface for data communication using the communication network 5. The bus line 510 is an address bus, a data bus, or the like, for electrically connecting the components, such as the CPU 501, shown in FIG. 2.

[0020] The keyboard 511 is a type of input means having multiple keys for inputting characters, numbers, various instructions, etc. The pointing device 512 is a type of input means for selecting and executing various instructions, selecting a processing target, moving a cursor, etc. The DVD-RW drive 514 controls reading and writing of various data from a DVD-RW 513, which is an example of a removable recording medium. Note that the medium is not limited to a DVD-RW, and may be a DVD-R or a Blu-ray (registered trademark) Disc, etc. The media I / F 516 controls reading and writing (storing) of data from a recording medium 515, such as a flash memory.

[0021] Each of the above programs may be recorded as an installable or executable file on a computer-readable recording medium and distributed. Examples of recording media include CD-Rs (Compact Disc Recordables), DVDs (Digital Versatile Disks), Blu-ray Discs, SD cards, and USB memory. The recording media may also be provided domestically or internationally as a program product. For example, the service providing device 70 according to each embodiment realizes the service providing method according to the present invention by executing the program according to the present invention.

[0022] ● Software configuration Next, computer software installed in the communication terminal 10 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the software configuration of the communication terminal according to the embodiment. As shown in Fig. 3, an OS (Operating System) 150, an e-book application 170a, a video distribution application 170b, and an energy trading application 170c run on the working area 130 of the RAM 503. The OS 150 is basic software that provides basic functions of the communication terminal 10 and manages the entire communication terminal 10.

[0023] The e-book application 170a, the video distribution application 170b, and the energy trading application 170c are applications that run on the OS 150. The e-book application 170a, the video distribution application 170b, and the energy trading application 170c each execute processing independently to execute services or functions provided by the service providing device 70. The e-book application 170a is an application for viewing e-books distributed from the service providing device 70. The video distribution application 170b is an application for listening to video data or music data distributed from the service providing device 70. The energy trading application 170c is an application for conducting energy trading with an energy retailer or the like. Note that while FIG. 3 shows an example in which three applications are installed in the communication terminal 10, the number or types of applications installed in the communication terminal 10 are not limited to this.

[0024] First embodiment Overview Next, an outline of the processing of the network system according to the first embodiment will be explained using Fig. 4. Note that Fig. 4 simply explains the outline of the network system according to the first embodiment, and the details of the functions and the like realized by the network system 1a will be explained using the drawings and the like described later.

[0025] 4 is a diagram showing an example of an outline of processing in the network system according to the first embodiment. FIG. 4 shows an example in which a user A purchases an electronic book, which is an example of a transaction object, from a publisher A.

[0026] The service providing device 70 of publisher A registers information about the e-book to be traded with the user in advance in the blockchain 8. At this time, the service providing device 70 does not register the e-book data itself in the blockchain 8, but registers a hash value uniquely assigned to the e-book. The hash value is a unique value that identifies the e-book, and it is not possible to reverse-calculate from the hash value what the original data represents. Information about the e-books to be traded, sent from multiple service providing devices 70, is registered in the blockchain 8 as asset information.

[0027] The communication terminal 10 of user A uses the e-book application 170a (see FIG. 3) provided by the service management device 30 to send a purchase request for an e-book to the blockchain 8 (step S1a). Next, the blockchain 8 sends the purchase request sent from the communication terminal 10 to the service providing device 70 of publisher A, which issues the e-book to be purchased (step S2a).

[0028] Next, the service providing device 70 transmits an update request for asset information to the blockchain 8 (step S3a). Then, the blockchain 8 updates the information of the owner of the electronic book to be purchased from the registered asset information (step S4a). As a result, the owner of the electronic book published by publisher A is changed from publisher A to user A. The blockchain 8 transmits the access key for the requested electronic book to the requesting communication terminal 10 (step S5a).

[0029] Then, User A can access the service providing device 70 of Publisher A using the access key transmitted from the blockchain 8, thereby viewing the purchased electronic book (Step S6a).

[0030] Digital Rights Management (DRM) is used to protect copyrights of copyrighted works, such as e-books, video data, still image data, music data, audio data, and document data, as a means to prevent unauthorized copying. DRM has functions such as preventing unauthorized copying of data and limiting the number of copies that can be made. DRM allows providers of copyrighted works, such as authors, publishers, and libraries, to provide copyright-protected data to users. However, services with DRM require each provider to use their own proprietary system, which increases the costs of developing, operating, and managing the service. Furthermore, because copyrights are managed on a service-by-service basis, DRM makes it difficult to transfer data to other services or to third parties. For users, for example, it is necessary to identify the provider from which to purchase e-books, and different user registrations, apps, and fee structures are required for each service, which can be inconvenient.

[0031] Therefore, the network system 1a can enhance the fault tolerance of the system by conducting transactions of ownership rights, which are the rights to use objects of transactions such as e-books, on the blockchain 8, and can also ensure tamper resistance by making it difficult to falsify the contents written on the blockchain 8. This allows the network system 1 to improve the convenience of transactions between service providers and users.

[0032] ●Function configuration Next, the functional configuration of the network system according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the functional configuration of the network system according to the first embodiment. Fig. 5 shows terminals or devices shown in Fig. 1 that are related to the processing or operation described below.

[0033] ○Functional configuration of communication terminal○ First, the functional configuration of communication terminal 10 will be described with reference to Fig. 5. Communication terminal 10 has communication unit 11, reception unit 12, display control unit 13, determination unit 14, application execution unit 15, and storage / readout unit 19. Each of these units is a function or means realized when any of the components shown in Fig. 2 operates in response to an instruction from CPU 501 in accordance with a program loaded from ROM 502 onto RAM 503. Communication terminal 10 also has a storage unit 1000 constructed by ROM 502 and HD 504 shown in Fig. 2.

[0034] The communication unit 11 is mainly realized by the processing of the CPU 501 on the network I / F 509, and communicates various data or information with other devices or terminals via the communication network 5. The communication unit 11 transmits, for example, to the service providing device 70, a transaction request for a transaction object provided by a service provider. The communication unit 11 also receives, for example, electronic data related to the transaction object transmitted from the service providing device 70.

[0035] The reception unit 12 is mainly realized by the processing of the CPU 501 using the keyboard 511 or the pointing device 512, and receives various selections or inputs from the user. The display control unit 13 is mainly realized by the processing of the CPU 501, and displays various images on the display 506. The determination unit 14 is mainly realized by the processing of the CPU 501, and makes various determinations.

[0036] Application execution unit 15 is realized by the processing of CPU 501, and executes an application installed in communication terminal 10. Communication terminal 10 receives a transaction object provided by a service provider by, for example, causing application execution unit 15 to execute a predetermined application shown in FIG.

[0037] The storage / readout unit 19 is mainly realized by the processing of the CPU 501 , and stores various data (or information) in the storage unit 1000 and reads out various data (or information) from the storage unit 1000 .

[0038] ○Functional configuration of the service management device○ Next, the functional configuration of service management device 30 will be described with reference to Fig. 5. Service management device 30 has a communication unit 31, an authentication unit 32, an application management unit 33, a data management unit 34, and a storage / readout unit 39. Each of these units is a function or means realized when any of the components shown in Fig. 2 operates in response to an instruction from CPU 501 in accordance with a program loaded on RAM 503. Service management device 30 also has a storage unit 3000 constructed by ROM 502 and HD 504 shown in Fig. 2.

[0039] The communication unit 31 is mainly realized by processing of the CPU 501 on the network I / F 509, and communicates various data or information with other devices or terminals via the communication network 5. The communication unit 31 receives, for example, login request information transmitted from the communication terminal 10.

[0040] The authentication unit 32 is realized by the processing of the CPU 501, and performs authentication processing of the requesting user based on a login request received by the communication unit 31. The authentication unit 32 searches the authentication management DB 3001 using, for example, the user ID and password included in the login request received by the communication unit 31 as search keys. The authentication unit 32 then performs user authentication by determining whether the same set of user ID and password is managed in the authentication management DB 3001.

[0041] The application management unit 33 is mainly realized by the processing of the CPU 501, and manages applications used by the network system 1. The data management unit 34 is mainly realized by the processing of the CPU 501, and manages data related to the transaction object registered in the blockchain 8.

[0042] The storage / readout unit 39 is mainly realized by the processing of the CPU 501 , and stores various data (or information) in the storage unit 3000 and reads out various data (or information) from the storage unit 3000 .

[0043] Authentication management table FIG. 6A is a conceptual diagram showing an example of an authentication management table according to the first embodiment. An authentication management DB 3001 configured with an authentication management table such as that shown in FIG. 6A is constructed in the storage unit 3000. In this authentication management table, each password is associated with each user ID of a user who uses an application provided by the service management device 30 and managed. The user ID is user identification information uniquely assigned to each user, such as a UUID (Universally Unique Identifier) ​​or a GUID (Globally Unique Identifier). The authentication management table shown in FIG. 6A indicates that the user ID of user A is "userA" and the password is "abab."

[0044] Owner management table 6B is a conceptual diagram showing an example of an owner management table according to the first embodiment. An owner management DB 3003 configured with an owner management table such as that shown in FIG. 6B is constructed in the storage unit 3000. This owner management table stores and manages data including information about the owner of the transaction object registered in the blockchain 8. The owner management table stores, in association with one another, an owner ID that identifies the owner of the transaction object, the name of the transaction object, a hash value uniquely assigned to the transaction object, an access key for accessing the electronic data that is the transaction object, and provider information that indicates the address of the service provider.

[0045] ○Functional configuration of the service provider○ Next, the functional configuration of the service providing device 70 will be described with reference to Fig. 5. The service providing device 70 has a communication unit 71, a reception unit 72, a display control unit 73, a determination unit 74, a data management unit 75, and a storage / readout unit 79. Each of these units is a function or means realized when any of the components shown in Fig. 2 operates in response to an instruction from the CPU 501 in accordance with a program loaded on the RAM 503. The service providing device 70 also has a storage unit 7000 constructed by the ROM 502 and HD 504 shown in Fig. 2.

[0046] The communication unit 71 is mainly realized by the processing of the CPU 501 on the network I / F 509, and communicates various data or information with other devices or terminals via the communication network 5. The communication unit 71 receives, for example, a transaction request for a specific transaction object from the communication terminal 10. The communication unit 71 also transmits a request to change the usage authority for the specific transaction object to the blockchain 8. Furthermore, the communication unit 71 provides the specific transaction object to the communication terminal 10 whose usage authority has been changed in accordance with the change request transmitted to the blockchain 8.

[0047] The reception unit 72 is mainly realized by the processing of the CPU 501 using the keyboard 511 or the pointing device 512, and receives various selections or inputs from the user. The display control unit 73 is mainly realized by the processing of the CPU 501, and displays various images on the display 506. The determination unit 74 is mainly realized by the processing of the CPU 501, and makes various determinations.

[0048] The data management unit 75 is mainly realized by the processing of the CPU 501, and manages data related to the transaction object registered in the blockchain 8.

[0049] The storage / readout unit 79 is mainly realized by the processing of the CPU 501 , and stores various data (or information) in the storage unit 7000 and reads out various data (or information) from the storage unit 7000 .

[0050] Data management table 7A is a conceptual diagram showing an example of a data management table according to the first embodiment. A data management DB 7001 configured with a data management table such as that shown in FIG. 7A is constructed in a storage unit 7000. This data management table stores and manages electronic data, which is the subject of a transaction exchanged with a user. The data management table stores, in association with each other, the name of the subject of a transaction to be provided to the user, the file name of the electronic data, which is the subject of a transaction, a hash value uniquely assigned to the electronic data, and an access key for accessing the electronic data.

[0051] Owner management table 7B is a conceptual diagram showing an example of an owner management table according to the first embodiment. An owner management DB 7003 configured with an owner management table such as that shown in FIG. 7B is constructed in the storage unit 7000. This owner management table stores and manages data including information about the owner of the transaction object registered in the blockchain 8. The owner management table stores an owner ID that identifies the owner of the transaction object and a hash value that is uniquely assigned to the transaction object, in association with each other.

[0052] ○Node functional configuration○ Next, the functional configuration of the node 80 constituting the blockchain 8 will be described using FIG. 5. Note that the multiple nodes 80 constituting the blockchain 8 will be described as each having the same function. The node 80 has a communication unit 81, an issuing unit 82, a transaction processing unit 83, an asset processing unit 84, and a storage / reading unit 89. Each of these units is a function or means realized when any of the components shown in FIG. 2 operates in response to an instruction from the CPU 501 in accordance with a program deployed on the RAM 503. The node 80 also has a storage unit 8000 constructed by the ROM 502 and HD 504 shown in FIG. 2.

[0053] The communication unit 81 is mainly realized by processing of the CPU 501 on the network I / F 509, and communicates various data or information with other devices or terminals. The communication unit 81 receives, for example, registration request information transmitted from the service providing device 70.

[0054] The issuing unit 82 is mainly realized by the processing of the CPU 501, and issues an access key for accessing electronic data.

[0055] The transaction processing unit 83 is realized by the processing of the CPU 501, and performs processing such as generating transaction information and storing it in the storage unit 8000. Transaction information is information in which the transaction history of the transaction object on the blockchain 8 is continuously stored. The asset processing unit 84 is realized by the processing of the CPU 501, and performs processing such as generating asset information in accordance with the transaction information and storing it in the storage unit 8000. Details of the transaction information and asset information will be described later.

[0056] The storage / readout unit 89 is mainly realized by the processing of the CPU 501 , and stores various data (or information) in the storage unit 8000 and reads out various data (or information) from the storage unit 8000 .

[0057] Processing or operation of the first embodiment ○Electronic data registration processing○ Next, the processing or operation of the network system according to the first embodiment will be described using Figures 8 to 24. In the following description, an example will be described in which processing is performed between one node 80 constituting the blockchain 8, but each device such as the service providing device 70 and the communication terminal 10 may be configured to perform processing between any of the nodes 80 constituting the blockchain 8.

[0058] First, the process of registering electronic data, which is the object of transaction provided from the service providing device 70, in the blockchain 8 will be described with reference to Figs. 8 to 12. Fig. 8 is a sequence diagram showing an example of the registration process of electronic data provided from the service providing device in the network system according to the first embodiment. Fig. 9 is a diagram showing an example of a data registration screen displayed on the service providing device according to the first embodiment.

[0059] The display control unit 73a of the service providing device 70a receives a predetermined operation from the service provider, and thereby displays the data registration screen 700 shown in Fig. 9 on the display 506 (step S11). The data registration screen 700 shown in Fig. 9 is a display screen for registering electronic data to be provided to the user. The data registration screen 700 includes a data selection area 705 for selecting electronic data to be registered, a data display area 707 showing the electronic data to be registered, a "Register" button 708 to be pressed when registering electronic data, and a "Cancel" button 709 to be pressed when canceling the registration process.

[0060] Next, the receiving unit 72a of the service providing device 70a receives a request to register electronic data when the service provider selects electronic data to be registered and presses the "Register" button 708 (step S12). When the receiving unit 72a receives the request to register electronic data, the data management unit 75a of the service providing device 70a assigns a hash value corresponding to the electronic data to be registered (step S13). The data management unit 75a of the service providing device 70a associates the data file of the electronic data related to the registration request received in step S12 with the hash value assigned in step S13 and stores them in the data management DB 7001a (see FIG. 8) (step S14). In this case, the data management unit 75a stores the name of the electronic data entered in the data selection area 705 together with the hash value, in association with the data file of the electronic data.

[0061] Next, the communication unit 71a of the service providing device 70a transmits, to the node 80, registration request information indicating a request to register unique data related to the data file registered in the data management DB 7001a (step S15). This registration request information includes the name and amount of the electronic data entered in the data selection area 705, the assigned hash value, and identification information (e.g., ID; pressA) that identifies the service provider. As a result, the communication unit 81 of the node 80 receives the registration request information transmitted from the service providing device 70a.

[0062] The asset processing unit 84 of the node 80 generates asset information indicating electronic data to be exchanged on the blockchain 8, using various data indicated in the registration request information received by the communication unit 81 (step S16). Then, the storage and reading unit 89 of the node 80 stores the asset information generated by the asset processing unit 84 in the storage unit 8000 (step S17).

[0063] FIG. 10 is a conceptual diagram illustrating an example of asset information stored in a node according to the first embodiment. Here, asset information is various types of unique information related to the transaction object. In the example of FIG. 10, unique information related to an e-book being traded is shown as the asset. The asset information stores, for each asset ID assigned to each asset, a hash value assigned by the service providing device 70, the name of the transaction object, the owner and publisher of the transaction object, and the transaction amount of the transaction object, all of which are associated with each other. Each item of the asset information contains the corresponding data indicated in the registration request information received by the communication unit 81. For example, the asset information associated with asset ID "B0001" contains the hash value uniquely assigned to the e-book being traded, the name "Book A," the owner "press A," the publisher "press A," and the transaction amount "500."

[0064] Next, the transaction processing unit 83 generates transaction information indicating the transaction history of data exchanged on the blockchain 8 (step S18). Then, the storage / reading unit 89 of the node 80 stores the transaction information generated by the transaction processing unit 83 in the storage unit 8000 (step S19).

[0065] FIG. 11 is a conceptual diagram showing an example of transaction information stored in a node according to the first embodiment. The transaction information stores the transaction history of a transaction object. The transaction information has a record called a block corresponding to one transaction, and the blocks are listed in a continuously increasing order. Each block contains a timestamp and a link to the previous block. In other words, once transaction information is recorded, the data in the block cannot be retroactively changed. Therefore, the blockchain 8 can ensure the reliability of transactions by referencing the transaction information and checking its validity among the multiple nodes 80 that make up the blockchain 8.

[0066] As shown in Figure 11, each block of transaction information stores a transaction ID assigned to each transaction, a hash value that uniquely identifies the transaction, a transaction type that indicates the type of transaction, a timestamp that indicates the date and time the transaction was made, an asset ID that identifies the object of the transaction, a hash value corresponding to the object of the transaction, and information on the issuer and owner of the corresponding object of the transaction.

[0067] 11A. The transaction processing unit 83 generates the first transaction shown in FIG. 11A as a block associated with the transaction ID "T0011." The transaction processing unit 83 generates the following: a hash value "4390s058239052..." that identifies the transaction; a transaction type "Asset Creation" that indicates that an asset was created in step S16; a timestamp that indicates the date and time when the asset was created; Transaction information (first transaction information) is generated that describes unique information (asset ID, hash value, issuer, and owner) related to the generated asset.

[0068] When the asset is registered, the communication unit 81 of the node 80 transmits a registration completion notification of the electronic data to the service providing device 70a (step S20). As a result, the communication unit 71a of the service providing device 70a receives the registration completion notification transmitted from the node 80.

[0069] Meanwhile, the display control unit 73b of the service providing device 70b receives a predetermined operation from the service provider, thereby displaying the data registration screen 700 shown in FIG. 9 on the display 506 (step S21). Next, the service provider selects electronic data to be registered and presses the "Register" button 708, thereby causing the accepting unit 72b of the service providing device 70b to accept a registration request for the electronic data (step S22). Then, when the accepting unit 72b accepts the registration of the electronic data, the data management unit 75b of the service providing device 70b assigns a hash value corresponding to the electronic data to be registered (step S23). Then, the data management unit 75b of the service providing device 70b associates the data file of the electronic data related to the registration request accepted in step S22 with the hash value assigned in step S23 and stores them in the data management DB 7001b (step S24). In this case, the data management unit 75b stores the name of the electronic data input in the data selection area 705 together with the hash value, in association with the data file of the electronic data.

[0070] Next, the communication unit 71b of the service providing device 70b transmits, to the node 80, registration request information indicating a request to register unique data related to the data file registered in the data management DB 7001b (step S25). This registration request information includes the name and amount of the electronic data entered in the data selection area 705, the assigned hash value, and identification information (e.g., ID; pressR) that identifies the service provider. As a result, the communication unit 81 of the node 80 receives the registration request information transmitted from the service providing device 70b.

[0071] The asset processing unit 84 of the node 80 generates asset information indicating electronic data to be exchanged on the blockchain 8, using various data indicated in the registration request information received by the communication unit 81 (step S26). Then, the storage / reading unit 89 of the node 80 stores the asset information generated by the asset processing unit 84 in the storage unit 8000 (step S27). In this case, the asset processing unit 84 generates asset information describing the hash value assigned by the service providing device 70b, the name "Book B", the owner "pressR", the issuer "pressR", and the transaction amount "800" as the asset associated with the asset ID "B0002" shown in FIG. 10.

[0072] Next, the transaction processing unit 83 generates transaction information indicating the transaction history of data exchanged on the blockchain 8 (step S28). In this case, the transaction processing unit 83 generates the second transaction information shown in FIG. 11B. The transaction processing unit 83 generates transaction information (second transaction information) as a block associated with the transaction ID "T0021," which includes the hash value "6g764368d50fdk..." for identifying the transaction, the transaction type "asset generation" indicating that the asset was generated in step S26, a timestamp indicating the date and time when the asset was generated, and unique information about the generated asset (asset ID, hash value, issuer, and owner). Then, the storage / reading unit 89 of the node 80 stores the transaction information (second transaction information) generated by the transaction processing unit 83 in the storage unit 8000 (step S29).

[0073] When the asset is registered, the communication unit 81 of the node 80 transmits a registration completion notification of the electronic data to the service providing device 70b (step S30). As a result, the communication unit 71b of the service providing device 70b receives the registration completion notification transmitted from the node 80.

[0074] Here, the node 80 shares the asset information and transaction information stored in the storage unit 8000 in steps S17 and S19, and steps S27 and S29, by transmitting the information to other nodes 80 constituting the blockchain 8. This allows the blockchain 8 to have multiple nodes 80 hold the same information.

[0075] In this way, the service providing device 70 can register information for identifying electronic data to be provided to a user in the nodes 80 that make up the blockchain 8. Furthermore, the nodes 80 that make up the blockchain 8 can uniquely identify the data registered by the service providing device 70 based on the hash value assigned to each piece of data.

[0076] In the following description, an example will be described in which transaction information is generated for each asset (first transaction information and second transaction information) as shown in FIG. 11, but the transaction processing unit 83 may be configured to generate transactions on the blockchain 8 as one piece of transaction information as shown in FIG. 12. The order of the processing of steps S16 to S17 and the processing of steps S18 to S19 may be reversed. Similarly, the order of the processing of steps S26 to S27 and the processing of steps S28 to S29 may be reversed.

[0077] Electronic data transactions Next, electronic data transactions in the network system 1a will be described with reference to Figures 13 to 18. Figures 13 and 16 are sequence diagrams showing an example of a method for trading electronic data between a communication terminal and a service providing device according to the first embodiment. In the following description, an example of a case where a user uses the communication terminal 10 to view an electronic book will be described as an example of electronic data transactions using the communication terminal 10 and the service providing device 70.

[0078] First, when user A operates the communication terminal 10, the application execution unit 15 of the communication terminal 10 launches the e-book application 170a, which is a specific application installed on the communication terminal 10 (step S31). Next, the display control unit 13 of the communication terminal 10 displays, on the display 506, a login screen 100 that prompts the user to enter user information for logging in to the launched e-book application 170a (step S32). FIG. 14 is a diagram showing an example of a login screen displayed on the communication terminal according to the first embodiment. The login screen 100 shown in FIG. 14 includes an input field 101 and an input field 103 for entering the user's user ID and password, an "OK" button 107 to be pressed when logging in, and a cancel button 109 to be pressed when canceling the login.

[0079] Next, when user A enters his / her user ID in input field 101, enters his / her password in input field 103, and presses "OK" button 107, acceptance unit 12 of communication terminal 10 accepts the login request (step S33). Then, communication unit 11 transmits login request information indicating the login request to service management device 30 (step S34). This login request information includes the user ID and password entered in step S33. As a result, communication unit 31 of service management device 30 receives the login request information transmitted from communication terminal 10. Note that the user ID and password may be configured to be stored in advance in communication terminal 10 or in a storage medium such as a SIM (Subscriber Identity Module Card) card or SD card connected to communication terminal 10. In this case, communication terminal 10 transmits the login request information to service management device 30 from communication unit 11 via communication network 5 in response to the activation of e-book application 170a in step S31.

[0080] Next, the authentication unit 32 of the service management device 30 searches the authentication management table (see FIG. 6A) using the user ID and password received by the communication unit 31 as search keys, and authenticates the user by determining whether the same user ID and the same password are managed (step S35). Below, a case will be described in which the authentication unit 32 determines that user A is a user with valid usage authority. Then, the communication unit 31 transmits a login notification indicating that user A's login has been successful to the requesting communication terminal 10 (step S36). As a result, the communication unit 11 of the communication terminal 10 receives the login notification transmitted from the service management device 30.

[0081] Next, the communication unit 11 of the communication terminal 10 transmits a data list request to the node 80, requesting a list of data indicated in the asset information registered in the blockchain 8 (step S37). As a result, the communication unit 81 of the node 80 receives the data list request transmitted from the communication terminal 10.

[0082] Next, the storage / read unit 89 of the node 80 reads out the asset information stored in the storage unit 8000 (step S38). Then, the communication unit 81 transmits the asset information read out by the storage / read unit 89 to the requesting communication terminal 10 (step S39). As a result, the communication unit 11 of the communication terminal 10 receives the asset information transmitted from the node 80.

[0083] The display control unit 13 of the communication terminal 10 then displays on the display 506 a data list screen 200 displaying a list of data for the e-books related to the asset information transmitted from the node 80 (step S40). FIG. 15 is a diagram showing an example of a data list screen displayed on the communication terminal according to the first embodiment. The data list screen 200 shown in FIG. 15 includes an input area 201 for inputting search criteria for searching for e-books, a list display area 203 showing search results using the input area 201, a "Purchase" button 208 pressed to purchase the e-book, and a "Close" button 209 pressed to cancel the transaction of electronic data. Bibliographic information such as the author's name or title, or keywords related to the owner of the e-book, are input into the input area 201. Pressing the "Search" button 202 causes the communication terminal 10 to perform a search using the input keywords. The list display area 203 also displays the names and owner information of the e-books included in the received asset information. Furthermore, the list display area 203 includes a selection menu 204 for selecting the asset information to be displayed.

[0084] 16, when user A selects predetermined data from selection menu 204 and presses "Purchase" button 208, acceptance unit 12 of communication terminal 10 accepts a purchase request for the selected electronic book (step S41). Then, communication unit 11 of communication terminal 10 transmits purchase request information indicating a purchase request for the selected electronic book to node 80 (step S42). This purchase request information includes user identification information (e.g., user ID) that identifies user A authenticated in step S35, and information on a hash value assigned to the selected electronic book. As a result, communication unit 81 of node 80 receives the purchase request information transmitted from communication terminal 10.

[0085] Next, the issuing unit 82 of the node 80 issues an access key for the electronic book to be purchased (step S43). The communication unit 81 transmits purchase request information to the service providing device 70 of the service provider who is the owner of the electronic book to be purchased (step S44). This purchase request information includes the hash value indicated in the asset information stored in the storage unit 8000 and the access key issued by the issuing unit 82. As a result, the communication unit 71 of the service providing device 70 receives the purchase request information transmitted from the node 80.

[0086] Next, the data management unit 75 of the service providing device 70 associates the hash value and the access key received by the communication unit 71 and stores them in the data management DB 7001 (see FIG. 7A) (step S45).

[0087] Next, the communication unit 71 of the service providing device 70 transmits update request information indicating a request to update the data registered in the blockchain 8 to the node 80 (step S46). This update request information includes the user identification information (e.g., user ID) that identifies user A received in step S42, a hash value that indicates the electronic data to be updated, and provider information that indicates the destination of the service providing device 70. The provider information is, for example, the URL (Uniform Resource Locator) or URI (Uniform Resource Identifier) ​​of the service providing device 70. As a result, the communication unit 81 of the node 80 receives the update request information transmitted from the service providing device 70.

[0088] The asset processing unit 84 of the node 80 updates the asset information stored in the storage unit 8000 (step S47). FIG. 17 is a conceptual diagram showing an example of the asset information updated in step S47. As shown in FIG. 17, the asset processing unit 84 changes the owner information of the asset with asset ID "B0001" from "pressA" to "userA." As a result, the ownership of "book A" corresponding to asset ID "B0001" is transferred from "pressA" to "userA." Then, the owner of "book A" corresponding to asset ID "B0001" becomes "userA," and the usage authority for "book A" corresponding to asset ID "B0001" is granted to user A, who is identified by user ID "userA." In other words, user A obtains access authority to "book A."

[0089] The transaction processing unit 83 also generates transaction information corresponding to the update of the asset information in step S47 (step S48). Then, the storage / reading unit 89 stores the transaction information generated by the transaction processing unit 83 in the storage unit 8000 (step S49). FIG. 18 is a conceptual diagram showing an example of the transaction information generated in step S48. The transaction processing unit 83 generates a new transaction block in the first transaction information so as to correspond to the transaction in which the ownership of book A is assigned from "pressA" to "userA". As shown in FIG. 18, the transaction processing unit 83 writes the transaction type "asset allocation", which corresponds to the process in which the asset is assigned to a new owner in step S48, in the block with the newly assigned transaction ID "T0012". Furthermore, the transaction processing unit 83 writes, in the block of transaction ID "T0012", a hash value "862ywj8j98wqcn..." that identifies the transaction, a timestamp "2020 / 01 / 15 / 19:15:07" indicating the date and time when the asset was allocated, and unique information about the allocated asset (asset ID "B0001", hash value "169467983253a7...", and new owner "userA"). Note that the order of the processing of step S47 and the processing of steps S48 to S49 may be reversed.

[0090] Next, the communication unit 81 of the node 80 transmits to the service providing device 70 a data update notification indicating that the data registered in the blockchain 8 has been updated (step S50). This data update notification includes various information indicated in the asset information updated in step S47. As a result, the communication unit 71 of the service providing device 70 receives the data update notification transmitted from the node 80. The data management unit 75 of the service providing device 70 updates the owner information registered in the owner management DB 7003 (see FIG. 7B) (step S51). In this case, the data management unit 75 changes the owner of "book A" included in the owner information from "pressA" to "userA." In addition, the communication unit 81 transmits to the communication terminal 10 a data update notification indicating that the data registered in the blockchain 8 has been updated (step S52). This data update notification includes the access key issued in step S43 and the provider information received in step S46. As a result, the communication unit 11 of the communication terminal 10 receives the data update notification transmitted from the node 80.

[0091] In this way, the ownership of "Book A" is transferred from "pressA" to "userA." User A, who uses the communication terminal 10, is then able to view the electronic book of Book A. The communication unit 11 of the communication terminal 10 transmits view request information indicating a data view request for Book A to the service providing device 70, which is the publisher of Book A indicated in the provider information received in step S52 (step S53). This view request information includes the access key for Book A received in step S52. As a result, the communication unit 71 of the service providing device 70 receives the view request information transmitted from the communication terminal 10. The storage / reading unit 79 of the service providing device 70 retrieves the electronic data of Book A by searching the data management table (see FIG. 7A) using the access key received by the communication unit 71 as a search key (step S54). Then, the communication unit 71 of the service providing device 70 transmits the electronic data of Book A to the communication terminal 10 (step S55). As a result, the communication unit 11 of the communication terminal 10 receives the electronic data transmitted from the service providing device 70.

[0092] In this way, the communication terminal 10 can select and purchase a desired electronic book from among a plurality of electronic books registered on the blockchain 8 by a plurality of service providers. As a result, a user who owns the electronic book can view the purchased electronic book by accessing the service providing device 70 using the access key transmitted from the blockchain 8.

[0093] Note that Figure 16 shows an example in which, in steps S53 to S55, the communication terminal 10 accesses the service providing device 70 using an access key each time the communication terminal 10 views an electronic book, but the communication terminal 10 may also be configured to download an electronic data file of a specific electronic book from the service providing device 70.

[0094] In the above explanation, an example of the transaction of an e-book was given as an example of electronic data that is the subject of the transaction, but the electronic data that is the subject of the transaction is not limited to this and may be video data, still image data, music data, audio data, document data, etc. In this case, the communication terminal 10 conducts a transaction with the service providing device 70 using the blockchain 8 by using a dedicated app corresponding to the subject of the transaction as shown in FIG.

[0095] The network system 1 may also be configured such that the service provider device 70 provides an electricity trading service using data indicating a user's electricity consumption, using an energy trading app 170c installed on the communication terminal 10. In this case, the service provider using the service provider device 70 acts as an electricity retailer (intermediary) between the user and an electricity producer such as an electric power company. The user and the service provider trade electricity assets based on data indicating the amount of electricity (electricity production and electricity consumption) described in the blockchain 8. The service provider also acts as a certificate issuing business (intermediary) that issues electricity certificates or electronic certificates to users to certify their electricity consumption or electricity production methods. The electricity production method refers to a method of generating electricity (production method) using renewable energy sources such as solar, wind, biomass, geothermal, hydroelectric, solar heat, atmospheric heat, or other heat present in nature.

[0096] Compared to power generation using fossil fuels such as oil, coal, and liquefied natural gas, renewable energy is an environmentally friendly energy source because it emits almost no CO2, a cause of global warming, compared to power generation using fossil fuels such as oil, coal, and liquefied natural gas. An electricity certificate is a certificate issued by a certification authority, such as a certificate issuing business authorized by a national or local government, to certify the transaction of electricity produced by such renewable energy. An electricity certificate is also called a green power certificate, for example. For example, if the user is a company, the company can apply for a certificate and use the issued certificate to certify added value to the environment, thereby improving its corporate value. In this case, the transaction object is electricity produced by an electricity producer, such as an electric power company, and provided (mediated) by a service provider, and the associated data associated with the electricity transaction object is an electricity certificate.

[0097] The communication unit 71 of the service providing device 70 receives, for example, a request for trading electricity from the communication terminal 10 of user A, and transmits a request for changing the usage authority for electricity, which is an example of an asset, to a node 80 constituting the blockchain 8. The asset processing unit 84 of the node 80 changes the owner of the electricity, which is an example of an asset, to user A. Then, the service providing device 70 provides an electricity certificate, which is associated data associated with the electricity, which is the object of trading, to the communication terminal 10 of user A, who is the changed owner in accordance with the transmitted change request. This allows user A to use the production method certificate to apply for public subsidies based, for example, on the renewable energy utilization rate (CO2 reduction rate).

[0098] ○Transactions between users○ Here, another example of the network system according to the first embodiment will be described. A network system 1aa as shown in FIG. 19 is an example in which electronic data, which is the object of transaction, is traded between a plurality of communication terminals. FIG. 19 is a diagram showing an example of an outline of a method for trading electronic data between users in the network system according to the first embodiment. FIG. 19 shows the process in which user B purchases from user A an electronic book (e.g., "book A") that user A has purchased and owns through the above-described process.

[0099] First, user B, who wishes to purchase an electronic book, uses communication terminal 10b to send a purchase request for the electronic book to service management device 30 (step S1aa). Next, service management device 30 sends the purchase request for the electronic book to communication terminal 10a of user A, who is the owner of the requested electronic book (step S2aa). User A then sends a notice of acceptance of the purchase request from user B to service management device 30 (step S3aa), and service management device 30 sends a request to update asset information corresponding to the electronic book to be purchased to blockchain 8 (step S4aa).

[0100] Next, the node 80 constituting the blockchain 8 updates the asset information corresponding to the electronic book to be traded in response to the update request transmitted from the service management device 30 (step S5aa). Specifically, the node 80 changes the owner of the electronic book to be traded from user A to user B. As a result, on the blockchain 8, the owner of the purchased electronic book becomes user B.

[0101] The service management device 30 also transmits an access key for the electronic book to the communication terminal 10b (step S6aa). Then, the communication terminal 10b can access the service providing device 70 using the access key transmitted from the service management device 30, thereby becoming able to view the purchased electronic book (step S7aa).

[0102] As a result, User B, who has acquired ownership of the electronic book, can view the electronic book purchased from User A. Increasing the number of pieces of copyrighted work such as electronic books provided by the service providing device 70 complicates copyright management and increases the management burden. Therefore, the network system 1aa allows transactions between users for the objects of trade provided by the service providing device 70, thereby reducing the management burden on the service provider caused by the accumulation of the number of objects of trade.

[0103] Fig. 19 is a sequence diagram showing an example of a method for trading electronic data between a plurality of communication terminals according to the first embodiment. Note that the process up to displaying a display screen (for example, the data list screen 200 shown in Fig. 15) on the communication terminal 10b for selecting an electronic book to be purchased is similar to the process of steps S31 to S40 in Fig. 13, and therefore description thereof will be omitted. In addition, a case will be described in which the owner of the electronic book corresponding to asset ID "B0001" among the asset information registered in the blockchain 8 is "userA" (see Fig. 17).

[0104] The reception unit 12b of the communication terminal 10b receives a purchase request for the selected electronic book (step S61). The following description will be given assuming that "Book A" has been selected by user B. Next, the communication unit 11b transmits purchase request information indicating a purchase request for the selected "Book A" to the service management device 30 (step S62). This purchase request information includes user identification information (e.g., a user ID) that identifies user B and information on a hash value assigned to "Book A." As a result, the communication unit 31 of the service management device 30 receives the purchase request information transmitted from the communication terminal 10b.

[0105] Next, the communication unit 31 of the service management device 30 transmits the purchase request information transmitted from the communication terminal 10b to the communication terminal 10a used by user A, who is the owner of "Book A" (step S63). As a result, the communication unit 11a of the communication terminal 10a receives the purchase request information transmitted from the service management device 30. Then, the display control unit 13a of the communication terminal 10a displays on the display 506 a selection screen 250 for selecting whether or not to accept the purchase request information transmitted from the service management device 30 (step S64). FIG. 21 is a diagram showing an example of the selection screen displayed on the communication terminal according to the first embodiment. The selection screen 250 shown in FIG. 21 includes an "Accept" button 255 to be pressed when accepting the purchase request and a "Reject" button 257 to be pressed when rejecting the purchase request.

[0106] Next, when User A presses the "Accept" button 255, the acceptance unit 12a of the communication terminal 10a accepts the acceptance of the purchase request (step S65). Then, the communication unit 11a of the communication terminal 10a transmits an acceptance notice for the purchase request to the service management device 30 (step S66). This acceptance notice includes information about the hash value assigned to the accepted electronic book. As a result, the communication unit 31 of the service management device 30 receives the acceptance notice transmitted from the communication terminal 10a.

[0107] Next, the storage / reading unit 39 of the service management device 30 searches the owner management table (see FIG. 6B) using the hash value included in the purchase request information received in step S62 or the acceptance notice received in step S66 as a search key, and reads out the corresponding access key and provider information (step S67). Furthermore, the data management unit 34 of the service management device 30 updates the owner information of "Book A" stored in the owner management DB 3003 (step S68). In this case, the data management unit 34 changes the owner of "Book A" from "userA" to "userB."

[0108] Then, the communication unit 31 of the service management device 30 transmits update request information indicating a request to update the registered data to the node 80 (step S69). This update request information includes user identification information (e.g., a user ID) for identifying the user who is the owner of the data updated in step S68, and hash value information indicating the electronic data to be updated. As a result, the communication unit 81 of the node 80 receives the update request information transmitted from the service management device 30.

[0109] Next, the asset processing unit 84 of the node 80 updates the asset information stored in the storage unit 8000 (step S70). FIG. 22 is a conceptual diagram showing an example of the asset information updated in step S70. As shown in FIG. 22, the asset processing unit 84 changes the owner information of the asset with asset ID "B0001" from "userA" to "userB." As a result, the ownership of "Book A" corresponding to asset ID "B0001" is transferred from "userA" to "userB." Then, the owner of "Book A" corresponding to asset ID "B0001" becomes "userB," and the usage authority for "Book A" corresponding to asset ID "B0001" is granted to user B, who is identified by user ID "userB." In other words, user B obtains access authority to "Book A."

[0110] Furthermore, the transaction processing unit 83 generates transaction information corresponding to the update of the asset information in step S70 (step S71). Then, the storage / reading unit 89 stores the transaction information generated by the transaction processing unit 83 in the storage unit 8000 (step S72). FIG. 23 is a conceptual diagram showing an example of the transaction information generated in step S71. The transaction processing unit 83 generates a new transaction block in the first transaction information so as to correspond to the transaction in which the ownership of book A has been changed from "userA" to "userB." As shown in FIG. 23, the transaction processing unit 83 writes the transaction type "asset allocation," which corresponds to the process in which the asset has been allocated to a new owner in step S70, in the block with the newly assigned transaction ID "T0013." Furthermore, the transaction processing unit 83 writes, in the block of transaction ID "T0013", a hash value "175v8j4ttkfkd3..." that identifies the transaction, a timestamp "2020 / 01 / 24 / 19:35:09" indicating the date and time when the asset was allocated, and unique information about the updated asset (asset ID "B0001", hash value "169467983253a7...", and new owner "userB"). Note that the order of the processing of step S70 and the processing of steps S71 to S72 may be reversed.

[0111] The communication unit 81 of the node 80 transmits a data update notification to the service providing device 70 indicating that the data registered in the blockchain 8 has been updated (step S73). This data update notification includes various information indicated in the asset information updated in step S70. As a result, the communication unit 71 of the service providing device 70 receives the data update notification transmitted from the node 80. The data management unit 75 of the service providing device 70 updates the owner information of "book A" stored in the owner management DB 7003 (see FIG. 7B) (step S74). In this case, the data management unit 75 changes the owner of "book A" included in the owner information from "userA" to "userB."

[0112] Furthermore, the communication unit 81 of the node 80 transmits to the service management device 30 a data update notification indicating that the data registered in the blockchain 8 has been updated (step S75). As a result, the communication unit 31 of the service management device 30 receives the data update notification transmitted from the node 80. The communication unit 31 of the service management device 30 transmits to the communication terminal 10b a data update notification indicating that the data registered in the blockchain 8 has been updated (step S76). This data update notification includes the access key and provider information read in step 67. As a result, the communication unit 11b of the communication terminal 10b receives the data update notification transmitted from the node 80.

[0113] As a result, the ownership of "Book A" is transferred from "user A" to "user B." User B, who uses communication terminal 10b, is then able to view the electronic book of Book A. The communication unit 11b of communication terminal 10b transmits view request information indicating a data view request for Book A to the service providing device 70, which is the publisher of Book A indicated in the provider information received in step S76 (step S77). This view request information includes the access key for Book A received in step S76. As a result, the communication unit 71 of the service providing device 70 receives the view request information transmitted from communication terminal 10b. The storage / reading unit 79 of the service providing device 70 retrieves the electronic data of Book A by searching the data management table (see FIG. 7A) using the access key received by the communication unit 71 as a search key (step S78). Then, the communication unit 71 of the service providing device 70 transmits the electronic data of Book A to communication terminal 10b (step S79). As a result, the communication unit 11b of the communication terminal 10b receives the electronic data transmitted from the service providing device .

[0114] In this way, the network system 1aa can perform transactions with guaranteed reliability not only between users and service providers but also between multiple users by using asset information managed in the blockchain 8. Note that even in transactions between service providers and users in the network system 1a described above, the communication terminal 10 may be configured to transmit and receive various data or information to and from the node 80 via the service management device 30.

[0115] 19 to 23 show an example in which a transaction is carried out between a plurality of communication terminals 10 (10a, 10b) via the service management device 30, but as shown in Fig. 24, the plurality of communication terminals 10 (10a, 10b) may be configured to directly communicate with each other without going through the service management device 30. This will be explained in detail below.

[0116] The reception unit 12b of the communication terminal 10b receives a purchase request for the selected electronic book (step S81). The following description will be given assuming that "Book A" has been selected by user B. Next, the communication unit 11b transmits purchase request information indicating a purchase request for the selected "Book A" to the communication terminal 10a (step S82). This purchase request information includes user identification information (e.g., a user ID) for identifying user B and information on a hash value assigned to "Book A." As a result, the communication unit 11a of the communication terminal 10a receives the purchase request information transmitted from the communication terminal 10b.

[0117] The display control unit 13a of the communication terminal 10a causes the display 506 to display a selection screen 250 (see FIG. 21) for selecting whether or not to accept the purchase request information transmitted from the communication terminal 10a (step S83). Next, the accepting unit 12a accepts the acceptance of the purchase request when the user A presses the "Accept" button 255 (step S84). Then, the communication unit 11a transmits purchase request information indicating a purchase request for "Book A" to the node 80 (step S85). This purchase request information includes the user identification information received in step S82 and information on the hash value assigned to "Book A." Furthermore, the communication unit 81 of the node 80 transmits the purchase request information transmitted from the communication terminal 10a to the service providing device 70 (step S86). As a result, the communication unit 71 of the service providing device 70 receives the purchase request information transmitted from the node 80.

[0118] Next, the storage / reading unit 79 of the service providing device 70 searches the data management table (see FIG. 7A) using the hash value included in the purchase request information received in step S86 as a search key, and reads out the corresponding access key (step S87).

[0119] Next, the communication unit 71 of the service providing device 70 transmits update request information indicating a request to update the data registered in the blockchain 8 to the node 80 (step S88). This update request information includes the access key read in step 87, the user identification information received in step S85, a hash value indicating the electronic data to be updated, and provider information indicating the destination of the service providing device 70. As a result, the communication unit 81 of the node 80 receives the update request information transmitted from the service providing device 70.

[0120] Next, the asset processing unit 84 of the node 80 updates the asset information stored in the storage unit 8000 (step S89), as shown in Fig. 22. Furthermore, the transaction processing unit 83 generates transaction information corresponding to the update of the asset information in step S89 (step S90), as shown in Fig. 23. Then, the storage / reading unit 89 stores the transaction information generated by the transaction processing unit 83 in the storage unit 8000 (step S91). Note that the order of the processing in step S89 and the processing in steps S90 to S91 may be reversed.

[0121] The communication unit 81 transmits a data update notification to the service providing device 70 indicating that the data registered in the blockchain 8 has been updated (step S92). This data update notification includes various information indicated in the asset information updated in step S89. As a result, the communication unit 71 of the service providing device 70 receives the data update notification transmitted from the node 80. The data management unit 75 of the service providing device 70 updates the owner information of "Book A" stored in the owner management DB 7003 (see FIG. 7B) (step S93). In this case, the data management unit 75 changes the owner of "Book A" from "userA" to "userB." In addition, the communication unit 81 transmits a data update notification to the communication terminal 10a indicating that the data registered in the blockchain 8 has been updated (step S94). This data update notification includes the access key and provider information received in step 88. Then, the communication unit 11a of the communication terminal 10a transmits the data update notification transmitted from the node 80 to the communication terminal 10b (step S95). As a result, the communication unit 11b of the communication terminal 10b receives the data update notification sent from the communication terminal 10a.

[0122] In this way, the ownership of "Book A" is transferred from "user A" to "user B." User B, who uses communication terminal 10b, is then able to view the electronic book of Book A. The communication unit 11b of communication terminal 10b transmits view request information indicating a data view request for Book A to the service providing device 70, which is the publisher of Book A indicated in the provider information received in step S95 (step S96). This view request information includes the access key for Book A received in step S95. As a result, the communication unit 71 of the service providing device 70 receives the view request information transmitted from communication terminal 10b. The storage / reading unit 79 of the service providing device 70 retrieves the electronic data of Book A by searching the data management table (see FIG. 7A) using the access key received by the communication unit 71 as a search key (step S97). Then, the communication unit 71 of the service providing device 70 transmits the electronic data of Book A to communication terminal 10b (step S98). As a result, the communication unit 11b of the communication terminal 10b receives the electronic data transmitted from the service providing device .

[0123] In this way, the network system 1aa can perform transactions between multiple users with guaranteed reliability by communicating between multiple communication terminals 10 (10a, 10b) even without going through the service management device 30.

[0124] Effects of the first embodiment As described above, the network system 1 can improve the convenience of transactions by conducting transactions between service providers and users for transaction objects such as electronic books provided from multiple service providing devices 70 via the blockchain 8. Furthermore, by conducting transactions using the service providing devices 70 and the communication terminals 10 via the blockchain 8, the network system 1 can improve the fault tolerance of the system and the resistance to tampering with the transaction contents.

[0125] Second embodiment Next, a network system according to a second embodiment will be described with reference to Figures 25 to 31. The same configurations and functions as those of the above-described embodiment are denoted by the same reference numerals, and their description will be omitted. The network system 1b is a system for lending out transaction objects as a service provided by a service provider.

[0126] FIG. 25 is a diagram showing an example of an outline of processing in a network system according to the second embodiment. The difference from the outline of the network system 1a shown in FIG. 4 is that the transaction of the transaction object is a loan rather than a purchase. The network system 1b uses a blockchain 8 to manage the loan process, loan period, return process, etc. of the traded transaction object. Note that, like the example shown in FIG. 4, FIG. 25 shows an example in which an electronic book is traded as an example of electronic data, which is the transaction object.

[0127] The service providing device 70 registers in advance the hash value of the electronic book that the user wishes to trade with in the blockchain 8. Information about the electronic book to be traded is registered in the blockchain 8 as asset information from each of the service providing devices 70 used by multiple service providers.

[0128] First, the communication terminal 10 used by user A uses the e-book application 170a (see FIG. 3) provided by the service management device 30 to send an e-book lending request to the blockchain 8 (step S1b). Next, the blockchain 8 sends the lending request sent from the communication terminal 10 to the service providing device 70 of library A, which issues the target e-book (step S2b).

[0129] Next, the service providing device 70 sends an update request for asset information to the blockchain 8 (step S3b). Then, the blockchain 8 updates the information on the user and expiration date of the e-book to be lent out of the registered asset information (step S4b). As a result, the user of the e-book issued by library A will be user A until the set expiration date. The blockchain 8 sends the access key for the requested e-book to the requesting communication terminal 10 (step S5b).

[0130] The communication terminal 10 can then access the service providing device 70 of library A using the access key transmitted from the blockchain 8, thereby allowing the user A using the communication terminal 10 to view the loaned electronic book. When the usage period set in the blockchain 8 expires, the access key is updated, and user A using the communication terminal 10 will no longer be able to view the electronic book. In this way, the network system 1b can perform loan processing with the reliability of the electronic data guaranteed by updating the user of the electronic book according to the set usage period and managing it in the blockchain 8.

[0131] 26 is a conceptual diagram showing an example of a user management table according to the second embodiment. In place of the owner management DB 7003, a user management DB 7005 configured with a user management table as shown in FIG. 26 is constructed in the storage unit 7000. This user management table stores and manages data including information on users of the transaction objects registered in the blockchain 8. The user management table stores a user ID that identifies the user of the transaction object, a hash value uniquely assigned to the transaction object, and information on the expiration date of the transaction object, all of which are associated with each other.

[0132] FIG. 27 is a conceptual diagram illustrating an example of asset information stored in a node according to the second embodiment. The asset information shown in FIG. 27 stores, for each asset ID assigned to each asset, a hash value assigned by the service providing device 70, the name of the transaction object, the issuer and user of the transaction object, the transaction amount of the transaction object, a loan flag indicating whether the transaction object is loaned, and expiration information indicating the expiration date for the user's use of the transaction object. Among these, the issuer indicates information about the service provider issuing the transaction object, and the user indicates information about the user to whom the transaction object is loaned and who can use the electronic data. In other words, in the asset information shown in FIG. 27, the user entered as the user has the authorization to use the transaction object. Furthermore, the transaction amount is, for example, "0" in the case of loan. In the example of FIG. 27, the user, loan flag, and expiration date fields are blank, and the transaction amount is "0," indicating that the transaction object associated with any of the asset information is not loaned to any user.

[0133] Fig. 28 is a sequence diagram showing an example of a method for trading electronic data in a network system according to the second embodiment. Note that the process up to when the communication terminal 10 downloads the data indicated in the asset information from the node 80 is the same as the process from step S31 to step S39 in Fig. 13, and therefore a description thereof will be omitted.

[0134] The display control unit 13 of the communication terminal 10 causes the display 506 to display a data list screen 300, which displays a list of e-book data related to the asset information transmitted from the node 80 (step S111). FIG. 29 is a diagram showing an example of a data list screen displayed on a communication terminal according to the second embodiment. The data list screen 300 shown in FIG. 29 includes an input area 301 for inputting search criteria for searching e-books, a list display area 303 showing search results using the input area 301, a "Lend" button 308 pressed to request lending of an e-book, and a "Close" button 309 pressed to cancel the transaction of the e-book. Bibliographic information such as the author name or title, or keywords related to the owner of the e-book, are input into the input area 301. Then, by pressing the "Search" button 302, the communication terminal 10 executes a search using the input keywords. The list display area 303 also displays the name and owner information of the e-book indicated in the received asset information, as well as a selection menu 305 for selecting the lending period of the e-book. Furthermore, the list display area 303 includes a selection menu 304 for selecting the asset information to be displayed.

[0135] Next, user A selects predetermined data from selection menu 304, selects a lending period using selection menu 305, and presses "Lend" button 308, whereby acceptance unit 12 of communication terminal 10 accepts a lending request for the selected electronic book (step S112). The following description will be given assuming that "Book A" has been selected by user A. Next, communication unit 11 of communication terminal 10 transmits lending request information indicating a lending request for the selected "Book A" to node 80 (step S113). This lending request information includes user identification information (e.g., user ID) for identifying user A, the selected lending period, and information on a hash value assigned to "Book A." As a result, communication unit 81 of node 80 receives the lending request information transmitted from communication terminal 10.

[0136] Next, the issuing unit 82 of the node 80 issues an access key for the electronic book to be lent (step S114). The communication unit 81 transmits lending request information to the service providing device 70 of the service provider who is the owner of the electronic book to be lent (step S115). This lending request information includes the hash value indicated in the asset information stored in the storage unit 8000 and the access key issued by the issuing unit 82. As a result, the communication unit 71 of the service providing device 70 receives the purchase request information transmitted from the node 80.

[0137] Next, the data management unit 75 of the service providing device 70 associates the hash value and the access key received by the communication unit 71 and stores them in the data management DB 7001 (see FIG. 7A) (step S116).

[0138] Next, the communication unit 71 of the service providing device 70 transmits update request information indicating a request to update the data registered in the blockchain 8 to the node 80 (step S117). This update request information includes user identification information (e.g., a user ID) for identifying user A, a hash value indicating the electronic book to be updated, and provider information indicating the destination of the service providing device 70. As a result, the communication unit 81 of the node 80 receives the update request information transmitted from the service providing device 70.

[0139] The asset processing unit 84 of the node 80 updates the asset information stored in the storage unit 8000 (step S118). FIG. 30 is a conceptual diagram showing an example of the asset information updated in step S118. As shown in FIG. 30, the asset processing unit 84 enters "userA" in the user field of the asset with asset ID "C0001." The asset processing unit 84 also changes the loan flag to "on loan" and enters the date and time corresponding to the loan period received in step S113 in the usage expiration field. As a result, the usage authority for "book A" corresponding to asset ID "C0001" is granted to user A identified by user ID "userA" until the usage expiration date has passed. In other words, user A has access authority to "book A" until the usage expiration date has passed.

[0140] Furthermore, the transaction processing unit 83 generates transaction information corresponding to the update of the asset information in step S118 (step S119). Then, the storage / reading unit 89 stores the transaction information generated by the transaction processing unit 83 in the storage unit 8000 (step S120). FIG. 31 is a conceptual diagram showing an example of the transaction information generated in step S119. The transaction processing unit 83 generates a new transaction block in the third transaction information so that it corresponds to the transaction in which the usage authority for book A is assigned to "userA".

[0141] As shown in FIG. 31, the transaction processing unit 83 writes, in the block with the newly assigned transaction ID "T0032," a transaction type "asset lending" corresponding to the process in which the asset was lent to the user in step S118. The transaction processing unit 83 also writes, in the block with the transaction ID "T0032," a hash value "5yvmtwcyxqq4xq..." that identifies the transaction, a timestamp "2020 / 01 / 18 / 20:21:43" indicating the date and time the asset was lent, and unique information about the allocated asset (asset ID "C0001," hash value "48678v9mtwppcq...," and user "userA"). Furthermore, when the lending period received in step S113 has elapsed, the transaction processing unit 83 generates a new block with the transaction type "asset return" as indicated by the transaction ID "T0033." In this case, the transaction processing unit 83 leaves the fields for user, lending flag, and usage period blank (blank). Note that the order of the process of step S118 and the processes of steps S119 to S120 may be reversed.

[0142] Next, the communication unit 81 of the node 80 transmits to the service providing device 70 a data update notification indicating that the data registered in the blockchain 8 has been updated (step S121). This data update notification includes various information indicated in the asset information updated in step S118. As a result, the communication unit 71 of the service providing device 70 receives the data update notification transmitted from the node 80. The data management unit 75 of the service providing device 70 updates the user information registered in the user management DB 7005 (see FIG. 26) (step S122). In this case, the data management unit 75 registers "userA" as the user of "book A" included in the user information, and the expiration date information received in step S121 is included. In addition, the communication unit 81 transmits to the communication terminal 10 a data update notification indicating that the data registered in the blockchain 8 has been updated (step S123). This data update notification includes the access key issued in step S114 and the provider information received in step S117. As a result, the communication unit 11 of the communication terminal 10 receives the data update notification transmitted from the node 80.

[0143] In this way, the usage authority for "book A" is assigned to "user A." User A, who uses the communication terminal 10, is then able to view the electronic book of book A during the selected lending period. The communication unit 11 of the communication terminal 10 transmits view request information indicating a data view request for book A indicated in the provider information received in step S123 to the service providing device 70, which is the publisher of book A (step S124). This view request information includes the access key for book A received in step S85. As a result, the communication unit 71 of the service providing device 70 receives the view request information transmitted from the communication terminal 10. The storage / reading unit 79 of the service providing device 70 retrieves the electronic data of book A by searching the data management table (see FIG. 7A) using the access key received by the communication unit 71 as a search key (step S125). The communication unit 71 of the service providing device 70 then transmits the electronic data of book A to the communication terminal 10 (step S126). As a result, the communication unit 11 of the communication terminal 10 receives the electronic data transmitted from the service providing device 70.

[0144] In addition, in Figure 28, in steps S124 to S126, if the communication terminal 10 is configured to download an electronic data file of a specific electronic book from the service providing device 70, viewing restrictions may be imposed by changing (invalidating) the access key after the lending period has expired.

[0145] Furthermore, the network system 1b according to the second embodiment may be configured in a manner such that transactions (lending) are conducted between users using multiple communication terminals 10 (10a, 10b), similar to the case shown in Figures 19 to 24 of the first embodiment.

[0146] Effect of the second embodiment As a result, the network system 1b can not only buy and sell e-books but also lend them with a usage period by managing the usage rights and usage period of e-books using the blockchain 8. Furthermore, by using such a method for managing usage rights and usage periods using the blockchain 8, a user can borrow e-books from multiple service providers, not just one such service provider such as a library.

[0147] ●Application example of the embodiment● In the above-described embodiments, transactions between service providers and users of transaction objects that are electronic data such as electronic books, video data, still image data, music data, audio data, or document data, or transactions between users of transaction objects, have been described. The following describes application examples of the above-described embodiments. The application examples described below are examples in which the transaction objects are not electronic data but are actually physical products.

[0148] FIG. 32 is a diagram illustrating an example of an outline of processing in a network system according to an application example of an embodiment. The network system 1c illustrated in FIG. 32 is a system in which, when a transaction for a transaction object is conducted, a service provider provides a user with electronic key data, which is associated data associated with the transaction object. As illustrated in FIG. 32, for example, user A uses an electronic key to enter or exit a building such as an apartment building or each room in the building. At that time, user A uses a communication terminal 10 to obtain electronic key data used to unlock an electronic lock from the service provider as associated data associated with the transaction object, such as the building or each room in the building. Furthermore, to use a vehicle as a common entity shared by multiple users, user A uses the communication terminal 10 to obtain electronic key data used to unlock an electronic lock for using the common entity from the service provider as associated data associated with the transaction for the common entity. A common entity is an object, service, space (room), location, or information shared by multiple people or organizations. A common entity is not limited to a vehicle, but also includes, for example, an electronic device such as a PC shared by multiple users, a conference room, etc. The vehicle also includes a car, a motorcycle, a bicycle, a wheelchair, etc. Details will be explained below.

[0149] The communication terminal 10 of user A transmits a request to purchase or lend the transaction object to the blockchain 8 (step S1c). Next, the blockchain 8 transmits the request transmitted from the communication terminal 10 to the service providing device 70 of business operator A that handles the requested transaction object (step S2c).

[0150] Next, the service providing device 70 transmits an update request for the asset information to the blockchain 8 (step S3c). Then, the blockchain 8 updates the information on the owner or user of the transaction object from the registered asset information (step S4c). As a result, the owner or user of the transaction object is changed from business operator A to user A. The blockchain 8 transmits the access key for the requested transaction object to the requesting communication terminal 10 (step S5c).

[0151] Then, user A can obtain electronic key data for the purchased or rented transaction object by accessing the service providing device 70 of business operator A using the access key transmitted from the blockchain 8 (step S6c). The communication terminal 10 can enter and exit the building that is the transaction object or use the common facility by registering the obtained electronic key data in the electronic key. Note that the communication terminal 10 may also be configured to have the function of an electronic key. In this way, in response to a transaction request for the transaction object from user A, the network system 1c transmits associated data, such as electronic key data, associated with the transaction object from the service providing device 70 to the communication terminal 10.

[0152] Furthermore, in the network system 1cc shown in FIG. 33, electronic data (accompanying data) such as instruction manuals accompanying the transaction object is transmitted from the service providing device 70 to the communication terminal 10 in response to a request from the communication terminal 10. The product that is the transaction object is delivered from the service provider to user A by delivery, personal delivery, or the like. When a transaction for the transaction object with user A is concluded, the service providing device 70 transmits accompanying data such as a contract or instruction manual for the transaction object to the communication terminal 10, and the service provider delivers the transaction object to user A by delivery, personal delivery, or the like. Note that the processing flow of S1cc to S6cc shown in FIG. 33 is the same as S1c to S6c shown in FIG. 32, and therefore description thereof will be omitted.

[0153] In this way, the network systems 1c and 1cc relating to the application examples conduct transactions of usage rights for the transaction object on the blockchain 8, and by transmitting accompanying data associated with the transaction object from the service providing device 70 to the communication terminal 10, the reliability of the transaction can be ensured even if the actual transaction of the transaction object involves work such as delivery.

[0154] ●Summary● As described above, a service providing device according to one embodiment of the present invention is a service providing device 70 capable of communicating with a blockchain 8 that stores usage authorization for a transaction object (e.g., an e-book) provided by a service provider. The service providing device 70 receives a transaction request for the transaction object provided by the service provider from the communication terminal 10 and transmits a request to change the usage authorization for the transaction object to the blockchain 8. The service providing device 70 then provides the transaction object or associated data associated with the transaction object to the communication terminal 10 that has the usage authorization changed in accordance with the change request. In this way, the service providing device 70 can improve the convenience of transactions between service providers and users by utilizing information on the usage authorization for the transaction object managed on the blockchain 8. Furthermore, by conducting transactions using the blockchain 8, which is highly tamper-resistant, the service providing device 70 can reduce the management burden for the transaction object or increase the reliability of data related to the user of the transaction object.

[0155] Furthermore, in a service providing device according to one embodiment of the present invention, the transaction object is electronic data provided by a service provider, and the usage authority is access authority to the electronic data. Furthermore, the change request sent to the blockchain 8 includes user identification information (e.g., a user ID) that identifies the user using the communication terminal 10, and usage authority for the transaction object is granted to the user identified by the user identification information. As a result, the service providing device 70 can allow only users with access authority to view the electronic data by having the blockchain 8 manage information on users who have access authority to the electronic data.

[0156] Furthermore, in the service providing device 70 according to one embodiment of the present invention, the change request sent to the blockchain 8 includes expiration information indicating the expiration date of the transaction object, and the user identified by the user identification information (e.g., user ID) is granted usage authority until the expiration date indicated in the expiration information has passed. As a result, the service providing device 70 can lend the transaction object to the user by managing the usage authority and expiration date of the transaction object using the blockchain 8.

[0157] Furthermore, a network system according to one embodiment of the present invention is a network system 1 (1a, 1aa, 1b) including a service providing device 70 capable of communicating with a blockchain 8 that stores usage authorization for a transaction object provided by a service provider, and a communication terminal 10 capable of communicating with the service providing device 70. The service providing device 70 receives a transaction request for the transaction object provided by the service provider from the communication terminal 10, transmits a request to change the usage authorization for the transaction object to the blockchain 8, and provides the transaction object or associated data associated with the transaction object to the communication terminal 10 that has the usage authorization changed in response to the change request. The communication terminal 10 transmits a request to acquire the transaction object and acquires the transaction object or associated data associated with the transaction object provided by the service providing device 70 in response to the acquisition request. As a result, the network system 1 (1a, 1aa, 1b) can improve the convenience of transactions between the service providing device 70 and the communication terminal 10 by managing information on usage authorization for the transaction object using the blockchain 8.

[0158] Furthermore, the network system according to one embodiment of the present invention includes a service management device 30 (an example of a management device) that manages transactions between multiple communication terminals 10 (10a, 10b). The service management device 30 receives a transaction request from the communication terminal 10b, and in response to receiving a notice of acceptance of the transaction request from another communication terminal 10a used by a user who has authorization to use the transaction object, transmits a request to change the authorization to use the transaction object to the blockchain 8. As a result, by using information managed in the blockchain 8, the network system 1aa can conduct not only transactions between users and service providers, but also transactions between multiple users with guaranteed reliability.

[0159] Furthermore, a node according to one embodiment of the present invention is a node 80 in a blockchain 8 that manages the usage authority of a transaction object traded between a service providing device 70 and a communication terminal 10. The node receives identification information (e.g., a hash value) of the transaction object from the service providing device 70 and generates asset information indicating the received identification information and the usage authority of the transaction object associated with the identification information. The node 80 also receives a request to change the usage authority of the transaction object from the service providing device 70, the request including user identification information that identifies the user using the communication terminal 10, and changes the usage authority indicated in the generated asset information to the user identified by the user identification information included in the received change request. In this way, the node 80 manages the usage authority of the transaction object traded between the user and the service provider on the blockchain 8, thereby improving the convenience and reliability of transactions between the user and the service provider.

[0160] ●Additional Information● Each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in the present embodiment includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices designed to perform each of the above-described functions, such as an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), a system on a chip (SOC), a graphics processing unit (GPU), and a conventional circuit module.

[0161] Furthermore, the various tables in the embodiments described above may be generated by the learning effects of machine learning, and tables may not be used by classifying data for each associated item using machine learning. Here, machine learning refers to a technology that allows a computer to acquire human-like learning capabilities, in which the computer autonomously generates algorithms necessary for judgments such as data classification from previously acquired learning data and applies these algorithms to new data to make predictions. The learning method for machine learning may be any of supervised learning, unsupervised learning, semi-supervised learning, reinforcement learning, and deep learning, or may be a combination of these learning methods. Any learning method for machine learning is acceptable.

[0162] So far, we have described a service providing device, service providing system, network system, service providing method, program, node, and blockchain according to one embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and other embodiments can be added, modified, or deleted within the scope that can be conceived by a person skilled in the art, and any aspect is included in the scope of the present invention as long as it achieves the functions and effects of the present invention. [Explanation of symbols]

[0163] 1(1a,1aa,1b,1c,1cc) Network System 5. Communication Network 8. Blockchain 10. Communication terminals 11 Communication unit (an example of a request transmission means, an example of an acquisition means) 30 Service management device (an example of a management device) 31 communication unit (an example of a second receiving means, an example of a second transmitting means) 70 Service provision device 71 communication unit (an example of a first receiving means, an example of a first transmitting means, an example of a providing means, and an example of a fourth receiving means) 80 nodes 81 communication unit (an example of a third receiving means) 83 Transaction Processing Unit 84 Asset processing unit (an example of a processing means)

Claims

1. A node of a blockchain system, A storage unit that stores the owner of the transaction object provided by the service provider, A receiving unit that receives a request to use the transaction target from the user's communication terminal, An update means for updating the information of the owner of the transaction object stored in the memory unit to the user, The service provider includes a transmission means for sending an update notification to the service provider indicating that the information of the traded item has been updated, A node that has

2. The node according to claim 1, wherein the usage request includes identification information that identifies the user.

3. The node according to claim 1 or 2, wherein the transmitting means transmits request information to the service provider in response to the receiving unit receiving the request for use.

4. The node according to any one of claims 1 to 3, further comprising transaction means for generating transaction information corresponding to the update of the owner of the transaction object.

5. The node according to any one of claims 1 to 4, further comprising an issuing means for issuing an access key for accessing the transaction object.

6. The node according to any one of claims 1 to 5, wherein the update notification includes an access key for accessing the transaction object.

7. The receiving unit receives a request to register the transaction object from the service providing device, The node according to any one of claims 1 to 6, further comprising a generation means for generating asset information relating to the transaction object based on the data indicated in the registration request.

8. A node in the blockchain system, A storage step that stores the owner of the transaction object provided by the service provider, A receiving step of receiving a request for use of the transaction target from the user's communication terminal, An update step which updates the user with the information of the owner of the transaction object stored in the storage step, A transmission step of sending an update notification to the service provider indicating that the information of the traded item has been updated, A program to execute.

Images