Information provision system, information provision method, and program

Abstract

An information provision unit (28) performs a search in a distributed ledger (4), using a search key serving as at least a portion of public information included in an information provision request. The information provision unit (28) acquires, from the distributed ledger (4), BC registration information corresponding to the search key. The information provision unit (28) uses the search key to perform a search in an information DB (12). The information provision unit (28) acquires, from the information DB (12), work approval information corresponding to the search key. The information provision unit (28) uses a prescribed hash function to convert private information acquired from the information DB (12) through the search into a verification hash value. The information provision unit (28) compares the verification hash value to a registered hash value. If the registered hash value and the verification hash value match, the information provision unit (28) transmits, to a transmission source, the public information corresponding to the search key and the private information acquired from the information DB (12) through the search.

Description

[Technical field]

[0001] The present invention relates to an information providing system, an information providing method, and a non-transitory computer-readable medium. [Background technology]

[0002] Patent Document 1 discloses multiple traceability information management servers that construct a distributed ledger system using a blockchain. Patent Document 1 states that it is undesirable from the viewpoint of protecting personal information if traceability information is accessible without restriction to anyone other than the product owner, and grants individual access rights to each user client. Each traceability information management server transmits a portion of the traceability information registered in the traceability information management server to the user client according to the access rights of the user client. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-21134 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it is well known that the authenticity of information regarding a product's life cycle can be ensured by registering the information in a distributed ledger.

[0005] Information related to the product lifecycle may typically include organization name information, product model number information, serial number information, process name information, workflow name information, timestamp information, approver information and worker information for the workflow, work procedure information and work result information for the workflow.

[0006] Of these pieces of information, organization name information, product model number information, serial number information, process name information, workflow name information, and timestamp information can be said to be information that can be obtained by anybody. In contrast, the approver information and worker information of the workflow, and the work procedure information and work result information of the workflow are technical information and personal information, and therefore should only be available to certain people. In short, the former can be said to be public information with no access restrictions, while the latter is private information with access restrictions. In this way, information related to the product lifecycle includes two types of information with different scopes of disclosure, namely public information and private information.

[0007] However, if private information is registered in a distributed ledger along with public information, there is a risk that the private information may be leaked.

[0008] Here, it is conceivable to set individual access rights for each user client accessing the distributed ledger and limit the information sent to the user client according to the access rights, as in Patent Document 1. Even in this case, as long as private information is registered in the distributed ledger, the risk of private information leaks cannot be eliminated.

[0009] The purpose of the present disclosure is to provide technology that ensures the authenticity of public information and private information using a distributed ledger while reducing the risk of private information being leaked, in consideration of the above-mentioned problems. [Means for solving the problem]

[0010] According to a first aspect of the present disclosure, An information providing system including an information storage server and an information providing server, The information storage server includes: A first information acquisition means for acquiring first information including public information and private information; a first information transmitting means for transmitting the first information acquired by the first information acquiring means to the information providing server; a first information storage means for storing the first information; Equipped with The information providing server includes: A second information acquisition means for acquiring the first information from the information storage server; a conversion means for converting the private information of the first information into a first hash value using a predetermined hash function; an information generating means for generating second information including the public information of the first information and the first hash value; A registration means for registering the second information in a distributed ledger based on a blockchain; a request receiving means for receiving a request for information including at least a portion of the public information; a second information transmitting means for transmitting the public information and the private information to the sender of the information request in response to the information request if the sender of the information request has an access right to the private information; Equipped with The second information transmitting means is performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; performing a search in the first information storage means using the search key; acquiring the first information corresponding to the search key from the first information storage means; converting the private information retrieved from the first information storage means into a second hash value using the predetermined hash function; comparing the first hash value with the second hash value; if the first hash value and the second hash value match, transmit to the source the public information corresponding to the search key and the private information obtained by searching from the first information storage means; An information provision system is provided.

[0011] According to a second aspect of the present disclosure, An information providing system including an information storage server and an information providing server, The information storage server includes: A first information acquisition means for acquiring first information including public information and private information; a first information transmitting means for transmitting the first information acquired by the first information acquiring means to the information providing server; a first information storage means for storing the private information of the first information; Equipped with The information providing server includes: A second information acquisition means for acquiring the first information from the information storage server; a conversion means for converting the private information of the first information into a first hash value using a predetermined hash function; an information generating means for generating second information including the public information of the first information and the first hash value; A registration means for registering the second information in a distributed ledger based on a blockchain; a request receiving means for receiving a request for information including at least a portion of the public information; a second information transmitting means for transmitting the public information and the private information to the sender of the information request in response to the information request if the sender of the information request has an access right to the private information; Equipped with The second information transmitting means is performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; acquiring the plurality of pieces of private information stored in the first information acquisition means from the first information storage means; converting the plurality of pieces of private information acquired from the first information storage means into a second hash value using the predetermined hash function; comparing the first hash value with a plurality of the second hash values; sending, to the source, the public information corresponding to the search key and the private information corresponding to the second hash value that matches the first hash value; An information provision system is provided.

[0012] According to a third aspect of the present disclosure, An information providing method using an information providing system including an information storage server and an information providing server, a first information acquisition step in which the information storage server acquires first information including public information and private information; a first information transmission step in which the information storage server transmits the first information acquired in the first information acquisition step to the information providing server; a first information storage step in which the information storage server stores the first information; a second information acquisition step in which the information providing server acquires the first information from the information storage server; a conversion step in which the information providing server converts the private information of the first information into a first hash value using a predetermined hash function; an information generating step in which the information providing server generates second information including the public information of the first information and the first hash value; A registration step in which the information providing server registers the second information in a distributed ledger using a blockchain; a request receiving step in which the information providing server receives an information providing request including at least a portion of the public information; a second information transmission step of transmitting the public information and the private information to the sender of the information request in response to the information request, when the sender of the information request has an access right to the private information; Including, In the second information transmission step, performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; performing a search in the information storage server using the search key; acquiring the first information corresponding to the search key from the information storage server; converting the private information obtained by search from the information storage server into a second hash value using the predetermined hash function; comparing the first hash value with the second hash value; If the first hash value and the second hash value match, the public information corresponding to the search key and the private information obtained by search from the information storage server are transmitted to the transmission source. A method for providing information is provided.

[0013] According to a fourth aspect of the present disclosure, An information providing method using an information providing system including an information storage server and an information providing server, a first information acquisition step in which the information storage server acquires first information including public information and private information; a first information transmission step in which the information storage server transmits the first information acquired in the first information acquisition step to the information providing server; a first information storage step in which the information storage server stores the private information of the first information; a second information acquisition step in which the information providing server acquires the first information from the information storage server; a conversion step in which the information providing server converts the private information of the first information into a first hash value using a predetermined hash function; an information generating step in which the information providing server generates second information including the public information of the first information and the first hash value; A registration step in which the information providing server registers the second information in a distributed ledger using a blockchain; a request receiving step in which the information providing server receives an information providing request including at least a portion of the public information; a second information transmission step of transmitting the public information and the private information to the sender of the information request in response to the information request, when the sender of the information request has an access right to the private information; Including, In the second information transmission step, performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; acquiring the plurality of pieces of private information stored in the information storage server from the information storage server; converting the plurality of pieces of private information acquired from the information storage server into second hash values ​​using the predetermined hash function; comparing the first hash value with a plurality of the second hash values; sending, to the source, the public information corresponding to the search key and the private information corresponding to the second hash value that matches the first hash value; A method for providing information is provided. Effect of the Invention

[0014] According to the present disclosure, the authenticity of public and private information is guaranteed by a distributed ledger, while the risk of private information leakage is reduced. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a functional block diagram of an information providing system according to a first embodiment. [Diagram 2] FIG. 13 is a schematic diagram of an information providing system according to a second embodiment. [Diagram 3] FIG. 11 is a functional block diagram of an information storage server (second embodiment). [Figure 4] 13 is a diagram showing a specific example of work approval information (second embodiment). [Diagram 5]13 is a diagram showing a specific example of a plurality of pieces of work approval information stored in an information DB (second embodiment); [Figure 6] FIG. 11 is a functional block diagram of an information providing server according to a second embodiment. [Figure 7] FIG. 11 is a specific example of multiple BC registration information registered in a distributed ledger (second embodiment). [Figure 8] FIG. 11 is a sequence diagram of an information providing system (second embodiment). [Figure 9] FIG. 11 is a sequence diagram of an information providing system (second embodiment). [Figure 10] 13 is a specific example of BC registration information acquired by an information provider from a distributed ledger (second embodiment). [Figure 11] 13 is a diagram showing a specific example of work approval information acquired by an information providing unit from an information accumulation server (second embodiment); [Figure 12] 13 is a diagram showing a specific example of information provided by an information providing unit to a search terminal (second embodiment); [Figure 13] 13 is a diagram showing a specific example of a plurality of pieces of private information stored in an information DB (third embodiment). [Figure 14] FIG. 13 is a sequence diagram of an information providing system (third embodiment). [Figure 15] FIG. 13 is a diagram showing a correspondence relationship between a plurality of pieces of private information and their hash values ​​(third embodiment). [Figure 16] FIG. 13 is a diagram illustrating a process of replacing a registered hash value with private information (third embodiment). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (First embodiment) The information providing system 100 will be described below with reference to FIG.

[0017] The information providing system 100 includes an information accumulation server 110 and an information providing server 120 .

[0018] The information storage server 110 includes a CPU 110a (Central Processing Unit) as a central processing unit, a read / write RAM 110b (Random Access Memory), a read-only ROM 110c (Read Only Memory), and a communication interface 110d. The CPU 110a reads and executes a control program stored in the ROM 110c, causing hardware such as the CPU 110a to function as various functional units.

[0019] The various functional units include a first information acquisition unit 111, a first information transmission unit 112, and a first information storage unit 113.

[0020] The first information acquisition unit 111 acquires first information including public information and private information. The first information acquisition unit 111 is a specific example of a first information acquisition means.

[0021] The first information transmitting unit 112 transmits the first information acquired by the first information acquiring unit 111 to the information providing server 120. The first information transmitting unit 112 is a specific example of a first information transmitting means.

[0022] The first information storage unit 113 accumulates the first information. The first information storage unit 113 is a specific example of a first information storage means.

[0023] The information providing server 120 includes a CPU 120a (Central Processing Unit) as a central processing unit, a read / write RAM 120b (Random Access Memory), a read-only ROM 120c (Read Only Memory), and a communication interface 120d. The CPU 120a reads and executes a control program stored in the ROM 120c, causing hardware such as the CPU 120a to function as various functional units.

[0024] The various functional units include a second information acquisition unit 121 , a conversion unit 122 , an information generation unit 123 , a registration unit 124 , a request reception unit 125 , and a second information transmission unit 126 .

[0025] The second information acquisition unit 121 acquires the first information from the information accumulation server 110. The second information acquisition unit 121 is a specific example of a second information acquisition means.

[0026] The conversion unit 122 converts the private information of the first information into a first hash value using a predetermined hash function. The conversion unit 122 is a specific example of a conversion means.

[0027] The information generating unit 123 generates second information including the public information of the first information and a first hash value. The information generating unit 123 is a specific example of an information generating means.

[0028] The registration unit 124 registers the second information in a distributed ledger based on the blockchain. The registration unit 124 is a specific example of a registration means.

[0029] The request receiving unit 125 receives an information provision request including at least a part of the public information. The request receiving unit 125 is one specific example of a request receiving means.

[0030] If the sender of the information request has the right to access the private information, the second information sending unit 126 sends the public information and the private information to the sender in response to the information request. The second information sending unit 126 is a specific example of a second information sending means.

[0031] The second information transmission unit 126 performs a search in the distributed ledger using a search key as at least a part of the public information included in the information request.

[0032] The second information transmission unit 126 acquires the second information corresponding to the search key from the distributed ledger.

[0033] The second information transmission unit 126 executes a search in the first information storage unit 113 using the search key.

[0034] The second information transmitting unit 126 acquires the first information corresponding to the search key from the first information storage unit 113.

[0035] The second information transmission unit 126 converts the private information retrieved from the first information storage unit 113 into a second hash value using a predetermined hash function.

[0036] The second information transmitting unit 126 compares the first hash value with the second hash value.

[0037] Then, if the first hash value and the second hash value match, the second information transmission unit 126 transmits to the source the public information corresponding to the search key and the private information obtained by search from the first information storage unit 113.

[0038] With the above configuration, the authenticity of public information and private information can be guaranteed by the distributed ledger, while the risk of private information being leaked can be reduced.

[0039] Second embodiment Next, a second embodiment will be described with reference to Figures 2 to 12. First, a problem with the second embodiment will be described.

[0040] In other words, it is well known that by registering information about a product's lifecycle in a distributed ledger, the authenticity of the information can be ensured.

[0041] Information related to the product lifecycle may typically include organization name information, product model number information, serial number information, process name information, workflow name information, timestamp information, approver information and worker information for the workflow, work procedure information and work result information for the workflow.

[0042] Of these pieces of information, organization name information, product model number information, serial number information, process name information, workflow name information, and timestamp information can be said to be information that can be obtained by anybody. In contrast, the approver information and worker information of the workflow, and the work procedure information and work result information of the workflow are technical information and personal information, and therefore should only be available to certain people. In short, the former can be said to be public information with no access restrictions, while the latter is private information with access restrictions. In this way, information related to the product lifecycle includes two types of information with different scopes of disclosure, namely public information and private information.

[0043] However, if private information is registered in a distributed ledger along with public information, there is a risk that the private information may be leaked.

[0044] Here, it is conceivable to set individual access rights for each user client accessing the distributed ledger and limit the information sent to the user client according to the access rights, as in Patent Document 1. Even in this case, as long as private information is registered in the distributed ledger, the risk of private information leaks cannot be eliminated.

[0045] The problem of this embodiment is as described above, and in order to solve the problem, an information provision system 1 is shown in Fig. 2. The information provision system 1 has a feature of ensuring the authenticity of public information and private information by a distributed ledger, and suppressing the risk of private information leakage. The information provision system 1 shown in Fig. 2 will be described in detail below.

[0046] The information providing system 1 includes at least one information storage server 2 and an information providing server 3. As shown in Fig. 2, the information providing system 1 of this embodiment includes a plurality of information storage servers 2. The information providing system 1 may further include a distributed ledger 4.

[0047] The information providing system 1 may further include at least one work terminal 5 and at least one search terminal 6. The information providing system 1 of this embodiment includes a plurality of work terminals 5 and a plurality of search terminals 6.

[0048] The multiple information storage servers 2 are servers managed by business owners engaged in various processes that constitute the product lifecycle. The multiple information storage servers 2 typically include a server managed by a business owner engaged in product inspection work, a server managed by a business owner engaged in product shipping work, a server managed by a business owner engaged in product logistics work, etc.

[0049] Each work terminal 5 is a terminal capable of communicating with any one of the information storage servers 2. A worker involved in the product life cycle executes a workflow according to a predetermined work procedure and obtains a work result as a result of the execution. The worker registers organization name information, product model number information, serial number information, process name information, workflow name information, work procedure information, work result information, and worker information in the information storage server 2 using the work terminal 5. The worker requests approval of the work procedure and the work result from an approver. In response to this request, the approver approves the work procedure and the work result and registers approver information in the information storage server 2 using the work terminal 5. Information including the information registered by the worker in the information storage server 2 and the information registered by the approver in the information storage server 2 is hereinafter referred to as work approval information. The work approval information is a specific example of first information.

[0050] Fig. 3 shows a functional block diagram of the information storage server 2. As shown in Fig. 3, the information storage server 2 is equipped with a CPU 2a (Central Processing Unit) as a central processing unit, a read / write RAM 2b (Random Access Memory), a read-only ROM 2c (Read Only Memory), and a communication interface 2d. The CPU 2a reads and executes a control program stored in the ROM 2c, which causes hardware such as the CPU 2a to function as various functional units.

[0051] The various functional units include a workflow unit 10 , an information transmission unit 11 , and an information DB 12 .

[0052] The workflow unit 10 acquires work approval information including public information and private information from each work terminal 5, and registers the acquired work approval information in the information DB 12. Specifically, the workflow unit 10 adds timestamp information to the acquired work approval information, and then registers the work approval information in the information DB 12. The workflow unit 10 is a specific example of a first information acquisition means.

[0053] FIG. 4 shows the work approval information acquired by the workflow unit 10. As shown in FIG. 4, the work approval information includes public information and private information (information that needs to be concealed). The public information includes organization name information, product model number information, serial information, process name information, workflow name information, and time stamp information. The private information includes approver information, worker information, work procedure information, and work result information. In this embodiment, the public information includes multiple pieces of information, but may alternatively be composed of only one piece of information. Similarly, in this embodiment, the private information includes multiple pieces of information, but may alternatively be composed of only one piece of information.

[0054] The information transmitting unit 11 transmits the work approval information acquired by the workflow unit 10 and to which the time stamp information has been added, to the information providing server 3. The information transmitting unit 11 is a specific example of a first information transmitting means.

[0055] The information DB 12 stores the work approval information. The information DB 12 is a specific example of a first information storage means. FIG. 5 shows a plurality of pieces of work approval information stored in the information DB 12.

[0056] Fig. 6 shows a functional block diagram of the information providing server 3. As shown in Fig. 6, the information providing server 3 includes a CPU 3a (Central Processing Unit) as a central processing unit, a readable and writable RAM 3b (Random Access Memory), a read-only ROM 3c (Read Only Memory), and a communication interface 3d. The CPU 3a reads and executes a control program stored in the ROM 3c, which causes hardware such as the CPU 3a to function as various functional units.

[0057] The various functional units include an information receiving unit 20, a hash conversion unit 21, a registration information generating unit 22, a BC registration unit 23, an account generating unit 24, an account paying unit 25, an account information storage unit 26, a request receiving unit 27, and an information providing unit 28.

[0058] The information receiving unit 20 receives and acquires the work approval information from the information storage server 2. The information receiving unit 20 is a specific example of a second information acquiring means.

[0059] The hash conversion unit 21 converts the private information of the work approval information acquired by the information receiving unit 20 into a registered hash value using a predetermined hash function. The registered hash value is a specific example of a first hash value.

[0060] The registration information generating unit 22 generates BC registration information including the public information of the work approval information and the registration hash value. The BC registration information is a specific example of the second information.

[0061] The BC registration unit 23 registers the BC registration information in the distributed ledger 4.

[0062] Here, the distributed ledger 4 will be described with reference to Fig. 2. The distributed ledger 4 is typically a distributed ledger based on consortium-type blockchain technology, and is composed of multiple nodes. The multiple information providing servers 3 shown in Fig. 2 may function as multiple nodes that make up the distributed ledger 4, or multiple servers different from the multiple information providing servers 3 may function as multiple nodes that make up the distributed ledger 4.

[0063] Fig. 7 shows multiple BC registration information registered in the distributed ledger 4. As shown in Fig. 7, the BC registration information registered in the distributed ledger 4 does not include private information, but instead includes a registered hash value obtained by hash-transforming the private information. Therefore, private information will not be directly leaked from the distributed ledger 4, because the hash transformation is an irreversible transformation.

[0064] Returning to Fig. 6, when a user who wishes to refer to work approval information applies for an account via search terminal 6, account generation unit 24 generates account information for that user. The account information typically includes account name information and access authority information regarding the presence or absence of authority to access private information. Account generation unit 24 stores the generated account information in account information storage unit 26.

[0065] The account information storage unit 26 stores information on a plurality of accounts.

[0066] The account issuing unit 25 issues account information to the user.

[0067] For example, when an auditor applies for an account, the account generation unit 24 generates account information having access rights to private information and issues the account information to the auditor. On the other hand, when a person who is not an auditor applies for an account, the account generation unit 24 generates account information having no access rights to private information and issues the account information to the person.

[0068] The request receiving unit 27 receives an information provision request. The information provision request typically includes at least a portion of the public information. The information provision request may include all of the public information. When an auditor or other person operates the search terminal 6, the search terminal 6 transmits an information provision request to the information providing server 3. The request receiving unit 27 receives the information provision request from the search terminal 6. The request receiving unit 27 is a specific example of a request receiving means.

[0069] When the sender of the information request has the right to access the private information, the information providing unit 28 transmits the public information and the private information to the sender in response to the information request. The information providing unit 28 is a specific example of a second information transmitting means.

[0070] Next, the operation of the information providing system 1 will be described with reference to Fig. 8 to Fig. 12. Fig. 8 and Fig. 9 show sequence diagrams of the information providing system 1.

[0071] 8, first, the worker and the approver input work approval information to the work terminal 5. The work terminal 5 transmits the input work approval information to the information storage server 2 (S100).

[0072] The workflow unit 10 of the information accumulation server 2 acquires work approval information from the work terminal 5 (S100), and adds time stamp information to the work approval information. The information transmission unit 11, triggered by the workflow unit 10 acquiring the work approval information from the work terminal 5, transmits the work approval information illustrated in Fig. 4 to the information providing server 3 (S110). Furthermore, the workflow unit 10 accumulates the acquired work approval information in the information DB 12 (S120), as shown in Fig. 5.

[0073] The information receiving unit 20 of the information providing server 3 receives and acquires the work approval information from the information storage server 2 (S110). The hash conversion unit 21 converts the private information of the work approval information acquired by the information receiving unit 20 into a registered hash value using a predetermined hash function (S130).

[0074] The registration information generation unit 22 generates BC registration information including the public information of the work approval information and the registration hash value (S140). The BC registration unit 23 registers the BC registration information generated by the registration information generation unit 22 in the distributed ledger 4 (S150). Multiple pieces of BC registration information stored in the distributed ledger 4 are shown in FIG.

[0075] The process from step S100 to step S150 is repeated every time work approval information is input to the work terminal 5.

[0076] Next, when a user who wants to refer to the work approval information applies for an account via the search terminal 6 (S160), the account generation unit 24 generates account information for the user (S170). The account generation unit 24 stores the generated account information in the account information storage unit 26, and issues the account information to the user (S180).

[0077] Please continue to refer to FIG. 9. When a user who wants to refer to the work approval information logs in to the search terminal 6 using account information provided by the information providing server 3 and operates the search terminal 6, the search terminal 6 transmits an information request to the information providing server 3 (S200). Specifically, a user who wants to refer to the work approval information inputs public information of the work approval information he or she wants to refer to into the search terminal 6. Typically, a user who wants to refer to the work approval information inputs at least a part of the public information of the work approval information he or she wants to refer to into the search terminal 6. The search terminal 6 creates an information request including at least a part of the public information input by the user, and transmits the created information request to the information providing server 3 (S200). In this embodiment, the information request may include at least a part of the public information and account information of the user who is the sender.

[0078] The information providing unit 28 of the information providing server 3 refers to the account information storage unit 26 to determine whether the account that is the sender of the information provision request has the right to access private information (S210).

[0079] [If you have access rights] If it is determined in step S210 that the account that sent the information request has access rights to the private information, the information provider 28 executes a search in the distributed ledger 4 using a search key that is at least a part of the public information included in the information request (S220). For ease of explanation, it is assumed here that the above search key includes "product number information", "serial number information", and "process name information", the "product number information" is "ABC15000", the "serial number information" is "12345", and the "process name information" is "inspection".

[0080] Next, the information providing unit 28 acquires BC registration information corresponding to the above search key from the distributed ledger 4 (S230). Fig. 10 shows the BC registration information acquired by the information providing unit 28 from the distributed ledger 4. As shown in Fig. 10, two pieces of BC registration information match the above search key. Therefore, the information providing unit 28 acquires the two pieces of BC registration information shown in Fig. 10 (BC registration information 4X, BC registration information 4Y) from the distributed ledger 4.

[0081] Returning to Fig. 9, the information providing unit 28 executes a search in the information DB 12 of the information accumulation server 2 using the above search key (S240). Then, the information providing unit 28 acquires work approval information corresponding to the above search key from the information DB 12 (S250). Fig. 11 shows the work approval information acquired by the information providing unit 28 from the information DB 12. As shown in Fig. 11, two pieces of work approval information match the above search key. Therefore, the information providing unit 28 acquires the two pieces of work approval information shown in Fig. 11 (work approval information 2X, work approval information 2Y) from the information DB 12.

[0082] Next, the information providing unit 28 converts the private information obtained by searching the information DB 12 into a verification hash value using a predetermined hash function (S260). The verification hash value is a specific example of a second hash value.

[0083] Then, the information providing unit 28 compares the registration hash value of the BC registration information acquired in step S230 with the verification hash value converted in step S260 (S270). Hereinafter, the above comparison will be specifically described with reference to Figs. 10 and 11.

[0084] Fig. 10 shows two pieces of BC registration information, BC registration information 4X and BC registration information 4Y, and Fig. 11 shows two pieces of work approval information, work approval information 2X and work approval information 2Y.

[0085] 10, BC registration information 4X includes a registered hash value A obtained by hash converting approver information, a registered hash value B obtained by hash converting worker information, a registered hash value C obtained by hash converting work procedure information, and a registered hash value D obtained by hash converting work result information. Similarly, BC registration information 4Y includes a registered hash value E obtained by hash converting approver information, a registered hash value F obtained by hash converting worker information, a registered hash value G obtained by hash converting work procedure information, and a registered hash value H obtained by hash converting work result information.

[0086] 11, the work approval information 2X includes approver information a, worker information b, work procedure information c, and work result information d. Similarly, the work approval information 2Y includes approver information e, worker information f, work procedure information g, and work result information h.

[0087] The information providing unit 28 compares the registered hash value A of the BC registration information 4X with the verification hash value obtained by hash-converting the approver information a of the work approval information 2X (S270). If the comparison shows that the two match, the information providing unit 28 determines that the approver information a of the work approval information 2X has not been tampered with.

[0088] Similarly, the information providing unit 28 compares the registered hash value B of the BC registration information 4X with the verification hash value obtained by hash-converting the worker information b of the work approval information 2X. If the comparison shows that the two match, the information providing unit 28 determines that the worker information b of the work approval information 2X has not been tampered with.

[0089] The information providing unit 28 also compares the registered hash value C with the work procedure information c, and the registered hash value D with the work result information d in the same manner, to determine whether or not they have been tampered with.

[0090] The information providing unit 28 compares the registered hash value E of the BC registration information 4Y with the verification hash value obtained by hash-converting the approver information e of the work approval information 2Y. If the comparison shows that the two match, the information providing unit 28 determines that the approver information e of the work approval information 2Y has not been tampered with.

[0091] Similarly, the information providing unit 28 compares the registered hash value F of the BC registration information 4Y with the verification hash value obtained by hash-converting the worker information f of the work approval information 2Y. If the comparison shows that the two match, the information providing unit 28 determines that the worker information f of the work approval information 2Y has not been tampered with.

[0092] The information providing unit 28 also compares the registered hash value G with the work procedure information g, and the registered hash value H with the work result information h in the same manner, to determine whether or not they have been tampered with.

[0093] As shown in Fig. 10, the public information of multiple pieces of BC registration information will never be completely identical to each other. Similarly, as shown in Fig. 11, the public information of multiple pieces of work approval information will never be identical to each other. In the example of Fig. 10, the workflow name information and time stamp information, which are information not included in the search key among the public information of each piece of BC registration information, differ from one another among the multiple pieces of BC registration information. The same is true in Fig. 11. Therefore, when comparing the registration hash value with the verification hash value, the information providing unit 28 can easily recognize which BC registration information corresponds to which piece of work approval information by referring to the workflow name information or time stamp information one by one.

[0094] If it is determined as a result of the above comparison that none of the approver information, worker information, work procedure information, and work result information included in the private information of the work approval information has been tampered with, the information providing unit 28 determines that the private information of the work approval information has not been tampered with as a whole. After this determination, the information providing unit 28 transmits the public information corresponding to the search key and the private information acquired by search from the information DB 12 to the sender (S280). Here, the "public information corresponding to the search key" may be the public information acquired by search from the distributed ledger 4, or may be the public information acquired by search from the information DB 12. This is because these pieces of public information are the same. In other words, after the above determination, the information providing unit 28 may transmit the work approval information acquired by search from the information DB 12 to the sender.

[0095] If it is determined as a result of the above comparison that any of the approver information, worker information, work procedure information, and work result information included in the private information of the work approval information has been tampered with, the information providing unit 28 determines that the private information of the work approval information stored in the information DB 12 has been tampered with. After this determination, the information providing unit 28 transmits a tampering message to the search terminal 6 indicating that the private information of the work approval information stored in the information DB 12 has been tampered with (S290).

[0096] [If you do not have access rights] If it is determined in step S210 that the account from which the information request was sent does not have the authority to access private information, the information provider 28 performs a search in the distributed ledger 4 using a search key as at least a part of the public information included in the information request (S300).

[0097] Next, the information providing unit 28 acquires BC registration information corresponding to the above search key from the distributed ledger 4 (S310). Fig. 10 shows the BC registration information acquired by the information providing unit 28 from the distributed ledger 4. As shown in Fig. 10, two pieces of BC registration information match the above search key. Therefore, the information providing unit 28 acquires the two pieces of BC registration information shown in Fig. 10 (BC registration information 4X, BC registration information 4Y) from the distributed ledger 4.

[0098] Then, the information providing unit 28 transmits the public information of the BC registration information acquired from the distributed ledger 4 to the search terminal 6 (S320). At this time, as shown in Fig. 10, the information providing unit 28 may transmit the BC registration information to the search terminal 6 without deleting the registration hash value of the BC registration information acquired from the distributed ledger 4. Alternatively, as shown in Fig. 12, the information providing unit 28 may transmit only the public information of the BC registration information to the search terminal 6 after deleting the registration hash value of the BC registration information acquired from the distributed ledger 4.

[0099] The second embodiment of the present disclosure has been described above. The second embodiment has the following features.

[0100] The information providing system 1 includes an information accumulation server 2 and an information providing server 3 .

[0101] The information accumulation server includes a workflow unit 10, an information transmission unit 11, and an information DB 12. The workflow unit 10 (first information acquisition means) acquires work approval information (first information) including public information and private information. The information transmission unit 11 (first information transmission means) transmits the work approval information acquired by the workflow unit 10 to the information providing server 3. The information DB 12 (first information storage means) accumulates the work approval information.

[0102] The information providing server 3 includes an information receiving unit 20, a hash conversion unit 21, a registration information generating unit 22, a BC registration unit 23, a request receiving unit 27, and an information providing unit 28. The information receiving unit 20 (second information acquisition means) acquires the work approval information from the information storage server 2. The hash conversion unit 21 (conversion means) converts the private information of the work approval information into a registration hash value (first hash value) using a predetermined hash function. The registration information generating unit 22 (information generation means) generates BC registration information (second information) including the public information of the work approval information and the registration hash value. The BC registration unit 23 (registration means) registers the BC registration information in the distributed ledger 4 by the blockchain. The request receiving unit 27 (request receiving means) receives an information provision request including at least a part of the public information. If the sender of the information provision request has access authority to the private information, the information providing unit 28 (second information transmission means) transmits the public information and the private information to the sender in response to the information provision request.

[0103] The information providing unit 28 executes a search in the distributed ledger 4 using a search key as at least a part of the public information included in the information request (S220). The information providing unit 28 acquires the BC registration unit 23 corresponding to the search key from the distributed ledger 4 (S230). The information providing unit 28 executes a search in the information DB 12 using the search key (S240). The information providing unit 28 acquires the work approval information corresponding to the search key from the information DB 12 (S250). The information providing unit 28 converts the private information acquired by search from the information DB 12 into a verification hash value (second hash value) using a predetermined hash function (S260). The information providing unit 28 compares the registered hash value with the verification hash value (S270). If the registered hash value and the verification hash value match, the information providing unit 28 transmits the public information corresponding to the search key and the private information acquired by search from the information DB 12 to the sender (S280).

[0104] According to the above-described information providing system 1, the authenticity of public information and private information can be guaranteed by the distributed ledger, and the risk of private information being leaked can be reduced.

[0105] Furthermore, if the registration hash value and the verification hash value do not match, the information providing unit 28 determines that the private information stored in the information DB 12 has been tampered with (S270, S290).

[0106] Furthermore, if the sender of the information request does not have access authority to the private information, the information providing unit 28 executes a search in the distributed ledger using a search key (S300). The information providing unit 28 acquires public information of the BC registration information corresponding to the search key from the distributed ledger 4 (S310). The information providing unit 28 transmits the public information acquired from the distributed ledger 4 to the sender (S320). With the above configuration, a configuration is realized in which private information is not transmitted to a sender that does not have access authority to the private information.

[0107] (Modification) The second embodiment can be modified, for example, as follows.

[0108] 9, the information providing unit 28 may compare the public information of the work approval information acquired by search from the information DB 12 with the public information of the BC registration information acquired from the distributed ledger 4. If the two do not match, the information providing unit 28 may determine that the public information stored in the information DB 12 has been tampered with. In this case, in step S290, the information providing unit 28 may transmit to the search terminal 6 a tampering message indicating that the public information stored in the information DB 12 has been tampered with.

[0109] Third embodiment Next, a third embodiment will be described with reference to Figures 13 to 16. Below, the differences between this embodiment and the second embodiment will be mainly described, and overlapping descriptions will be omitted.

[0110] In the second embodiment, as shown in FIG. 5, the information DB 12 stores work approval information including public information and private information.

[0111] In contrast, in this embodiment, as shown in FIG. 13, the information DB 12 stores only private information among the work approval information (S120).

[0112] 9, the information providing unit 28 executes a search in the information DB 12 of the information storage server 2 using the search key (S240). Then, the information providing unit 28 acquires work approval information corresponding to the search key from the information DB 12 (S250).

[0113] 14, the information providing unit 28 acquires a plurality of pieces of private information from the information DB 12 of the information storage server 2 (S251). Specifically, the information providing unit 28 acquires all pieces of private information accumulated in the information DB 12 of each information storage server 2.

[0114] Next, as shown in FIG. 15, the information providing unit 28 converts the multiple pieces of private information acquired in step S251 into a verification hash value using a predetermined hash function (S261).

[0115] Then, the information providing unit 28 compares the registration hash value of the BC registration information acquired in step S230 with the verification hash value generated in step S261 (S271).

[0116] Then, the information providing unit 28 transmits to the sender the public information corresponding to the search key and the private information corresponding to the verification hash value that matches the registered hash value (S281). Typically, this is as follows.

[0117] Fig. 10 shows the BC registration information acquired by the information provider 28 from the distributed ledger 4. As shown in Fig. 10, two pieces of BC registration information match the search key. Therefore, the information provider 28 acquires the two pieces of BC registration information shown in Fig. 10 (BC registration information 4X and BC registration information 4Y) from the distributed ledger 4.

[0118] Next, the information providing unit 28 first identifies a verification hash value that matches the registered hash value A of the BC registration information 4X from among the multiple verification hash values ​​shown in FIG. 15. Then, as shown in FIG. 16, the information providing unit 28 replaces the registered hash value A of the BC registration information 4X with private information corresponding to the identified verification hash value. The information providing unit 28 executes the same process for the registered hash value B to the registered hash value D of the BC registration information 4X. As a result, the BC registration information 4X is converted into work approval information. In this way, when all the registered hash values ​​of the BC registration information 4X can be converted to private information, the information providing unit 28 transmits the public information and the private information to the sender (S281). The same process is performed for the BC registration information 4Y.

[0119] If the information providing unit 28 can identify multiple verification hash values ​​that match the registered hash value A of the BC registration information 4X among the multiple verification hash values ​​shown in Fig. 15, the information providing unit 28 determines that the private information stored in the information DB 12 has been tampered with. If the information providing unit 28 cannot identify any verification hash value that matches the registered hash value A of the BC registration information 4X among the multiple verification hash values ​​shown in Fig. 15, the information providing unit 28 determines that the private information stored in the information DB 12 has been tampered with. Then, the information providing unit 28 transmits a tampering message indicating that the private information stored in the information DB 12 has been tampered with to the search terminal 6 (S291).

[0120] The third embodiment of the present disclosure has been described above, and the third embodiment has the following features.

[0121] As shown in FIG. 13, the information DB12 (first information storage means) accumulates private information of the work approval information (first information). As shown in FIG. 14, the information providing unit 28 (second information transmission means) executes a search in the distributed ledger 4 using a search key as at least a part of the public information included in the information provision request (S220). The information providing unit 28 acquires BC registration information (second information) corresponding to the search key from the distributed ledger 4 (S230). The information providing unit 28 acquires a plurality of pieces of private information accumulated in the information DB12 from the information DB12 (S251). The information providing unit 28 converts the plurality of pieces of private information acquired from the information DB12 into a verification hash value (second hash value) by a predetermined hash function (S261). The information providing unit 28 compares the registration hash value with the plurality of verification hash values ​​(S271). The information providing unit 28 transmits to the sender the public information corresponding to the search key and the private information corresponding to the verification hash value that matches the registered hash value (S281). According to the above information providing system 1, the authenticity of the public information and the private information can be guaranteed by the distributed ledger, and the risk of private information leakage can be reduced. In addition, since there is no need to store the public information in the information DB 12 of the information storage server 2, this contributes to saving resources of the information DB 12.

[0122] In this embodiment, similarly to the second embodiment, the information DB 12 may store work approval information including public information and private information.

[0123] Furthermore, if there are a plurality of verification hash values ​​that match the registered hash value, or if there are none, the information providing unit 28 determines that the private information stored in the information DB 12 has been tampered with (S291). With the above configuration, it can be determined that the private information stored in the information DB 12 has been tampered with.

[0124] In the above example, the program can be stored and provided to the computer using various types of non-transitory computer readable media. The non-transitory computer readable media includes various types of tangible storage media. Examples of the non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives) and magneto-optical recording media (e.g., magneto-optical disks). Examples of the non-transitory computer readable media further include CD-ROM (Read Only Memory), CD-R, CD-R / W, and semiconductor memory (e.g., mask ROM. Examples of the non-transitory computer readable media further include PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, and RAM (random access memory). The program may also be provided to the computer by various types of transitory computer readable media. Examples of the transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire or an optical fiber, or via a wireless communication path.

[0125] A part or all of the above-described embodiments may be described as follows, but is not limited to the following.

[0126] (Appendix 1) An information providing system including an information storage server and an information providing server, The information storage server includes: A first information acquisition means for acquiring first information including public information and private information; a first information transmitting means for transmitting the first information acquired by the first information acquiring means to the information providing server; a first information storage means for storing the first information; Equipped with The information providing server includes: A second information acquisition means for acquiring the first information from the information storage server; a conversion means for converting the private information of the first information into a first hash value using a predetermined hash function; an information generating means for generating second information including the public information of the first information and the first hash value; A registration means for registering the second information in a distributed ledger based on a blockchain; a request receiving means for receiving a request for information including at least a portion of the public information; a second information transmitting means for transmitting the public information and the private information to the sender of the information request in response to the information request if the sender of the information request has an access right to the private information; Equipped with The second information transmitting means is performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; performing a search in the first information storage means using the search key; acquiring the first information corresponding to the search key from the first information storage means; converting the private information retrieved from the first information storage means into a second hash value using the predetermined hash function; comparing the first hash value with the second hash value; if the first hash value and the second hash value match, transmit to the source the public information corresponding to the search key and the private information obtained by searching from the first information storage means; Information provision system.

[0127] (Appendix 2) the second information transmitting means determines that the private information stored in the first information storing means has been tampered with when the first hash value and the second hash value do not match; 2. An information provision system as described in appendix 1.

[0128] (Appendix 3) the second information transmission means, when the public information of the first information acquired by search from the first information storage means does not match the public information of the second information acquired from the distributed ledger, determines that the public information stored in the first information storage means has been tampered with; 3. An information provision system according to claim 1 or 2.

[0129] (Appendix 4) The second information transmitting means is if the sender of the information request does not have access to the private information, performing a search in the distributed ledger using the search key; Obtaining the public information of the second information corresponding to the search key from the distributed ledger; Transmitting the public information obtained from the distributed ledger to the source; 4. An information provision system according to any one of appendix 1 to 3.

[0130] (Appendix 5) An information providing system including an information storage server and an information providing server, The information storage server includes: A first information acquisition means for acquiring first information including public information and private information; a first information transmitting means for transmitting the first information acquired by the first information acquiring means to the information providing server; a first information storage means for storing the private information of the first information; Equipped with The information providing server includes: A second information acquisition means for acquiring the first information from the information storage server; a conversion means for converting the private information of the first information into a first hash value using a predetermined hash function; an information generating means for generating second information including the public information of the first information and the first hash value; A registration means for registering the second information in a distributed ledger based on a blockchain; a request receiving means for receiving a request for information including at least a portion of the public information; a second information transmitting means for transmitting the public information and the private information to the sender of the information request in response to the information request if the sender of the information request has an access right to the private information; Equipped with The second information transmitting means is performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; acquiring the plurality of pieces of private information stored in the first information acquisition means from the first information storage means; converting the plurality of pieces of private information acquired from the first information storage means into a second hash value using the predetermined hash function; comparing the first hash value with a plurality of the second hash values; sending, to the source, the public information corresponding to the search key and the private information corresponding to the second hash value that matches the first hash value; Information provision system.

[0131] (Appendix 6) The second information transmitting means is if there are a plurality of second hash values ​​that match the first hash value, or if there is no second hash value that matches the first hash value, it is determined that the private information stored in the first information storage means has been tampered with. 6. An information provision system as described in appendix 5.

[0132] (Appendix 7) The second information transmitting means is if the sender of the information request does not have access to the private information, performing a search in the distributed ledger using the search key; Obtaining the public information of the second information corresponding to the search key from the distributed ledger; Transmitting the public information obtained from the distributed ledger to the source; 7. An information provision system according to claim 5 or 6.

[0133] (Appendix 8) An information providing method using an information providing system including an information storage server and an information providing server, a first information acquisition step in which the information storage server acquires first information including public information and private information; a first information transmission step in which the information storage server transmits the first information acquired in the first information acquisition step to the information providing server; a first information storage step in which the information storage server stores the first information; a second information acquisition step in which the information providing server acquires the first information from the information storage server; a conversion step in which the information providing server converts the private information of the first information into a first hash value using a predetermined hash function; an information generating step in which the information providing server generates second information including the public information of the first information and the first hash value; A registration step in which the information providing server registers the second information in a distributed ledger using a blockchain; a request receiving step in which the information providing server receives an information providing request including at least a portion of the public information; a second information transmission step of transmitting the public information and the private information to the sender of the information request in response to the information request, when the sender of the information request has an access right to the private information; Including, In the second information transmission step, performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; performing a search in the information storage server using the search key; acquiring the first information corresponding to the search key from the information storage server; converting the private information obtained by the search from the information storage server into a second hash value using the predetermined hash function; comparing the first hash value with the second hash value; If the first hash value and the second hash value match, the public information corresponding to the search key and the private information obtained by search from the information storage server are transmitted to the transmission source. Information provision method.

[0134] (Appendix 9) An information providing method using an information providing system including an information storage server and an information providing server, a first information acquisition step in which the information storage server acquires first information including public information and private information; a first information transmission step in which the information storage server transmits the first information acquired in the first information acquisition step to the information providing server; a first information storage step in which the information storage server stores the private information of the first information; a second information acquisition step in which the information providing server acquires the first information from the information storage server; a conversion step in which the information providing server converts the private information of the first information into a first hash value using a predetermined hash function; an information generating step in which the information providing server generates second information including the public information of the first information and the first hash value; A registration step in which the information providing server registers the second information in a distributed ledger using a blockchain; a request receiving step in which the information providing server receives an information providing request including at least a portion of the public information; a second information transmission step of transmitting the public information and the private information to the sender of the information request in response to the information request, when the sender of the information request has an access right to the private information; Including, In the second information transmission step, performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; acquiring the plurality of pieces of private information stored in the information storage server from the information storage server; converting the plurality of pieces of private information acquired from the information accumulation server into a second hash value using the predetermined hash function; comparing the first hash value with a plurality of the second hash values; sending, to the source, the public information corresponding to the search key and the private information corresponding to the second hash value that matches the first hash value; Information provision method.

[0135] (Appendix 10) A non-transitory computer-readable medium having stored thereon a program for causing a computer to execute the information providing method according to claim 8.

[0136] (Appendix 11) A non-transitory computer-readable medium having stored thereon a program for causing a computer to execute the information providing method according to claim 9. [Explanation of symbols]

[0137] 1 Information provision system 2. Information storage server 2X Work Approval Information 2Y Work approval information 3. Information Server 4. Distributed Ledgers 4X BC Registration Information 4Y BC Registration Information 5. Work terminal 6 Search Terminal 10 Workflow Section 11 Information transmission section 12 Information DB 20 Information Receiving Section 21 Hash conversion unit 22 Registration information generation unit 23 BC Registration Department 24 Account Creation Section 25 Account Payment Department 26 Account information storage unit 27 Request Reception Unit 28 Information Provision Department

Claims

1. An information providing system including an information storage server and an information providing server, The information storage server includes: A first information acquisition means for acquiring first information including public information and private information; a first information transmitting means for transmitting the first information acquired by the first information acquiring means to the information providing server; a first information storage means for storing the private information of the first information; Equipped with The information providing server includes: A second information acquiring means for acquiring the first information from the information storage server; a conversion means for converting the private information of the first information into a first hash value using a predetermined hash function; an information generating means for generating second information including the public information of the first information and the first hash value; A registration means for registering the second information in a distributed ledger based on a blockchain; a request receiving means for receiving a request for information including at least a portion of the public information; a second information transmitting means for transmitting the public information and the private information to the sender of the information request in response to the information request if the sender of the information request has an access right to the private information; Equipped with The second information transmitting means is performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; acquiring the plurality of pieces of private information stored in the first information acquisition means from the first information storage means; converting the plurality of pieces of private information acquired from the first information storage means into a second hash value using the predetermined hash function; comparing the first hash value with a plurality of the second hash values; sending the public information corresponding to the search key and the private information corresponding to the second hash value that matches the first hash value to the source; The second information transmitting means is if there are a plurality of the second hash values ​​that match the first hash value, it is determined that the private information stored in the first information storage means has been tampered with; Information provision system.

2. The second information transmitting means is if the sender of the information request does not have access to the private information, performing a search in the distributed ledger using the search key; Obtaining the public information of the second information corresponding to the search key from the distributed ledger; Transmitting the public information obtained from the distributed ledger to the source; 2. The information providing system according to claim 1.

3. An information providing method using an information providing system including an information storage server and an information providing server, a first information acquisition step in which the information storage server acquires first information including public information and private information; a first information transmission step in which the information storage server transmits the first information acquired in the first information acquisition step to the information providing server; a first information storage step in which the information storage server stores the private information of the first information; a second information acquisition step in which the information providing server acquires the first information from the information storage server; a conversion step in which the information providing server converts the private information of the first information into a first hash value using a predetermined hash function; an information generating step in which the information providing server generates second information including the public information of the first information and the first hash value; A registration step in which the information providing server registers the second information in a distributed ledger using a blockchain; a request receiving step in which the information providing server receives an information providing request including at least a portion of the public information; a second information transmission step of transmitting the public information and the private information to the sender of the information request in response to the information request, when the sender of the information request has an access right to the private information; Including, In the second information transmission step, performing a search on the distributed ledger using a search key as at least a portion of the public information included in the request for information; Obtaining the second information corresponding to the search key from the distributed ledger; acquiring the plurality of pieces of private information stored in the information storage server from the information storage server; converting the plurality of pieces of private information acquired from the information storage server into second hash values ​​using the predetermined hash function; comparing the first hash value with a plurality of the second hash values; sending the public information corresponding to the search key and the private information corresponding to the second hash value that matches the first hash value to the source; In the second information transmission step, if there are a plurality of the second hash values ​​that match the first hash value, it is determined that the private information stored in the first information storage step has been tampered with; Information provision method.

4. A program that causes a computer to execute the information provision method described in claim 3.

Images