Information processing system, information processing method, server in an information processing system, blockchain node, and computer program product

Abstract

An information processing system includes a server, multiple blockchain nodes, and multiple terminals. The multiple blockchain nodes each read, from a blockchain, each first transaction data item that is associated with second transaction data broadcast by the server and is past transaction data. Based on a relationship between a commitment value of a target item included in the second transaction data and a commitment value of a source item included in the first transaction data, the multiple blockchain nodes each verify whether an item in the second transaction data is composed of a raw material included in the source item in the first transaction data.

Description

Technical Field

[0001] The present invention relates to an information processing system, an information processing method, a server, a blockchain node, and a program. Background Art

[0002] Conventionally, a technique for recording tracking information for items being moved on a blockchain while reducing the amount of data required is known (e.g., Japanese Patent Application Laid-Open No. 2021-64219). In the technique disclosed in Japanese Patent Application Laid-Open No. 2021-64219, upon receiving a request signal containing identification information for an item being tracked, the server retrieves from the blockchain a sequence of transaction data related to the movement of the item corresponding to the identification information included in the request signal, as well as a sequence of accumulators corresponding to the sequence of transaction data. The server then verifies whether each accumulator in the retrieved sequence of accumulators stores the identification information for the item being tracked, and outputs the verification result. Summary of the Invention

[0003] Problems to be solved by the invention

[0004] However, users who use items as goods or services sometimes want to know what elements the items are made of. For example, consider the case of manufacturing an industrial product. It should be noted that industrial products are often made of various raw materials (such as rare metals).

[0005] In particular, in recent years, the United Nations has established Sustainable Development Goals (SDGs), which require the provision of projects that take the global environment into consideration. Therefore, if it can be verified that the elements that constitute a project are elements that take the global environment into consideration, it is believed that the verification results can be used as SDGs indicators. However, it is difficult to distinguish the differences between processed products or industrial products using the same raw materials from their appearance. On the other hand, if information related to the raw materials of the project (or information related to the process of providing energy) is traceable, it is possible to set, measure, and evaluate indicators based on this information, and it is also possible to restrict the movement of projects whose indicators do not meet the specified standards.

[0006] In addition, before industrial products are delivered to consumers, a supply chain of raw materials and intermediate materials is often formed by multiple operators. For example, operator A purchases multiple raw materials a1, a2, and a3, and manufactures intermediate material M from these raw materials a1, a2, and a3. A Next, operator B purchases intermediate material M from operator A. A , to the intermediate material M AAdd raw materials b1 and b2 to produce intermediate material M B Next, operator C purchases intermediate material M from operator B. B , the intermediate material M B Combined with several other different intermediate materials to produce industrial products M C Then, the industrial product M is provided from the operator C to the consumer. C .

[0007] In this case, for example, consumers or quality inspection organizations may want to know the C The origin of the raw materials, the content of recycled materials, the purity measured during the purification process, and the proportion of elements or molecules in the components are all related to information. C In addition, each business operator may also want to know information about the raw materials or parts they purchase.

[0008] If data related to items subject to such transactions were publicly available using network technologies such as blockchain, multiple businesses and consumers would be able to freely access information related to the transaction items. For example, by viewing information related to the origin of raw materials contained in a component, the percentage of recycled materials, the purity measured during the purification process, and the ratio of elements or molecules, multiple businesses and consumers could confirm the composition of the components or intermediate materials they have acquired. This information could be used to identify the products they have shipped or to distinguish between components or intermediate materials that do not meet their set standards.

[0009] However, when such data is recorded and made public on a blockchain, it can be freely accessed by numerous unspecified third parties. For example, if the data recorded on a blockchain includes key technologies used in manufacturing industrial products, it could potentially undermine the competitiveness of the business operator.

[0010] For example, a specific business operator may wish to keep information related to the mixing ratio of raw materials confidential from competing businesses. This information may be disclosed to businesses with whom it has a direct contractual relationship, but may not be disclosed to third parties with whom it has no contractual relationship.

[0011] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to verify that there is no fraud in the transaction of raw materials included in an item while keeping the quantity of raw materials included in the item confidential.

[0012] Solutions for solving problems

[0013] In order to achieve the above-mentioned purpose, the information processing system of the present invention includes: a server, multiple blockchain nodes, and multiple terminals, and the terminal sends to the server: generation target project identification data, which represents the identification information of the generation target project; raw material identification data, which is the identification information of the raw material used when generating the generation target project; quantity data, which represents the quantity of the raw material; and generation source project identification data, which represents the identification information of the generation source project, and the server calculates the commitment value of the generation target project by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, stores the combination of the raw material identification data and the generation target project identification data in a prescribed data structure, obtains first transaction data, which is the transaction data recorded in the blockchain stored in the storage unit of the blockchain node, and is the transaction data in which the generation source project identification data is included in the output data, broadcasts second transaction data to multiple blockchain nodes, and the second transaction data The transaction data includes an address representing a sending source of the generation target item, an address representing a sending destination of the generation target item, and the data structure. The generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. Multiple blockchain nodes respectively read out each first transaction data as past transaction data associated with the second transaction data broadcast by the server from the blockchain, and verify whether the generation target item of the second transaction data is composed of the raw materials included in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item included in the second transaction data and the commitment value of the generation source item included in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

[0014] In addition, the server of the present invention is a server in an information processing system, and the information processing system includes: the server, multiple blockchain nodes, and multiple terminals, and the terminal sends to the server: generation target project identification data, which represents identification information of the generation target project; raw material identification data, which is identification information of the raw material used when generating the generation target project; quantity data, which represents the quantity of the raw material; and generation source project identification data, which represents identification information of the generation source project, and the server calculates the commitment value of the generation target project by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, stores the combination of the raw material identification data and the generation target project identification data in a prescribed data structure, obtains first transaction data, the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node, and is transaction data in which the generation source project identification data is included in the output data, and broadcasts second transaction data to multiple blockchain nodes. The second transaction data is transaction data including an address representing a sending source of the generation target item, an address representing a sending destination of the generation target item, and the data structure, and is transaction data in which the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. A plurality of blockchain nodes respectively read out from the blockchain each first transaction data as past transaction data associated with the second transaction data broadcast by the server, and verify whether the generation target item of the second transaction data is composed of the raw materials included in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item included in the second transaction data and the commitment value of the generation source item included in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

[0015] In addition, the blockchain node of the present invention is a blockchain node in an information processing system, and the information processing system includes: a server, multiple blockchain nodes, and multiple terminals, and the terminal sends to the server: generation target project identification data, which represents the identification information of the generation target project; raw material identification data, which is the identification information of the raw material used when generating the generation target project; quantity data, which represents the quantity of the raw material; and generation source project identification data, which represents the identification information of the generation source project, and the server calculates the commitment value of the generation target project by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, stores the combination of the raw material identification data and the generation target project identification data in a prescribed data structure, obtains first transaction data, which is the transaction data recorded in the blockchain stored in the storage unit of the blockchain node, and is the transaction data included in the output data of the generation source project identification data, and broadcasts the second transaction data to multiple blockchain nodes. The second transaction data is transaction data including an address representing a sending source of the generation target item, an address representing a sending destination of the generation target item, and the data structure, and is transaction data in which the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. A plurality of blockchain nodes respectively read out from the blockchain each first transaction data as past transaction data associated with the second transaction data broadcast by the server, and verify whether the generation target item of the second transaction data is composed of the raw materials included in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item included in the second transaction data and the commitment value of the generation source item included in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

[0016] In addition, the information processing method of the present invention is an information processing method executed by an information processing system, wherein the information processing system includes: a server, multiple blockchain nodes, and multiple terminals, wherein the terminal sends to the server: generation target project identification data, which represents identification information of the generation target project; raw material identification data, which is identification information of the raw material used when generating the generation target project; quantity data, which represents the quantity of the raw material; and generation source project identification data, which represents identification information of the generation source project, wherein the server calculates the commitment value of the generation target project by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, stores the combination of the raw material identification data and the generation target project identification data in a prescribed data structure, obtains first transaction data, which is transaction data recorded in the blockchain stored in the storage unit of the blockchain node, and is transaction data in which the generation source project identification data is included in the output data, and broadcasts a second transaction data to multiple blockchain nodes. The second transaction data is transaction data including an address representing a sending source of the generation target item, an address representing a sending destination of the generation target item, and the data structure, and is transaction data in which the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. A plurality of blockchain nodes respectively read out from the blockchain each first transaction data as past transaction data associated with the second transaction data broadcast by the server, and verify whether the generation target item of the second transaction data is composed of the raw materials included in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item included in the second transaction data and the commitment value of the generation source item included in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

[0017] The program of the present invention is a program for being used to enable a server in an information processing system to execute, and the information processing system includes: the server, multiple blockchain nodes, and multiple terminals, the terminal sends to the server: generation target item identification data, which represents identification information of the generation target item; raw material identification data, which is identification information of the raw material used when generating the generation target item; quantity data, which represents the quantity of the raw material; and generation source item identification data, which represents identification information of the generation source item, the server calculates the commitment value of the generation target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, stores the combination of the raw material identification data and the generation target item identification data in a prescribed data structure, obtains first transaction data, the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node, and is transaction data in which the generation source item identification data is included in the output data, and broadcasts second transaction data to multiple blockchain nodes. Transaction data, the second transaction data is transaction data including an address representing a sending source of the generation target item, an address representing a sending destination of the generation target item, and the data structure, and is transaction data in which the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. A plurality of blockchain nodes respectively read out from the blockchain each first transaction data as past transaction data associated with the second transaction data broadcast by the server, and verify whether the generation target item of the second transaction data is composed of the raw materials included in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item included in the second transaction data and the commitment value of the generation source item included in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

[0018] The program of the present invention is a program for causing a blockchain node in an information processing system to execute, the information processing system comprising: a server, a plurality of the blockchain nodes, and a plurality of terminals, the terminal sending to the server: generation target item identification data, which represents identification information of the generation target item; raw material identification data, which is identification information of the raw material used when generating the generation target item; quantity data, which represents the quantity of the raw material; and generation source item identification data, which represents identification information of the generation source item, the server calculates the commitment value of the generation target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, stores the combination of the raw material identification data and the generation target item identification data in a prescribed data structure, obtains first transaction data, the first transaction data being transaction data recorded in the blockchain stored in the storage unit of the blockchain node, and being transaction data in which the generation source item identification data is included in the output data, broadcasts a second transaction data to a plurality of blockchain nodes. Transaction data, the second transaction data is transaction data including an address representing a sending source of the generation target item, an address representing a sending destination of the generation target item, and the data structure, and is transaction data in which the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. A plurality of blockchain nodes respectively read out from the blockchain each first transaction data as past transaction data associated with the second transaction data broadcast by the server, and verify whether the generation target item of the second transaction data is composed of the raw materials included in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item included in the second transaction data and the commitment value of the generation source item included in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

[0019] Effects of the Invention

[0020] According to the present invention, it is possible to obtain an effect of being able to verify that there is no fraud in the transaction of the raw materials included in the project while keeping the quantity of the raw materials included in the project confidential. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram showing an example of a schematic configuration of an information processing system according to this embodiment.

[0022] Figure 2 This is a schematic block diagram showing a computer functioning as each device constituting the information processing system.

[0023] Figure 3It is an explanatory diagram for explaining the processing of the information processing system of this embodiment.

[0024] Figure 4 It is a diagram for explaining this embodiment. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

[0026] <System Structure of Information Processing System>

[0027] Figure 1 FIG is a block diagram showing the information processing system 10 of this embodiment. Figure 1 As shown, the information processing system 10 of this embodiment includes a terminal 12, a server 14, and a blockchain node 16. The various devices in the information processing system 10 are connected via a network 20, such as the Internet. The blockchain node will be abbreviated as "blockchain node 16" except when describing a specific node among the multiple blockchain nodes 16A, 16B, and 16C. Furthermore, the terminal will be abbreviated as "terminal 12" except when describing a specific terminal among the multiple terminals 12A, 12B, 12C, ..., 12X.

[0028] In addition, Figure 1 Although three blockchain nodes are shown in FIG, more blockchain nodes may be included. Figure 1 Although four terminals are shown, more terminals may be included.

[0029] In recent years, there has been an increasing demand for disclosure of some of the events occurring during the production or distribution of goods or services (hereinafter referred to as "projects"). For example, businesses are sometimes required to disclose the utilization rate of renewable energy, CO2 emissions, or the recycling rate of raw materials used in projects as evidence of their environmental impact.

[0030] Currently, such information disclosure is often reported as the sum of corporate activities over a certain period (e.g., a year). However, by providing detailed information for each item, this information can be considered as added value. Furthermore, by providing detailed information for each item, it is possible to demonstrate that the item complies with international distribution regulations.

[0031] Therefore, if a business operator U1 delivers item X to another business operator U2, and then business operator U2 manufactures a new item Y based on item X, consider a scenario where this series of events is represented as data representing a transaction ticket. This data representing the transaction ticket is then recorded in the blockchain. Because the data representing the transaction ticket is stored in the storage units (not shown) of multiple blockchain nodes 16A, 16B, and 16C, the transaction data recorded in the blockchain is public. This transaction data is accessible to third parties. This adds details to the item, making public the series of information involved in the manufacture or provision of the item.

[0032] On the other hand, some information generated during the production or provision of items may be kept confidential. For example, a business operator that mixes multiple raw materials to produce an intermediate product may want to keep confidential information regarding the mixing ratio of the raw materials, which is considered key technology. This information, which represents the intellectual property of each business operator, is therefore generally considered to avoid disclosing this intellectual property to third parties without compensation.

[0033] Therefore, in the information processing system 10 of this embodiment, information related to the quantity of raw materials included in the project is not recorded in the blockchain. While the quantity of raw materials included in the project is kept confidential, it is verified that there is no improper behavior in the transaction of the raw materials included in the project.

[0034] Specifically, in the information processing system 10 of this embodiment, a predetermined secure calculation is performed based on the quantity data representing the quantity of raw materials included in the project and the parameter values set for each raw material, thereby calculating the commitment value for each project. In the information processing system 10 of this embodiment, this commitment value is recorded in the blockchain, and the commitment value is used to verify that there is no fraud in the transactions of the raw materials included in each project. This prevents information related to the quantity of raw materials included in the project from being recorded in the blockchain, ensuring that the quantity of raw materials included in the project is kept confidential while verifying that there is no fraud in the transactions of the raw materials included in the project.

[0035] Each device included in the information processing system 10 is implemented by a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory) storing programs for implementing each processing routine, a RAM (Random Access Memory) for temporarily storing data, a memory as a storage unit, a network interface, etc.

[0036] The terminal 12, the server 14, and the blockchain node 16 can be, for example, Figure 2The computer 70 shown is implemented as shown. The computer 70 includes a CPU 71, a memory 72 serving as a temporary storage area, and a nonvolatile storage unit 73. Furthermore, the computer 70 includes an input / output interface (I / F) 74 to which input / output devices (not shown) are connected, and a read / write (R / W) unit 75 that controls the reading and writing of data in a storage medium. Furthermore, the computer 70 includes a network I / F 76 for connection to a network such as the Internet. The CPU 71, memory 72, storage unit 73, I / O I / F 74, R / W unit 75, and network I / F 76 are interconnected via a bus 77.

[0037] The storage unit 73 can be implemented by a hard disk drive (HDD), a solid-state drive (SSD), a flash memory, or the like. The storage unit 73, serving as a storage medium, stores programs for enabling the computer 70 to function. The CPU 71 reads the programs from the storage unit 73, loads them into the memory 72, and sequentially executes the processing specified by the programs.

[0038] <Functions of Information Processing System 10>

[0039] Next, the function of the information processing system 10 of this embodiment will be described. In this embodiment, the case where the information processing system 10 records the details of product C in the blockchain will be described as an example.

[0040] Furthermore, Product C is composed of cobalt, nickel, and manganese as its raw materials. The following description uses as an example a case where cobalt, nickel, and manganese, the raw materials for Product C, are extracted from Products A and B, and Product C is produced using the extracted raw materials. Furthermore, the description uses as an example a case where, during the production of Product C, some (or all) of the raw materials for Product A or some (or all) of the raw materials for Product B remain unconsumed, resulting in the production of Product D, which corresponds to the remaining unconsumed raw materials. Therefore, Products A and B are examples of source items, and Product C is an example of a target item.

[0041] In this embodiment, it is possible to track the combination of a project product and its raw materials (for example, Product C is composed of 5% cobalt, 4% nickel, and 9% manganese as raw materials). In this case, the raw material quantity data must be kept confidential. On the other hand, third parties must be able to prove that Product C, for example, was produced from Product A and Product B.

[0042] Therefore, in this embodiment, it is possible to prove that the item has been properly manufactured while keeping the quantity data of the raw materials constituting the item confidential.

[0043] When the user operating the terminal 12 inputs information related to the product C as the target item to be generated into the terminal 12, Figure 3 sequence shown.

[0044] In step S100, terminal 12 receives project-related information input by the user. This project-related information includes, for example, quantity data indicating the quantity of raw materials that constitute product C, the target project. For example, the quantity (or composition ratio) of raw materials that constitute product C is as follows.

[0045] Cobalt: 5

[0046] Nickel: 4

[0047] Manganese: 9

[0048] Furthermore, the quantities of raw materials constituting product A, which is a generation source item, are as follows.

[0049] Cobalt: 3

[0050] Nickel: 7

[0051] Manganese: 5

[0052] Furthermore, the quantities of raw materials constituting the product B, which is a generation source item, are as follows.

[0053] Cobalt: 4

[0054] Manganese: 8

[0055] Furthermore, the amounts of raw materials constituting the product D corresponding to the remaining raw materials that have not been consumed are as follows.

[0056] Cobalt: 2

[0057] Nickel: 3

[0058] Manganese: 4

[0059] In step S102, the terminal 12 sends to the server 14: item identification data (hereinafter referred to as "item ID") representing identification information of the target product C; item ID of the source product A; item ID of the source product B; raw material identification data (hereinafter referred to as "raw material ID") serving as identification information of the raw materials constituting the product C; and quantity data representing the quantity (or ratio) of the raw materials consumed when generating the product C.

[0060] In step S104, server 14 receives the data transmitted from terminal 12 in step S102. Furthermore, in step S104, server 14 acquires the parameter value corresponding to the raw material of the received raw material ID, the blinding parameter value G corresponding to the blinding factor, and the random coefficient r associated with the blinding parameter value G. The blinding factor rG is data representing a fictitious raw material that is not actually included in product C. The random coefficient r associated with the blinding parameter value G is also the value of blind quantity data corresponding to the number of blinding factors.

[0061] Furthermore, the parameter value and blind parameter value G are obtained by calculation using a commitment scheme with additive isomorphism. For example, the parameter value and blind parameter value G are calculated using a Pedersen commitment, a well-known example of a method (e.g., see Section 3 of https: / / link.springer.com / content / pdf / 10.1007%2F3-540-46766-1_9.pdf#page=3!). When calculating the parameter value and blind parameter value G using a Pedersen commitment, points (coordinates) on the elliptic curve with unknown discrete logarithms are selected as the parameter value and blind parameter value G corresponding to each raw material. Thus, parameter values and blind parameter values G with additive isomorphism are obtained. For example, the following are obtained as parameter values for each raw material.

[0062] Cobalt:H C

[0063] Nickel: H N

[0064] Manganese: H M

[0065] Blind parameter value: G

[0066] It should be noted that the committed value C of product A, which is the source project, A and the committed value C of product B, which is the source project B Calculate according to the following formula. r1, r2 are random coefficients relative to the blind parameter value G. These commitment values C A 、C B As described later, this is recorded in the past transaction data in the blockchain.

[0067] [Number 1]

[0068] C A =r1G+3H C +7H N +5H M

[0069] C B =r2G+4H C +0H N +8H M

[0070] In step S106, the server 14 calculates the commitment value C of the product C by performing a secure calculation as shown in the following formula: C , the safety calculation is to calculate the parameter value H corresponding to each raw material C 、H N 、H MThe blind parameter value G, the quantity data of each raw material, and the random coefficient r3 relative to the blind parameter value G are multiplied and added.

[0071] [Number 2]

[0072] C C =r3G+5H C +4H N +9H M

[0073] In addition, the above commitment value is equivalent to a point on the elliptic curve whose discrete logarithm is unknown. Therefore, it is impossible to pass the above commitment value C C Calculate how much of the raw material is contained in Product C.

[0074] Furthermore, in step S106, the server 14 calculates the commitment value C of the product D by performing a secure calculation as shown in the following formula: D , the safety calculation is to calculate the parameter value H corresponding to each raw material C 、H N 、H M The blind parameter value G, the quantity data of each raw material, and the random coefficient r4 relative to the blind parameter value G are multiplied and added.

[0075] [Number 3]

[0076] C D =r4G+2H C +3H N +4H N

[0077] Furthermore, when calculating the commitment value without introducing the blinding factor rG, the commitment value will be the same for different items composed of the same number of raw materials or the same ratio of raw materials. By introducing the blinding factor rG, the commitment value can be made different for different items even when they are composed of the same number of raw materials or the same ratio of raw materials.

[0078] Furthermore, in order to establish the following formula (A) described later, random coefficients r1, r2, r3, and r4 are adjusted and set in advance so as to satisfy the following formula (B).

[0079] [Number 4]

[0080] C A +C B -(C C +C D )=0G

[0081] (A)

[0082] r1+r2-(r3+r4)=0

[0083] (B)

[0084] In step S108, server 14 stores the combination of Product C's item ID and the raw material IDs of each ingredient in an accumulator, such as that disclosed in Japanese Patent Application Laid-Open No. 2021-064219. Storing various data in the accumulator reduces the amount of item tracking information and allows for the recording of item tracking information on the blockchain. Similarly, server 14 stores the combination of Product D's item ID and the raw material IDs of each ingredient in a predetermined data structure.

[0085] In addition, as described above, the server 14 sets the parameter value H C 、H N 、H M And the blind parameter value G. Based on the parameter value H C 、H N 、H M The commitment value calculated by using the blind parameter value G, the quantity data corresponding to the combination of raw materials, and the random coefficient is different from the commitment value calculated using other combinations of raw materials and is unique. Therefore, the commitment value can also be used as identification data. The parameter value H used in calculating the commitment value C 、H N 、H M The blind parameter value G is stored and managed in a storage unit (not shown) of the server 14 .

[0086] Next, server 14 accesses blockchain node 16 to obtain: transaction data for an accumulator whose output data contains the item ID of product A, the source of generation; and transaction data for an accumulator whose output data contains the item ID of product B, the source of generation. Furthermore, server 14 obtains transaction data based on the transaction ID attached to the transaction data.

[0087] Specifically, in step S110, the server 14 sends a request signal to the blockchain node 16 in order to obtain the transaction data of the accumulator that records the item ID of the product A of the generation source and the item ID of the product B of the generation source in the output data.

[0088] In step S112, upon receiving the request signal sent by server 14 in step S110, blockchain node 16 transmits to server 14: past transaction data recorded with the item ID of product A as output information; and past transaction data recorded with the item ID of product B as output data. In this embodiment, such past transaction data is also referred to as first transaction data.

[0089] In step S114 , the server 14 obtains the first transaction data output by the blockchain node 16 .

[0090] In step S116 , the server 14 generates second transaction data including an address indicating a source of product C, an address indicating a destination of product C, and the aforementioned data structure.

[0091] Specifically, the server 14 includes the output data of the past first transaction data in the input data of the second transaction data. In addition, the server 14 generates the second transaction data in such a way that the input data of the second transaction data also includes the transaction ID on the blockchain related to the past first transaction data. In addition, the server 14 includes the project ID, raw material ID, and commitment value of product C in the output data constituting the second transaction data. In addition, as described above, the project ID and raw material ID of product C are stored in an accumulator as a prescribed data structure. In addition, the commitment value may also be further stored in the accumulator. Although the present embodiment uses the case where the project ID and raw material ID are stored in the accumulator as an example, the project ID and raw material ID may also be recorded directly in the output data constituting the second transaction data instead of being stored in the accumulator.

[0092] Furthermore, as described above, if some (or all) of the raw materials are not consumed during the production of product C, data related to product D corresponding to the remaining unconsumed raw materials is also included in the accumulator. This recording method is one example of expressing the conservation law between the raw materials represented by the input data and the raw materials represented by the output data within a single transaction data. As another method, it is also conceivable to record the waste of the remaining raw materials generated during the production of the target item in another blockchain and reference it between different blockchains.

[0093] Figure 4 is a diagram showing the data structure used to describe transaction data. Figure 4 As shown, the transaction data TX2 includes an address indicating a product's shipping source and an address indicating a product's shipping destination.

[0094] Furthermore, if Figure 4 As shown, the input data of the transaction data TX2 includes the output data of the past transaction data TX1-1 and the output data of the past transaction data TX1-2.

[0095] On the other hand, Figure 4As shown, the output data of transaction data TX2 includes an accumulator containing the item ID and raw material ID of product C, the target for production. Furthermore, this accumulator also contains the item ID and raw material ID of product D, which is produced from the remaining raw materials. Furthermore, the output data of transaction data TX1-1 and transaction data TX1-2, which serve as the transaction data for the production source items, also include accumulators storing the item IDs and raw material IDs of products A and B, which were previously produced.

[0096] In step S118 , the server 14 broadcasts the second transaction data generated in step S118 to multiple blockchain nodes 16 .

[0097] In step S120, each of the plurality of blockchain nodes 16 receives the second transaction data. In step S120, each of the plurality of blockchain nodes 16 reads from the blockchain each piece of first transaction data, which is past transaction data, associated with the second transaction data. Specifically, each of the plurality of blockchain nodes 16 reads from the blockchain each piece of first transaction data according to a prescribed protocol based on the identification data on the blockchain associated with the past first transaction data contained in the second transaction data.

[0098] In step S122, the plurality of blockchain nodes 16 respectively determine the commitment value C of the product C contained in the second transaction data TX2. C and the remaining committed value C of product D D , and the commitment value C of product A included in the first transaction data TX1-1 A and the commitment value C of product B contained in the first transaction data TX1-2 B The relationship between the two is used to verify whether the product C, which is the generation target item of the second transaction data TX2, is composed of the raw materials of the products A and B, which are the generation source items of the first transaction data TX1-1 and TX1-2.

[0099] As described above, when each parameter value and blinding factor are generated using a Pedersen commitment, the commitment value of the past transaction data included in the input data within the second transaction data must be equal to the commitment value included in the output data. Therefore, if, for example, the sum of the commitment values included in the input data within the second transaction data is not equal to the sum of the commitment values included in the output data within the second transaction data, the target item was not properly generated for some reason.

[0100] Therefore, multiple blockchain nodes 16 record the second transaction data in the blockchain when the sum of the commitment values contained in the output data in the first transaction data (the sum of the commitment values contained in the input data in the second transaction data) is equal to the sum of the commitment values contained in the output data in the second transaction data.

[0101] On the other hand, when the sum of the commitment values contained in the output data within the first transaction data (the sum of the commitment values contained in the input data within the second transaction data) is not equal to the sum of the commitment values contained in the output data within the second transaction data, multiple blockchain nodes 16 do not record the second transaction data in the blockchain and discard it.

[0102] In addition, for example, when the output data includes multiple item IDs, the total value of the multiple commitment values included in the output data of the transaction data is also disclosed on the blockchain.

[0103] Specifically, as shown in the following calculation formula, the commitment value C of the product C included in the second transaction data TX2 is C The promised value C is equivalent to the remaining amount of raw materials produced when producing product C D The sum of the committed values of the raw materials included in the first transaction data TX1-1 and TX-2 (C A with C B When the sum of the second transaction data TX2 and the second transaction data TX1-1 and TX-2 are equal, multiple blockchain nodes 16 respectively determine that the product C of the second transaction data TX2 is composed of the raw materials of multiple first transaction data TX1-1 and TX-2.

[0104] [Number 5]

[0105] C A +C B -(C C +C D )=0

[0106] In step S124 , when it is determined that the product C of the second transaction data TX2 is composed of the raw materials of the first transaction data TX1 - 1 and TX- 2 , the plurality of blockchain nodes 16 respectively record the second transaction data TX2 in the blockchain.

[0107] Furthermore, depending on the commitment value recorded in the transaction data, overflow may occur when adding the commitment value implemented by each blockchain node 16, potentially resulting in an erroneous calculation result. Therefore, it is preferable to include proof that the commitment value is within an appropriate range. This implementation may include, for example, a range proof. As an example of a known method, proof schemes such as Borromean Ring Signatures (https: / / www.semanticscholar.org / paper / Borromean-Ring-Signatures-%E2%88%97-Maxwell-Poelstra / 4160470c7f6cf05ffc81a98e8fd67fb0c84836ea) and Bulletproofs (https: / / eprint.iacr.org / 2017 / 1066.pdf) can be used.

[0108] Furthermore, when server 14 receives a request signal from terminal 12 requesting disclosure of parameter values corresponding to the raw material ID, it performs authentication processing with terminal 12, the source of the request signal. Furthermore, if terminal 12, the source of the request signal, is previously permitted to disclose parameter values, server 14 discloses the parameter values to terminal 12, the source of the request signal. Terminal 12 verifies whether product C has been properly manufactured based on the disclosed parameter values and the committed values recorded in the transaction data.

[0109] For example, a user who has received the target product C decommits the product using the commitment value recorded in the blockchain in order to confirm whether the product C is manufactured using appropriate raw materials.

[0110] In addition, when the Pedersen commitment is used to calculate the commitment value, the commitment can be released by following the steps below.

[0111] Specifically, for example, the terminal 12X operated by the user who received the product C or a third party user sends a predetermined request signal to the server 14 according to the user's operation. In response to the request signal, the server 14 sends the parameter value H to the terminal 12X operated by the user after the above-mentioned authentication process. C 、H N 、H M , the quantity data of the raw materials (cobalt: 5, nickel: 4, manganese: 9), and the blinding factor rG. In addition, the terminal 12X accesses the blockchain node 16 to obtain the commitment value C of the product C recorded in the second transaction data. C .

[0112] The terminal 12X is based on the parameter value HC 、H N 、H M , the quantity data of raw materials (cobalt: 5, nickel: 4, manganese: 9), the blinding factor rG, and the commitment value C of the second transaction data recorded in the blockchain C , using a known decommitment method, generates a verification result indicating whether product C is properly manufactured by products A and B. The commitment value C of product C recorded in the second transaction data C If the calculation is based on the quantity data of the raw materials and the product C is properly manufactured from the products A and B (hereinafter referred to as "the product C is properly produced"), the terminal 12X displays the verification result on the display unit (not shown). On the other hand, if the product C is not properly produced, the terminal 12X displays the verification result on the display unit (not shown).

[0113] Furthermore, it is highly likely that the user who received the product C received the ingredient list of the product C from the user who created the product C. Therefore, the terminal 12X operated by the user who received the product C can also generate the product C based on the quantity data of the raw materials (cobalt: 5, nickel: 4, manganese: 9) and the parameter value H recorded in the ingredient list. C 、H N 、H M , and the blinding factor rG, calculate the commitment value C of product C by yourself C Therefore, the terminal 12X operated by the user who receives the product C can also calculate the commitment value C C 'With the commitment value C recorded in the blockchain C The comparison is performed and a verification result is generated indicating whether the product C is properly produced.

[0114] Alternatively, the blinding factor rG may be generated by the terminal 12X operated by the user who received the product C, and the generated values may be sent to the server 14. In this case, the terminal 12X operated by the user who received the product C sends the blinding factor rG to the server 14 in step S104.

[0115] Furthermore, without disclosing the blinding factor rG to the terminal 12X, a known decommitment method can be used to generate a verification result indicating whether the product C was properly generated based on the subtraction value obtained by subtracting the blinding factor rG from each commitment value and the digital signature generated by the blinding factor rG.

[0116] Alternatively, the KZG commitment can be used to calculate the commitment value (see, for example, https: / / www.iacr.org / archive / asiacrypt2010 / 6477178 / 6477178.pdf). When using the Pedersen commitment, the quantity data of the raw materials included in the commitment value must be disclosed when the commitment is released. In contrast, when using the KZG commitment, which is a commitment scheme using polynomials, only the quantity data of some raw materials can be disclosed.

[0117] Specifically, when using KZG commitments to calculate commitment values, the quantity data of only the raw materials that constitute a portion of the project can be disclosed, while the quantity data of other raw materials can be kept confidential. When using KZG commitments to calculate commitment values, the commitment values are calculated using polynomials. Furthermore, when using KZG commitments to calculate commitment values, the property of additive isomorphism can be exploited to add commitment values calculated using different polynomials.

[0118] When the KZG commitment is used in the calculation of the commitment value, the parameter value and blind parameter value representing the raw material of the object are set to x, and the value calculated by the polynomial f(x) is used as the quantity of the raw material of the object and the blind factor value to form the polynomial f(x). A KZG commitment is generated for the polynomial to generate a commitment value that keeps the raw material and its quantity confidential.

[0119] In addition, the above-mentioned blind parameter value may not be included when constructing the polynomial.

[0120] In addition, although the above examples have been described using Pedersen commitment and KZG commitment as examples for the calculation of commitment values, any commitment scheme can be used as long as it has additive isomorphism.

[0121] As described above, the terminal of the information processing system of this embodiment transmits to the server: target item identification data representing identification information of the target item; raw material identification data representing identification information of the raw materials used when generating the target item; quantity data representing the quantity of the raw materials; and source item identification data representing identification information of the source item. The server calculates the commitment value of the target item by performing secure calculations based on the parameter values corresponding to the raw materials and the quantity data. The server stores the combination of the commitment value, raw material identification data, and target item identification data in a predetermined data structure. The server obtains first transaction data, which is transaction data recorded in a blockchain stored in the storage unit of a blockchain node and includes the source item identification data in the output data. Furthermore, the server broadcasts second transaction data to multiple blockchain nodes, which includes an address representing the source of the target item, an address representing the destination of the target item, and a data structure, and includes the source item identification data in the input data, and includes the data structure including the target item identification data in the output data. Multiple blockchain nodes each read, from the blockchain, each first transaction data item associated with the second transaction data broadcast by the server as past transaction data. Based on the relationship between the commitment value of the target item included in the second transaction data and the commitment value of the source item included in the first transaction data, each blockchain node verifies whether the item in the second transaction data is composed of the raw material included in the source item in the first transaction data. If it is determined that the target item in the second transaction data is composed of the raw material in the first transaction data, the second transaction data is recorded in the blockchain. This ensures that the quantity of the raw material included in the item is kept confidential while verifying that there is no fraud in the transaction of the raw material included in the item.

[0122] Furthermore, by introducing a blinding factor rG when calculating the committed value of an item, it is possible to prevent committed values of different items from becoming the same value.

[0123] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible without departing from the spirit of the present invention.

[0124] For example, items are not limited to real objects but also include specific data.

[0125] Furthermore, although the above embodiment describes the case where a blinding factor rG is introduced when calculating a commitment value, the present invention is not limited thereto and the commitment value may be calculated without introducing the blinding factor rG.

[0126] Furthermore, while the above embodiment describes an example where the random coefficients r1, r2, r3, and r4 are pre-adjusted to satisfy equation (B), this is not limiting. If the random coefficients r1, r2, r3, and r4 do not satisfy equation (B), a digital signature can be added to the value corresponding to the right side of the following equation to verify, using known methods, whether the target product is properly manufactured from the source product.

[0127] [Number 6]

[0128] C A +C B -(C C +C D )=(r1+r2-(r3+r4))G

[0129] In this case, as described above, the server 14 uses the blinding factor rG to calculate the commitment value C of the product C of the generation target. C Then, the server 14 calculates the commitment value C of the product C included in the second transaction data. C The promised value C equivalent to the remaining amount of raw materials D The sum (C C +C D ), and the sum of the commitment values of the products A and B of the generation sources included in the plurality of first transaction data (C A +C B ) between the two, generate the digital signature of the server 14, and add the digital signature to the second transaction data. A +C B )-(C C +C D ) is not 0, since a digital signature is attached to the result of the operation, it is possible to verify based on the digital signature whether the product of the generation target is properly manufactured from the product of the generation source.

[0130] Furthermore, in the above embodiment, the case where product D corresponding to unconsumed surplus raw materials is produced when product C is produced is described as an example, but the present invention is not limited thereto and this embodiment is applicable even when no surplus raw materials are produced.

[0131] In addition, in the above embodiment, the case where the server 14 executes various processes is described as an example, but part or all of these various processes may also be executed by the terminal 12 or the blockchain node 16.

[0132] In addition, although the present specification describes an embodiment in which a program is pre-installed, the program can also be provided by being stored in a computer-readable recording medium. For example, the program can also be provided by being stored in a non-transitory storage medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), or a USB (Universal Serial Bus) memory. In addition, the program can also be provided by being downloaded from an external device via a network.

[0133] In addition, the processing of the software (program) read and executed by the CPU in the above embodiment can also be performed by various processors other than the CPU. As the processor in this case, FPGA (Field-Programmable Gate Array) and other PLDs (Programmable Logic Devices) whose circuit structure can be changed after manufacturing are exemplified; and ASIC (Application Specific Integrated Circuit) and other dedicated circuits as processors with circuit structures specially designed for performing specific processing. Alternatively, GPGPU (General-purpose graphics processing unit) can also be used as a processor. In addition, each process can also be performed by one of these various processors, or by a combination of two or more processors of the same or different types (for example, multiple FPGAs, and a combination of a CPU and an FPGA, etc.). In addition, more specifically, the hardware structure of these various processors is a circuit that combines circuit elements such as semiconductor elements.

[0134] Furthermore, each process of this embodiment may be implemented by a computer or server having a general-purpose processing unit and a storage device, and each process may be executed by a program. The program may be stored in a storage device, or may be recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or may be provided via a network. Of course, any other structural elements do not necessarily need to be implemented by a single computer or server, but may be implemented by being distributed across multiple computers connected by a network.

[0135] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

[0136] Furthermore, it should be noted that in the above embodiments, unless there is a description of "only" such as "only based on XX," "only according to XX," or "only in the case of XX," this specification assumes that additional information is considered. For example, a description such as "if XX is present, perform XX" does not necessarily mean "if XX is present, perform XX at all times." This does not necessarily mean "if XX is present, perform XX at all times."

[0137] In addition, even if there are aspects in certain methods, programs, terminals, devices, servers or systems (hereinafter referred to as "methods, etc.") that perform operations different from those described in this specification, each method of the disclosed technology is also aimed at operations that are the same as any of the operations described in this specification. The existence of operations that are different from the operations described in this specification does not exclude the method, etc. from the scope of the various methods of the technology of the present invention.

[0138] This specification incorporates by reference the entire contents of Japanese Patent Application No. 2022-061015 filed on March 31, 2022, and Japanese Patent Application No. 2023-018759 filed on February 9, 2023. All documents, patent applications, and technical standards described in this specification are incorporated by reference into this specification to the same extent as if each document, patent application, and technical standard were specifically and individually described as being incorporated by reference.

Claims

1. An information processing system comprising: Server, multiple blockchain nodes, and multiple terminals, The terminal sends to the server: generated target item identification data, which represents identification information of the generated target item; Raw material identification data, which is identification information of a raw material used when generating a target item; Quantity data indicating the quantity of the raw material; and generation source item identification data indicating identification information of the generation source item, The server calculates the commitment value of the production target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, The server stores the combination of the raw material identification data and the production target item identification data in a predetermined data structure, The server obtains first transaction data, where the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node and the generation source item identification data is included in the output data. The server broadcasts second transaction data to multiple blockchain nodes, wherein the second transaction data includes an address indicating a source of the generation target item, an address indicating a destination of the generation target item, and the data structure, wherein the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. The plurality of blockchain nodes respectively read out, from the blockchain, first transaction data as past transaction data associated with the second transaction data broadcasted by the server, Multiple blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials contained in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item contained in the second transaction data and the commitment value of the generation source item contained in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

2. The information processing system according to claim 1, wherein When the plurality of blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials of the plurality of first transaction data, When the sum of the commitment value of the generation target item contained in the second transaction data, the commitment value equivalent to the remaining amount of the raw material generated when the generation target item is generated, and the sum of the commitment values of the generation source items contained in multiple first transaction data are equal, it is determined that the generation target item of the second transaction data is composed of the raw materials of multiple first transaction data.

3. The information processing system according to claim 1 or 2, wherein: When the server receives a request signal indicating a request to disclose the parameter value, it performs authentication processing between itself and the terminal that sent the request signal. When the terminal that sent the request signal is a terminal that has been previously authorized to disclose the parameter value, the server discloses the parameter value to the terminal that sent the request signal.

4. The information processing system according to claim 1 or 2, wherein: When the server calculates the commitment value of the target project, The commitment value of the production target project is calculated by adding the result of the multiplication and accumulation operation of the blind parameter value corresponding to the blind factor representing the raw material that is not actually included in the production target project and the blind quantity data representing the quantity of the pre-adjusted blind factor to the result of the multiplication and accumulation operation of the parameter value and the quantity data.

5. The information processing system according to claim 1 or 2, wherein: When the server calculates the commitment value of the target project, The commitment value of the production target item is calculated by adding the result of a multiplication and accumulation operation of a blind parameter value corresponding to a blind factor representing a raw material substantially not included in the production target item and blind quantity data representing the number of random blind factors to the result of a multiplication and accumulation operation of the parameter value and the quantity data, For information representing the difference between the sum of the commitment value of the generation target item contained in the second transaction data and the commitment value of the remaining amount of the raw material generated when the generation target item is generated, and the sum of the commitment values of the generation source items contained in multiple first transaction data, the server generates a digital signature and adds the digital signature to the second transaction data.

6. The information processing system according to claim 1 or 2, wherein: When the server calculates the commitment value of the target project, By adding a blind parameter value corresponding to a blind factor representing a raw material that is not substantially contained in the generation target item and blind quantity data representing the number of pre-adjusted blind factors to the input of the security calculation, the commitment value of the generation target item is calculated, thereby improving confidentiality.

7. The information processing system according to claim 1, wherein: When calculating the commitment value, KZG commitment is used, and only a portion of the quantity data of the raw materials can be disclosed. The KZG commitment is a commitment scheme using polynomials.

8. A server in an information processing system, the information processing system comprising: The server, multiple blockchain nodes and multiple terminals, The terminal sends to the server: generated target item identification data, which represents identification information of the generated target item; Raw material identification data, which is identification information of a raw material used when generating a target item; Quantity data indicating the quantity of the raw material; and generation source item identification data indicating identification information of the generation source item, The server calculates the commitment value of the production target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, The server stores the combination of the raw material identification data and the production target item identification data in a predetermined data structure, The server obtains first transaction data, where the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node and the generation source item identification data is included in the output data. The server broadcasts second transaction data to multiple blockchain nodes, wherein the second transaction data includes an address indicating a source of the generation target item, an address indicating a destination of the generation target item, and the data structure, wherein the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. The plurality of blockchain nodes respectively read out, from the blockchain, first transaction data as past transaction data associated with the second transaction data broadcasted by the server, Multiple blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials contained in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item contained in the second transaction data and the commitment value of the generation source item contained in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

9. A blockchain node, which is a blockchain node in an information processing system, the information processing system comprising: A server, a plurality of said blockchain nodes, and a plurality of terminals, The terminal sends to the server: generated target item identification data, which represents identification information of the generated target item; Raw material identification data, which is identification information of a raw material used when generating a target item; Quantity data indicating the quantity of the raw material; and generation source item identification data indicating identification information of the generation source item, The server calculates the commitment value of the production target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, The server stores the combination of the raw material identification data and the production target item identification data in a predetermined data structure, The server obtains first transaction data, where the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node and the generation source item identification data is included in the output data. The server broadcasts second transaction data to multiple blockchain nodes, wherein the second transaction data includes an address indicating a source of the generation target item, an address indicating a destination of the generation target item, and the data structure, wherein the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. The plurality of blockchain nodes respectively read out, from the blockchain, first transaction data as past transaction data associated with the second transaction data broadcasted by the server, Multiple blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials contained in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item contained in the second transaction data and the commitment value of the generation source item contained in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

10. An information processing method, which is an information processing method executed by an information processing system, the information processing system comprising: Server, multiple blockchain nodes, and multiple terminals, The terminal sends to the server: generated target item identification data, which represents identification information of the generated target item; Raw material identification data, which is identification information of a raw material used when generating a target item; Quantity data indicating the quantity of the raw material; and generation source item identification data indicating identification information of the generation source item, The server calculates the commitment value of the production target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, The server stores the combination of the raw material identification data and the production target item identification data in a predetermined data structure, The server obtains first transaction data, where the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node and the generation source item identification data is included in the output data. The server broadcasts second transaction data to multiple blockchain nodes, wherein the second transaction data includes an address indicating a source of the generation target item, an address indicating a destination of the generation target item, and the data structure, wherein the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. The plurality of blockchain nodes respectively read out, from the blockchain, first transaction data as past transaction data associated with the second transaction data broadcasted by the server, Multiple blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials contained in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item contained in the second transaction data and the commitment value of the generation source item contained in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

11. A computer program product for causing a server in an information processing system to execute the computer program product, the information processing system comprising: The server, multiple blockchain nodes, and multiple terminals, The terminal sends to the server: generated target item identification data, which represents identification information of the generated target item; Raw material identification data, which is identification information of a raw material used when generating a target item; Quantity data indicating the quantity of the raw material; and generation source item identification data indicating identification information of the generation source item, The server calculates the commitment value of the production target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, The server stores the combination of the raw material identification data and the production target item identification data in a predetermined data structure, The server obtains first transaction data, where the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node and the generation source item identification data is included in the output data. The server broadcasts second transaction data to multiple blockchain nodes, wherein the second transaction data includes an address indicating a source of the generation target item, an address indicating a destination of the generation target item, and the data structure, wherein the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. The plurality of blockchain nodes respectively read out, from the blockchain, first transaction data as past transaction data associated with the second transaction data broadcasted by the server, Multiple blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials contained in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item contained in the second transaction data and the commitment value of the generation source item contained in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

12. A computer program product for causing a blockchain node in an information processing system to execute the computer program product, the information processing system comprising: A server, a plurality of said blockchain nodes, and a plurality of terminals, The terminal sends to the server: generated target item identification data, which represents identification information of the generated target item; Raw material identification data, which is identification information of a raw material used when generating a target item; Quantity data indicating the quantity of the raw material; and generation source item identification data indicating identification information of the generation source item, The server calculates the commitment value of the production target item by performing a secure calculation based on the parameter value corresponding to the raw material and the quantity data, The server stores the combination of the raw material identification data and the production target item identification data in a predetermined data structure, The server obtains first transaction data, where the first transaction data is transaction data recorded in the blockchain stored in the storage unit of the blockchain node and the generation source item identification data is included in the output data. The server broadcasts second transaction data to multiple blockchain nodes, wherein the second transaction data includes an address indicating a source of the generation target item, an address indicating a destination of the generation target item, and the data structure, wherein the generation source item identification data is included in the input data, and the data structure including the generation target item identification data is included in the output data. The plurality of blockchain nodes respectively read out, from the blockchain, first transaction data as past transaction data associated with the second transaction data broadcasted by the server, Multiple blockchain nodes verify whether the generation target item of the second transaction data is composed of the raw materials contained in the generation source item of the first transaction data based on the relationship between the commitment value of the generation target item contained in the second transaction data and the commitment value of the generation source item contained in the first transaction data. If it is determined that the generation target item of the second transaction data is composed of the raw materials of the first transaction data, the second transaction data is recorded in the blockchain.

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