Information processing system for allowing token owner on block chain base being belonging subject of content data to certify and verify bidirectional unique correspondence between content data and belonging subject by digital watermark embedded in content data

Abstract

To provide an information processing system for verifying that content data and a belonging subject uniquely correspond to each other, and a block chain data structure.SOLUTION: An information processing system having two networks of a block chain base connected to the Internet and a network of a distributed system including a digital watermarked original processing part verifies that content data 30 and a non-fungible token (NFT) 32 issued on the block chain based with the content data as an object uniquely correspond to each other by comparatively referring token IDs and belonging subject identifiers including in both a digital watermark 31 embedded in the content data 30 and the NFT 32.SELECTED DRAWING: Figure 4

Description

Detailed Description of the Invention [Technical Field]

[0001] This invention relates to non-fungible tokens (hereinafter referred to as NFTs) issued on a blockchain network platform, digital images and other content data that are the subject of the NFTs electronically recorded on a recording medium, and electronic watermarks embedded in the content data. [Background technology]

[0002] A method of embedding a digital watermark in the content data is known as a method of verifying its modification (tampering in the case of unauthorized access), copying, and deletion after the fact without damaging the appearance of the content data as seen by the human eye. On the other hand, as a method of indicating the relationship between the content data and an entity (hereinafter referred to as the "owner") that holds some rights or control over the content data that does not amount to rights (hereinafter referred to as the "ownership"), and as a method of the owner transferring the ownership to another entity (hereinafter referred to as the "transferee") and demonstrating the transfer to the transferee or other third parties, a service is provided on a blockchain network platform that issues an NFT for the content data to the owner, and the owner transfers the NFT to the transferee and autonomously proves the transfer within the blockchain platform through mining on the platform. For example, such a service is provided on the Ethereum platform, and standards such as ERC-721 have also been published. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Digital Watermarking as a Copyright Protection Technology" (Independent Administrative Institution National Center for Industrial Property Information and Training (INPIT) https: / / www.inpit.go.jp / blob / katsuyo / pdf / chart / fdenki12.pdf) introduces various digital watermarking methods as a way to verify after-the-fact tampering (unauthorized changes), unauthorized copying, and deletion of content data without damaging its appearance as seen by the human eye. [Non-patent document 2] The Ethereum Foundation has proposed and published the ERC-721 standard for NFTs as part of its ERC (Ethereum Request for Comments) technical proposals. https: / / ethereum.org / ja / developers / docs / standards / tokens / erc-721 / In the Ethereum system, there are two types of accounts on the Ethereum blockchain platform, which communicates over the internet: holder accounts and contracts (called smart contracts) that receive work requests via messages from holder accounts and perform tasks. Contract tasks include creating and transferring NFTs containing information identifying the storage location and other related information for the target content data, as well as information identifying the token. The work of a contract is called a transaction. Furthermore, a block containing the transaction is formed as a result of the transaction and is connected to the previous blocks. The validity of this transaction is verified by node participants on the blockchain platform. [Non-patent document 3] The following website of Number One Solutions Co., Ltd. (7F Idemitsu Ikejiri Building, 3-15-1 Higashiyama, Meguro-ku, Tokyo 153-0043) provides, although details are unclear, a statement that "digital data is provided with meta-information (ancillary information) such as author information, comments, and usage," and "hashed metadata is inserted into the digital watermark file." https: / / no1s.biz / press / 3807 / [Patent documents]

[0004] [Patent Document 1] JP 2004-139184 A, Decision of Rejection (Patent Application No. 2002-300911) proposes assigning identification information to identify content data each time the content data is edited, and physically adding the assigned identification information as a digital watermark to the storage medium on which the content data is recorded. However, the decision of rejection was made on the grounds that re-embedding a digital watermark each time the content data is edited is easily conceivable based on publicly known facts. Since separating the content data and the digital watermark containing the identification information requires skill and time, the content data are recorded as a single entity on the storage medium. Therefore, if the digital watermark is deleted or another digital watermark is embedded in the content data, it can be verified after the fact that the original digital watermark is no longer in its original state. Therefore, the content data and the original digital watermark have a unique correspondence (one corresponds to the other, and only one). Since the digital watermark is invisible to the human eye, even if the appearance of the content data looks the same to the human eye, it is possible to verify that the content data is no longer the original content data by confirming that it is not the original digital watermark. [Patent Document 2] Patent No. 7158073 describes a transaction support system that includes a license information storage unit that identifies and stores the ownership relationship (referred to as the license information for the content data in Patent Document 2) between content data and the attribution entity (referred to as the user in Patent Document 2 and the owner in Patent Document 4, but since ownership is a concept that applies to tangible objects, the term "attribution entity" will be used below) and an NFT issuing unit that issues an NFT to the attribution entity's wallet containing information indicating the content data (the content data itself or a URI indicating the storage location of the content data and other related information (hereinafter collectively referred to as the content URI; URI stands for Uniform Resource Identifier, a generic term for an identifier used to identify any file on the Internet)) and the license information for the content data. The problem the invention aims to solve is the time-consuming process of embedding digital watermarks in content to manage copyright. When trading NFTs between the attribution entities, the system is also equipped with a transaction processing unit that can issue a transaction on the blockchain platform that sets the transferee as the NFT holder (referred to as the owner in Patent Document 2) (item number 0029).This is a system that clarifies the attribution relationship between the content data and the attribution entity on the Internet without using a digital watermark. [Patent Document 3] Patent No. 6710401 describes a method for enabling access to the Internet using data including a token ID (NFT identifier) ​​tradable on a blockchain platform on the Internet, which is assigned to content data (referred to as an object in Patent Document 3). The method calls for a smart contract running on the blockchain to perform operations on the NFT. Furthermore, if the content data is treated as a tangible object, scanning a two-dimensional code assigned to the tangible object reads the URI containing the token ID indicated by the two-dimensional code. The smart contract then changes the NFT's attribution entity (referred to as the owner in Patent Document 3) and transmits it to the new attribution entity (Item No. 0070). Here, the two-dimensional code assigned to the tangible object contains information about the token ID and content URI, but does not contain an attribution entity identifier. Therefore, a change in attribution entity does not require a change to the two-dimensional code. For this reason, the original author or administrator of the content data (hereinafter referred to as the "original author"; this includes both cases where the original author acts directly and cases where the administrator is entrusted with the work) cannot identify the attribution entity (the NFT owner) with which the attribution relationship exists from the 2D code attached to the content. A change in attribution entity cannot be asserted as invalid within the system (claims outside the system, such as non-transfer agreements, are separate issues). Furthermore, since the 2D code is not an inseparable part of the object and can be replaced by anyone with different content, the system does not guarantee that the content and the 2D code correspond uniquely to each other. [Patent Document 4] JP 2020-068388, Patent Publication No. 2020-068388, Granted. The address (internet address) of the attributing entity (referred to as the rights holder in Patent Document 4) for content data is set as the attributing entity identifier (referred to as owner information in Patent Document 4). The attributing entity's attribution relationship with the content data (referred to as the type of rights in Patent Document 4) is included. Metadata related to the token, which is distinguishable from other tokens by its token ID (including the content URI indicating the storage location of the content data and other information related to the token; referred to as token data in Patent Document 4), can be generated, and the attributing entity identifier, token ID, and metadata can be registered in a distributed ledger on the Internet. Furthermore, when the attributing entity transfers a token, the attributing entity identifier is changed from the address of the transferor to the address of the transferee (referred to as the recipient in Patent Document 4). This content contract system features these features. The attributing entity identifier, token ID, and content URI are included in the NFT. Patent Document 4 also states that the content data may be provided with information corresponding to the address of the transferee set in the attribution entity identifier. Furthermore, when providing the content data, adding information about the transferee of the content data as identifiable information using a digital watermark or the like makes it possible to identify the transferee, who is the source of the illegal distribution, even if the content data is illegally distributed (see item 0096). Here, the information included in the digital watermark or the like contains only information about the transferee of the content data, not the token ID. It is anticipated that the transferee of the content data may transfer or distribute the NFT corresponding to the content data to a third party, exceeding the rights held by the attribution relationship, without obtaining the consent of the original author of the content data.In other words, based on the attribution identifier information contained in the digital watermark included in the content data, if an NFT is transferred from the current attribution subject to the next attribution subject without permission, the original author can claim that the attribution subject of the content data is the current attribution subject, and that the attribution relationship with the next attribution subject contained in the transferred NFT is invalid.However, because the digital watermark of the content data located at the location indicated by the content URI included in the NFT does not contain token ID information, the original author cannot read the token ID from the digital watermark, change the attribution subject of the NFT to the smart contract, and send it to the new attribution subject, and cannot generate an NFT uniquely corresponding to the content data. Summary of the Invention [Problem to be solved by the invention]

[0005] With the development of the Internet, there is an increasing demand for original authors and attribution entities who have ownership of original works and copies of electronically recorded content data, such as digital art and document records, to create, transfer, and terminate such ownership (including secondary rights such as exploitation rights, in the case of original authors) to third parties. However, because content data is recorded electronically, it is easy to create copies, and it is even possible to create copies that are identical to the original work. This has led to a growing demand for original authors and current attribution entities to be able to create and maintain unique attribution entities (one for each, and only one for each) with respect to the original work and its copies, as well as to transfer and terminate such attribution entities while maintaining unique attribution. To address this demand, there are two challenges that must be overcome to enable autonomous transfer and assignment between the transferor and the recipient without the involvement of an authoritative administrator (e.g., a public entity). The first is to prevent the original author of the content data from making a copy and establishing a new attribution relationship with a third party other than the party previously agreed upon between the original author and the current attribution entity, or at least to make it possible to verify after the fact that dual attribution has not been established. While it is possible to prevent copying and the establishment of dual attribution in advance through contracts or other means, it is not possible to completely prevent it. However, if the current attribution entity can verify after the fact that dual attribution has not been established with a party other than the party previously agreed upon, it can be a strong deterrent to the establishment of dual attribution by the original author. The second is that the current attribution entity can prove by itself that the attribution relationship between the content data and itself has been generated and maintained in accordance with the attribution relationship (autonomous attribution proof). Since the current attribution entity cannot directly grasp the content data, this proof requires a method for the entity to prove the attribution relationship itself, without relying on a third party. Furthermore, based on the attribution relationship, the current attribution entity must be able to transfer the attribution relationship to an assignee, and the assignee must be able to confirm and verify that it has uniquely established a new attribution relationship with the content data.

[0006] To solve the first problem, electromagnetically recorded content data is easily copied, necessitating a method for individually identifying the original work and its copies, or each copy from another. Furthermore, if the content data is a digital artwork, adding an identification method to the artwork and damaging its aesthetic would diminish its value. Therefore, a method that is invisible to the human eye but identifiable by a machine or other means is conceivable. One such method would be to embed a digital watermark containing information identifying the current attribution entity (attribution entity identifier) ​​into the content data in a form that is indiscernible to the human eye (Patent Document 1). Several specific methods for digital watermarking that are difficult to tamper with have been proposed (Non-Patent Documents), and it is sufficient to select an appropriate method for embedding the watermark into the content data. Furthermore, each time the attribution entity changes, the content data containing the previous digital watermark can be discarded and new content data containing a new digital watermark can be created, or only the previous digital watermark can be deleted and the content data can be created with an embedded digital watermark containing information identifying the new attribution entity (transferee). The new attribution entity can confirm that it is the new attribution entity by checking the new digital watermark and confirming that the previous digital watermark does not exist. In this way, the attribution entity is uniquely determined for the content data containing the digital watermark. However, the digital watermark described in Non-Patent Document 1 and Patent Document 1 alone does not provide evidence of an agreement between the current assignor (the current owner) and the new assignee (the new owner). Another problem is that in order to confirm the existence of an attribution relationship between the content data and the owner, it is necessary to check the digital watermark each time, which requires time and effort. A second challenge remains: is it possible to inexpensively create evidence of an agreement regarding the creation, transfer, and deletion of an attribution relationship, or some other record other than a digital watermark that uniquely corresponds to the attribution relationship?

[0007] To address the second issue, a method is known in which a current owner of content data issues an NFT using a blockchain platform on the Internet as a way to prove that they have an ownership relationship with the content data (Patent Documents 2 to 4). The information constituting the NFT includes an owner identifier for identifying the owner who is the NFT holder, a token ID for distinguishing the NFT from other NFTs, and a content URI (a URI indicating the location of the content data and other information) (Non-Patent Document 2). The original author of the content data approves a person requesting to become a new owner and provides the token ID and content URI. In response, the original author or the person seeking to become the new owner sends a message on the blockchain platform requesting the issuance of an NFT, and an NFT is issued. The owner, who has now become the NFT holder, then uses the information constituting the NFT to confirm that they have newly acquired ownership of the content data. Furthermore, assuming this attribution, the attribution entity sends a message to the contract requesting the transfer of the NFT to the next attribution entity (transferee), and the contract replaces the NFT's attribution entity identifier (such as the current attribution entity's address) with the identifier of the next attribution entity (transferee) (such as the next attribution entity's address), maintains the token ID (uniquely corresponding to the contract address; see Non-Patent Document 2), and transfers the NFT. The next attribution entity, who becomes the new NFT holder, uses the information constituting the new NFT to confirm that it has attribution to the content data. This method makes it possible to provide evidence of agreement between the current attribution entity (transferor) to transfer the NFT to the new attribution entity (transferee) and to prove the legitimacy of the transfer on the blockchain, thereby solving the second problem. However, the method of Patent Document 2 does not add data related to the NFT (token ID and attribution entity identifier) ​​to the content data as information that uniquely corresponds to the content data. Therefore, although the content data and the NFT are related by the content URI (indicating the storage location of the content data, etc.) included in the NFT, the content data is referenced by the NFT's content URI, but the content data does not reference a specific NFT. In other words, because there is no information related to the NFT in the content data, it is possible to create multiple different types of NFTs that reference the content data, each with a different token ID. This creates a problem in that it is impossible to verify that the new NFTs created in this way are invalid in relation to the original NFT held by the attribution entity. In other words, because the original author of the content data can issue multiple different types of NFTs from the same content data, the current attribution entity cannot prove that the content data and the NFTs they hold are uniquely related to each other.

[0008] In this regard, the method of Patent Document 3 makes it possible to uniquely identify an NFT using "data used to call a smart contract (which is described as being included in a uniform resource locator)" attached to an object such as content data. However, the method in Patent Document 3 presumes that the object is preferably a tangible object (using a trading card as an example), and associates it with the object by assigning a uniform resource locator represented by a two-dimensional code or the like. However, the method of assigning a two-dimensional code does not take into consideration security concerns such as tamper resistance, as it is easily tampered with, such as by replacing the object with another, and is therefore not appropriate as a method for identifying the owner. Furthermore, the method presumes that the object is not limited to a tangible object and may be an intangible object such as digital data, but does not mention how to assign information represented by a two-dimensional code to content data in such a case. There is no mention of methods such as whether to display the code in a visible form within the digital image of the object or simply add it as data, nor does it acknowledge the risk of the code being tampered with or provide solutions to address this. Furthermore, uniform resource locators, such as two-dimensional codes, that are supposed to be assigned to objects do not include an attribution entity identifier. Therefore, the original author of the content data cannot identify the attribution entity (the NFT owner) with which they have an attribution relationship from the uniform resource locator. Therefore, they cannot assert invalidity within the system against the transfer of attribution by the current attribution entity (claims outside the system, such as non-transfer agreements, are separate issues). In the method of Patent Document 3, the content data and the NFT are related by a content URI, but the relationship between the two is such that the content data is referenced by the content URI and attribution entity identifier included in the NFT, while the uniform resource locator, etc., assigned to the content data references a token ID (Patent Document 3 states that it may include data for identifying the NFT), but does not include the attribution entity identifier. Because the uniform resource locator does not include an attribution entity identifier, the original author cannot prove that the content data and the NFT have a unique relationship based on the content data alone.

[0009] On the other hand, the method of Patent Document 4 allows the address of the NFT holder, the current attribution subject (which serves as the attribution subject identifier), to be embedded in the content data using a digital watermark or the like. However, because the digital watermark does not contain token ID information, the original author cannot generate an NFT that uniquely corresponds to the content data. This is because, although the content data and the NFT are related by the attribution subject identifier and content URI in the method of Patent Document 4, the relationship between the two is such that the content data is uniquely referenced by the content URI in the NFT, while the token ID cannot be identified from the digital watermark information embedded in the content data, and therefore the corresponding NFT cannot be uniquely referenced. Because the digital watermark does not contain a token ID, the original author cannot prove that the content data and the NFT are uniquely related to each other from the content data alone.

[0010] Non-Patent Document 3 states that "digital data is provided with meta-information (ancillary information) such as author information, comments, and usage," which could be interpreted as embedding a digital watermark in the content data. However, there is no mention of including a token ID that uniquely identifies the NFT or an attribution identifier for the NFT holder. Unless such information is included in the digital watermark, it is impossible to ensure the uniqueness of both the content data and the NFT. Therefore, although the details are unclear, this invention is novel. [Means for solving the problem]

[0011] The present invention, which solves the above problems, is an information processing system that verifies that content data and a token issued on a blockchain platform for that content data uniquely correspond to each other by comparing and referencing the token ID and attribution entity identifier contained in both the digital watermark embedded in the content data and the token.

[0012]

[0011] The information processing system may be characterized in that, upon receiving a transfer request from the holder of the token, the original author of the content data discards the digital watermark embedded in the content data, creates a digital watermark containing the same token ID and the next attribution entity identifier instead, embeds the created digital watermark in the content data, and stores it in a storage location indicated by the content URI, while the holder of the token transfers the token to another attribution entity who is the transferee on the blockchain platform, and the attribution entity verifies that the content data with the changed digital watermark and the token uniquely correspond to each other.

[0013] The information processing system of

[0011] or

[0012] may be characterized in that, upon receiving a request for deletion from the holder of the token, the original author discards the digital watermark embedded in the content data, creates a digital watermark instead that includes the same token ID and the identifier of a non-existent attribution entity, embeds the digital watermark in the content data, and stores it in a storage location indicated by the content URI, while the holder transfers the token to a non-existent attribution entity on the blockchain platform, thereby deleting the token.

[0014] The information processing system of

[0011] or

[0012] or

[0013] may be characterized in that the management of the content data is implemented as a system in which a distributed system and a smart contract on a blockchain platform are linked.

[0015] The information processing system of

[0011] or

[0012] or

[0013] or

[0014] may be characterized by having an original watermark processing unit that embeds the electronic watermark each time the original work of the content data and the attributive rights holder are created, transferred, or destroyed.

[0016] The information processing system of

[0011] or

[0012] or

[0013] or

[0014] or

[0015] may be characterized in that the digital watermark original processing unit is implemented as a system in which a distributed system and a smart contract on a blockchain platform are linked. [Effects of the Invention]

[0017] On the Internet, the original author of content data or the current attribution entity that has received a transfer of ownership, such as control over the content data, from the original author can independently verify that they are maintaining a unique attribution relationship with the content data, which is the original work, or with the content data, which is a copy thereof. Furthermore, while maintaining the unique attribution relationship, the current attribution entity can represent the attribution relationship in an NFT that is issued, transferred, and destroyed on a blockchain platform on the Internet, and transfer the unique relationship between the NFT it holds and the content data to the next attribution entity on the blockchain platform. This proof can be autonomously verified between the transferor and the next attribution entity, which is the transferee, without the involvement of an authoritative administrator (e.g., a public entity). Furthermore, the next attribution entity, which is the transferee, can independently verify that the unique attribution relationship with the original work of the content data or the content data, which is a copy thereof, has been transferred. Thereafter, the next owner, who is the transferee, can at any time verify that the content data exists and that the content data and the NFT uniquely correspond to each other. The next owner can also verify the uniqueness of other NFTs by checking the information in the NFT to see if a third party is illegally distributing the content data, and by comparing the information contained in both the content data and the NFT to see if the information contained in the content data points to the NFT, and conversely, by showing that the information contained in the NFT points to the content data. [Brief explanation of the drawings]

[0018] [Figure 1]1 is a block diagram illustrating an example of a schematic configuration of an information processing system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram illustrating an example of a schematic configuration of a node or an account according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic block diagram of a computer that functions as a node or account (including both on a blockchain network and on a distributed system including a digital watermark original processing unit) in an embodiment of the present invention. [Figure 4] 1 is a schematic diagram of content data according to an embodiment of the present invention, a digital watermark embedded therein, and a digital watermark, an NFT, and information contained therein; [Figure 5]

[0011] An explanatory diagram for explaining each step of the information processing for generating an NFT after confirming uniqueness by comparing and referencing the token ID and attribution entity identifier contained in both the digital watermark embedded in the content data listed in

[0011] and the NFT to be generated (an explanatory diagram for the steps for generating an NFT after confirming uniqueness). [Figure 6]

[0012] This is an explanatory diagram for explaining each step of the information processing in which the NFT described in

[0012] is transferred, and then the transferee compares and references the token ID and attribution entity identifier contained in both the new digital watermark embedded in the content data and the NFT to confirm and verify uniqueness, and finalize the transfer (an explanatory diagram for the steps in which the transferee verifies uniqueness and finalizes the transfer after the NFT is transferred). [Figure 7]

[0013] This is an explanatory diagram for explaining each step of the information processing for extinguishing an NFT (an explanatory diagram for the steps for extinguishing an NFT). DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, examples of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. [Example]

[0020] A method according to an embodiment involves issuing, transferring, and destroying an NFT on a blockchain platform connected to the internet (Non-Patent Document 2), creating a digital watermark (Non-Patent Document 1) containing the same token ID and attribution identifier as those contained in the NFT on a distributed network including a digital watermark original data processor, and embedding the digital watermark in content data whose storage location is indicated by the NFT's content URI in the digital watermark original data processor (Non-Patent Document 1). Because modifying or deleting a digital watermark embedded in content data requires skill and time (Non-Patent Document 1), the content data and the digital watermark are unique to each other (one corresponds to the other, and there is only one). Furthermore, the holder of the NFT (the attribution entity of the content data) and the next holder (next attribution entity, transferee) who receives a transfer from the holder (transferor) can confirm that the token ID and attribution identifier contained in the NFT and the digital watermark are the same, ensuring the uniqueness of the NFT and the content data they hold. This verifies the uniqueness of the content data and the NFTs held. The blockchain infrastructure here can be the Ethereum blockchain infrastructure developed by the Ethereum Foundation, but is not limited to this, and multiple blockchain infrastructures may be connected (Figures 1 and 13). An internet environment is considered, but the same thing can be achieved within a closed network. The digital watermark can be any one of the various types shown in Non-Patent Document 1. <System configuration of information processing system>

[0021] In the method according to the embodiment of

[0020] , there are two networks: a blockchain infrastructure (FIG. 1 11) connected to the Internet, and a network of a distributed system (FIG. 1 12) including a digital watermark original processing unit. The distributed system (Fig. 1 12) stores content data (Fig. 4 30) and metadata related to the content (Fig. 4 33) in the digital watermark original processing unit, creates and stores a digital watermark (Fig. 4 31) to be embedded in the content data, embeds the digital watermark in the content data X (Fig. 4 30), and stores the embedded content data (with digital watermark). The distributed system (11) may store metadata (associated information related to NFT and content identifier) ​​where the content URI indicates the storage location (Fig. 4), or may manage and store the content URI directly indicating the storage location of the content rather than the storage location of the content identifier (Fig. 4). The original author A (including the administrator) who manages the content data, B who intends to establish a new ownership relationship with the content data and become the ownership entity, C who intends to take over the ownership relationship from B and become the next ownership entity, and other miners and validators D, E, and F who have nodes in the blockchain network infrastructure each have accounts (Fig. 1 10A, 10B, 10C) and nodes (Fig. 1 10D, 10E, 10F, etc.), and communicate with the distributed system (Fig. 1 12) and blockchain infrastructure (Fig. 1 11) from computers (Fig. 2, Fig. 3 20) that have processing units (Fig. 2 14) and communication units (Fig. 2 15). The blockchain platform (11 in Figure 1) includes nodes (10D, 10E, 10F, etc. (all in Figure 1), which may or may not be able to communicate with the distributed system) and accounts (10B, 10C (all in Figure 1), which are also able to communicate with the distributed system) that can communicate with the blockchain platform. These may be nodes, but they do not have to be nodes. The node or account has a CPU (21), an input / output device (22), a R / W unit (23), an I / F (interface, 24) with the blockchain platform, a distributed system I / F (interface, 25), a storage unit (26, with a storage medium), and memory (27) on a platform bus (28) (Figure 3). The original author (including the administrator) of the content data, A, has access to a distributed system (12) that manages the content data, metadata, and digital watermarks as an administrator and can communicate with accounts (10B, 10C) on the blockchain platform (11). He or she may also be able to communicate with nodes (10D, 10E, 10F, etc.). B (the transferor), who intends to become the owner of the content data, and C (the transferee), who will become the next owner, have access to the distributed system and accounts that can communicate with the blockchain platform (10B, 10C, Figure 1). In the Ethereum blockchain platform, when a message requesting the creation, transfer, or destruction of an NFT (including a token ID, content URI, and an attribution entity identifier, and requiring that this information be stored in the NFT) is sent from a node or account to a contract that creates or previously created an NFT and receives it, the contract executes a transaction to create, transfer, or destroy an NFT containing the information (Non-Patent Document 2, ERC-721). <1. Example of steps to generate an NFT after verifying uniqueness>

[0022] Using Figure 5 as an example, we will compare and refer to the token ID and attribution entity identifier contained in both the digital watermark embedded in the content data listed in

[0011] and the NFT to be generated, confirm that they are the same, and then explain each step of the information processing to generate the NFT (Figure 5).

[0023] The original author (including its administrator, hereinafter) A of content data X (e.g., digital image, hereinafter the same) communicates with a distributed system (12) and manages and stores the content data X and its metadata. The original author A may also have a node or account on the Internet, for example, on the Ethereum blockchain platform (11, but not limited to other blockchain platforms). Also, on the Ethereum blockchain platform, there are B, who has an account (which may be a node) (10B, 10C) and intends to become the NFT's owner (initial owner), C, who intends to become the next owner after receiving a transfer from the current owner (initial owner) B, and node participants (D, E, F, etc.) who own nodes (10D, 10E, 10F, etc.). The accounts (10B, 10C) are capable of communicating with the distributed system (12).

[0024] Original author A creates a cryptographic digest value (hash# value) of content data X, transmits it to a node on the blockchain platform, and makes it public (S51). This is so that participants in the blockchain platform, such as nodes and accounts, can calculate the digest of content data X', even if it is unclear whether it is the authentic content data X, and compare it with the published digest value to confirm that content data X' is the same as content data X. This allows an attribution entity that has some rights (attribution relationship) to content data X to verify that the NFT they hold has a unique relationship with the content data, as well as to confirm that the content data has not been altered or tampered with. However, this only applies if content data X is publicly available; if it is not publicly available, such as being accessible only to original author A, the verifier must request disclosure from original author A.

[0025] B, who wishes to establish a new ownership relationship for the content data X and become the owner, requests the distributed system (12) from the computer of account 10B (hereinafter, only the account and node name will be described, and the description of "from that computer" will be omitted) to establish ownership relationship for the content data X and to issue an NFT as proof of that (S52). Upon receiving the request, the original author A of the content data X creates a digital watermark B including (1) the token ID of the NFT to be issued, (2) the identifier of the attributing entity B (such as B's address), and other information (such as an identifier indicating the blockchain, a contract address, etc.), embeds it in the content data X, creates content data XB, and stores it in the distributed system (S53). Then, the content URI B, which indicates the direct or indirect storage location of the content data and other information, is sent to B (account 10B) through the distributed system (12) (S54). In response, B communicates with the distributed system (12) from account 10B and confirms that the content data XB matches the content data X for which B has requested to be the attributing entity, and that the digital watermark B contains (1) the token ID of the NFT to be issued and (2) the attributing entity B identifier, which indicate that B will be the attributing entity (S55). After confirmation, B broadcasts an NFT issuance request message (including (1) the token ID, (2) the attributing entity B identifier, (3) the content URI B, other information, and ETH) with B as the holder in the blockchain platform to the contract that generates the NFT (this contract may also have the function of transferring and destroying the NFT at the same time) (S56). In response, the contract that creates the NFT initiates a transaction to create the NFT, and the mining (or validating (as of September 2022, the Ethereum Foundation changed the means of validating from POW through mining to POS through validation)) nodes (10D, 10E, 10F, etc.) verify the validity of the NFT issuance and add the block to the chain (S57). B becomes the holder of the issued NFT (S58).

[0026] In S55, B confirms that (1) the token ID and (2) the attribution subject B identifier are embedded in the digital watermark B, which is embedded integrally with the content data XB that is to become the attribution subject and cannot be easily tampered with. Then, in S56, B sends a message to the contract that initiates the NFT generation transaction requesting the generation of an NFT, including (1) the token ID, (2) the attribution subject B identifier, and (3) the content URI B, thereby confirming that the content data XB (which looks the same as content data X) and the NFT are unique. Thereafter, NFT holder B can communicate with the distributed system (12) from account 10B at any time to confirm that the content data XB exists, and that the digital watermark B embedded in the content data and the (1) token ID and (2) attribution entity B identifier in the NFT are the same, thereby verifying that the content data and the NFT uniquely correspond. For other NFTs, if the information in the NFT includes (1) a token ID, (2) an attribution subject B identifier, and (3) a content URI B, it is possible to connect to the URI in (3) and, if the content data is not the content data XB, verify whether the original author A has deleted or altered the content data XB. It is also possible to check whether there are any changes to (1) the token ID and (2) the attribution subject B identifier in the digital watermark B embedded in the content data XB, and verify whether the content data has been altered or deleted. <2. Example of steps for the transferee to verify uniqueness and finalize the transfer after transferring the NFT>

[0027] Using Figure 6 as an example, we will explain each step of the information processing in which the NFT listed in

[0012] is transferred, and then the transferee compares and references the token ID and attribution entity identifier contained in both the new digital watermark embedded in the content data and the NFT to confirm and verify their uniqueness, thereby finalizing the NFT transfer (Figure 6).

[0028] B, the owner of content data XB (which appears identical to content data X) with digital watermark B embedded in it, holds an NFT covering content data XB. B (the transferor) intends to transfer the ownership relationship between content data XB and B to C (the transferee) and to transfer the NFT to C (the transferee). From account 10B, B notifies original author A of his intention to transfer the ownership relationship between content data XB and B to C (transferee) and to transfer the NFT to C (transferee) via the distributed system (12) (S61). Upon receiving the request, original author A creates a digital watermark C including (1) the token ID of the NFT to be issued (the same as the NFT held by B), (2) the identifier of C who will be the attribution subject (such as C's address), and other information (an identifier indicating the blockchain, a contract address, etc.), embeds it in the content data X, creates content data XC (which looks the same as content data X), and stores it in the distributed system (S62). Then, he sends content URI C, which indicates the direct or indirect storage location of the content data and other information, to B (account 10B) and C (account 10C) via the distributed system (12) (S63). In response, B communicates with the distributed system (12) from account 10B and confirms that the content data XC matches the content data X in appearance and that the digital watermark C contains (1) the token ID of the NFT to be transferred and (2) the identifier of the attributing entity C, indicating that C (the transferee) will be the attributing entity (S64). After confirmation, B broadcasts an NFT transfer request message (including (1) the token ID, (2) the identifier of the attributing entity C, (3) the content URI C, other information, and ETH) with C (the transferee) as the holder in the blockchain platform to the contract that transfers the NFT (this contract may also have the function of simultaneously generating and destroying NFTs) (S65). In response, the contract that transfers the NFT initiates a transaction to transfer the NFT, and the mining (or validating) node (10D, 10E, 10F, etc.) verifies the legitimacy of the NFT transfer and adds the block to the chain (S66).

[0029] Up to

[0028] , the NFT has been provisionally transferred from B (transferor) to C (transferee), in the sense that the transferee can rewind it after confirming it. However, thereafter, C (transferee), who has become the owner of the content data XC, verifies the uniqueness of the content data XC and the NFT by confirming that the digital watermark C embedded in the content data XC is the same as (1) the token ID and (2) the identifier of the owner C in the NFT. With the addition of a step in which a miner (validator) verifies the legitimacy (S67 below), C (transferee) can confirm and verify it himself and receive the NFT transfer, i.e., become the owner of the content data XC. That is, C (the transferee) communicates with the distributed system (12) from account 10C, confirms the content data XC using the content URI C in the transferred NFT, and confirms that the token ID and the attribution entity C identifier in the NFT and the digital watermark match (S67). After confirmation, C (the transferee) sends a message from account 10C to other nodes on the blockchain platform to confirm the transfer of the NFT to C (the transferee) (S68). In response, the contract that confirms the transfer of the NFT (which may also have the function of generating and destroying NFTs) initiates a transaction, and the mining (or validating) nodes (10D, 10E, 10F, etc.) verify the legitimacy of the NFT transfer and add the block to the chain (S69). C (the transferee) becomes the holder of the transferred NFT (S70).

[0030] In S67, C receives the transfer of ownership and confirms that (1) the token ID and (2) the identifier of the attributing entity C are embedded in the digital watermark C, which is embedded integrally with the content data XC for which it wishes to become the attributing entity and cannot be easily altered. Then, in S68, C sends a message to the contract that initiates the NFT transfer transaction, requesting confirmation of receipt of the NFT transfer, including (1) the token ID, (2) the identifier of the attributing entity C, and (3) the content URI·C. This ensures the uniqueness of the content data XC (which appears identical to the content data X) and the NFT. Furthermore, if C discovers that another NFT contains (1) the token ID, (2) a different attributing entity identifier, and (3) the content URI·C, C can confirm by checking the digital watermark of the content data XC stored in the distributed system (11) whether original author A has swapped the digital watermark and issued another NFT targeting the content data XC. However, it is not possible to check that, outside of this system, the original author, at the request of the person Q who wishes to become the attribution subject, embeds ▲1▼ another token ID and ▲2▼ the attribution subject Q identifier into a digital watermark Q that is embedded together with the content data XQ and cannot be easily tampered with, and issues a different NFT Q containing this information (if this were to be prohibited, a separate restriction such as a contract would be necessary). <3. Example of steps to destroy an NFT>

[0031] Using Figure 7 as an example, we will explain each step of the information processing to eliminate the NFT listed in

[0013] (Figure 7).

[0032] C, the owner of content data XC (which appears identical to content data X) with a digital watermark C embedded in it, holds an NFT for the content data XC. C, the owner, intends to destroy the attribution relationship between content data XC and C and the NFT representing the attribution relationship. For example, C may sell the attribution relationship to original author A, thereby extinguishing the rights, but this is not limited to this. C notifies the original author A from account 10C via the distributed system (12) of his intention to terminate the ownership relationship between content data XC and C and to destroy the NFT (S71). Upon receiving the request, original author A creates a digital watermark Z including (1) the token ID of the NFT to be issued (the same as the NFT held by C), (2) a null identifier (such as a non-existent address) indicating that the attribution entity is absent (null), and other information (an identifier indicating the blockchain, a contract address, etc.), embeds it in the content data X, creates content data XZ (which looks the same as content data X), and stores it in the distributed system (S72). Then, he sends content URI Z, which indicates the direct or indirect storage location of the content data and other information, to C (account 10C) via the distributed system (12) (S73). In response, C communicates with the distributed system (12) from account 10C and confirms that the content data XZ matches the content data X in appearance and that the digital watermark Z contains (1) the token ID of the NFT to be destroyed and (2) an attribution entity null identifier, indicating that there is no attribution entity (S74). After confirmation, C sends an NFT transfer destruction message (including (1) the token ID, (2) the attribution entity null identifier, (3) the content URI Z, other information, and ETH) to the contract that destroys the NFT (this contract may also have the function of simultaneously generating and transferring NFTs) in the blockchain platform (S75). In response, the contract that deletes the NFT initiates a transaction to delete the NFT, and the mining (or validating) node (10D, 10E, 10F, etc.) verifies the validity of the NFT deletion and adds the block to the chain (S76). [Explanation of symbols]

[0033] 10. Information processing system (consisting of an internet-based blockchain platform and distributed system, and multiple nodes and accounts of the blockchain platform that have a communication unit with the internet-based blockchain platform and distributed system) 10A, 10B, 10C Accounts that can communicate with distributed systems and blockchain platforms on the Internet (may be nodes on the blockchain platform) 10D, E, F: Can also communicate with blockchain-based nodes and distributed systems on the Internet 11 Internet-based blockchain infrastructure 12 Distributed systems 13 Another Internet-based blockchain platform 14 Processing unit at node or account 15 Communication section in a node or account 20 Nodes or Computers in an Account 21 CPU 22 Storage unit 23 Memory 24 Input / output I / F 25 R / W unit 26 Internet-based blockchain infrastructure I / F 27 Distributed system I / F 28 Base Bus 30 Content Data 31 Digital Watermark 32 NFT 33 Metadata S51~S76 Information Processing Steps ("Step" is abbreviated as "S")

Claims

1. An information processing system that verifies that a document or other content data and a token issued on a blockchain platform for the content data correspond uniquely to each other by comparing and referencing information that identifies the token (hereinafter referred to as a token ID) contained in both a digital watermark embedded in the content data and the token, and information that identifies the holder of the token, who is the subject to which the content data belongs (hereinafter referred to as a subject identifier).

2. The information processing system of claim 1, characterized in that, upon receiving a transfer request from the original author of the content data or an administrator commissioned by the original author (hereinafter simply referred to as the original author), the original author of the content data discards the electronic watermark embedded in the content data, and instead embeds information containing the same token ID and the next attribution entity identifier as an electronic watermark in the content data, and stores the content data in a storage location indicated by information (hereinafter simply referred to as the content URI) indicating the direct or indirect storage location of the content data and other information contained in the token, while the owner transfers the token to the next attribution entity, who is the transferee, on the blockchain platform, and the next attribution entity verifies that the content data with the changed electronic watermark and the token uniquely correspond to each other.

3. The information processing system of claim 1, characterized in that the original author, upon request from the owner, discards the electronic watermark embedded in the content data and instead embeds information containing the same token ID and an identifier of a non-existent attribution entity as a digital watermark in the content data and stores it in a storage location indicated by the content URI, while the owner cancels the token by transferring the token to a non-existent attribution entity on the blockchain platform.

4. The information processing system of claim 2, wherein the original author, upon request from the owner, discards the electronic watermark embedded in the content data and instead embeds information containing the same token ID and an identifier of a non-existent attribution entity as an electronic watermark in the content data and stores it in a storage location indicated by the content URI, while the owner cancels the token by transferring the token to a non-existent attribution entity on the blockchain platform.

5. The information processing system according to any one of claims 1 to 4, characterized in that management of the content data and the electronic watermark is implemented as a system in which a distributed system and a smart contract on a blockchain platform are linked.

6. The information processing system according to any one of claims 1 to 4, characterized in that it has a processing unit (hereinafter referred to as an electronic watermark original processing unit) that executes a process of embedding the electronic watermark in the content data each time an original work of the content data and the attribution entity are created and the attribution relationship is transferred or destroyed.

7. The information processing system according to claim 5, characterized in that the electronic watermark original processing unit is implemented as a system in which a distributed system and a smart contract on a blockchain platform are linked.

8. A blockchain data structure in which the content data and a token issued on a blockchain platform for the content data uniquely correspond to each other, A block chain data structure used for verifying by comparing and referring to a token ID and an attribution subject identifier included in both the digital watermark embedded in the content data and the token.

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