Information processing device, communication system, and program

Abstract

The purpose of the present disclosure is to lessen the burden of a procedure even when a user uses a virtual currency wallet and an identity wallet.　To achieve this purpose, the present disclosure provides an information processing device having a digital virtual currency wallet for conducting virtual currency transactions. The virtual currency wallet includes a virtual currency wallet address indicating a transfer destination of the virtual currency, and in association with the address, user identification information of a digital identity wallet of a self-sovereign identity, and has an address issuing unit that issues an address digital certificate including a digital signature obtained using an address secret key linked to the virtual currency wallet address.

Description

Information Processing Apparatus, Communication System, and Program

[0001] The present disclosure relates to a technique for performing refunds and the like using self-sovereign identity (SSI).

[0002] Currently, many virtual currency wallets are widespread (Non-Patent Document 1). In this virtual currency wallet, it is possible to prove that the ownership of virtual currency or NFT (Non-Fungible Token) managed on the blockchain belongs to the owner of the virtual currency wallet.

[0003] On the other hand, at the same time, the spread of digital identity wallets is also expected (Non-Patent Document 2). In the digital identity wallet, VCs (Verifiable Credentials), which are various electronic certificates associated with each individual, are stored.

[0004] Holding the Key to the Digital Future (https: / / ethereum.org / ja / wallets / )The European Digital Identity Wallet Digital Identity (https: / / eu-digital-identity-wallet.github.io / eudi-doc-architecture-and-reference-framework / latest / )

[0005] However, generally, virtual currency wallets and identity wallets are separate applications (or systems), and there is no means to link them. Therefore, when a verification device transfers tokens (virtual currency, NFT, etc.) to the address (transfer destination) of a virtual currency wallet based on an electronic (digital) certificate presented from an identity wallet, the user not only needs to present the electronic certificate to the verification device but also needs a separate procedure to notify the address (transfer destination) of the virtual currency wallet.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to suppress the burden of procedures even when a user uses a virtual currency wallet and an identity wallet.

[0007] To solve the above problems, this disclosure provides an information processing device having a digital cryptocurrency wallet for conducting cryptocurrency transactions, wherein the cryptocurrency wallet includes a cryptocurrency wallet address indicating the destination of the cryptocurrency and user identification information of a digital identity wallet in a self-sovereign identity, and the information processing device has an address issuing unit that issues a digital certificate for an address including a digital signature using a private key for the address associated with the address.

[0008] As explained above, this disclosure has the effect of reducing the burden of procedures even when users utilize cryptocurrency wallets and identity wallets.

[0009] This is a schematic diagram showing a general example of a verification mechanism using SSI. This is a schematic diagram of a communication system according to an embodiment. This is an electrical hardware configuration diagram of a user terminal. This is a functional configuration diagram of a service provision system in an embodiment. This is a sequence diagram showing processing in a communication system. This is a sequence diagram showing processing in a communication system.

[0010] Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the embodiments shown below, and various modifications are possible without departing from the technical spirit of the invention. Since the drawings are for conceptual explanation of the present invention, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.

[0011] [General Examples of Mechanisms for Consideration Using SSI] In recent years, Self Sovereign Identity (SSI) has been attracting attention. SSI is an identity management concept (idea) that aims to enable users to manage their own identifiers and identities without relying on centralized identity providers (ID providers), and to present only the information selected by the user based on their own judgment to service providers and other recipients (References 1, 2).

[0012] <Reference 1> W3C DID (https: / / www.w3.org / TR / DID-core / ) <Reference 2> W3C VC (https: / / www.w3.org / TR / VC-data-model / ) Here, we will briefly explain the mechanism of verification using SSI using Figure 1. Figure 1 is a schematic diagram showing the mechanism of verification using SSI. In the world of SSI, there are three parties: Holder, Issuer, and Verifier.

[0013] A Holder is a user, such as a student or working professional, who creates and holds their own decentralized identifier, such as a DID (Decentralized Identifier), and registers it in a decentralized database (DB) 110, such as a decentralized repository or blockchain network.

[0014] Issuers are digital certificate issuers for schools, hospitals, government agencies, etc. They issue digital certificates such as VCs (Verifiable Credentials) that include the user's distributed identifier obtained from the user, register them in the database, and present them to the user. In this process, the Issuer, as an example, verifies the user's attribute information such as name (name, age, address, etc.) and qualification information such as the name of the company to which the user belongs (being an employee of a certain company, being a member of a service provided by a certain company, etc.), and then issues a digital certificate (e.g., a VC) that includes the attribute information and qualification information.

[0015] The Verifier is a service provider, such as a company, that uses a distributed DB110 to verify the Holder's attributes and qualifications based on a digital certificate presented by the Holder, and determines whether or not to provide services to the Holder. Examples of services include video streaming, storage usage, and communication.

[0016] [Outline of the Communication System According to the Embodiment] Next, an outline of the configuration of the communication system according to this embodiment will be described using Figure 2. Figure 2 is a schematic diagram of the communication system according to this embodiment. Here, an example is shown in which, when user (purchaser) B receives a certain product or service from provider (seller) A, user B requests a refund from provider A in virtual currency because the product is defective or the service is incomplete.

[0017] As shown in Figure 2, the communication system 1 of this embodiment utilizes an existing verification mechanism using SSI as shown in Figure 1, and is constructed with at least an issuing device 2, a user terminal 3, a verification device 6, and a predetermined node 7 of the blockchain network. The issuing device 2, user terminal 3, verification device 6, and node 7 can communicate via a communication network 100 such as the Internet or a LAN (Local Area Network). The connection method of the communication network 100 may be either wireless or wired.

[0018] For example, if Provider A is a person or organization that provides goods or services to User B, Provider A plays the role of Issuer as shown in Figure 1 by using Issuing Device 2 and the role of Verifier as shown in Figure 1 by using Verification Device 6. User B plays the role of Holder as shown in Figure 1 by using User Terminal 3.

[0019] The issuing device 2, verification device 6, and node 7 are computers such as servers. User terminals 3 include node PCs, desktop PCs, tablet terminals, smartphones, etc. There are multiple (many) issuing devices 2, user terminals 3, verification devices 6, and nodes 7, but for the sake of explanation, only one of each is shown in Figure 2.

[0020] Furthermore, a digital identity wallet 4 and a digital cryptocurrency wallet 5 are installed on the user terminal 3. At least one of the identity wallet 4 and the digital cryptocurrency wallet 5 may be installed on a predetermined server v1 on the cloud infrastructure, rather than on the user terminal 3, and can be remotely accessed from the user terminal 3. Alternatively, both the identity wallet 4 and the digital cryptocurrency wallet 5 may be installed on the same server v1 on the cloud, or they may be installed on different servers v1 and v2. Note that the user terminal 3, server v1, and server v2 are examples of information processing devices.

[0021] Furthermore, as shown in Figure 1, the issuing device 2, user terminal 3, verification device 6, and node 7 can access a distributed database 110 such as a distributed repository or a predetermined blockchain network.

[0022] <Issuing Device> The issuing device 2 issues an electronic (digital) certificate c1 related to the electronic (digital) receipt for the purchase in response to an issuance request from the user terminal 3. The certificate c1 is a VC (Verifiable Credential), etc.

[0023] Certificate c1, as shown in Figure 2, includes an electronic (digital) receipt (product name, purchase price, etc.), the identity wallet user ID, the provider ID, and an electronic (digital) signature s1 using the private key p1 associated with this issuer ID.

[0024] The receipt shows the purchase history, including the product name (or service name) and purchase price.

[0025] The "Identity Wallet User ID" is an example of user identification information used to identify user B, who uses Identity Wallet 4. This user identification information also includes the user's DID (Decentralized Identity). When the issuing device 2 receives a request to issue certificate c1 from Identity Wallet 4, it obtains the Identity Wallet User ID and issues both a receipt and certificate c1.

[0026] The "Provider ID" is an example of provider identification information used to identify provider A as an issuer, and is held by the issuing device 2. The provider identification information also includes the provider's DID.

[0027] "Private key r1 associated with the provider ID" indicates that the provider (issuer) ID is generated by converting the public key u1 (of the pair) corresponding to private key r1.

[0028] "Signature s1" is an electronic (digital) signature.

[0029] <Cryptocurrency Wallet> The cryptocurrency wallet 5 can perform the basic functions necessary for trading cryptocurrencies. Furthermore, the cryptocurrency wallet 5 issues a certificate c2 in response to an issuance request from the identity wallet 4. As shown in Figure 2, this certificate c2 includes the address of the cryptocurrency wallet as the destination (recipient) for cryptocurrency transfers, the user ID of the identity wallet, the address of the cryptocurrency wallet as the issuer ID, and an electronic (digital) signature s2 using the private key r2 associated with this cryptocurrency wallet address.

[0030] Certificate c2 links the cryptocurrency wallet (address) with the identity wallet (user ID). Furthermore, certificate c2 contains a digital signature s2, generated by the private key r2 associated with the cryptocurrency wallet. Certificate c2 is a VC, etc.

[0031] Note that "Waddr" in Figure 2 is an abbreviation for "Wallet address". Also, the user ID of the identity wallet included in certificate c2 is the same as the user ID of the identity wallet included in certificate c1. As a result, the verification unit 67, described later, can verify (determine) that the provider indicated in certificate c1 and the user indicated in certificate c2 are the same person.

[0032] A "cryptocurrency wallet address" is a unique string of characters used to identify the destination of cryptocurrency transfers (deposits), acting like a bank account number in the physical world, and is held by the cryptocurrency wallet. Cryptocurrency refers to fungible currencies such as Bitcoin and Ethereum, and is an example of a token. This category also includes non-fungible tokens (NFTs).

[0033] "Private key r2 associated with the cryptocurrency wallet address" refers to the fact that the cryptocurrency wallet address is generated by converting the public key u2 (of the pair) corresponding to private key r2.

[0034] "Signature s2" is an electronic (digital) signature.

[0035] Thus, in certificate c2, cryptocurrency wallet 5 links the cryptocurrency wallet (address) with the identity wallet (user ID) and signs it with the private key r2 associated with the cryptocurrency wallet address.

[0036] <Identity Wallet> Identity Wallet 4 issues a set of certificates c3, including certificates c1 and c2, in response to an issuance request from the verification device 6. The set of certificates c3 is subject to VP (Verifiable Presentation), etc.

[0037] As shown in Figure 2, the certificate set c3 includes certificate c1, certificate c2, the identity wallet user ID as the issuer ID, and an electronic (digital) signature s3 using the private key r3 associated with this identity wallet user ID.

[0038] "Private key r3 associated with the Identity Wallet user ID" refers to the fact that the Identity Wallet user ID is generated by converting the public key u2 (of the pair) corresponding to private key r3.

[0039] "Signature s3" is an electronic (digital) signature.

[0040] Furthermore, the distributed DB 110 manages the provider ID of provider A and the signature s1 encrypted with private key r1 in association with each other by the issuing device 2. In addition, the distributed DB 110 manages the cryptocurrency wallet address and the signature s2 encrypted with private key r2 in association with each other by the cryptocurrency wallet 5. Moreover, the distributed DB 110 manages the identity wallet user ID and the signature s3 encrypted with private key r3 in association with each other by the identity wallet 4.

[0041] [Hardware Configuration] Next, the electrical hardware configuration of the user terminal 3 will be explained using Figure 3. Figure 3 is an electrical hardware configuration diagram of the user terminal.

[0042] As shown in Figure 3, the user terminal 3 has a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a processor 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, etc., which are all interconnected by a bus 1010.

[0043] A program for realizing the processing on the computer is provided by a recording medium 1001 such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 via the drive device 1000 to the auxiliary storage device 1002. However, the installation of the program does not necessarily have to be performed from the recording medium 1001, and it may be downloaded from another computer via the communication network 100. The auxiliary storage device 1002 stores the installed program and also stores necessary files, data, etc.

[0044] When an activation instruction for the program is given, the memory device 1003 reads out and stores the program from the auxiliary storage device 1002. The processor 1004 realizes the functions related to the device according to the program stored in the memory device 1003. The processor 1004 may include not only a CPU (Central Processing Unit) but also a GPU (Graphics Processing Unit).

[0045] The interface device 1005 is used as an interface for connecting to a communication network such as the Internet. The display device 1006 displays a GUI (Graphical User Interface) etc. by the program. The input device 1007 is composed of a keyboard, a mouse, buttons, or a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the calculation result to an external device such as a printer or an external display.

[0046] Note that since the issuing device 2, the verification device 6, and the node 7 have the same hardware configuration as the user terminal 3, the description thereof is omitted.

[0047] [Functional Configuration of the Embodiment] Next, the functional configuration of the present embodiment will be described with reference to FIG. 4. Note that since the node 7 has a general functional configuration, the description thereof is omitted.

[0048] <Functional Configuration of the Issuing Device>The issuing device 2 includes an acquisition unit 22, an issuing unit 24, and a presentation unit 26. Each of these units is a function realized by an instruction from the processor 1004 in FIG. 3 based on a program.

[0049] The acquisition unit 22 acquires a request for issuing a certificate c1 of a receipt from the identity wallet 4 (see S11).

[0050] Based on the acquisition of the issuance request by the acquisition unit 22, the issuing unit 24 issues a receipt certificate c2 using the user ID of the identity wallet (see S12).

[0051] The presentation unit 25 presents the certificate c1 issued by the issuing unit 24 to the identity wallet 4 (see S13).

[0052] <Functional Configuration of the User Terminal>An identity wallet 4 and a virtual currency wallet 5 are installed in the user terminal 3 as applications (programs). Hereinafter, the functions of the identity wallet 4 and the virtual currency wallet 5 will be described.

[0053] (Identity Wallet) In FIG. 4, the identity wallet 4 includes a reception unit 40, a request unit 41, an acquisition unit 42, a management unit 43, an issuing unit 44, a notification unit 45, and a presentation unit 46. Each of these units is a function realized by an instruction from the processor 1004 in FIG. 3 based on a program.

[0054] The reception unit 40 receives a request for issuing a certificate c2 such as VC of a virtual currency wallet address from the user B (see S21). At this time, the user B notifies (inputs) an endpoint for the virtual currency wallet 5 to issue the certificate c2 to the identity wallet 4 to give an instruction for the issuance request.

[0055] The request unit 41 requests the issuing device 2 to issue a certificate c1 such as a receipt VC (see S11). The request unit 41 also requests the cryptocurrency wallet 5 to issue a certificate c2 of the cryptocurrency wallet address (see S22). At this time, the request unit 41 notifies the cryptocurrency wallet 5 of the user ID of the identity wallet 4 to which the certificate c2 of the cryptocurrency wallet address will be issued. If at least one of the identity wallet 4 and the cryptocurrency wallet 5 is installed on a server on the cloud, or if both are installed on different servers on the cloud, the owner of that user ID may be proven by challenge response or the like.

[0056] The acquisition unit 42 acquires the receipt certificate c1 from the issuing device 2 (see S13). The acquisition unit 42 also acquires the cryptocurrency wallet address certificate c2 from the cryptocurrency wallet 5 (see S25). Furthermore, the acquisition unit 42 acquires the issuance request for a set of certificates c3, including certificates c1 and c2, such as a VP certificate, from the verification device 6 (see S31).

[0057] The management unit 43 stores and manages the certificate c1 obtained from the issuing device 2 and the certificate c2 obtained from the cryptocurrency wallet 5 in the auxiliary storage device 1002 or memory device 1003 (see S13, S25).

[0058] The issuing unit 44 issues a set of certificates c3, including certificates c1 and c2, such as a VP certificate (see S32).

[0059] The notification unit 45 notifies user B (user terminal 3) that the issuance of certificate c2 has been completed as a response to the acceptance of the request for issuance (see S26).

[0060] The presentation unit 46 presents the certificate set c3, including certificates c1 and c2, to the verification device 6 (see S33).

[0061] (Cryptocurrency Wallet) In Figure 4, the cryptocurrency wallet 5 has a receiving unit 50, an acquisition unit 52, an issuance unit 54, and a presentation unit 56. Each of these units is a function that is implemented by instructions from the processor 1004 in Figure 3 based on a program.

[0062] The reception unit 50 accepts an operation from user B to issue certificate c2 (see S23). However, if the identity wallet 4 and the cryptocurrency wallet 5 have already been authorized to issue certificate c2 through technologies such as ID linkage, no operation by user B is required.

[0063] The acquisition unit 52 obtains a request from the identity wallet 4 for the issuance of a certificate c2 for the cryptocurrency wallet address (see S22).

[0064] The issuing unit 54, upon receiving an issuance request from the identity wallet 4 and an operation from user B by the receiving unit 50, issues an electronic (digital) certificate c2 of the cryptocurrency wallet address, which indicates the relationship between the identity wallet 4 and the cryptocurrency wallet 5, using the user ID of the identity wallet (see S24). Thus, the cryptocurrency wallet 5 of this embodiment has the function of issuing a certificate c2 of the cryptocurrency wallet address.

[0065] The presentation unit 56 presents the certificate c2 issued by the issuing unit 54 to the identity wallet 4 (see S25).

[0066] <Functional Configuration of the Verification Device> The verification device 6 has a request unit 61, an acquisition unit 62, a verification unit 67, and a determination unit 68. Each of these units is a function that is realized by instructions from the processor 1004 in Figure 3 based on a program.

[0067] The request unit 61 requests the identity wallet 4 to issue a certificate c3 such as a VP (see S31). The request unit 61 also requests a transaction from a designated node 7 on the blockchain network to transfer (refund) the cryptocurrency of the refund amount based on the receipt contained in certificate c1 to the cryptocurrency wallet address contained in certificate c2 (see S36). Even if user B paid in fiat currency when purchasing goods, the refund will be made in cryptocurrency.

[0068] The acquisition unit 62 acquires a set of certificates c3, including certificates c1 and c2, from the identity wallet 4 (see S33).

[0069] The verification unit 67 verifies the validity of certificates c1 to c3 (see S34).

[0070] Specifically, the verification unit 67 uses the issuer ID contained in certificate c1 to search the distributed DB 110 and obtains the public key u1 corresponding to this issuer ID. Then, the verification unit 67 uses this public key u1 to decrypt the signature s1 and verifies the authenticity of certificate c1.

[0071] Furthermore, the verification unit 67 uses the address of the cryptocurrency wallet contained in certificate c2 to search the decentralized DB 110 and obtains the public key u2 corresponding to this cryptocurrency wallet address. Then, the verification unit 67 uses this public key u2 to decrypt the signature s2 and verifies the authenticity of certificate c2.

[0072] Furthermore, the verification unit 67 uses the user ID of the identity wallet contained in certificate c3 to search the decentralized DB 110 and obtain the public key u3 corresponding to this user ID. Then, the verification unit 67 uses this public key u3 to decrypt the signature s3 and verify the authenticity of certificate c3.

[0073] Note that the order in which certificates c1 to c3 are verified does not matter.

[0074] If the verification unit 67 determines that all of the certificates c1 to c3 are valid, the determination unit 68 determines the refund amount based on a predetermined contract or rule and the receipt data included in certificate c1 (see S35). The refund amount may be a full refund or a partial refund.

[0075] [Processing according to the embodiment] Next, the processing in the communication system according to this embodiment will be explained using Figures 5 and 6. Figures 5 and 6 are sequence diagrams showing the processing in the communication system.

[0076] <Processing of Service Application> S11: The request unit 41 requests the issuing device 2 to issue a certificate c1 such as a receipt VC. This issuance request includes the user ID of the identity wallet. As a result, the acquisition unit 22 acquires the issuance request for the receipt certificate c1 from the identity wallet 4.

[0077] S12: Based on the acquisition of the issuance request by the acquisition unit 22, the issuance unit 24 issues an electronic (digital) certificate c2 of the receipt using the user ID of the identity wallet.

[0078] S13: The presentation unit 25 presents the certificate c1 issued by the issuing unit 24 to the identity wallet 4. As a result, the acquisition unit 42 acquires the receipt certificate c1 from the issuing device 2.

[0079] S21: The reception unit 40 receives a request from user B to issue a certificate c2 such as a VC for a cryptocurrency wallet address.

[0080] S22: The request unit 41 requests the cryptocurrency wallet 5 to issue a certificate c2 of the cryptocurrency wallet address. This request includes the user ID of the identity wallet. As a result, the acquisition unit 52 obtains the request for issuance of the certificate c2 of the cryptocurrency wallet address from the identity wallet 4.

[0081] S23: The reception unit 50 receives an operation from user B to issue certificate c2.

[0082] S24: Upon receiving the issuance request from Identity Wallet 4 and the operation from User B by the Reception Unit 50, an electronic (digital) certificate c2 of the cryptocurrency wallet address, which indicates the relationship between Identity Wallet 4 and Cryptocurrency Wallet 5, is issued using the User ID of Identity Wallet.

[0083] S25: The presentation unit 56 presents the certificate c2 issued by the issuing unit 54 to the identity wallet 4. As a result, the acquisition unit 42 acquires the certificate c2 of the cryptocurrency wallet address from the cryptocurrency wallet 5.

[0084] S26: User B (user terminal 3) is notified that the issuance of certificate c2 has been completed, as a response to the acceptance of the request for issuance.

[0085] Next, using Figure 6, we will explain the case where User B requests a refund from Provider A via telephone, email, Provider A's website, etc., because the purchased product was defective.

[0086] S31: Next, proceeding to Figure 6, the request unit 61 requests the identity wallet 4 to issue a certificate c3, such as a VP. As a result, the acquisition unit 42 obtains the issuance request for a set of certificates c3, including certificates c1 and c2, such as a VP, from the verification device 6.

[0087] S32: The issuing unit 44 issues a set of certificates c3, including certificates c1 and c2, such as a VP certificate, based on the processing S31.

[0088] S33: The presentation unit 46 presents the certificate set c3, including certificates c1 and c2, to the verification device 6. As a result, the acquisition unit 62 acquires the certificate set c3, including certificates c1 and c2, from the identity wallet 4.

[0089] S34: Verify the validity of certificates c1 to c3.

[0090] S35: If the verification unit 67 determines that all of the certificates c1 to c3 are valid, the determination unit 68 determines the refund amount based on a predetermined contract or rule and the receipt data included in certificate c1.

[0091] S36: The request unit 61 requests a transaction from a predetermined node 7 of the blockchain network to transfer (refund) the cryptocurrency of the refund amount specified in the receipt in certificate c1 to the address of the cryptocurrency wallet specified in certificate c2.

[0092] S37: Node 7 executes the transaction based on process 36.

[0093] Note that in Figure 5, the order of processes S11-S13 and S21-S26 may be reversed. However, it is necessary to ensure that certificate c2 is issued to the same wallet as certificate c1. For example, the issuer ID of certificate c1 and the issuer ID of certificate c2 must match.

[0094] Furthermore, in Figure 6, of the processes S31 to S37, only process S31 may be executed before processes S11 to S13 and processes S21 to S26. In this case, the identity wallet 4 automatically requests the issuance of certificate c1 from the appropriate issuer of certificate c1 in accordance with the issuance request of process S31 (see S11), and also automatically requests the issuance of certificate c2 (see S22).

[0095] [Main Effects of the Embodiments] As described above, according to each embodiment, the cryptocurrency wallet 5 has an issuing unit 54, which enables the issuing unit 54 to issue a certificate c2 using the user ID of the identity wallet. This certificate c2 allows the cryptocurrency wallet (address) to be linked with the identity wallet (user ID), and the certificate c2 can include a signature s2 using the private key r2 associated with the cryptocurrency wallet (address).

[0096] As a result, when the identity wallet 4 presents the certificate set c3, including certificates c1 and c2, to the verification device 6, the verification device 6 can transfer (deposit) the cryptocurrency equivalent to the refund amount according to the contents of the receipt included in certificate c1 to the cryptocurrency wallet address included in certificate c2, without having to go to the trouble of identifying and obtaining a receipt for user B from the issuing device 2. This reduces the procedural burden on user B.

[0097] Furthermore, it is possible to suppress tampering when sending electronic (digital) receipts from the issuing device 2 to the verification device 6. In addition, it is possible to suppress tampering with the cryptocurrency wallet address, which is the destination of the cryptocurrency transfer (remittance).

[0098] [Supplement] The present invention is not limited to the embodiments described above, and may also have the following configurations or processes (operations).

[0099] (1) The issuing device 2, user terminal 3, and verification device 6, as well as the servers v1 and v2 described above, can be implemented using a computer and a program. This program can be recorded on a (non-temporary) recording medium or provided via a communication network such as the Internet.

[0100] (2) The processor 1004 as hardware shown in Figure 3 may be a single unit or multiple units.

[0101] 1 Communication system 2 Issuing device 3 User terminal 4 Identity wallet 5 Cryptocurrency wallet 6 Verification device 7 Node 22 Acquisition unit 23 Issuing unit (Example of receipt issuance unit) 26 Presentation unit 40 Reception unit 41 Request unit 42 Acquisition unit 43 Management unit 44 Issuing unit (Example of complete set issuance unit) 45 Notification unit 46 Presentation unit 50 Reception unit 52 Acquisition unit 54 Issuing unit (Example of address issuance unit) 56 Presentation unit 61 Request unit 62 Acquisition unit 67 Verification unit 68 Determination unit 110 Distributed DB c1 Certificate (Example of digital certificate for receipts) c2 Certificate (Example of digital certificate for addresses) c3 Certificate (Example of digital certificate for complete set) r1 Private key (Example of private key for receipts) r2 Private key (Example of private key for addresses) r3 Private key (an example of a private key for a set)

Claims

1. An information processing device having a digital cryptocurrency wallet for conducting cryptocurrency transactions, wherein the cryptocurrency wallet includes a cryptocurrency wallet address indicating the destination of the cryptocurrency and user identification information of a digital identity wallet in a self-sovereign identity, and the information processing device having an address issuing unit that issues a digital certificate for an address including a digital signature using a private key for the address associated with the address.

2. The identity wallet comprises: an acquisition unit that acquires a digital receipt for the provision of the goods or services, user identification information, provider identification information for identifying the provider of the goods or services, and a digital signature using a private key for receipts linked to the provider identification information from an issuing device of a provider of goods or services; a set issuing unit that issues a set of digital certificates including the address digital certificate and the digital receipt certificate, as well as the user identification information and a digital signature using a private key for sets linked to the user identification information; and a presentation unit that presents the set of digital certificates to a verification device in the self-sovereign identity, the information processing device according to claim 1.

3. A communication system having the information processing device and the verification device described in claim 2, wherein the verification device comprises: a verification unit that verifies the validity of the set of digital certificates, the digital certificate for addresses, and the digital certificate for receipts; and a request unit that, if all verifications by the verification unit are valid, requests a transaction to a predetermined node in the blockchain network to transfer the cryptocurrency of the refund amount contained in the digital receipt certificate to the address of the cryptocurrency wallet contained in the digital certificate for addresses.

4. A program that is a digital cryptocurrency wallet for conducting cryptocurrency transactions, the program includes a cryptocurrency wallet address indicating the destination of the cryptocurrency and user identification information of a digital identity wallet in a self-sovereign identity, and causes a computer to execute an issuance process to issue a digital certificate for an address that includes a digital signature using a private key for the address associated with the address.

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