KR102331971B1 - Method and System for Providing Voucher based Blockchain - Google Patents

Abstract

This embodiment relates to a method for providing a voucher and a system therefor that allow an anonymous transmission of a voucher without exposing the connection information between the sender account and the recipient account in the Ethereum platform based on a blockchain, particularly a smart contract.

Description

Method and System for Providing Voucher based Blockchain

The present invention relates to a method and system for providing a voucher based on a blockchain. More specifically, it relates to a method of not exposing a link between a sender who transmits a voucher and a recipient of a voucher to receive it in a blockchain-based voucher transmission application and a method for configuring the system.

The content described in this section merely provides background information for the present embodiment and does not constitute the prior art.

Blockchain technology is a distributed ledger technology with a systemic feature that provides integrity and is copied to all nodes once stored. There is a problem that it has a very large impact on the privacy of people and can be used for criminal purposes.

In the prior art, in order to transmit cryptocurrency, the sender digitally signs the transaction to be transmitted with his/her private key and then transmits it. Such a transaction contains the recipient information about which user will receive the cryptocurrency, and if this information is not included, the recipient's information must be included and digitally signed with the sender's private key, because it is unknown to whom the cryptocurrency is sent. Normal transactions take place. Therefore, every transaction has the characteristic of being able to trace who sent it.

Due to these characteristics, if a voucher system is developed on a blockchain smart contract, which sender account and how much voucher is transferred to which receiver account is exposed. In other words, if the voucher is sent without specifying the recipient, the voucher smart contract cannot verify the recipient, and there is a limit in that the owner of the money to be remitted cannot be found.

Therefore, in the Ethereum platform based on blockchain, especially smart contract, a technology is required to anonymously transmit the voucher without exposing the connection information between the sender's account and the receiver's account.

The purpose of the present invention is to provide a voucher providing method and a system for anonymously transmitting the voucher without exposing the connection information between the sender account and the recipient account on the Ethereum platform based on a blockchain, particularly a smart contract, and a system for the same. There is this.

In this embodiment, based on the virtual currency account information of the voucher recipient, a voucher ID (vid: voucher id) for sending a voucher is generated using a previously created voucher recipient ID (rid: recipient id), and the voucher ID and a voucher sender node that registers the voucher amount on the blockchain to generate a voucher according to a smart contract; a voucher recipient node that generates the voucher recipient ID and registers it on the blockchain, and receives the voucher amount corresponding to the voucher according to a recipient authentication result based on the voucher recipient ID; and a voucher contract node that issues and manages the voucher based on the block chain and the smart contract.

Further, according to another aspect of this embodiment, in the voucher providing method of the voucher providing system, the voucher recipient node generates a voucher recipient ID based on the virtual currency account information of the voucher recipient, and sets the voucher recipient ID on the blockchain the process of enrolling in; a process in which the voucher sender node generates a voucher ID based on the voucher recipient ID, and registers the voucher ID and voucher amount on the blockchain to generate a voucher according to a smart contract; and receiving, by the voucher recipient node, a recipient authentication based on the voucher recipient ID from a voucher contract node to receive the voucher, and receiving the voucher amount corresponding to the voucher according to the authentication result It provides a method of providing a voucher that is characterized.

According to this embodiment, since the Ethereum account information of the sender and receiver of the voucher is not included in the transaction, there is an effect that privacy can be provided without exposing the sender's sensitive information to the outside.

In addition, according to this embodiment, as the recipient of the voucher is anonymously authenticated, the voucher amount is issued and used as a service token without being remitted immediately, and the final voucher amount is deposited to the service provider so that the remittance history as well as the service usage history are displayed. It has the effect of being able to provide privacy for

In addition, in the case of the method of protecting personal information with a combination of a new verifiable ID in the block chain according to this embodiment, since it does not include a third party and proceeds on an executable smart contract, it is not exposed to man-in-the-middle attacks, etc. There is no possibility of risking a change of heart on one side.

In addition, according to this embodiment, an important factor for ID generation in the voucher user verification process is the actual Ethereum address of the verification requester, so there is no possibility that the requestor can pretend to be a voucher user and make a false request by pretending to be a third person. It also has an excellent effect.

1 is a structural diagram for explaining a system for providing a voucher based on a block chain according to this embodiment.
2 is a conceptual diagram for explaining an identity chain for providing an anonymous voucher according to the present embodiment.
3 is a diagram illustrating a voucher state transition according to the present embodiment.
4 is a conceptual diagram for explaining the steps for generating a voucher ID according to the present embodiment.
5 is a conceptual diagram for explaining the steps for verifying a voucher ID according to the present embodiment.
6 is a flowchart illustrating a method for providing a voucher according to the present embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Blockchain is an electronic ledger implemented as a computer-based distributed distributed system made up of blocks composed of transactions. Each transaction includes at least one input and at least one output. Each block is linked together to create a permanent and immutable record of every transaction written to the blockchain from the beginning, including the hash of the previous block.

A smart contract is a computer program designed to automate the execution of the terms of a contract or agreement. Unlike traditional contracts written in natural language, smart contracts are machine-executable programs that contain rules that can process inputs to produce results, from which actions can be triggered to be performed.

The present invention relates to a method of providing a voucher using such a block chain and smart contract. More specifically, we propose an anonymous voucher providing service structure that enables anonymous transmission of vouchers by preventing the link between the sender sending the voucher and the recipient of the receiving voucher from being exposed in a blockchain-based voucher sending application, etc.

1 is a structural diagram for explaining a system for providing a voucher based on a blockchain according to this embodiment, and FIG. 2 is a conceptual diagram for explaining an identity chain for providing an anonymous voucher according to this embodiment.

Hereinafter, with reference to FIGS. 1 and 2 together, the operation of the blockchain-based voucher providing system according to the present embodiment will be described.

Meanwhile, in the present invention, the blockchain can be implemented based on Ethereum supporting smart contract technology.

The voucher providing system 100 according to this embodiment includes a voucher sender node 110, a voucher recipient node 120, a voucher contract node 130, and a service provider node 140 constituting a blockchain network. . In this case, the components included in the voucher providing system 100 according to the present embodiment are not necessarily limited thereto. For example, in the voucher providing system 100, the type of node constituting the blockchain network for providing the voucher may have more or fewer components or different components than those shown depending on the type of service. It should be recognized that

Meanwhile, in this embodiment, each node constituting the blockchain network of the voucher providing system 100 may be implemented by a program in the computing device. For example, each node may be implemented by a DAPP (Decentralized Application), which is a kind of decentralized app in the computing device.

In the case of such a DAPP, it basically provides a function that allows participants to see the ledger in the block chain, input necessary data, and transmit/receive tokens.

The voucher sender node 110 means a node for a voucher sender that pays a desired amount of cryptocurrency to the smart contract, generates a voucher corresponding to the amount, and sends it to the voucher recipient. Such, the voucher sender node 110 owns the user account of the Ethereum smart contract and may be defined as EOA_vs (Externally Owned Account_voucher sender).

The voucher sender node 110 creates a voucher through a voucher contract on the Ethereum platform, which is a blockchain that provides smart contract technology, and specifies that only specific recipients can receive the voucher.

On the other hand, in this embodiment, when the voucher sender node 110 creates a voucher, by designating an anonymous voucher recipient ID without designating the voucher recipient's Ethereum account, the sender/receiver connection information for the voucher is Operate so as not to be exposed.

To this end, the voucher sender node 110 utilizes a new identity chain that allows the Ethereum account to be invisible, but to specify the voucher recipient.

That is, the voucher sender node 110 creates a voucher ID (vid: voucher id) for sending the voucher using the previously created voucher recipient ID (rid: recipient id) based on the virtual currency account information of the voucher recipient, , operates so that a voucher can be created based on this.

The anonymous voucher recipient ID used at this time is generated based on the actual voucher recipient's Ethereum account information, so that no one other than you can create it, and you cannot trace the voucher recipient's Ethereum account backwards from the created voucher recipient ID. has a characteristic that At the same time, there is a feature that contains information that allows only the recipient of the voucher to be authenticated as a true user when the voucher is requested to be used.

In other words, the voucher sender node 110 according to this embodiment presents the voucher to the voucher recipient, but the voucher recipient information can be processed anonymously so that the basis of how much amount was presented to which recipient does not remain in the block chain. has

Referring to FIG. 2 , each ID constituting the proposed identity chain is generated as a comprehensive hash value of several IDs and key values. At this time, the hash function generates an output of a certain length regardless of the input value, and a completely different ID is generated even if the input value is different by just one bit. It has the characteristic of a one-way function that cannot be extracted. Therefore, even if the virtual ID is disclosed, it is not possible to trace which Ethereum ID it was created from, so anonymity can be provided.

In this case, according to the identity chain, the voucher sender node 110 creates a virtual voucher ID (vvid: virtual voucher id) to replace the voucher sender's virtual currency account information, and creates a virtual voucher ID and voucher recipient Create a voucher ID (vid: voucher id) based on the ID.

Here, the virtual voucher ID is an ID generated by the voucher sender to use the voucher ID in addition to his/her own sender account. It can be generated by using a full hash value that incorporates the hash value (hnonce) of the text (vvid=hash(EOA_vs|rccv|hnonce)).

The voucher ID is an ID that the voucher sender sends to a specific voucher recipient, and can be generated by using the full hash value of the virtual voucher ID, voucher recipient ID, and time stamp (vid=hash(rid|vvid|ts) )). In this case, it is possible to authenticate who the owner of the voucher is based on the voucher ID.

The voucher sender node 110 registers the voucher ID and voucher amount on the blockchain to generate a voucher according to the smart contract. At this time, the process of registering the voucher amount means that the voucher sender wants to send money to the voucher contract.

The voucher recipient node 120 means a node corresponding to the owner of the voucher that can receive the voucher sent by the voucher sender and receive the service token corresponding to the voucher amount. This voucher recipient node 120 owns the user account of the Ethereum smart contract and may be defined as EOA_vr (Externally Owned Account_voucher recipient).

First, in this embodiment, the voucher recipient node 120 creates an anonymous voucher recipient ID based on the virtual currency account information of the voucher recipient and registers it on the blockchain, based on this, sensitive information about the voucher recipient It operates so that the voucher provision service can be supported without exposure of

Referring to FIG. 4 , the voucher recipient node 120 may generate a voucher recipient ID through a total of three steps.

In step 1, the voucher recipient node 120 generates a randomly created new identity for recipient (rccr), which is a new 20-byte ID corresponding to the voucher recipient.

In step 1, the voucher recipient node 120 may create an rccr using the createNewIdentity() function provided in the Ethereum encryption package (ethCypto).

In step 2, the voucher recipient node 120 uses the rccr generated in step 1 to generate a virtual recipient ID (rvid: virtual recipent id) used by the voucher recipient to generate their own voucher recipient ID.

In step 2, the voucher recipient node 120 generates a virtual recipient ID by using the entire hash value that integrates rccr, the virtual currency account information of the voucher recipient, and the hash value (hnonce) of the randomly generated cipher text. (rvid=hash(EOA_vr|rccr|hnonce).

In step 3, the voucher recipient node 120 replaces the virtual currency account information of the voucher recipient based on the virtual recipient ID generated in step 2 to generate a voucher recipient ID, which is information disclosed to the outside.

In step 3, the voucher recipient node 120 may be composed of a virtual recipient ID and a hash value of a time stamp generated in the voucher contract (rid=hash(rvid|ts)).

The voucher recipient node 120 receives a recipient authentication from the voucher contract node 130 based on the voucher recipient ID in order to receive a voucher published through the voucher contract node 130 .

To this end, the voucher recipient node 120 generates signature information using rccr, which is the identity information generated in the process of generating the voucher recipient ID, and consists of a hash value of the signature information and a predefined cipher text. A voucher reception request signal may be transmitted to the voucher contract node 130 .

Thereafter, the voucher recipient node 120 receives a voucher amount corresponding to the voucher according to the authentication result for the voucher recipient from the voucher contract node 130 . At this time, the voucher recipient node 120 is preferably provided with a service token corresponding to the voucher amount from the voucher contract node 130, but is not necessarily limited thereto.

The voucher recipient node 120 transfers the received service token to the service provider node 140 , and receives a service corresponding to the service token from the service provider node 140 .

The voucher contract node 130 performs a function of issuing and managing vouchers based on blockchain and smart contracts. Such, the voucher contract node 130 means a voucher contract distributed on the Ethereum platform as smart contract software corresponding to the block chain.

The voucher contract node 130 receives the voucher recipient ID generated from the voucher recipient node 120, registers it on the block chain, and uses it to issue and manage the voucher.

When the voucher ID and voucher amount are registered from the voucher sender node 110, the voucher contract node 130 creates a voucher according to the smart contract, activates it, and allows it to be exposed to the voucher recipient.

On the other hand, the voucher contract node 130 maps the voucher recipient ID to information related to the voucher amount registered on the blockchain in more detail when the transfer of the voucher amount from the voucher sender node 110 is confirmed. to activate the voucher.

When a specific voucher recipient requests receipt of a voucher, the voucher contract node 130 verifies whether the voucher recipient is a legitimate recipient, and provides a voucher to the voucher recipient only when verification is completed.

In this embodiment, the voucher contract node 130 performs authentication for the voucher recipient based on the voucher recipient ID. That is, the voucher contract node 130 can authenticate the voucher recipient by verifying that the voucher recipient, which is the subject of authentication, is the Ethereum account holder who directly generated the voucher recipient ID.

For example, the voucher recipient ID is recovered from the signature information included in the voucher reception request signal received from the voucher recipient node 120, and the recovered voucher recipient ID and the voucher recipient ID mapped on the voucher are verified to be identical to the voucher recipient. perform authentication for

Referring to FIG. 5 , the voucher contract node 130 may perform authentication for the voucher recipient through a total of three steps.

In step 1, the voucher contract node 130 recovers rccr from the signature information included in the voucher reception request signal.

In step 1, the voucher contract node 130 can recover rccr using the recoverSigner() function of the Ethereum encryption package. In this case, the restored rccr may be expressed as rccr'.

In step 2, the voucher contract node 130 recovers rvid' using the rccr' recovered in step 1.

The EOA_vr used in the process of recovering 'rvid' in step 2 is the Ethereum address of the recipient of the voucher requesting verification, and it can be provided through the msg.sender function provided by Ethereum. Since the requester's address is used in the above, false information cannot be used.

In step 3, the voucher contract node 130 recovers rid' using the rvid' recovered in step 2.

Thereafter, the voucher contract node 130 verifies that if the restored rid' and the rid mapped to the voucher are the same, the user who requested authentication is a voucher recipient who is entitled to receive the voucher. At this time, if each rid is different, the verification fails because a different ID is used for the signature information initially generated by the voucher recipient or the recipient's Ethereum address requesting the voucher is not the same as the original owner's address. do.

The voucher contract node 130 issues a service token corresponding to the voucher amount to the voucher recipient node 120 when authentication for the voucher recipient is completed.

On the other hand, there is a limitation that it is difficult to delete or modify information once registered in the block chain. Due to this, the voucher contract node 130 operates to flexibly apply the voucher status by continuously updating the status information of the voucher in accordance with event occurrence information related to one voucher.

3 is an exemplary diagram illustrating a voucher state transition diagram according to the state information of the voucher.

Referring to FIG. 3 , the voucher contract node 130 converts the voucher status information to the created step when a voucher ID is generated ( S302 ). On the other hand, the creation of a voucher ID means that hashing related to the voucher recipient ID has been performed, so it means that a valid voucher recipient ID has already been used to generate the voucher ID.

The voucher contract node 130 checks whether the money that the sender of the voucher wants to send has been transferred to the voucher contract (S302), and when the transfer is confirmed, the status information of the voucher is converted to delivered (S303) . This delivered state means that the voucher recipient can receive the voucher. At this time, until the voucher is accepted by the voucher recipient, the voucher sender can cancel the transmission of the voucher.

The voucher contract node 130 checks the voucher sent to the voucher recipient and determines to receive it (S304), and converts the voucher status information to the accepted state (S305). On the other hand, when the voucher is converted to the accepted state, the sender of the voucher cannot cancel the transmission of the voucher.

The voucher contract node 130 converts the voucher status information to a micro-payed state when the voucher recipient requests issuance of a desired amount as a service token within the voucher limit (S306).

When the voucher amount is exhausted, the voucher contract node 130 switches the voucher state to the transferred state, and ends the voucher state transition (S307).

On the other hand, if the voucher contract node 130 cancels the voucher transmission before the voucher recipient accepts the voucher reception, it switches the voucher state to the cancelled state (S308).

Even when the voucher is transmitted, the voucher contract node 130 converts the status information of the voucher into a rejected state when the voucher recipient rejects the voucher reception (S309). In this case, the voucher amount may be refunded when the voucher sender requests a refund.

The voucher contract node 130 converts the voucher state to a refunded state when the voucher sender requests a refund if the voucher sender requests a cancellation or is canceled or the voucher receiver rejects the reception and is rejected.

The service provider node 140 receives a service token corresponding to the voucher deductible from the voucher recipient, exchanges it with cryptocurrency, and provides a service corresponding to the cryptocurrency to the voucher recipient. The service provider owns the user account of the Ethereum smart contract and can be expressed as EOA_sp (Externally Owned Account_service provider).

6 is a flowchart illustrating a method for providing a voucher according to the present embodiment.

The voucher recipient node 120 generates an anonymous voucher recipient ID based on the virtual currency account information of the voucher recipient, and registers the generated voucher recipient ID on the block chain (S602). In step S602, the voucher recipient node 120 generates a virtual recipient ID corresponding to the voucher recipient, and generates a voucher recipient ID based on the virtual recipient ID and timestamp.

The voucher sender node 110 generates a voucher ID based on the voucher recipient ID generated in step S602, and registers the generated voucher ID and voucher amount on the block chain (S604). In step S604, the voucher sender node 110 generates a virtual voucher ID, and generates a voucher ID based on the virtual voucher ID and the voucher recipient ID.

The voucher recipient node 120 receives a recipient authentication based on the voucher recipient ID from the voucher contract node 130 to receive the voucher, and receives a voucher amount corresponding to the voucher according to the authentication result (S606). In step S606, the voucher contract node 130 recovers the voucher recipient ID from the signature information included in the voucher reception request signal received from the voucher recipient node 120, and the restored voucher recipient ID and the voucher mapped on the voucher Authenticate the voucher recipient by verifying that the recipient ID is the same.

Here, since steps S602 to S606 correspond to the operation of each component of the voucher providing system described above, further detailed description will be omitted.

Although it is described that each process is sequentially executed in FIG. 6 , the present invention is not limited thereto. In other words, since it may be applicable to changing and executing the process described in FIG. 6 or executing one or more processes in parallel, FIG. 6 is not limited to a time series sequence.

As described above, the voucher providing method of the voucher providing system described in FIG. 6 is implemented as a program and readable recording medium (CD-ROM, RAM, ROM, memory card, hard disk, magneto-optical disk, storage device, etc.).

The above description is merely illustrative of the technical idea of this embodiment, and various modifications and variations will be possible by those skilled in the art to which this embodiment belongs without departing from the essential characteristics of the present embodiment. Accordingly, the present embodiments are intended to explain rather than limit the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the following claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present embodiment.

100: Voucher providing system 110: Voucher sender node
120: voucher recipient node 130: voucher contract node
140: service provider node

Claims (12)

Based on the virtual currency account information of the voucher recipient, create a voucher ID (vid: voucher id) for sending the voucher by using the previously created voucher recipient ID (rid: recipient id), and block the voucher ID and voucher amount a voucher sender node that registers on the chain to generate a voucher according to a smart contract;
a voucher recipient node that generates the voucher recipient ID and registers it on the blockchain, and receives the voucher amount corresponding to the voucher according to a recipient authentication result based on the voucher recipient ID; and
A voucher contract node that issues and manages the voucher based on the blockchain and the smart contract
Voucher providing system comprising a. The method of claim 1,
The voucher sender node,
Creating a virtual voucher id (vvid) for use as a substitute for the virtual currency account information of the voucher sender, and generating the voucher ID based on the virtual voucher ID and the voucher recipient ID Voucher providing system. 3. The method of claim 2,
The voucher sender node,
The virtual voucher ID is generated by using the entire hash value integrating the virtual currency account information of the voucher sender, rccv (randomly created new identity for voucher sender), and the hash value (hnonce) of the randomly generated cipher text,
Voucher providing system, characterized in that generating the voucher ID by using the virtual voucher ID, the voucher recipient ID and the entire hash value of the time stamp (time stamp). The method of claim 1,
The voucher recipient node,
Generates a virtual recipient ID (rvid: virtual recipent id) corresponding to the voucher recipient, and replaces the virtual currency account information of the voucher recipient based on the virtual recipient ID and timestamp. Voucher providing system, characterized in that for generating a voucher recipient ID. 5. The method of claim 4,
The voucher recipient node,
Generates rccr (randomly created new identity for recipient), which is new identity information corresponding to the voucher recipient, and integrates the rccr, virtual currency account information of the voucher recipient, and hash value (hnonce) of the randomly generated cryptographic text A system for providing a voucher, characterized in that it generates a virtual recipient ID by using the entire hash value. The method of claim 1,
The voucher recipient node,
Generates signature information using rccr, which is the identity information generated in the process of generating the voucher recipient ID, and sends a voucher reception request signal composed of a hash value of the signature information and a predefined cipher text to the voucher controller A system for providing a voucher, characterized in that it is delivered to a tract node. The method of claim 1,
The voucher contract node is
When it is confirmed that the remittance of the voucher amount is completed, the voucher providing system characterized in that the voucher is activated by mapping the voucher recipient ID on the voucher. 8. The method of claim 7,
The voucher contract node is
When the voucher ID is generated, the voucher status information is converted to a created step, and when the mapping is made, the voucher status information is converted to a delivered step, and according to the event occurrence information related to the voucher Voucher providing system, characterized in that the status information of the voucher is continuously updated. The method of claim 1,
The voucher contract node is
Authenticate the voucher recipient by recovering the voucher recipient ID from the signature information included in the voucher reception request signal received from the voucher recipient node, and verifying that the recovered voucher recipient ID and the voucher recipient ID mapped on the voucher are the same Voucher providing system, characterized in that to perform. 10. The method of claim 9,
The voucher contract node is
When authentication of the voucher recipient is completed, a service token corresponding to the voucher amount is issued to the voucher recipient node. The method of claim 1,
Voucher providing system, characterized in that it further comprises a service provider node that receives a service token corresponding to the voucher amount from the voucher recipient, exchanges it with cryptocurrency, and provides a service corresponding to the cryptocurrency to the voucher recipient. In the voucher providing method of the voucher providing system,
A process in which the voucher recipient node generates a voucher recipient ID based on the virtual currency account information of the voucher recipient, and registers the voucher recipient ID on the block chain;
a process in which the voucher sender node generates a voucher ID based on the voucher recipient ID, and registers the voucher ID and voucher amount on the blockchain to generate a voucher according to a smart contract; and
A process in which the voucher recipient node receives recipient authentication based on the voucher recipient ID from the voucher contract node to receive the voucher, and receives the voucher amount corresponding to the voucher according to the authentication result
Voucher providing method comprising a.

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