KR102074381B1 - Method, device and recording medium for processing confidential transaction based on blockchain - Google Patents

Abstract

According to one embodiment of the present disclosure, a method for performing anonymous transactions on general purpose blockchain comprises the steps of: checking whether a value encrypted and stored in each note is included within a preset valid range when a transaction is requested on blockchain; checking whether a sum of values of input notes and a sum of values of output notes are the same while the value is encrypted; and deleting the input notes stored in a note registry and newly storing the output notes when the value is identified.

Description

METHOD, DEVICE AND RECORDING MEDIUM FOR PROCESSING CONFIDENTIAL TRANSACTION BASED ON BLOCKCHAIN}

The present disclosure relates to a blockchain based anonymous transaction method, apparatus and recording medium, and more particularly, to a method, apparatus and record for performing anonymous transaction on a general purpose blockchain using smart contract and zero-knowledge proof. It is about the medium.

Recently, as the interest in blockchain technology has been concentrated, blockchain has been utilized in various fields. Such blockchains can be divided into public blockchains and private blockchains.

The public blockchain is an unspecified number of people participating in the network, which has the advantage of high reliability because everyone who trades has a record, but has the disadvantage of changing the initial rules and being slow.

Private blockchain is a blockchain with limited participants, which has the advantage of faster time and higher efficiency than public, but has a disadvantage of poor accessibility.

Accordingly, there is an increasing demand for solving the problems of the public blockchain and the private blockchain.

Meanwhile, the smart contract function has emerged to conclude and implement various types of contracts such as financial transactions, real estate contracts, and notaries on a blockchain basis. This is a program that records the contract terms on the blockchain and automatically executes the contract when the terms are met. In principle, developers can code the contract terms and contents themselves, so in principle, any kind of contract that humans can imagine. Can be implemented. For example, various kinds of contracts can be implemented using the Ethereum platform.

However, there is a problem that all the information is disclosed when using the smart contract, and the demand to perform a transaction by making only a desired item private during the transaction is increasing.

The present disclosure is to solve the above-mentioned problems of the prior art, and to provide a method, an apparatus and a recording medium for performing anonymous transactions on a general-purpose blockchain using smart contract and zero-knowledge proof.

The purpose of the present disclosure is not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood from the following description.

According to an embodiment of the present disclosure, in the method for performing anonymous transactions on a blockchain for general purpose, when a transaction is requested on the blockchain, a value stored by encrypting each note within a preset valid range is set. Checking whether it is included; Checking whether the sum of the values of the input notes and the sum of the values of the output notes are equal when the value is encrypted; And if the value is confirmed, deleting the input note stored in the note register and newly storing the output note. A blockchain-based anonymous transaction performing method is provided.

The validity verification step of the value may include encryption information generated using a reference common string corresponding to a value of the note, a viewing key to be used for encryption, and a value registered in a signature database. On the basis, the step of checking whether the value is included in the valid range in the state where the value is not disclosed.

In the step of checking whether the value agreement is the same, if the proof of the personal information is approved through a Zero-Knowledge Proof protocol without the witness of the value being disclosed, the value is disclosed. Even if it is not, the step of determining whether the value agreement is the same or not, the normal result; may include.

Whether or not the approval of the personal information is approved, transmitting a message a from the prover node to the verifier node; Transmitting an arbitrary challenge value c from the verifier node to the prover node; And when a response z for the challenge value c is transmitted from the prover node to the verifier node, a common input value x between the prover node and the verifier node, the message a, the challenge value c, the response based on z, determining whether to approve the proof of the personal information that is not disclosed at the prover node.

The challenge value may be calculated using a cryptographic hash function.

The step of checking whether the value agreement is the same may include performing an addition operation on the value of the encrypted state through an elliptic curve cryptosystem in the state where the value is not disclosed. .

According to another embodiment of the present disclosure, in the apparatus for performing anonymous transactions on a blockchain for general purpose, comprising a plurality of nodes sharing information on the blockchain, if a transaction is requested from any of the plurality of nodes, At least one of the plurality of nodes checks whether or not the stored value encrypted in each note is within a preset valid range, and if the sum of values of the input notes and the sum of the values of the output notes are the same while the value is encrypted. A blockchain-based anonymous transaction performing apparatus is provided which checks whether or not and if the value is confirmed, deletes the input note stored in the note register and newly stores the output note.

At least one of the plurality of nodes is configured to display the value in the undisclosed state based on cryptographic information generated using a signature corresponding to a value of the note, an arbitrary value to be used for encryption, and a value registered in a signature database. You can check whether the value falls within the valid range.

At least one of the plurality of nodes is equal to the value agreement, even if the personal information of the value is not disclosed and the proof of the personal information is approved through a zero-knowledge proof protocol, even if the value is not disclosed. It can be determined that the result of checking whether or not is normal.

The prover node, which is one of the plurality of nodes, sends a message a to the verifier node, which is the other one of the plurality of nodes, the verifier node sends a random challenge value c to the prover node, and A prover node sends a response z to the challenge value c to the verifier node, the verifier node having a common input value x between the prover node and the verifier node, the message a, the challenge value c. On the basis of the response z, it is possible to determine whether to approve the proof for the personal information that is not disclosed in the prover node.

The challenge value may be calculated using a cryptographic hash function.

At least one of the plurality of nodes may perform an addition operation on the value of an encrypted state by using an elliptic curve cryptography method while the value is not disclosed.

According to another embodiment of the present disclosure, a method of performing an anonymous transaction on a blockchain for general purpose, comprising: determining, according to a user's input, some items that require encryption among a plurality of items used for a transaction; Configuring a smart contract to encrypt the partial items using an elliptic curve cryptography; Performing a first transaction using the smart contract by performing proof through zero-knowledge proof for the some items; And storing a plurality of result values obtained as a result of the performance of the first transaction.

The blockchain based anonymous transaction performing method may include: performing an operation on the plurality of result values to obtain an updated result value; And performing a second transaction using the smart contract by using the updated result value.

According to another embodiment of the present disclosure, an apparatus for performing an anonymous transaction on a blockchain for general purpose, comprising: a receiver for receiving a user input; And determining some items requiring encryption among the plurality of items used for the transaction according to the user's input, and configuring a smart contract to encrypt the some items by using an elliptic curve cryptography method. The blockchain-based anonymous transaction performing apparatus includes a processor configured to perform a first transaction using the smart contract by performing proof through knowledge proof and to store a plurality of result values obtained as a result of the first transaction. Is provided.

The processor may perform an operation on the plurality of result values to obtain an updated result value, and perform a second transaction using the smart contract using the updated result value.

According to another embodiment of the present disclosure, a computer-readable non-transitory recording medium having a program recorded thereon for executing a blockchain based anonymous transaction method may execute the method according to any one of the above steps.

According to one embodiment of the present disclosure, since the private blockchain can be substantially implemented using the public blockchain and zero-knowledge proof, anyone can make the private blockchain universally available, thereby realizing real estate, finance, and all other areas. There is an effect that can be easily used.

In addition, according to an embodiment of the present disclosure, by using the smart contract and zero-knowledge proof, there is an effect that general trading is possible through a blockchain that can be used universally.

In addition, according to an embodiment of the present disclosure, when encrypting a part of an encrypted item in a smart contract, an additional transaction may be performed by performing an operation on a result value using an elliptic curve cryptography.

In addition, according to an embodiment of the present disclosure, the data is not limited to the book, but the data is not limited to the book, widen the smart contract, encrypts a portion, and proves that the encrypted through the zero-knowledge proof so that transactions can be made, smart contract By selectively selecting and encrypting the desired parts, the creators of the software can use it universally and can easily use it through the Ethereum infrastructure.

The effects of the present disclosure are not limited to the above-described effects, but should be understood to include all the effects deduced from the configurations of the invention described in the detailed description or claims of the present disclosure.

1 is a block diagram of an anonymous transaction performing device based on an embodiment of the present disclosure.
2 is a diagram illustrating a process of performing an anonymous transaction on a general-purpose blockchain according to an embodiment of the present disclosure.
FIG. 3 is a diagram illustrating a process of checking whether a value sum of an input note and a value sum of an output note are the same according to an embodiment of the present disclosure.
4 illustrates an elliptic curve cryptogram according to an embodiment of the present disclosure.
5 is a diagram illustrating a process of performing an anonymous transaction on a general-purpose blockchain according to another embodiment of the present disclosure.

Hereinafter, the present disclosure will be described with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

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

1 is a block diagram of an anonymous transaction performing device based on an embodiment of the present disclosure.

Referring to FIG. 1, the blockchain-based anonymous transaction execution apparatus according to an embodiment of the present disclosure may be configured with a plurality of nodes 100 that can communicate with each other through a communication network, and the plurality of nodes 100 may be blockchains. Information can be shared on the web.

First, the block chain will be described. Blockchain is a decentralized data storage technology that stores data in blocks, connects them in a chain, and replicates and stores them on many computers at the same time. The transaction is sent to all users who participate in the transaction without having to maintain transaction records on a centralized server.Each trader can not share information and collate data to forge or tamper with each other.

Blockchain maintains and manages the network of individual servers participating in a transaction without keeping and managing transaction records in a centralized server. The individual server, or participant, is called a node. Because there is no central administrator, the role of the node distributing the block is important, and at least half of the participating nodes must agree to create a new block. Nodes have their blockchains stored on their computers, and even if some nodes are hacked and the existing contents fail, data remains on multiple nodes, so that data can be preserved continuously.

In the present disclosure, a block chain is implemented using a plurality of nodes 100 as participants, and the plurality of nodes 100 includes a first node 110, a second node 120, and the like. Each 100 may be implemented in the form of a terminal, or may be implemented in the form of a server.

In addition, in the present disclosure, by providing a protocol that enables anonymous transactions even on a general purpose blockchain, the plurality of nodes 100 may perform anonymous transactions on a general purpose blockchain. In this case, an anonymous transaction may refer to a transaction in which a value occurring in the public blockchain network is hidden.

2 is a diagram illustrating a process of performing an anonymous transaction on a general-purpose blockchain according to an embodiment of the present disclosure.

First, all notes can be stored in the note registry, and each note can be stored encrypted with its value and who owns it.

Referring to FIG. 2, when an anonymous transaction occurs, if a transaction is requested from any one of the plurality of nodes 100 on the blockchain, at step S201, at least one of the plurality of nodes 100 is assigned to each note. You can check whether the stored value is encrypted within the preset validity level. In other words, you can verify that the value of each note is within the valid range.

In the transaction transaction step S202, at least one of the plurality of nodes 100 may determine whether the sum of the values of the input notes and the sum of the values of the output notes are the same while the values are encrypted. That is, it is possible to check whether the sum of values of the input notes and the sum of the values of the output notes are the same.

In a result storing step S203, at least one of the plurality of nodes 100 may delete the input note stored in the note registry and newly store the output note when the value is confirmed. In other words, once both the proof of range and the transaction of merging are confirmed, the input notes of the note registry can be deleted and the output notes can be created and registered.

As described above, the overall flow of the protocol for enabling anonymous transactions on a general-purpose blockchain has been described. Hereinafter, the configuration required to perform anonymous transactions on the blockchain will be described in detail by function. .

Encrypted notes

Rather than the way a user transacts with one wallet, each note has a value, and the way a user owns multiple notes, how much information each note should have, Value 'information, and' ownership 'information about who owns it.

The information disclosed in relation to the value is encryption information corresponding to the encryption of the value, and the value of the note may include a note value, a viewing key, and the like.

Information disclosed in relation to ownership is a public key corresponding to a spending key, and the spending key may be included as the witness of ownership.

On the other hand, in order to perform anonymous transactions on the blockchain, a technique for encrypting values in the form of notes and a technique for proving [sum of values of input notes = sum of values of output notes] while the values are encrypted are required.

With respect to the technique of encrypting the value in the form of a note, it is possible to encrypt the value through the "prove range" procedure described below, and that the sum of the values of the input notes and the sum of the values of the output notes is the same through the sum protocol. Can be.

FIG. 3 is a diagram illustrating a process of checking whether a value sum of an input note and a value sum of an output note are the same according to an embodiment of the present disclosure.

As shown in FIG. 3, the following equation may be used in the summation protocol.

As described above, according to an embodiment of the present disclosure, at least one of the plurality of nodes 100 uses the summation protocol represented by the above formula, and in the state where the value is encrypted, the sum of the values of the input notes and the values of the output notes. You can check whether this is the same.

Elliptic Curve Password

In order to perform the addition operation without revealing the encrypted value of each note, homomorphic encryption is required. An elliptic curve cryptosystem is typically used.

4 illustrates an elliptic curve cryptogram according to an embodiment of the present disclosure.

First, the following equation may be used to add.

R can be calculated by adding the points P and Q on the elliptic curve.

The following formula can be used for Scalar Multiplication.

The scalar product is a one-way function, given the integer x and the point P on the elliptic curve. It's hard to bet.

For equation addition, the following equation can be used.

Homogeneous addition allows for addition in the encrypted state.

As such, according to an embodiment of the present disclosure, at least one of the plurality of nodes 100 performs an addition operation on the value of the encrypted state through an elliptic curve cryptography method in an encrypted state where the value is not disclosed. can do.

However, since elliptic curve cryptography uses modulo, problems arise when performing operations that are out of range. In order to solve this problem, it is possible to limit the range of values actually used through the range proof to be described later.

Scope proof

Range Proof ensures that all encrypted values are smaller than the preset value (k_max), which is a very computationally expensive operation. To solve this, you can create an electronic signature for all possible values, register them in a signature database, and use them to prove that the values are in the valid range.

The password information in each note is created using the value k of the note, an arbitrary value to be used to encrypt the value (corresponding to the viewing key), and a reference common string corresponding to the value k in the signature database. Can be used to prove that the value k is within the valid range, but does not disclose the value k of the note, thereby making it possible to encrypt the value.

As such, according to an embodiment of the present disclosure, at least one of the plurality of nodes 100 may generate cryptographic information generated by using a signature corresponding to a value of a note, an arbitrary value to be used for encryption, and a value registered in a signature database. On the basis, it can be checked whether the value falls within the validity range without the value being disclosed.

Proof of knowledge

Zero-Knowledge Proof is required in situations where you want to prove that the sum of the values of the input notes and the sum of the values of the output notes is the same, without revealing the value of each encrypted note.

For example, in the relationship between witness w of R = (w, x, crs), public input string x, common reference string crs, prover P is equal to (w, x, crs for x already given to verifier V. When we want to prove that we know w that satisfies R, but we don't want to release w, we can prove that we know w using zero-knowledge proof.

As such, according to one embodiment of the present disclosure, if at least one of the plurality of nodes 100 is authorized for proof of personal information through a zero-knowledge proof protocol while the witness of the value is not disclosed, However, even if the value is not disclosed, it can be judged that the result of checking whether the value agreement is the same is normal.

Sigma protocol

The sigma protocol is a proof protocol consisting of a request phase, a challenge phase, and a response phase. The sigma protocol is a common input value x between the prover P and the verifier V, and the undisclosed input value of the prover P. , We can prove that we know the value of w.

First, in the commitment phase, the verifier P may send a message a to the verifier V.

In the challenge phase, the verifier V can send any challenge value c to the prover P.

In the response phase, the verifier P may send a response z to the challenge value c to the verifier V, which verifies whether to accept the proof from the common input value x, the message a, the challenge value c, and the response z. You can decide whether or not.

For example, in the discrete logarithm problem, P wants to prove that he knows that x satisfies y = g ^x , but does not want to reveal the value of x for y and g that are already public. The following process can be performed.

The prover P can pick any value v, calculate t = g ^v and send t to the verifier V.

The verifier V may pick a challenge value c and send it to the verifier P. At this time, if the verifier V does not transmit the challenge value and the prover P makes the challenge value c by itself, communication between the prover P and the verifier V can be reduced.

The prover P can send r to the verifier V by calculating r = v-cx.

The verifier V checks if t ≡ g ^r y ^c, and if a correct value is obtained, then g ^r y ^c = g ^v-cx g ^x c = g ^v = t, so that x cannot be given without revealing the value of x. Knowing can be proved.

As such, according to an embodiment of the present disclosure, the first node 110, which is one of the plurality of nodes 100, is the prover node, and the second node 120 which is the other one of the plurality of nodes 100. If is a verifier node, the first node 110 can send a message a to the second node 120, the second node 120 can send any challenge value c to the first node (110). In addition, the first node 110 may transmit a response z to the conductivity value c to the second node 120.

The second node 120 is not published at the first node 110 based on the common input value x, the message a, the challenge value c, the response z between the first node 110 and the second node 120. You can decide whether to approve proof of personal information.

Meanwhile, the challenge value may be calculated using a cryptographic hash function.

For example, in the discrete logarithm problem, P wants to prove that he knows that x satisfies y = g ^x , but does not want to reveal the value of x for y and g that are already public. , The prover P chooses a random value v, computes t = g ^v , the prover P computes the challenge value c = H (g, y, t) using the cryptographic hash function H (), The prover P calculates r = v-cx and publishes (t, r), so anyone can see that t ≡ g ^r y ^c .

5 is a diagram illustrating a process of performing an anonymous transaction on a general-purpose blockchain according to another embodiment of the present disclosure.

First, each of the plurality of nodes 100 may include a receiver (not shown) that receives a user input and a processor (not shown) that performs a substantial operation.

Referring to FIG. 5, in the step of determining an encryption item (S501), if some items requiring encryption among a plurality of items used for a transaction are determined according to a user's input through a receiver, the processor may determine an encryption item.

Then, in the smart contract configuration step (S502), the processor may configure the smart contract so that some items determined as encryption items are encrypted using an elliptic curve cryptography.

Smart Contract is a smart contract system that registers the terms and conditions of the contract and the applicable laws and procedures are automatically applied and the results are sent to the trading parties. Thus, the transaction procedure is simplified and the costs incurred in the transaction can be reduced, as well as a secure contract between the trading parties.

For example, smart contracts allow insurers and hospitals to automate premium payments while protecting patient medical records, simplifying the payment settlement system, creating insurance ledgers that are hard to forge, and supporting smart contracts. Ethereum is a representative platform.

Then, in the zero knowledge proof step (S503), the processor may perform proof through zero knowledge proof for some encrypted items.

Then, in the transaction execution step (S504), the processor may perform a first transaction using the smart contract.

Subsequently, in a result storing step S505, the processor may store a plurality of result values obtained as a result of performing the first transaction.

Thereafter, the processor may perform an operation on the plurality of result values to obtain an updated result value, and perform step S504 again to perform a second transaction using the smart contract using the updated result value. .

Meanwhile, according to an embodiment of the present disclosure, a transaction using a smart contract may be performed differently according to the type or number of encrypted items. For example, when the first item is encrypted to form a smart contract, both the first transaction and the second transaction may be performed. When the second item is encrypted to form the smart contract, only the first transaction is performed. Transactions can be restricted from being performed. In other words, when the smart contract is configured, the user only selects an item to be encrypted to adjust the number of transactions using the smart contract.

As such, according to an embodiment of the present disclosure, since the private blockchain can be substantially implemented using the public blockchain and zero-knowledge proof, anyone can use the private blockchain universally, such as real estate, finance, and the like. Available in all areas.

For example, the proof of zero knowledge proves that the balance is larger than the amount to be remitted while the balance of the account balance is hidden. Here, an elliptic curve cipher is used, and the result of the arithmetic operation of the result encrypted by the elliptic curve cipher corresponds to each other.

In other words, if 100 and 50 before encryption are encrypted with A and B, respectively, 100 + 50 = 150, the result of encryption becomes 150 when C is A + B = C. Since the original value is not disclosed, only the encrypted value can be compared.

In using smart contracts, it is essential that some information be encrypted, in which case all of the information is shared and the advantage of blockchain is that it cannot be forged or forged. Thus, zero-proof proof can be used to solve this problem.

However, there is no general way of using zero-knowledge proof, and there is no technology that incorporates elliptic curve encryption into the blockchain.

In the present disclosure, the data going up on the blockchain is not limited to books, but the smart contract is widened, partly encrypted, and the encrypted part is proved through proof of knowledge so that transactions can be made. By selectively selecting and encrypting, a method, apparatus, and recording medium for universal use are provided.

In addition, it is possible to implement the scheme according to the present disclosure more easily by applying the scheme according to the present disclosure to the platform that is conventionally implemented. For example, a great effect is expected in that the Ethereum infrastructure makes it easier to implement the method according to the present disclosure in reality.

The foregoing description of the disclosure is provided by way of example, and it will be understood by those skilled in the art that the present disclosure may be easily modified into other specific forms without changing the technical spirit or essential features of the present disclosure. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present disclosure is indicated by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present disclosure.

On the other hand, the above-described method can be written in a program that can be executed in a computer, it can be implemented in a general-purpose digital computer to operate the program using a computer-readable recording medium. In addition, the structure of the data used in the above-described method can be recorded on the computer-readable recording medium through various means. The computer readable recording medium may include a storage medium such as a magnetic storage medium (eg, ROM, RAM, USB, floppy disk, hard disk, etc.), an optical reading medium (eg, CD-ROM, DVD, etc.). do.

Those skilled in the art will appreciate that the present invention may be embodied in a modified form without departing from the essential characteristics of the above-described substrate. Therefore, the disclosed methods should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

100: multiple nodes
110: first node
120: second node

Claims (17)

In the method of performing anonymous transaction on a general purpose blockchain,
If a transaction is requested on the blockchain, verifying whether the stored value is encrypted in each note to be included in a preset valid range;
Checking whether the sum of the values of the input notes and the sum of the values of the output notes are equal when the value is encrypted; And
If the value is verified, deleting the input note stored in the note registry, and storing the output note newly;
In carrying out the requested transaction,
Determining a portion of the plurality of items used for the transaction according to a user's input;
Configuring a smart contract to encrypt the partial items using an elliptic curve cryptography;
Performing a first transaction using the smart contract by performing proof through zero-knowledge proof for the some items;
Storing a plurality of result values obtained as a result of performing the first transaction;
Performing an operation on the plurality of result values to obtain updated result values;
Performing a second transaction using the smart contract using the updated result value; And
And controlling the number of transactions using the smart contract according to the type or number of encryption items determined according to the user's input.
When the first item of the plurality of items is encrypted to form a smart contract, both the first transaction and the second transaction may be performed, and when the second item of the plurality of items is encrypted to form a smart contract, Only the first transaction is performed, the second transaction is limited to not be performed, blockchain based anonymous transaction performing method. The method of claim 1,
Validation step of the value is,
Based on the value of the note, a viewing key to be used for encryption, and a reference common string corresponding to the value registered in the signature database, the value is not disclosed. Checking whether the value is within a valid range in a state; and a blockchain-based anonymous transaction performing method. The method of claim 1,
The step of checking whether the value agreement is the same,
If the proof of the personal information is approved through Zero-Knowledge Proof protocol with the witness of the value not disclosed, the value agreement is the same, even if the value is not disclosed. Determining whether or not the check result is normal; A blockchain-based anonymous transaction performing method. The method of claim 3,
Whether the approval of the personal information is approved,
Sending a message from the prover node to the verifier node;
Transmitting an arbitrary challenge value c from the verifier node to the prover node; And
When the response z for the challenge value c is transmitted from the prover node to the verifier node, a common input value x between the prover node and the verifier node, the message a, the challenge value c, and the response z And determining whether to approve the attestation for the personal information that is not disclosed at the attestor node. The method of claim 4, wherein
The challenge value is calculated using a cryptographic hash function (Cryptographic Hash Function), blockchain based anonymous transaction performing method. The method of claim 1,
The step of checking whether the value agreement is the same,
And performing an addition operation on the value of an encrypted state through an elliptic curve cryptosystem in the state where the value is not disclosed. An apparatus for performing anonymous transactions on a blockchain for general purpose,
Including a plurality of nodes sharing information on the blockchain,
When a transaction is requested at any one of the plurality of nodes, at least one of the plurality of nodes checks whether the value stored by encrypting each note is included in a preset valid range, and inputs the note with the value encrypted. Determine whether the sum of the values of and the sum of the values of the output notes are the same; if the value is found, delete the input notes stored in the note registry;
Any one of the plurality of nodes,
A receiver for receiving user input; And
Determining a part of the plurality of items used for the transaction is required according to the user's input,
Configure the smart contract to encrypt some of the items using an elliptic curve cryptography,
Performing a first transaction using the smart contract by performing proof through zero-knowledge proof for the some items,
And a processor configured to store a plurality of result values obtained as a result of performing the first transaction.
The processor is
Perform an operation on the plurality of result values to obtain updated result values,
Perform a second transaction using the smart contract using the updated result value,
Adjust the number of transactions using the smart contract according to the type or number of encryption items determined according to the user's input,
When the first item of the plurality of items is encrypted to form a smart contract, both the first transaction and the second transaction may be performed, and when the second item of the plurality of items is encrypted to form a smart contract, Only a first transaction is performed, the second transaction is limited to not be performed, blockchain based anonymous transaction performing apparatus. The method of claim 7, wherein
At least one of the plurality of nodes is configured to display the value in the undisclosed state based on cryptographic information generated using a signature corresponding to a value of the note, an arbitrary value to be used for encryption, and a value registered in a signature database. A blockchain-based anonymous transaction execution device that checks whether a value falls within the validity range. The method of claim 7, wherein
At least one of the plurality of nodes is equal to the value agreement, even if the personal information of the value is not disclosed and the proof of the personal information is approved through a zero-knowledge proof protocol, even if the value is not disclosed. Device for performing anonymous transaction based on blockchain, which determines whether the result of the check is normal. The method of claim 9,
The prover node, which is one of the plurality of nodes, sends a message a to the verifier node, which is the other one of the plurality of nodes,
The verifier node sends any challenge value c to the prover node,
The prover node sends a response z to the challenge value c to the verifier node,
The verifier node is based on the common input value x between the prover node and the verifier node, the message a, the challenge value c, and the response z, for the personal information not disclosed by the prover node. Blockchain-based anonymous transaction execution device that determines whether to approve proof. The method of claim 10,
And the challenge value is calculated using a cryptographic hash function. The method of claim 7, wherein
And at least one of the plurality of nodes performs an addition operation on the value in an encrypted state, using an elliptic curve cryptography, while the value is not disclosed. delete delete delete delete A non-transitory computer-readable recording medium having recorded thereon a program for implementing the method of any one of claims 1 to 6.

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