KR20200087913A - System and method for providing secret electronic voting service based on blockchain - Google Patents

Abstract

The present invention relates to a secret electronic voting system based on a blockchain network which can safely carry out secret electronic voting for a plurality of candidates. Each node making up the secret electronic voting system comprises: a voting process registration module to code a voting process to create a smart contract, and generate a transaction including the smart contract to store the transaction in a blockchain; a voter registration module allowing a node which is a potential voter to register as a voter in the smart contract in the blockchain; a voting module allowing a node registered as a voter to select and vote for one among a plurality of candidates to record the vote in the smart contract in the blockchain; and a vote-counting module allowing all voters to use voting information registered in the smart contract in the blockchain to count the votes. The voting process includes a non-interactive zero-knowledge proof function used for voter registration for potential voters, a 1-out-of-k non-interactive zero-knowledge proof function used for votes of voters, and a full-search vote-counting function.

Description

System and method for providing secret electronic voting service based on blockchain}

The present invention relates to a secret electronic voting system based on a blockchain network, and more specifically, a voter constructs a blockchain network as a participating node, codes the voting process, writes it as a smart contract, records it on the blockchain, and smart Through the voting process of the contract, the process of preliminary voter registration, voter voting and counting, and voting results of all voters are recorded and stored in the smart contract in the blockchain to ensure the enforceability and reliability of contract execution and confidential ballot. It relates to a secret electronic voting system.

With the development of wireless communication technologies such as the public Internet, research on electronic voting in place of the conventional paper voting method has been conducted in various ways. Electronic voting is an electronic voting using a network, and since voting is possible using a terminal capable of communication, there is no advantage in terms of time and space.

However, despite these advantages, several problems have been found with the conventional electronic voting method. In particular, it is very difficult for a conventional electronic voting system to prove that a voter has concealed a candidate who has voted and voted for one of the multiple candidates. In addition, in the conventional electronic voting system, since there is a central server that oversees the voting process, there is a single point of failure or data forgery and tampering in the central server. In addition, even if the voters design the electronic voting system by configuring a network among voters without a central server, it is very difficult to confirm that everyone voted during the voting process. If a node is occupied by a hacker for malicious purposes, packets containing the contents of the vote may be tampered with or corrupted, and information on which candidates voted for which candidates by tracing the terminal of the target who electronically voted Can leak.

On the other hand, zero knowledge proof (ZKP) is a mutual name that does not expose any knowledge except whether the proposition is true or false when principally proves that a certain statement is true to the other verifier in cryptography. Means the procedure of action. A person who wants to prove that a certain proposition is true is called a provider, and a person who participates in the verification process to send and receive information with the certificater is called a verifier. If the parties participating in the zero-knowledge proof change the protocol arbitrarily to deceive the other party, the parties are said to be dishonest or dishonest. In other cases, it is said to be honest.

Proof of zero knowledge must satisfy three properties: completeness, soundness and zero knowledge. Completeness is that, if a certain proposition is true, an honest prover must be able to convince the honest verifier. Soundness is that if any proposition is false, no dishonest attestor should be able to convince the honest verifier that this sentence is true. Finally, zero-knowledgeness is that if a certain proposition is true, the verifier must know nothing but the true falsehood of the sentence.

On the other hand, Blockchain (Blockchain) is also called a public transaction ledger, which is a distributed data storage technology that stores data in a block and connects it in a chain form, replicating and storing it simultaneously in numerous nodes. Blockchain technology does not store transaction records on a centralized server, but sends transaction details to all users participating in transactions, and every transaction participants share information and collate against each other to prevent data forgery and tampering. There will be.

In a blockchain network composed of multiple nodes storing a blockchain, when one node broadcasts an electronically signed transaction, all nodes that receive it proceed with the proof-of-work process, and accordingly the first nonce value The found node has the authority to create blocks after being verified by other nodes in the blockchain network. A node with block creation authority broadcasts block creation information, including transactions, to all nodes in the blockchain network, and all nodes that receive it create blocks containing transactions and create the blocks on their blockchain. Connect and save.

Accordingly, the present invention is to propose a secret electronic voting system using a zero-knowledge proof based on a blockchain network.

Korean Registered Patent Publication No. 10-1837169 Korean Registered Patent Publication No. 10-1908677

The object of the present invention for solving the above-mentioned problems is a voter registration process using a non-interactive zero-knowledge proof for a number of candidates and a plurality of voters based on a blockchain network, 1-out-of-k non-interactive The secret to enable the secret electronic voting for multiple candidates to be secured by coding the voting process, including the voting process using zero-knowledge proofs, and the fully-converted voting process, writing it in a smart contract, and thereby secure the secret electronic voting for multiple candidates. It is to provide an electronic voting system and method.

The secret electronic voting system according to the first aspect of the present invention for achieving the above-described technical problem relates to a secret electronic voting system based on a blockchain network configured by preliminary voters participating as a node, and configuring the blockchain network Each node that codes, creates a voting process as a smart contract, creates a transaction containing the smart contract, propagates it to the blockchain network, creates a block according to a preset consensus algorithm, and stores the voting process in the blockchain registration module ; A voter registration module in which the preliminary voter node registers as a voter in a smart contract in the blockchain; A voting module in which a node registered as a voter selects one of a plurality of candidates and votes to register in a smart contract in the blockchain; And a ballot counting module for counting all voters using the vote information registered in the smart contract in the blockchain.

In the secret electronic voting system according to the first feature described above, the voting process stored in the smart contract in the block chain by the voting process registration module is a non-interactive zero-knowledge proof function used for registering voters with respect to preliminary voters. It is desirable to include a 1-out-of-k non-interactive zero-knowledge proof function and a fully searched counting function used for voting by voters.

를 이용하여 공개 투표키와 증명에 쓰이는 공개값들을 포함하는 입력 인자값을 구하고, 상기 입력 인자값으로 상기 스마트 컨트랙트에 저장된 비대화형 영지식 증명 함수를 실행하는 지시 사항을 트랜잭션으로 생성하고 블록체인 내 스마트 컨트랙트에 기록하는 것이 바람직하다. In the secret electronic voting system according to the first feature described above, the voter registration module includes a node for which a preliminary voter is a personal voting key.

Use to obtain the input parameter value including the public voting key and the public values used for the proof, and generate an instruction to execute the non-interactive zero-knowledge proof function stored in the smart contract as the input parameter value as a transaction, and within the blockchain. It is desirable to record in a smart contract.

를 이용하여 입력 인자값들을 구하고, 상기 입력 인자값으로 상기 스마트 컨트랙트에 기록된 1-out-of-k 비대화형 영지식 증명 함수를 실행하는 지시 사항을 트랜잭션으로 생성하고 블록체인 내 스마트 컨트랙트에 기록하는 것이 바람직하다. In the secret electronic voting system according to the above-described first feature, the voting module, a personal voting key for voting for candidates selected by registered voters

Use to obtain the input factor values, generate the instructions to execute the 1-out-of-k non-interactive zero-knowledge proof function recorded in the smart contract as the input factor value as a transaction and record it in the smart contract in the blockchain It is desirable to do.

값과 각 후보자에 대응되는 변수인 후보값

를 이용하여 계산되는 것이 바람직하다. In the secret electronic voting system according to the first feature described above, the counting module is characterized in that it is executed and counted by each voter in a complete search manner after the voter's voting is finished, and recorded in a smart contract in the blockchain. 1-out-of-k non-interactive zero-knowledge proof,

Values and candidate values that are variables corresponding to each candidate

It is preferably calculated using.

The secret electronic voting method according to the second aspect of the present invention relates to a secret electronic voting method based on a blockchain network configured by preliminary voters participating as nodes, (a) a node constituting the blockchain network, voting Creating a smart contract by coding the process, generating a transaction including the smart contract, propagating it to the blockchain network, generating a block according to a preset consensus algorithm, and storing it as the first block of the blockchain; (b) preliminary voter nodes registering as voters in a smart contract in the blockchain; (c) nodes registered as voters select one of a plurality of candidates and vote to register in a smart contract in the blockchain; (d) counting using the vote information registered in the smart contract in the blockchain; It is provided.

The electronic voting system according to the present invention can code the voting process by using a smart contract technology, write it as a smart contract, and record it on a blockchain, thereby ensuring compulsory and reliable execution of contracts when executed. This enables the preliminary voter registration and voter voting to be performed by executing a smart contract in which the voting process is recorded.

In addition, in the electronic voting system according to the present invention, in order to proceed with the counting at the time when all voters have voted, by executing the counting-related code in the smart contract recorded on the blockchain, the voter can count by himself. As a result, the number of votes for each candidate can be checked.

In addition, the electronic voting system according to the present invention executes non-interactive zero-knowledge proof in a smart contract to register a preliminary voter as a voter, and when a voter performs a vote, a 1-out-of-k non-interactive zero in the smart contract By implementing the proof of knowledge, it is possible to confirm that a voter has voted for one of a number of candidates, but to hide who the voted candidate is.

In addition, all of these transactions are composed of blocks and stored and shared on the blockchain according to a preset consensus algorithm, so it can not only guarantee authentication and non-repudiation, integrity, but also hacking of malicious attackers and attempts to forge/tamper data It can be blocked by nature.

In addition, since the electronic voting system according to the present invention does not use a single central server, it is possible to prevent a problem of a single point of failure by the central server.

1 is a schematic diagram illustrating an entire system in an electronic voting system according to a preferred embodiment of the present invention.
FIG. 2 is a flow chart of an electronic voting process performed by each node through a smart contract recorded in a blockchain in an electronic voting system according to a preferred embodiment of the present invention.
FIG. 3 is a flow chart sequentially explaining the operation of the voter registration module 30 in the electronic voting system according to the preferred embodiment of the present invention, and FIG. 4 illustrates the process of verifying between the preliminary voter and the verifier in the voter registration module. It is a flowchart.
5 is a schematic diagram illustrating a process of setting a candidate value corresponding to each candidate in an electronic voting system according to a preferred embodiment of the present invention.
6 is a flow chart sequentially showing a process in which each voter performs a vote through the voting module 40 in the electronic voting system according to the preferred embodiment of the present invention.
FIG. 7 is a flow chart showing a process of voting by the voter when performing a 1-out-of-k non-interactive zero-knowledge proof in order to perform voting in an electronic voting system according to a preferred embodiment of the present invention. to be.
FIG. 8 is a flow chart showing a verification process by a validator when a voter performs 1-out-of-k non-interactive zero-knowledge proof in order to perform a vote in an electronic voting system according to a preferred embodiment of the present invention. to be.
9 is a flowchart illustrating the operation of the counting module 50 in the electronic voting system according to the preferred embodiment of the present invention.

In the electronic voting system based on the blockchain network according to the present invention, voters who wish to participate in voting construct a blockchain network as a node and code the voting process to create a smart contract and record it on the blockchain for the first time. The voting process is characterized by a non-interactive zero-knowledge proof, a one-out-of-k non-interactive zero-knowledge proof, and a full-search counting process.

Hereinafter, the configuration and operation of an electronic voting system based on a blockchain network according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram illustrating an entire system in an electronic voting system according to a preferred embodiment of the present invention, and FIG. 2 is an electronic voting system according to a preferred embodiment of the present invention, wherein each node is a blockchain It is a flowchart showing the electronic voting process performed through the smart contract recorded in the overall.

1 and 2, the electronic voting system 1 based on the blockchain network according to the present invention is made on the basis of the blockchain network 10 configured as nodes by preliminary voters who want to vote, and each node Has a blockchain 20, a voting process registration module 30, a voter registration module 40, a voting module 50, and a counting module 60.

The block chain 20 is a data store that sequentially stores blocks that store smart contracts that coded the voting process, information about voters, voter information, and counting information in a chain.

The voting process registration module 30 codes the pre-set voting process into a smart contract, generates it as a transaction, propagates it to the blockchain network, and records it as the first block of the blockchain according to the preset consensus algorithm. The coded and recorded voting process in the smart contract includes a non-interactive zero-knowledge proof function for voter registration, a 1-out-of-k non-interactive zero-knowledge proof function for voting by voters, and a fully searched counting function. .

를 이용하여 3개의 입력 인자값(공개 투표키

, 증명에 쓰이는 공개값

,

)을 구하고, 상기 입력 인자값으로 비대화형 영지식 증명을 실행하는 지시 사항을 트랜잭션으로 생성하고 블록체인 내 스마트 컨트랙트에 기록한다. 한편, 상기 개인 투표키

는 예비투표자들이 블록체인 네트워크에 참여할 때 생성되는 고유한 키로 본인만이 알 수 있는 값이다. The voter registration module 40 is a module in which preliminary voters participating in the blockchain network register as voters in order to participate in voting, and each preliminary voter has a personal voting key.

3 input factor values using (public voting key

, Public value used for proof

,

), and generates an instruction to execute a non-interactive zero-knowledge proof as the input argument value as a transaction and records it in a smart contract in the blockchain. Meanwhile, the above individual voting key

Is a unique key generated when pre-voting participants participate in the blockchain network, and is a value that only they can know.

를 이용하여 입력 인자값(x, y, c,

,

,

,

)을 구하고, 상기 입력 인자값으로 1-out-of-k 비대화형 영지식 증명을 실행하는 지시 사항을 트랜잭션으로 생성하고 블록체인 내 스마트 컨트랙트에 기록한다. 이 때 기록된 모든 투표자의

값으로 이후에 개표를 진행하게 된다. The voting module 50 is a personal voting key for voting for candidates selected by voters registered through the voter registration module.

Use the input factor values (x, y, c,

,

,

,

), and generates an instruction that executes 1-out-of-k non-interactive zero-knowledge proof as the input argument value as a transaction and records it in a smart contract in the blockchain. All voters recorded at this time

Values will be counted later.

값을 곱함으로써 시작된다. 곱한 값은 소거법에 의하여

이 되는데 이때

는 각 후보자에 대응되는 변수인 후보값으로 여기서는 투표자들이 투표한 모든 후보값을 더한 것이 지수가 된다. 완전 탐색 방식을 적용함으로써 후보자들 중 가장 큰 후보값부터 제수(divisor)로 두고

를 피제수(dividend) 두어 나눗셈을 수행한다. 이때 나눠지는 횟수를 해당 후보값에 대응되는 후보자의 투표 수로 집계할 수 있고, 해당 나눗셈 과정을 다음으로 큰 후보값을 제수로 둠으로써 가장 작은 후보값까지 반복 수행한다. 이 결과로 각 후보자에 대한 투표 수를 집계할 수 있다. The counting module 60 is to perform a counting by each voter in a full search method, and all voters verified by a 1-out-of-k non-interactive zero-knowledge proof recorded in a smart contract in the blockchain

It starts by multiplying the values. The multiplied value is

This time

Is a candidate value that is a variable corresponding to each candidate. Here, the index is the sum of all candidate values voted by voters. By applying the full search method, the largest candidate value is set as the divisor.

Divide by to perform division. At this time, the number of divisions can be counted as the number of votes of candidates corresponding to the candidate value, and the division process is repeated to the smallest candidate value by setting the next largest candidate value to the divisor. As a result, the number of votes for each candidate can be counted.

On the other hand, in the process performed by each module constituting the electronic voting system according to the present invention, all the transactions generated by each node are signed with the private key of the node and then propagated to the blockchain network, and other than the sending node. All nodes are composed of blocks through a consensus process called Proof of Work to verify the validity of the transaction and collect the transactions for a certain period of time to obtain the authority to create blocks, and then propagate back to the blockchain network. After that, the propagated block is confirmed by validity from all nodes, and then continues to an n+1th block in a block chain of n blocks. As a result, all transactions and data recorded on the blockchain are guaranteed integrity, and all nodes in the blockchain network share the records of the blockchain. Meanwhile, in the present invention, the use of a proof-of-work method as a consensus algorithm is exemplarily described, but is not limited to this, and other consensus algorithms may be used.

In addition, recording data in the blockchain is the same as recording in the smart contract because it records (or changes) the output value according to the input value of the function as a state in the smart contract when calling the function in the smart contract in the transaction. At this time, since the value recorded in the smart contract is the same as that recorded in the blockchain, the integrity of the recorded value is guaranteed.

Hereinafter, the voter registration module 30 of the electronic voting system according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

FIG. 3 is a flow chart sequentially explaining the operation of the voter registration module 30 in the electronic voting system according to the preferred embodiment of the present invention, and FIG. 4 illustrates the process of verifying between the preliminary voter and the verifier in the voter registration module. It is a flowchart.

를 이용하여 3개의 입력 인자값(공개 투표키

, 증명에 쓰이는 공개값

,

)으로 비대화형 영지식 증명을 실행하는 지시 사항을 트랜잭션으로 생성하고 블록체인 내 스마트 컨트랙트에 기록하는 과정으로 비대화형 영지식 증명은 구체적으로 다음과 같이 진행된다.Referring to FIG. 3, preliminary voters are registered as voters through the voter registration module 30 in order to participate in the vote. At this time, the individual voting key

3 input factor values using (public voting key

, Public value used for proof

,

) As a process of generating instructions to execute non-interactive zero-knowledge proof as a transaction and recording it in a smart contract in the blockchain, non-interactive zero-knowledge proof proceeds in detail as follows.

를 생성한 후

를 만족하는 소수

를 선택한다. 그리고 Prime-order

의 곱셈 순환군(Multiplicative cyclic groups)을

이라 하고,

의 생성원을

,

라고 한다. 이로써 초기값인 (

,

,

,

)가 생성된다(단계 300 및 도 4의 ①,②,③). 상기 g, h 는

의 생성원으로, g는 투표 자격 증명 과정과 이후 투표 과정에서 모두 사용되는 값이고, h는 투표 과정에서 사용되는 값이다. First, a small number of preliminary voters participating in the blockchain network

After creating

Prime to satisfy

Choose And Prime-order

Multiplicative cyclic groups of

And say

The origin of

,

It is said. Thus, the initial value (

,

,

,

) Is generated (steps 300 and ①, ②, ③ in FIG. 4). The g, h is

As a source of generation, g is a value used in both the voting credential process and the subsequent voting process, and h is a value used in the voting process.

와 공개 투표키

를 생성하고, 이번 증명에서만 사용될 임의의 비밀값

를 선택하고 공개값

를 생성한다(단계 310 및 도 4의 ④). 개인 투표키

와 비밀값

는 투표자만 알고 있는 값으로, 이 값을 검증자에게 알리지 않고 오직 생성된 공개 투표키

와 공개값

를 검증자에게 보내게 된다. 그리고 해시 함수를 이용하여 투표자가 조작할 수 없는 랜덤한 값

를 생성하고

을 생성한다(단계 320 및 도 4의 ⑤,⑥). 여기서, Zq는 q에 대한 수의 집합으로 1,2, ??, q-1 를 가지고 있는 수의 집합으로 이루어진다. Next, the preliminary voter is the individual voting key

And public voting key

And a random value to be used only for this proof.

Select and public value

Is generated (step 340 and ④ in FIG. 4). Individual voting key

And secret value

Is a value known only to the voter, and the public vote key is generated without notifying the validator of this value.

And public value

Is sent to the verifier. And a random value that voters cannot manipulate using the hash function

And create

To create (steps 320 and 4, ⑥). Here, Zq is a set of numbers for q and consists of a set of numbers having 1,2, ??, and q-1.

을 포함하게 된다.Next, a transaction that executes the non-interactive zero-knowledge proof function in the smart contract is generated (step 330), and values to be sent to the verifier are added to the transaction as input parameter values of the non-interactive zero-knowledge proof function (step 340). At this time, as a value to send to the verifier

It will include.

Next, the transaction is signed with its own private key, and then propagated to the blockchain network (step 350), and then through the proof-of-work (POW) process, the transaction is composed of blocks and propagated back to the blockchain (step 352). The validity of the block is verified by all the received nodes (step 354), and when more than a certain number of nodes approve the corresponding block, it is connected to the last block in the blockchain and stored and shared (step 356).

를 생성한 후 (도 4의 ⑦)

와

가 동일한지 검증함으로써(도 4의 ⑧) 투표자가 개인 투표키

를 보유하고 있다는 사실을 검증하면서 해당 사실 외의 정보를 얻지 못한다. 다음, 상기 비대화형 영지식 증명 함수의 동작 후 해당 검증 사실과 예비투표자에 대한 공개 투표키를 블록체인 내 스마트 컨트랙트에 기록함으로써, 예비 투표자에 대하여 투표자로서의 등록을 완료하게 된다(단계 372).Meanwhile, the smart contract that receives the input parameter value of the non-interactive zero-knowledge proof function of the smart contract performs verification as a verifier by executing the non-interactive zero-knowledge proof function (steps 370 and ⑦,⑧ in FIG. 4). . At this time, as a hash function

After creating (⑦ in Figure 4)

Wow

By verifying that is the same (⑧ in FIG. 4 ), the voter has a personal

While verifying the fact that the company holds the information, no information other than the fact is obtained. Next, after the operation of the non-interactive zero-knowledge proof function, the verification fact and the public voting key for the preliminary voter are recorded in the smart contract in the blockchain, thereby completing registration as a voter for the preliminary voter (step 372).

5 is a schematic diagram illustrating a process of setting a candidate value corresponding to each candidate in an electronic voting system according to a preferred embodiment of the present invention.

5, in the electronic voting system according to the present invention, in order to set a candidate value (v) corresponding to each candidate in order to place a plurality of candidates, the candidate value (vj) for the j-th candidate is Equation 1 It is decided as follows.

Here, m is a minimum integer satisfying 2 ^m > n when there are n voters.

Hereinafter, with reference to FIGS. 6 to 8, in the electronic voting system according to the preferred embodiment of the present invention, a process of voting by each voter through the voting module 40 will be described in detail.

를 이용하여 입력 인자값(x, y, c,

,

,

,

)으로 1-out-of-k 비대화형 영지식 증명을 실행하는 지시 사항을 트랜잭션으로 생성하고 블록체인 내 스마트 컨트랙트에 기록하는 과정으로 1-out-of-k 비대화형 영지식 증명은 다음과 같이 진행된다. 이때 1-out-of-k 비대화형 영지식 증명은 2가지를 증명하는 방식으로 먼저 투표자가 알고 있는 비밀 투표키가 참이라는 것을 검증자에게 증명할 때 해당 사실 외의 다른 어떤 것도 드러내지 않는다. 또한 동시에 k개의 후보자에 대하여 선택한 후보자를 드러내지 않고 k개 중 하나를 선택했다는 사실을 증명하게 된다.The voting module 40 is a personal voting key for voting for candidates selected by registered voters

Use the input factor values (x, y, c,

,

,

,

) Is a process of generating an instruction to execute 1-out-of-k non-interactive zero-knowledge proof as a transaction and recording it in a smart contract in the blockchain.The 1-out-of-k non-interactive zero-knowledge proof is as follows: Proceeds. At this time, the 1-out-of-k non-interactive zero-knowledge proof proves two things. When the first proves to the verifier that the secret ballot key known to the voter is true, nothing other than the fact is revealed. It also proves that one of the k candidates has been selected without revealing the selected candidates for the k candidates at the same time.

FIG. 6 is a flow chart sequentially showing a process in which each voter performs a vote through the voting module 40 in the electronic voting system according to the preferred embodiment of the present invention, and FIG. 7 is for the voters to perform the vote 1-out-of-k is a flow chart showing the process of the voter's proof when performing non-interactive zero-knowledge proof, and FIG. 8 is a 1-out-of-k non-interactive zero-knowledge proof for voters to perform voting It is a flow chart showing the verification process of the verifier when performing.

를 생성한 후

를 만족하는 소수

를 선택한다. 그리고 Prime-order

의 곱셈 순환군(Multiplicative cyclic groups)을

이라 하고,

의 생성원을

,

라고 한다. 이로써 초기값인 (

,

,

,

)가 생성된다(단계 600).Referring to Figure 6, first, the voter is a minority

After creating

Prime to satisfy

Choose And Prime-order

Multiplicative cyclic groups of

And say

The origin of

,

It is said. Thus, the initial value (

,

,

,

) Is generated (step 600).

로

를 생성하는데(단계 610), 이때

를 생성하는데 들어간

는 투표자가 선택한 후보자의 후보값이 된다. 개인 투표키

를 이용하여 입력 인자값(x, y, c,

,

,

,

)을 구하고, 상기 입력 인자값으로 1-out-of-k 비대화형 영지식 증명을 실행하는 지시 사항을 트랜잭션으로 생성한다(단계 620). 다음, 검증자에게 보낼 값들을 1-out-of-k 비대화형 영지식 증명 함수의 입력 인자값으로 트랜잭션에 추가한다(단계 630). Voter's Individual Voting Key

in

(Step 610), where

Into creating

Is the candidate value of the candidate chosen by the voter. Individual voting key

Use the input factor values (x, y, c,

,

,

,

), and generates an instruction to execute a 1-out-of-k non-interactive zero-knowledge proof as the input parameter value (step 620). Next, the values to be sent to the verifier are added to the transaction as the input argument value of the 1-out-of-k non-interactive zero-knowledge proof function (step 630).

,

,

,

)은 도 7에 도시된 바와 같이, x 및 y는

에 따라 계산되고, a 및 b는 자신이 선택한 투표자에 따라, 선택한 투표자의 경우 Here, the input factor values (x, y, c,

,

,

,

) As shown in Figure 7, x and y are

Calculated according to, and a and b are for the selected voters, according to the voters of their choice

,

가 되며, 그외 다른 경우는 각각

,

이며, 이때 r과 c는 Zq에 속해있는 투표자 값을 의미한다.

,

And other cases

,

Where r and c are voter values belonging to Zq.

,

은 투표자가 투표한 값에 따라 투표의 비밀성을 유지하기 위한 진짜 투표값과 가짜 투표값들의 집합을 나타내며 c는 자신이 투표한 후보자의 값과 앞선 투표값들의 집합을 해시 함수를 통해 해싱한 값이며,

,

은 자신이 한 투표가 유효함을 입증하기 위해 c값을 통해 생성되는 값이다.

,

Denotes a set of real votes and fake votes to maintain the secrecy of the vote according to the voter's voted value, and c is the value of the candidate's vote and the previous set of votes hashed through the hash function And

,

Is a value that is generated through the value of c to prove that your vote is valid.

Next, the transaction is signed with its own private key, and then propagated to the blockchain network (step 640), and then through the proof-of-work (POW) process, the transaction is composed of blocks and propagated back to the blockchain (step 642). The validity of the block is verified by all the received nodes (step 644), and if more than a certain number of nodes approve the block, it is connected to the last block in the blockchain and stored and shared (step 646).

와

를 이용하여 첫 번째 증명을,

를 이용하여 두 번째 증명을 진행하게 된다. 또한 k명의 후보자가 있을 때 실제 투표자가 선택한 후보자의 후보값에 대해서만 진짜 증명을 수행하고, 나머지 (k-1)명의 후보자에 대해서는 투표자가 값 형식에 맞춰 임의로 만든 값을 검증자에게 넘겨줌으로써 검증할 수 있도록 한다. 검증자는 k번의 검증을 수행하게 되는데 이 중 어떤 것이 실제 선택한 후보자의 후보값에 대한 검증인지는 모르지만 k번의 검증 중에 하나로 속해 있다고 판단한다.Meanwhile, the smart contract that receives the input parameter value of the 1-out-of-k non-interactive zero-knowledge proof function of the smart contract performs verification as a verifier by executing the 1-out-of-k non-interactive zero-knowledge proof function. Proceed (step 670). Therefore, the voter is the individual

Wow

Using the first proof,

Proceed with the second proof. In addition, when there are k candidates, real proof is performed only on the candidate value of the candidate selected by the actual voter, and the remaining (k-1) candidates can be verified by passing the randomly created value to the validator according to the value format. Make it possible. The verifier performs k verifications, but it is not known which of the candidates is actually a candidate value, but determines that it belongs to one of k verifications.

값을 블록의 형태로 블록체인 내 스마트 컨트랙트에 기록한다(단계 672) After executing the 1-out-of-k non-interactive zero-knowledge proof function, the verification facts and voters

The value is recorded in a smart contract in the blockchain in the form of a block (step 672).

Hereinafter, the operation of the counting module 50 in the electronic voting system according to the preferred embodiment of the present invention will be described in detail with reference to FIG. 9.

9 is a flowchart illustrating the operation of the counting module 50 in the electronic voting system according to the preferred embodiment of the present invention.

값을 호출하여 곱함으로써 시작된다. 곱한 값은 소거법에 의하여

이 되는데 이때

는 각 후보자에 대응되는 변수인 후보값으로 여기서는 투표자들이 투표한 모든 후보값을 더한 것이 지수가 된다. 완전 탐색 방식을 적용함으로써 후보자들 중 가장 큰 후보값부터 제수(divisor)로 두고

를 피제수(dividend) 두어 나눗셈을 수행한다. 이때 나눠지는 횟수를 해당 후보값에 대응되는 후보자의 투표 수로 집계할 수 있고, 해당 나눗셈 과정을 다음으로 큰 후보값을 제수로 둠으로써 가장 작은 후보값까지 반복 수행한다. 이 결과로 각 후보자에 대한 투표 수를 집계할 수 있다.Referring to FIG. 9, the counting module 50 performs counting by each voter in a complete search method after the voting is over, and the 1-out-of-k non-interactive zero-knowledge proof recorded in the smart contract in the blockchain Voters verified by

It starts by multiplying the values by calling them. The multiplied value is

This time

Is a candidate value that is a variable corresponding to each candidate. Here, the index is the sum of all candidate values voted by voters. By applying the full search method, the largest candidate value is set as the divisor.

Divide by to perform division. At this time, the number of divisions can be counted as the number of votes of candidates corresponding to the candidate value, and the division process is repeated to the smallest candidate value by setting the next largest candidate value to the divisor. As a result, the number of votes for each candidate can be counted.

In the above, the present invention has been mainly described for its preferred embodiment, but this is merely an example and does not limit the present invention, and those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications not illustrated above are possible in the scope. And, the differences related to these modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

1: Electronic voting system
10: blockchain network
20: Blockchain
30: voting process registration module
40: Voter registration module
50: voting module
60: counting module

Claims (12)

In a secret electronic voting system based on a blockchain network formed by preliminary voters participating as nodes, each node constituting the blockchain network,
A voting process registration module that encodes a voting process, writes it as a smart contract, generates a transaction including the smart contract, propagates it to the blockchain network, generates a block according to a preset consensus algorithm, and stores it in the blockchain;
A voter registration module in which the preliminary voter node registers as a voter in a smart contract in the blockchain;
A voting module in which a node registered as a voter selects one of a plurality of candidates and votes to record in a smart contract in the blockchain;
A counting module for counting all voters using the vote information registered in the smart contract in the blockchain;
Secret electronic voting system based on the blockchain network, characterized in that it comprises a. According to claim 1, The voting process stored in the smart contract in the blockchain by the voting process registration module,
It includes a non-interactive zero-knowledge proof function used for voter registration for preliminary voters, a one-out-of-k non-interactive zero-knowledge proof function used for voting by voters, and a fully searched counting function. Secret electronic voting system based on blockchain network. According to claim 1, The voter registration module,
The primary voter node is the individual vote key

Use to obtain the input parameter value including the public voting key and the public values used for the proof, and generate an instruction to execute the non-interactive zero-knowledge proof function stored in the smart contract as the input parameter value as a transaction, and within the blockchain. A secret electronic voting system based on a blockchain network characterized by recording in a smart contract. The method of claim 3, wherein the input factor value is a public voting key

, Public values used for proof

,

And
Public voting key

The

And public value

The

And public value

Characterized in that,
here,

Is the prime number generated by the preliminary voter,

The

Is a prime number that satisfies,

,

Prime-order

Multiplicative cyclic groups of

Is the source of

Is an arbitrary secret value

Is a value selected from among values satisfying,

Is a random value generated using a hash function, and Zq is

1,2,??, as a set of numbers for

A secret electronic voting system based on a blockchain network characterized by being a set of numbers with -1. According to claim 1, The voting module,
Private voting key to vote for candidates selected by registered voters

Use to obtain the input factor values, generate the instructions to execute the 1-out-of-k non-interactive zero-knowledge proof function recorded in the smart contract as the input factor value as a transaction and record it in the smart contract in the blockchain Secret electronic voting system based on a blockchain network, characterized by. The method of claim 5, wherein the input parameter value of the 1-out-of-k non-interactive zero-knowledge proof function in the voting module is x, y, c,

,

,

,

Characterized in that,
here,

And

Is the candidate value of the candidate chosen by the voter,

Is the prime number generated by the preliminary voter,

The

Is a prime number that satisfies,

,

Prime-order

Multiplicative cyclic groups of

Is the source of

Is an arbitrary secret value

Is a value selected from among values satisfying,

Is a random value generated using a hash function,

,

Denotes a set of real votes and fake votes to maintain the secrecy of the vote according to the voter's voted value, and c is the value of the candidate's vote and the previous set of votes hashed through the hash function And

,

Is a secret electronic voting system based on a blockchain network, characterized in that it is a value generated through a c value to prove that one vote is valid. According to claim 1, The counting module,
After the voter's vote is finished, it is executed and counted by each voter in a full search method.
The vote result of all voters verified by 1-out-of-k non-interactive zero-knowledge proof recorded in the smart contract in the blockchain

Values and candidate values that are variables corresponding to each candidate

A secret electronic voting system based on a blockchain network characterized by being calculated using. In a secret electronic voting method based on a blockchain network composed of preliminary voters participating as nodes,
(a) The nodes constituting the blockchain network code the voting process, write it as a smart contract, create a transaction that includes the smart contract, propagate it to the blockchain network, and generate a block according to a preset consensus algorithm to create a blockchain Storing as the first block of the;
(b) preliminary voter nodes registering as voters in a smart contract in the blockchain;
(c) nodes registered as voters select one of a plurality of candidates and vote to register in a smart contract in the blockchain;
(d) counting using the vote information registered in the smart contract in the blockchain;
Secret electronic voting method based on a blockchain network, characterized in that it comprises a. According to claim 8, The voting process stored in the smart contract in the blockchain,
Features include non-interactive zero-knowledge proof function used for voter registration for preliminary voters, 1-out-of-k non-interactive zero-knowledge proof function used for voting by voters, and a fully searched counting function Secret electronic voting method based on blockchain network. The method of claim 8, wherein the step (b),
The primary voter node is the individual vote key

Obtain an input parameter value including the public voting key and the public values used for authentication, and generate an instruction to execute a non-interactive zero-knowledge proof function stored in the smart contract as the input parameter value as a transaction and block chain Secret electronic voting method based on blockchain network, characterized by recording in my smart contract. The method of claim 8, wherein step (c),
Private voting key to vote for candidates selected by registered voters

Use to obtain the input factor values, generate the instructions to execute the 1-out-of-k non-interactive zero-knowledge proof function recorded in the smart contract as the input factor value as a transaction and record it in the smart contract in the blockchain Secret electronic voting method based on a blockchain network, characterized by. The method of claim 8, wherein (d) step,
After the voter's vote is finished, it is executed and counted by each voter in a full search method.
The vote result of all voters verified by 1-out-of-k non-interactive zero-knowledge proof recorded in the smart contract in the blockchain

Values and candidate values that are variables corresponding to each candidate

Secret electronic voting method based on a blockchain network, characterized by being calculated using.

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