KR20020071246A - Electronic voting method - Google Patents

Abstract

PURPOSE: An electronic election method is provided to generate a digital signature on a blind voting right by applying a digital signature scheme, based on a personal ID, in a voter registration, and to assure a transparency of a voting process by applying the digital signature scheme. CONSTITUTION: The method comprises steps of issuing a smart card to enable a voter to make a digital signature, obtaining the first and the second parameter for authenticating a blind voting right of the voter, and publicizing names of candidates and pseudonyms used in a voting(S100), enabling the voter to register at an election management center by generating a voting right, blinding the voting right, authenticating the blind voting right, and enabling the voter to obtain an authenticated voting right from the authenticated blind voting right(S200), enabling the voter to cast a vote for the candidates by using the authenticated voting right(S300), and opening the votes transmitted from the voter to count the votes by using the parameters(S400). The voter registration step(S200) includes steps of enabling the voter to select one among the publicized candidates, generating the voting right by using a pseudonym, making a digital signature on the blind voting right, enabling the voter to transmit the voting right, a voter ID, the digital signature, and parameters needed in an authentication process to the election management center, comparing the transmitted ID and a stored ID, storing the voter ID in a case that the digital signature is normal, transmitting the authenticated blind voting right to the voter, and enabling the voter to extract the authenticated voting right from the authenticated blind voting right.

Description

Electronic voting method

The present invention relates to an electronic election method, and in particular, in the voter registration process, the voter authentication is performed based on the voter's user ID, and the vote / counting process applies a challenge / response protocol to vote in the middle of the election. It is about an electronic election method that results are unknown.

Due to the spread of computers and the development of open communication networks such as the Internet, many social spheres of human beings are becoming electronic. The e-election method, which is the basis of the realization of electronic democracy as an important social action in democratic society, is the information for safe electronic election. Incorporation of protection technology is essential.

In general, existing electronic election methods suitable for large-scale elections are largely based on two concepts. First, it assumes the existence of an untraceable communication channel proposed by Chaum to ensure the anonymity of voters. The second is based on a reliable election management center, such as election chairman, as in everyday life elections. Here, the election management center registers voters, gives them legal voting rights, and is responsible for counting votes.

Conventional electronic election methods include, first, Boyd's A New Multiple Key Cipher and an Improved Voting Scheme, secondly Fujioka, Okamoto, Ohta proposed A Practical Secret Voting Scheme for Large Scale Elections, and third, blind multisignature schemes and their relevance for electronic elections. for ElectronicVoting 'and, fourthly, A Secure Voting Protocol Using Threshold Schemes.

The first method, described above, is an electronic election method proposed by Boyd based on the security of the multi-key cryptography method based on the difficulty of the discrete algebra problem. The anonymity of the voting process is based on the untraceable network proposed by Chaum.

However, the first method described above has a problem in that negative voting by the center is possible because the authority of the center is absolute.

The second method realizes fairness of the election by not being able to announce intermediate voting results during the election which may affect the election results.

However, the second method described above is problematic in that it is not suitable for large-scale elections because registered voters cannot give up voting rights in the middle.

The third method is an election method with multiple election managers to minimize the role of the Trusted Center. The application of the secret multiplexing signature technique ensures election safety if at least one election manager is trusted. If they all collude, they may leak intermediate voting results, and the whole election protocol may be broken. In particular, there is a problem that communication complexity for voting registration is not suitable for large-scale elections because the number of election managers per voter is doubled than in the general election method.

The fourth method, a more practical electronic election method, is proposed by improving the election technique proposed in the second method for large-scale elections. Even if registered voters do not attend the election in the middle, it does not affect the overall election result. Apply the concept of thresholds to minimize the negation of voters, candidates, and election managers.

However, the fourth method described above has a problem in that, in preparation for election, a trusted center must provide each voter with a pseudonym through a secure communication network. In addition, when a registered voter does not vote, there is a problem that negation by an election administrator becomes possible.

The present invention has been made to solve the above-mentioned problems, in the process of registering the voter by applying a digital signature technique based on the personal ID information to generate a digital signature for the blind ball (blind ballot), based on the personal information The purpose is to provide an electronic election method that reflects the transparency of the voting process by applying digital signature techniques.

1 is a view showing the configuration of an electronic election system in which the electronic election method according to the present invention is implemented.

2 is a flowchart for explaining an electronic election method according to the present invention.

3 is a flowchart for explaining a preparation process of FIG.

4 is a flowchart for explaining a voter registration process of FIG. 2.

5 is a flowchart for explaining the voting process of FIG.

6 is a flowchart for explaining the counting process of FIG. 2.

*** Explanation of symbols for the main parts of the drawing ***

10. Card Issuing Center, 20. Election administration center,

30. Voter terminal, 40. Election board

The electronic election method according to the present invention for achieving the above object, issuing a digitally signable card to the voter, obtains the first and second parameters for authenticating the voter's concealed voting rights, the name of the candidates Preparing to announce on the electoral bulletin a pseudonym to be used in the election and election; A voter registration process of generating and voting rights to authenticate the concealment voting rights, and obtaining an authenticated voting right from the authenticated concealment voting rights; A voting process for exercising voting rights using the authenticated voting rights; And a counting process for counting the voting rights based on parameters for opening a ballot received from the voter.

The voter registration process may include: generating a pseudonym to be used for voting, and selecting one candidate to be elected from candidates announced by the election management center; Generating a voting right using the generated pseudonym and the pseudonym of the selected candidate; Concealing the generated voting rights and generating a digital signature for the concealed voting rights based on user ID information of the voter recorded on the card; Sending the concealment voting rights, a voter's user ID, a digital signature for the concealment voting rights, and parameters necessary for authentication to the election management center; Verifying the digital signature for the concealed voting right when the voter registers for the first time by comparing the user ID of the received voter with the user ID of the voters previously authorized to vote; If the digital signature for the concealed voting right is correct as a result of the verification, storing the voter's user ID and authenticating the concealed voting right; Transmitting the authenticated concealment vote to the voter; And extracting the authorized voting right by removing the hidden information from the received authenticated hidden voting right.

The voting process may comprise: generating a challenge value for the authenticated voting right; Transmitting the generated challenge value and a pseudonym of a voter to the election management center; Generating a response to the received challenge value; And announcing the voter's alias, the challenge value, and the response to the challenge value to an election bulletin.

And, the counting process, from the voter's alias, the challenge value, the response to the challenge value announced in the election bulletin board authenticates the response to the challenge value, and transmits the parameters necessary for the counting and authentication to the election management center Making a step; Authenticating a voter's challenge value using the received count and parameters required for authentication; Increasing the count of the candidate when the pseudonym of the hobo extracted from the authenticated challenge value belongs to the candidate group; Announcing a voter's alias, a challenge value, a response to the challenge value, a voter's right to vote, a parameter to open a ballot, a voter's vote and a selected candidate's alias; Publishing the second parameter to verify the challenge / response protocol results.

Hereinafter, an electronic election method according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

First, in order to implement the electronic election method according to the present invention, a reliable election management center, a card issuing center exist, and an untraceable communication network capable of guaranteeing anonymity of the voter proposed by Chaum must be secured before the election day. However, digital signature techniques to generate digital signatures for voters' concealed voting rights must be safe from insider and outsider attacks.

After all of the above-described prerequisites are satisfied, the electronic election method according to the present invention is implemented. FIG. 1 is a diagram illustrating a configuration of an electronic election system in which the electronic election method according to the present invention is implemented.

As shown in FIG. 1, the electronic election system in which the electronic election method according to the present invention is implemented includes a card issuing center 10, an election management center 20, a voter terminal 30, and an election bulletin board 40. It is provided with.

In such a configuration, the card issuing center 10 issues a smart card capable of digital signature based on the user ID information of the voter. Here, the Fiat-Shamir digital signature technique can be used as the digital signature technique. In the Fiat-Shamir digital signature technique, the smart card issuing process randomly generates and secretly stores two large prime numbers p and q necessary for issuing the smart card. Calculating a method of modular multiplication N using Equation 1 using p and q, and randomly generating secret information S _A using ID _A which is identification information of user _A and one-way function f. Calculating as shown in Equation 2, and recording the law N, the one-way function f and the user A's secret information (S _A1 , ....., S _Ak ), which are public information of the card issuing center 10, on the smart card. The distribution is made.

N = p × q

In Equation 2, k is the number of secret information to be stored in the card.

On the other hand, the election management center 20 is responsible for voting and publicizing voting personnel, and randomly selects a large prime number p and announces it to the election bulletin board 40, where p is a discrete algebra problem for mod p. Choose to be impossible to calculate. Then, after obtaining the first parameter x and the second parameter y for authentication of the voter's concealment voting rights as shown in Equation 3, and securely stored, the names of the candidates registered before the election date and the pseudonyms to be used in the election, the election bulletin ( (40). Here, the pseudonym of the candidates has a value large enough to prevent voters from arbitrarily tampering with the right to vote.

In addition, the election management center 20 performs authentication on the concealment voting rights of the voters received from the voter terminals 30 connected through the public network, and performs the counting of the votes of the voters received from the voter terminals 30.

Meanwhile, the voter terminal 30 conceals the voting rights exercised by the voters through the public network, transmits the request to the election management center 20 to request authentication, and removes the concealment information from the concealed voting rights certified by the election management center 20. And transmit parameter values for voting release to the election management center 20.

The election bulletin board 40 announces the names of candidates registered under the control of the election management center 20 and the aliases to be used in elections, and the aliases, challenge values, response values, and signed voters of all voters who voted after opening the ballot. Announce the right to vote, the parameter value used to open the ballot, the voter's right to vote, and the candidate's pseudonym announced by the Trusted Ballot Certification Center.

2 is a flowchart illustrating an electronic election method according to the present invention. The electronic election method according to the present invention records and issues secret information of a voter on a smart card that can be digitally signed, and is used in candidate names and elections. Preparatory process (S100) to announce the pseudonym to the election bulletin board (40), the voter's pseudonym by using the pseudonym of the candidate and the candidate's pseudonym to be elected and concealed by the concealment of the right to vote from the election management center 20, Voter registration process for obtaining certified voting rights from certified concealed voting rights (S200), voting process for exercising voting rights using certified voting rights (S300), and the voter based on parameters for opening the ballot received from the voter It includes the counting process (S400) to count the right to vote.

FIG. 3 is a flowchart for explaining a preparation process S100 of FIG. 2.

First, the card issuing center 10 records the public information of the card issuing center 10, law N, the one-way function f, and the voter's secret information on the smart card capable of digital signature based on the voter's user ID information and issues it to the voter. (S110), the election management center 20 obtains a first parameter x and a second parameter y for authenticating voter's concealment voting rights (S120), and use the names and elections of candidates in the election bulletin board 40. Announce the pseudonym (S130).

4 is a flowchart for describing a voter registration process (S200) of FIG. 2.

Any voter i performs a voter registration process using a smart card issued before the election day from the card issuing center 10 by using a card reader (not shown) provided in the voter terminal 30. A pseudo random number generator is used to generate a pseudonym to be used for voting instead of the voter's user ID (S210), and select one candidate to be elected from the candidates announced by the election administration center 20 (S215). ).

Thereafter, the voting rights are generated by multiplying the pseudonyms generated in the process S210 with the pseudonyms of the candidates selected in the process S215 (S220). In the above-described process S220, the voter i adjusts the value of Ps _i (an alias of the voter i) so that the voter's ballot _i becomes a primitive root for p, as shown in Equation 4.

In Equation 4, cdname _i is the pseudonym of candidate i announced by a trusted voting certification center.

Thereafter, the secreted (blind) to the voter voting Ballot _i i to generate any random number bf (blinding factor), ubf ( unblinding factor) satisfying the equation 5 (S225).

In Equation 5, B (Ballot _i , bf) is a concealed voting right.

Thereafter, as shown in Equation 6, the digital signature for the voting ticket B (Ballot _i , bf) concealed in the process S225 based on the user ID information of the voter recorded in the smart card issued from the card issuing center 10. In order to generate the data, Fiat-Shamir based on the ID information of the individual is applied (S230).

In Equation 6, r _i is a randomly generated number.

Digital signature for, when through the above-described process S230 generates a digital signature for the concealment vote B (Ballot _i, bf), the concealment vote B (Ballot _i, bf) generating a vote management center 20, as described above Including (e _ij ), it transmits the concealed voting rights B (Ballot _i , bf), the voter's user ID and the parameters y ₁ ,..., y _t necessary for authentication (S235).

As described above, the election management center 20 receiving the voting rights generated by the voter i performs authentication of the received voting rights, and the concealed voting rights B (Ballot _i ) from the voter terminal 30 in the above-described process S235. , bf), the user ID of the voter, the digital signature (e _ij ) for the concealed ballot B (Ballot _i , bf), and the election administration center that received the parameters y ₁ , ....., y _t for authentication (20) ) Compares the user ID of the voters previously authorized to vote by the election management center 20 with the user ID of the voter i received from the voter terminal 30 in step S235, and the voter i registers for the first time. , Performs the right to vote authentication protocol (S240, S245).

First, the digital signature on the concealed ballot B (Ballot _i , bf) of the voter i is verified based on Equation 7 (S250).

As a result of verifying the digital signature of the concealed ballot B (Ballot _i , bf) of the voter i in the above-described process S250, if the digital signature of the concealed ballot B (Ballot _i , bf) of the voter i is incorrect, It is not a valid signature for the concealment vote B (ballot _i, bf) suspended voting rights issued and, if the digital signature for the concealment vote B (ballot _i, bf) the voter i is correct, store the user ID of the voter i, As shown in Equation 8, the concealed ballot B (Ballot _i , bf) is authenticated (S255, S260, S265). In step S265, the user ID of the voter i is stored to prevent the voter from registering more than once.

In the above-described process S255, the verification that the digital signature of the voter i's concealed ballot B (Ballot _i , bf) is correct is the hidden vote B (Ballot _i , bf) received from the voter terminal 30, the user ID of the voter and It is determined whether or not the digital signature e _ij generated based on the parameters y ₁ ,..., Y _t required for authentication matches the digital signature e _ij received from the voter terminal 30. .

Subsequently, the secret ballot S _A (B (Ballot _i , bf)) authenticated in the process S265 is transmitted to the voter i (S270).

As described above, after the voting rights generated in the above-described process S220 is authenticated in the election management center 20, the certified voting rights must be obtained from the certified concealment voting rights. After obtaining the signature for the authenticated hidden voting right as shown in Equation 9, an unblinded ballot is extracted from the authenticated hidden voting right as shown in Equation 10 (S275).

As described above, the voter who has obtained the authorized voting right is to exercise the voting right, Figure 5 is a flow chart for explaining the voting process (S300) of FIG.

First, in order to realize fairness of the election, the voter selects random random numbers a and b, proceeds with an undeniable challenge / response protocol, and as shown in Equation 11, The conductivity value CV _i is generated (S310).

In Equation 11, a and b are pseudo random numbers, which satisfy a · b ≡1 (mod p-1).

Subsequently, the pseudonym Ps _i and the challenge value CV _i of the voter _i are transmitted to the election management center 20 using the untraceable communication network proposed by Chaum (S320).

As described above, after the voting rights of the voter i are finished, the election management center 20 announces the voting rights of the voters i, and receives the pseudonym Ps _i and the challenge value CV _i from the voter terminal 30. The election management center 20 generates a response RP _i to the challenge value CV _i of the voter i, as shown in Equation 12 (S330).

Thereafter, the pseudonym Ps _i of the voter i, the challenge value CV _i of the voter i, and the response RP _i for the challenge value of the voter i are notified to the election bulletin board 40 (S340).

As described above, after the voters exercise their voting rights and the voting is closed, the votes are counted. FIG. 6 is a flowchart for explaining the counting process S400 of FIG. 2.

First, voter i is the response RP _i of the electoral boards (40) The voter i's pseudonym Ps _i, a challenge value from the response RP _i to challenge the value of the challenges the value of the voter _i CV i and voter _i CV i posted on authentication If the response RP _i and Ballot _i ^a for CV _i do not match, the voting protocol is rejected. If the response RP _i and Ballot _i ^a for CV _i match, voter i's ballot (Ballot _i ) Accept and authenticate (S410).

After that, the b value necessary for the counting and the authentication is transmitted to the election management center 20 (S420).

As described above, the election management center 20 having received the value necessary for opening the vote from the voter i performs the voting right authentication and counting, and the election management center having received the b value required for the voting right authentication and counting from the voter i. (20) authenticates the challenge value CV _i of the voter i by using the received value b (S430).

After authenticating the challenge value CV _i of the voter i in the process S430, if the pseudonym of the candidate i extracted from the challenge value belongs to the candidate group, the count of the candidate is increased (S440, S460) and the candidate extracted from the challenge value. If the pseudonym of i does not belong to the candidate group, the conventional voting protocol is rejected (S450).

Thereafter, the election management center 20 adds the pseudonym Ps, the challenge value CV _i , the response RP _i to the challenge value, the ballot _i ^x of the signed voter i, the parameter b for opening the vote, the voter i Ballot _i of Ballot _i , announce the pseudonym cdname _i of the selected candidate, and y value is released after the end of the counting (S470, S480).

The reason why the y value is disclosed after the counting process is finished in the process S480 is to allow all voters to verify the result of the challenge / response protocol.

The electronic election method of the present invention is not limited to the above-described embodiments, and may be modified and implemented in various ways within the scope of the technical idea of the present invention.

According to the electronic election method of the present invention as described above, in the voter registration process, by applying a digital signature method based on the ID information of the individual to generate a digital signature for concealed voting rights, digital signature technique based on personal information By applying this, it is suitable for large-scale elections such as the election of local governments in the era of electronic resident ID card or the parliamentary voting, and it is effective to reflect the transparency of the actual voting process.

And, the voter's pseudonym is generated during the voter registration process, and the voter decides to create the pseudonym, thereby reducing the dependence on the election management center and the risk of external hacking.

Claims (4)

Issuing a digitally signable card to the voter, obtaining first and second parameters for authenticating voter's concealment voting rights, and preparing to announce the names of candidates and aliases to be used in the election on the election board; A voter registration process of generating and voting rights to authenticate the concealment voting rights, and obtaining an authenticated voting right from the authenticated concealment voting rights; A voting process for exercising voting rights using the authenticated voting rights; An electronic election method comprising a counting process for counting the voting rights based on parameters for opening a ballot received from a voter. The method of claim 1, wherein the voter registration process comprises: Creating a pseudonym for voting and selecting one candidate to be elected from the candidates announced by the election management center; Generating a voting right using the generated pseudonym and the pseudonym of the selected candidate; Concealing the generated voting rights and generating a digital signature for the concealed voting rights based on user ID information of the voter recorded on the card; Sending the concealment voting rights, a voter's user ID, a digital signature for the concealment voting rights, and parameters necessary for authentication to the election management center; Verifying the digital signature for the concealed voting right when the voter registers for the first time by comparing the user ID of the received voter with the user ID of the voters previously authorized to vote; If the digital signature for the concealed voting right is correct as a result of the verification, storing the voter's user ID and authenticating the concealed voting right; Transmitting the authenticated concealment vote to the voter; And extracting the authenticated voting right by removing the hidden information from the received authenticated hidden voting right. The method of claim 1, wherein the voting process, Generating a challenge value for the authenticated voting right; Transmitting the generated challenge value and a pseudonym of a voter to the election management center; Generating a response to the received challenge value; And announcing the voter's alias, challenge value, and response to the challenge value to an election bulletin. According to claim 1, The counting process, Authenticating the response to the challenge value from the voter's alias, challenge value, and response to the challenge bulletin posted on the election bulletin board, and transmitting the parameters necessary for counting and authentication to the election management center; Authenticating a voter's challenge value using the received count and parameters required for authentication; Increasing the count of the candidate when the pseudonym of the hobo extracted from the authenticated challenge value belongs to the candidate group; Announcing a voter's alias, a challenge value, a response to the challenge value, a voter's right to vote, a parameter to open a ballot, a voter's vote and a selected candidate's alias; Publishing the second parameter to verify a challenge / response protocol result.