JP2019021296A - Electronic voting system and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic voting system capable of secret ballot. SOLUTION: An authentication server 200a has an authentication processing unit that authenticates a voter using authentication data including a first ID associated with a voter and authentication information of the voter, and the voter is authenticated. The voting server 300a is provided with a first synchronization unit that synchronizes the first blockchain including the first transaction data indicating the above with a plurality of authentication servers 200a and the like, and the voting server 300a is a second ID associated with the votes voted by the voters. There is a second ID that is independent of the first ID, a voting processing unit that receives voting data including voting information indicating the voting content of votes from the terminal, and a second transaction of voting information included in the voting data. A second synchronization unit that synchronizes the second blockchain included as data with a plurality of voting servers 300a or the like is provided, and the terminal sends the authentication data to the authentication server, and after the authentication is successful, the voting data is transmitted to the plurality of voting servers. Send to one of the voting servers. [Selection diagram] Fig. 1

Description

  The present invention relates to an electronic voting system and a control method.

  In recent years, electronic voting has been conducted in some local governments. In the electronic voting system, in order to keep the voter's vote contents secret, it is necessary not to associate the voter authentication information with the vote contents.

  In the electronic voting system disclosed in Patent Literature 1, a vote participation ticket is transmitted to a communication terminal used for voter authentication, and the communication terminal anonymizes and transmits the vote participation ticket. Secured.

  In addition, the electronic voting system needs to have the requirement that the reliability of the system is high and that the recorded voting content is not altered. Non-Patent Document 1 discloses the use of a block chain in order to realize high reliability of the system and prevention of alteration of voting contents.

Special Table 2011-517825

“Configuration of Collective Intelligence by Electronic Voting Using Blockchain Distributed Ledger” Information Processing Vol.57 No.12 pp. 1204-1209 "Introduction to privacy protection 6.1 k-anonymization (pp.135-138), 6.5 l-diversity (pp.157-159)

  When managing a vote with a block chain in an electronic voting system, there is a problem that if a block chain including a vote result is disclosed, a voter can be associated with the contents of the vote and a secret vote cannot be realized.

  Therefore, the present invention provides an electronic voting system that enables secret voting.

  An electronic voting system according to an aspect of the present invention is an electronic voting system including a terminal, a plurality of authentication servers, and a plurality of voting servers, and each of the plurality of authentication servers is associated with a voter. Authentication data including a first ID and authentication information of the voter is received from the terminal, and the voter is authenticated by the authentication processor by authenticating the voter using the received authentication data. A first storage unit storing a first block chain including first transaction data indicating that the first authentication unit has been authenticated, and the first block chain stored in the first storage unit, the plurality of authentication servers Each of the plurality of voting servers is a second ID associated with a vote voted by the voter. A voting processing unit that receives voting data including a second ID that is independent of the first ID and voting information indicating the voting content of the vote from the terminal, and the voting data received by the voting processing unit A second storage unit storing a second block chain including the voting information included as second transaction data, and the second block chain stored in the second storage unit are stored in the plurality of voting servers. A second synchronization unit that synchronizes with one or more voting servers excluding the voting server, wherein the terminal generates the authentication data and uses the generated authentication data as one of the plurality of authentication servers. A data generation unit for transmitting to the server, and the data generation unit further transmits the authentication data to the authentication server, whereby the voting is performed after successful authentication by the one authentication server. Generates over data, sending the created voted data to a voting server of the plurality of voting server.

  Note that these comprehensive or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, and the system, method, integrated circuit, and computer program. And any combination of recording media.

  According to the present invention, secret voting is possible.

FIG. 1 is a schematic diagram illustrating a configuration of an electronic voting system according to an embodiment. FIG. 2 is an explanatory diagram showing the data structure of the block chain. FIG. 3 is an explanatory diagram showing a data structure of transaction data. FIG. 4 is a block diagram showing a configuration of the voting terminal in the embodiment. FIG. 5 is a block diagram showing a configuration of the authentication server in the embodiment. FIG. 6 is a block diagram showing the configuration of the voting server in the embodiment. FIG. 7 is a sequence diagram illustrating an initialization process of the electronic voting system according to the embodiment. FIG. 8 is an explanatory diagram showing the owner of the authentication coin during the initialization process in the embodiment. FIG. 9 is an explanatory diagram showing owners of voting coins during initialization processing in the embodiment. FIG. 10 is a first sequence diagram illustrating voting processing of the electronic voting system according to the embodiment. FIG. 11 is a second sequence diagram illustrating a voting process of the electronic voting system according to the embodiment. FIG. 12 is an explanatory diagram showing the owner of the authentication coin during the voting process in the embodiment. FIG. 13 is an explanatory diagram showing owners of voting coins during voting processing in the embodiment. FIG. 14 is a first explanatory diagram of the criteria for anonymization by the voting server in the embodiment. FIG. 15 is a second explanatory diagram of the criteria for anonymization by the voting server in the embodiment. FIG. 16 is a flowchart illustrating processing relating to whether or not the consensus algorithm can be executed in the embodiment. FIG. 17 is a flowchart showing voting end processing of the electronic voting system in the embodiment. FIG. 18 is a sequence diagram illustrating a voting result disclosure process by the voting server in the embodiment. FIG. 19 is a schematic diagram illustrating a voting terminal used for voting in the electronic voting system according to the embodiment. FIG. 20 is a schematic diagram illustrating a terminal used for publishing a vote result in the electronic voting system according to the embodiment.

  An electronic voting system according to an aspect of the present invention is an electronic voting system including a terminal, a plurality of authentication servers, and a plurality of voting servers, and each of the plurality of authentication servers is associated with a voter. Authentication data including a first ID and authentication information of the voter is received from the terminal, and the voter is authenticated by the authentication processor by authenticating the voter using the received authentication data. A first storage unit storing a first block chain including first transaction data indicating that the first authentication unit has been authenticated, and the first block chain stored in the first storage unit, the plurality of authentication servers Each of the plurality of voting servers is a second ID associated with a vote voted by the voter. A voting processing unit that receives voting data including a second ID that is independent of the first ID and voting information indicating the voting content of the vote from the terminal, and the voting data received by the voting processing unit A second storage unit storing a second block chain including the voting information included as second transaction data, and the second block chain stored in the second storage unit are stored in the plurality of voting servers. A second synchronization unit that synchronizes with one or more voting servers excluding the voting server, wherein the terminal generates the authentication data and uses the generated authentication data as one of the plurality of authentication servers. A data generation unit for transmitting to the server, and the data generation unit further transmits the authentication data to the authentication server, whereby the voting is performed after successful authentication by the one authentication server. Generates over data, sending the created voted data to a voting server of the plurality of voting server.

  According to the above aspect, the electronic voting system uses data including IDs that are independent of each other for authentication of being a valid voter and for voting performed after authentication. Thereby, for example, even when the result of the authentication and the content of the vote are made public after the election, it is possible to prevent the voter who has voted for the content of the vote from being specified. Further, by managing the data indicating the authentication and the data indicating the contents of the voting with individual block chains, it is possible to suppress falsification of each data. Therefore, the electronic voting system enables secret voting.

  For example, each of a plurality of voting servers further generates second transaction data indicating second voting data included in the received voting data when the voting data is received from the terminal. And a second block generation unit that generates a second block including one or more second transaction data generated by the second transaction data generation unit and connects the generated second block to the second block chain And may be provided.

  According to the said aspect, an electronic voting system stores the data containing the content of the vote by a voter in a block chain. Therefore, the electronic voting system enables secret voting while suppressing falsification of the contents of the vote voted by the voting car.

  For example, the second transaction data generation unit generates and generates a third block including third transaction data indicating that the authentication processing unit is ready to authenticate each of a plurality of voters. When the third block is connected to the second block chain and the voter is authenticated by one authentication server of the plurality of authentication servers, the terminal receives input of the contents of the vote by the voter. A fourth block including the fourth transaction data indicating that the state is ready to be generated may be generated, and the generated fourth block may be connected to the second block chain.

  According to the above aspect, the electronic voting system causes the voter to input the contents of the vote based on the voter being authenticated by the authentication server. Therefore, the electronic voting system enables secret voting while restricting input of voting contents by an unauthenticated voter.

  For example, each of the plurality of voting servers further determines whether one or more of the second transaction data generated by the second transaction data generation unit satisfies a predetermined anonymity criterion, You may provide the anonymization part which makes the said 2nd block production | generation part generate | occur | produce the said 2nd block, and connects with said 2nd block chain, when satisfy | filling the said reference | standard.

  According to the said aspect, an electronic voting system suppresses the production | generation of a block until the content of voting by a voter gathers and the criteria for concealment are satisfied. If a plurality of voting contents that do not satisfy the anonymization standard are stored in one block, depending on the voting contents included in the block, collation with authentication data may be possible and a secret vote may not be realized. Therefore, the electronic voting system enables secret voting with higher secrecy by concealing the contents of voting in block units.

  For example, when the predetermined voting period is exceeded even when the anonymization unit determines that one or more of the second transaction data does not satisfy the standard, the second block generation unit May generate the second block and connect it to the second block chain.

  According to the above aspect, the electronic voting system can avoid remaining voting contents not being stored in the block when the voting period ends without the concealment criteria being satisfied. Therefore, the electronic voting system makes it possible to perform secret voting with higher secrecy by avoiding the voting contents remaining without being preserved while making the voting contents concealed in units of blocks.

  For example, when the first ID included in the received authentication data is already included in the first block chain, the authentication processing unit fails authentication and prohibits the terminal from transmitting the voting data You may let them.

  According to the above aspect, the electronic voting system can easily determine whether or not the ID used for authenticating the voter has already been used, that is, whether or not there is double use by using the block chain technology. Can do. Therefore, the electronic voting system enables secret voting while easily suppressing double use of IDs used for authentication.

  For example, each of the plurality of authentication servers further includes a first data generation unit that generates first transaction data indicating that the authentication of the terminal is successful when the authentication of the terminal is successful, and the first data You may provide the 1st block containing the said 1st transaction data which the production | generation part produced | generated, and the 1st block production | generation part which connects said produced | generated 1st block to said 1st block chain.

  According to the above aspect, the electronic voting system stores data indicating that the voter is authenticated in the block chain. Therefore, the electronic voting system enables secret voting while suppressing falsification that the voter is authenticated.

  For example, the voting processing unit may discard the received voting data when the second ID included in the received voting data is already included in the second block chain.

  According to the above aspect, the electronic voting system can easily determine whether or not the ID used for voting has already been used, that is, whether or not there is double use by using the block chain technology. Therefore, the electronic voting system enables secret voting while easily suppressing double use of IDs used for voting.

  An electronic voting system according to an aspect of the present invention is an electronic voting system including a plurality of authentication servers and a plurality of voting servers, and each of the plurality of authentication servers is associated with a voter. Authentication data including an ID and authentication information of the voter is received from the terminal, and the voter is authenticated by the authentication processing unit that authenticates the voter using the received authentication data. The first storage unit storing the first block chain including the first transaction data indicating that the transaction has been performed, and the first block chain stored in the first storage unit among the plurality of authentication servers A first synchronization unit that synchronizes with one or more authentication servers excluding the authentication server, and each of the plurality of voting servers is a second ID associated with a vote voted by the voter, Included in the voting processing unit that receives from the terminal voting data including a second ID that is independent of one ID and voting information indicating the voting content of the vote, and the voting data received by the voting processing unit A second storage unit storing a second block chain including the voting information as second transaction data, and the second block chain stored in the second storage unit are included in the plurality of voting servers. A second synchronization unit that synchronizes with one or more voting servers excluding the voting server.

  According to the above aspect, the electronic voting system enables secret voting as described above using a terminal not included in the electronic voting system.

  A voting server control method according to an aspect of the present invention is a voting server control method of a plurality of voting servers in an electronic voting system, and is a second method associated with a vote voted by a voter. The voting data received from the terminal is received voting data including a second ID that is independent of the first ID associated with the voter and voting information indicating the voting content of the vote. Storing the second block chain including the voting information included in the transaction data as the second transaction data, and storing the second block chain including at least one of the plurality of authentication servers excluding the one voting server When the voting data is received from the terminal in synchronization with the voting server, the second transaction data indicating the voting content included in the received voting data is generated, and the generated one or more previous A second block including second transaction data is generated, the generated second block is connected to the second block chain, and the generated one or more second transaction data has a predetermined anonymity standard. It is determined whether or not the condition is satisfied. When the criterion is satisfied, the second block is generated and connected to the second block chain.

  According to the above aspect, the voting server suppresses generation of blocks until a plurality of voting contents by the voter are collected and the concealment standard is satisfied. If multiple voting contents that do not satisfy the anonymization criteria are stored in one block, depending on the voting contents included in the block, it is possible to collate with authentication data by using the generation time of the block, etc. Voting may not be realized. Therefore, the voting server enables secret voting with higher confidentiality by concealing the voting contents in units of blocks.

  An electronic voting system control method according to an aspect of the present invention is an electronic voting system control method including a terminal, a plurality of authentication servers, and a plurality of voting servers, each of the plurality of authentication servers. The authentication data including the first ID associated with the voter and the voter authentication information is received from the terminal, and the voter is authenticated using the received authentication data. Storing a first block chain including first transaction data indicating that it has been authenticated, and synchronizing the stored first block chain with one or more authentication servers excluding the authentication server among the plurality of authentication servers A second ID associated with a vote voted by the voter by each of the plurality of voting servers, and a second ID independent of the first ID; Voting data including voting information indicating the second block chain including the voting information included in the received voting data as second transaction data is stored and stored. The chain is synchronized with one or more voting servers other than the voting server among the plurality of voting servers, the authentication data is generated by the terminal, and the generated authentication data is sent to one of the plurality of authentication servers. The authentication data is transmitted to the authentication server, and the authentication data is transmitted to the authentication server, so that the voting data is generated after the authentication by the one authentication server is successful, and the generated voting data is transmitted to the plurality of voting servers. Send to one of our voting servers.

  Thereby, there exists an effect similar to the said electronic voting system.

  Note that these comprehensive or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, and the system, method, integrated circuit, and computer program. Alternatively, it may be realized by any combination of recording media.

  Hereinafter, embodiments will be specifically described with reference to the drawings.

  It should be noted that each of the embodiments described below shows a comprehensive or specific example. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

(Embodiment)
In this embodiment, an electronic voting system that enables secret voting will be described.

1. System Configuration The electronic voting system is a system that allows a voter to electronically vote using a voting terminal. The electronic voting system performs an authentication process regarding voting between the voting terminal and the authentication server, and then performs a voting process between the voting terminal and the voting server. A period during which the electronic voting system accepts votes by voters is also referred to as a voting period. A person who votes by an electronic voting system is also called a “voter”, and a person who has the right to vote is called a voter.

  Hereinafter, the electronic voting system will be described with reference to the drawings.

1.1 Overall Configuration of Electronic Voting System 10 FIG. 1 is a diagram showing a configuration of the electronic voting system 10 according to the present embodiment. The electronic voting system 10 includes voting terminals 100a, 101a, 102a, 100b, 101b, 102b, 100c, 101c, and 102c (also referred to as voting terminals 100a) and authentication servers 200a, 200b, and 200c (also referred to as authentication servers 200a). And voting servers 300a, 300b, and 300c (also referred to as voting server 300a and the like), which are connected by a network N.

  The authentication server 200a etc. authenticates whether or not the voter is valid, and manages information indicating the authenticated voter. The authentication server 200a uses a known block chain technology for the above authentication and information management. That is, the authentication server 200a manages a transaction history of a virtual transaction (transaction) as a block chain. Here, a description will be given using a coin (also referred to as an authentication coin) as a virtual transaction target, but the virtual transaction target is not limited to a coin. In addition, the plurality of authentication servers 200a and the like share a block chain that stores the transaction history of authentication coins, and prevent the transaction history from being altered by mutually approving them. The authentication coin is generated by the authentication server 200a and provided to the voting terminal 100a and the like. When the voter authentication is successful, the authentication coin is provided from the voting terminal 100a to the authentication server 200a. The exchange of authentication coins is also called authentication transaction. The authentication coin is a virtual coin having no substance, and its transaction history is managed by the authentication server 200a or the like. The authentication coin has an ID (identifier) that can uniquely identify the authentication coin. The ID of the authentication coin is linked to the ID assigned to the voter on a one-to-one basis. The ID of the authentication coin is also called an authentication ID.

  The voting server 300a and the like manage voting contents by voters. The voting server 300a uses a known block chain technology for managing the contents of voting. In other words, the voting server 300a manages a transaction history of a virtual transaction target using a block chain. Here, a description will be given using a coin (also referred to as a voting coin) as a virtual transaction target, but the virtual transaction target is not limited to a coin. Further, the plurality of voting servers 300a and the like share a block chain containing the transaction history of voting coins, and prevent the transaction history from being altered by mutually approving them. The voting coin is generated by the voting server 300a and provided to the voting terminal 100a and the like through the authentication server 200a. The exchange of voting coins is also called a voting transaction, and the provision of voting coins from the voting terminal 100a to a candidate corresponds to voting in an election. The voting coin is a virtual coin having no substance, and its transaction history is managed by the voting server 300a or the like. And at the time of vote by a voter, it is provided to a candidate from the voting terminal 100a. The number of voting coins finally obtained by the candidate becomes the number of votes of the candidate in the electronic voting. The voting coin is equivalent to a ballot in a conventional election. The voting coin has an ID (identifier) that can uniquely identify the voting coin. The ID of the voting coin is associated with the vote voted by the voter on a one-to-one basis. The ID of the voting coin is also called a voting ID.

  The ID of the authentication coin and the ID of the voting coin are independent from each other.

  The electronic voting system 10 is divided into, for example, three subsystems A, B, and C. Note that the number of subsystems is not limited to three and may be any number of two or more.

  The electronic voting system 10 distributes processing and shares information with a plurality of authentication servers 200a and the like and a plurality of voting servers 300a and the like so that the electronic voting system 10 can be used for municipal, prefecture, or nationwide elections. Further, the transaction history is prevented from being falsified by performing mutual approval in the blockchain technology between the plurality of authentication servers 200a and between the plurality of voting servers 300a.

  For example, in a case where a voter votes using a voting terminal 100a installed at a polling place, the authentication server 200a and the voting server 300a are provided for each polling place. In this case, each of the subsystems A, B, and C is provided corresponding to the polling place. For example, in a nationwide election in Japan, the number of subsystems can be on the order of tens of thousands.

  Further, in a case where a voter votes at home or the like via a network, the authentication server 200a and the voting server 300a may be provided for each voter attribute (gender, place of residence, occupation, etc.). In this case, each of the subsystems A, B, and C is provided corresponding to each attribute of the voter.

  FIG. 2 is an explanatory diagram showing the data structure of the block chain.

  The block chain is a block in which the recording units are connected on a chain. Each block has a plurality of transaction data and a hash value of the immediately preceding block. Specifically, the block B2 includes the hash value of the previous block B1. Then, the hash value calculated from the plurality of transaction data included in the block B2 and the hash value of the block B1 is included in the block B3 as the hash value of the block B2. In this manner, by connecting the blocks in a chain shape while including the contents of the previous block as a hash value, it is possible to effectively prevent tampering with the regular transaction data.

  If past transaction data is changed, the hash value of the block will be different from that before the change, and in order to make the altered block appear correct, all subsequent blocks must be recreated. Is very difficult in practice.

  Each transaction data indicates new generation and exchange of coins. This coin corresponds to an authentication coin and a voting coin.

  FIG. 3 is a first explanatory diagram showing a data structure of transaction data.

  The transaction data shown in FIG. 3 is an example of transaction data D1 indicating that a coin is provided from the holder to the provider. The transaction data D1 includes an address P1 indicating the holder, an address P2 indicating the destination, and an electronic signature P3 generated by signing the hash values of the addresses P1 and P2 with the signature key of the holder. Contains. Transaction data is also generated when a new coin is generated. In the transaction data when a new coin is generated, the address P1 is blank.

  Hereinafter, the voting terminal 100a, the authentication server 200a, and the voting server 300a will be described in order. The same explanation holds true for other voting terminals, other authentication servers, and other voting servers.

1.2 Configuration of Voting Terminal 100a The voting terminal 100a is a terminal that receives the voter's authentication information and voting details from the voter and displays various information. The voting terminal 100a may be a mobile terminal held by a voter (specifically, a mobile phone terminal, a smartphone, a personal computer), or a terminal provided in a polling place.

  FIG. 4 is a block diagram showing a configuration of voting terminal 100a according to the present embodiment. The voting terminals 100b and 100c have the same configuration. The voting terminal 100a includes a display unit 111, an input unit 112, a transaction data generation unit 113, and a communication unit 114. The voting terminal 100a can be realized by a processor executing a predetermined program using a memory.

  The display unit 111 is a display device that displays a screen during voting. When simply referred to as “screen”, it means a screen displayed as an image displayed on a display device such as a liquid crystal display or an organic EL (Electro-Luminescence) display. The same applies to the following.

  The input unit 112 receives input of authentication information at the time of voting and input of voting contents from a voter.

  The transaction data generation unit 113 generates authentication data for voter authentication and vote data for vote by the voter. Further, the transaction data generation unit 113 generates authentication transaction data for exchange of authentication coins accompanying authentication and voting transaction data for exchange of voting coins accompanying voting by a voter. The authentication data includes authentication information including an authentication ID unique to the voter and an electronic signature (also simply referred to as a signature) of the voting terminal 100a. The electronic signature is a signature generated from a hash value of authentication information using a signature key. The authentication transaction data is transaction data indicating a transaction for providing an authentication coin from the voting terminal 100a to the authentication server 200a. The authentication transaction data is also referred to as first transaction data.

  The voting data includes the contents of voting in electronic voting and the signature of the voting terminal 100a. Specifically, the voting content is information indicating a voted candidate or information indicating confidence or non-confidence. The voting transaction data is transaction data indicating a transaction for providing a candidate with the voting coin provided from the authentication server 200a. Voting transaction data is also referred to as second transaction data.

  The transaction data generation unit 113 generates authentication data and transmits the generated authentication data to the authentication server 200a. Further, the transaction data generation unit 113 transmits the authentication data to the authentication server 200a, thereby generating voting data after successful authentication by the authentication server 200a, and transmits the generated voting data to the voting server 300a.

  Note that the signature key necessary for generating the signature by the voting terminal 100a may be held in advance by the voting terminal 100a, or may be acquired from the authentication server 200a when receiving input of authentication information by the voter. .

  The communication unit 114 is a communication interface that performs communication with each of the authentication server 200a and the voting server 300a. This communication may be performed by TLS (Transport Layer Security). In that case, the communication unit 114 may hold the encryption key for TLS communication.

1.3 Configuration of Authentication Server 200a FIG. 5 is a block diagram showing a configuration of the authentication server 200a in the present embodiment. The authentication servers 200b and 200c have the same configuration. The authentication server 200a includes a screen data generation unit 211, a transaction data verification unit 212, a transaction data generation unit 213, a block generation unit 214, a synchronization unit 215, a storage unit 216, and a communication unit 217. The authentication server 200a and the like can be realized by a processor executing a predetermined program using a memory.

  When there is an access for authentication from the voting terminal 100a, the screen data generation unit 211 generates screen data for rendering an authentication screen. Specifically, the screen data generation unit 211 generates screen data for rendering a screen for receiving input of authentication information from the voter at the voting terminal 100a.

  When the transaction data verification unit 212 receives the authentication transaction data from the voting terminal 100a, the transaction data verification unit 212 verifies the received authentication transaction data. When the transaction data verification unit 212 receives the authentication transaction data from the voting terminal 100a, the transaction data verification unit 212 verifies whether the signature included in the received authentication transaction data is valid, and verifies whether the authentication information is valid. . In the verification of the authenticity of the authentication information, it is verified whether the authentication information is issued in advance by the electronic voting system 10 and whether one authentication information is used more than once during the voting period. Whether or not one authentication information has been used more than once is determined by referring to the storage unit 216, and the authentication transaction based on the one authentication information is not stored in the storage unit 216. Check whether or not. If the transaction data verification unit 212 determines that the authentication information is valid as a result of the verification process, the transaction data verification unit 212 stores the authentication transaction data in the storage unit 216. Further, the valid authentication transaction data is transmitted to the other authentication servers 200b and 200c by the synchronization unit 215 and synchronized.

  Further, when receiving the voting transaction data from the voting server 300a, the transaction data verification unit 212 verifies whether the signature included in the voting transaction data is valid.

  The transaction data generation unit 213 generates authentication transaction data related to the authentication transaction. The transaction data generating unit 213 generates authentication transaction data for newly generating the same number of authentication coins as the number of voters in the initialization process. At this time, the owner of the authentication coin is each voter.

  Further, the transaction data generation unit 213 generates voting transaction data for providing the voting coin provided from the voting server 300a to the voting terminal 100a. Transaction data generation unit 213 corresponds to a first transaction data generation unit.

  The block generation unit 214 executes a consensus algorithm among the plurality of authentication servers 200a. As the consensus algorithm, a consensus algorithm called PBFT (Practical Byzantine Fault Tolerance) may be used, or other known consensus algorithms may be used. The block generation unit 214 generates a block including the authentication transaction data and stores the block in the storage unit 216 when the consensus algorithm can be formed with respect to one or more authentication transactions. Further, the block generation unit 214 connects the generated block to the block chain stored in the storage unit 216. The block generation unit 214 corresponds to a first block generation unit.

  The synchronization unit 215 synchronizes the blocks of the block chain and the authentication transaction data among the plurality of authentication servers 200a. Between a plurality of authentication servers 200a, blocks in the block chain are synchronized peer-to-peer. For example, when the authentication transaction data is received from the voting terminal 100a and the validity of the authentication transaction data is verified by the transaction data verification unit 212, the synchronization unit 215 copies the authentication transaction data to the other authentication servers 200b and 200c. By transmitting, the verified authentication transaction data is stored in the storage units 216 of the other authentication servers 200b and 200c. In addition, when the synchronization unit 215 receives the authentication transaction data from the other authentication servers 200b and 200c, the synchronization unit 215 stores the received authentication transaction data in the storage unit 216.

  The storage unit 216 is a storage device that stores authentication transaction data and blocks of the block chain. The block chain stored in the storage unit 216 is also referred to as a first block chain.

  The communication unit 217 is a communication interface that performs communication with each of the voting terminal 100a and the voting server 300a. This communication may be performed by TLS. In that case, the communication unit 217 may hold the encryption key for TLS communication.

  The transaction data verification unit 212 and the transaction data generation unit 213 receive authentication data including the authentication ID (that is, the first ID) associated with the voter and the voter authentication information from the voting terminal 100a. This corresponds to the authentication processing unit 212A that authenticates the voter using the received authentication data.

1.4 Configuration of Voting Server 300a FIG. 6 is a block diagram showing the configuration of the voting server 300a in the present embodiment. The voting servers 300b and 300c have the same configuration. The voting server 300 a includes a screen data generation unit 311, a candidate DB (database) 312, a transaction data verification unit 313, a transaction data generation unit 314, an anonymization unit 315, a block generation unit 316, and a synchronization unit 317. And a storage unit 318 and a communication unit 319. The voting server 300a can be realized by a processor executing a predetermined program using a memory.

  When there is an access for voting from the voting terminal 100a, the screen data generation unit 311 generates screen data that is drawing data for drawing a voting screen. Specifically, the screen data generation unit 311 obtains information related to the candidate from the candidate DB 312 and displays a screen that is displayed on the voting terminal 100a for receiving vote information input by the voter. Screen data that is drawing data to be generated is generated.

  The candidate DB 312 is a database in which information related to candidates is stored. The candidate DB 312 stores at least information for identifying a candidate. Specifically, the candidate DB 312 stores a character string indicating the candidate's name as information for identifying the candidate, and may further store an image or the like indicating the candidate's face photograph. .

  When receiving the voting transaction data from the voting terminal 100a, the transaction data verification unit 313 verifies the received voting transaction data. The transaction data verification unit 313 verifies whether the signature included in the voting transaction data is valid and verifies whether the voting information is valid. In the verification of the validity of the voting information, it is verified whether the voting information is issued in advance by the electronic voting system 10 or whether one voting information is used more than once during the voting period. Whether one piece of voting information is used more than once is confirmed by referring to the storage unit 318 based on whether the one piece of voting information is not stored in the storage unit 318. If the transaction data verification unit 313 determines that the voting information is valid as a result of the verification process, the transaction data verification unit 313 records the voting transaction data in the storage unit 318. In addition, the valid voting transaction data is transmitted to the other voting servers 300b and 300c by the synchronization unit 317 and synchronized.

  The transaction data generation unit 314 generates voting transaction data related to voting transactions. The transaction data generation unit 314 generates voting transaction data for newly generating the same number of voting coins as the number of voters in the initialization process. The owner of the voting coin at this time is the voting server 300a. Next, the transaction data generation unit 314 generates voting transaction data (corresponding to third transaction data) for providing voting coins to the authentication server 200a. The voting transaction data to be generated includes information indicating the owner of the voting coin of the providing destination (that is, information indicating the authentication server 200a) and the signature of the voting server 300a. When the voting transaction data for providing voting coins to the authentication server 200a is generated, the voting coin owner becomes the authentication server 200a. Transaction data generation unit 314 corresponds to a second transaction data generation unit.

  The anonymization unit 315 determines the anonymity of the voting transaction data recorded in the storage unit 318. The anonymization unit 315 determines whether the voting transaction data recorded in the storage unit 318 and not yet included in the block chain satisfies a predetermined criterion regarding anonymization. When it is determined that the voting transaction data satisfies the anonymization standard, the anonymization unit 315 causes the block generation unit 316 to generate a block. The standard of anonymization is predetermined based on the number of voters and the number of candidates. The criteria for anonymization are, for example, k-anonymity k = 3 and l-diversity l = 2 or more. Non-patent document 2 describes k-anonymity and l-diversity. Even if the anonymization unit 315 does not satisfy the criteria for anonymization, if the end time of the voting period has passed, that is, if the voting period has expired, the block generation unit 316 requests block generation. Send. The “anonymization standard” can be said to be an “anonymity standard”.

  The block generation unit 316 executes a consensus algorithm among the plurality of voting servers 300a and the like. Based on the consensus algorithm execution request from the anonymization unit 315, the block generation unit 316 executes the consensus algorithm among the plurality of voting servers 300a and the like. As the consensus algorithm, PBFT may be used, or other known consensus algorithms may be used. When the consensus algorithm has been reached for the voting transaction data that satisfies the anonymization standard, a block including the voting transaction data is generated and stored in the storage unit 318. Further, the block generation unit 316 connects the generated block to the block chain stored in the storage unit 318. The block generation unit 316 corresponds to a second block generation unit.

  The block generation unit 316 generates a block (corresponding to the third block) including voting transaction data (third transaction data) for providing voting coins to the authentication server 200a, and connects the generated block to the block chain. The third transaction data is transaction data indicating that the authentication processing unit 212A (transaction data verification unit 212) can authenticate each of a plurality of voters.

  In addition, the block generation unit 316 generates a block (corresponding to the fourth block) including voting transaction data (fourth transaction data) for providing voting coins from the authentication server 200a to the voting terminal 100a, and generates the generated fourth block. Connect to the second blockchain. The fourth transaction data is transaction data indicating that the voting terminal 100a can receive an input of voting content by the voter when the voter is authenticated by the authentication server 200a.

  The synchronization unit 317 synchronizes the blocks of the block chain and the voting transaction data among the plurality of voting servers 300a and the like. Between the plurality of voting servers 300a, the blocks of the block chain are synchronized by peer to peer. For example, when voting transaction data is received from the voting terminal 100a and the validity of the voting transaction data is verified by the transaction data verification unit 313, the synchronization unit 317 copies the voting transaction data to the other voting servers 300b and 300c. The voting transaction data that has been transmitted and verified is stored in the storage units 318 of the other voting servers 300b and 300c. Moreover, the synchronization part 317 will store the received voting transaction data in the memory | storage part 318, if voting transaction data are received from the other voting servers 300b and 300c.

  The storage unit 318 is a storage device that stores voting transaction data and blocks of the block chain. The block chain stored in the storage unit 318 is also referred to as a second block chain.

  The communication unit 319 is a communication interface that performs communication with each of the voting terminal 100a and the authentication server 200a. This communication may be performed by TLS. In that case, the communication unit 319 may hold the encryption key for TLS communication.

  The transaction data verification unit 313 and the transaction data generation unit 314 are a vote ID (that is, a second ID) associated with a vote voted by a voter, and a vote ID that is independent of the authentication ID, and a vote It corresponds to the voting processing unit 313A that receives the voting data including the voting information indicating the content of the voting from the voting terminal 100a.

1.5 Voting Sequence Between Voting Terminal and Server Hereinafter, processing by the electronic voting system 10 will be described. Here, while authenticating a voter between the voting terminal 100a and the like and the authentication server 200a using the authentication coin, the voting is performed between the voting terminal 100a and the voting server 300a using the voting coin. Processing will be described. At that time, in order to permit only the voter who has been authenticated to vote, the voting coin is provided to the voting terminal 100a through the authentication server 200a.

  Hereinafter, an initialization process, a voting process, an end process, and a voting result disclosure process will be described in order.

<Initialization process>
FIG. 7 is a sequence diagram showing an initialization process of the electronic voting system 10 in the present embodiment. 8 and 9 are explanatory diagrams showing owners of authentication coins and voting coins during initialization processing in the present embodiment, respectively. The owners of the authentication coin and the voting coin are managed by the authentication server 200a and the voting server 300a, respectively.

  The initialization process shown in FIG. 7 is a process executed once in advance for one election using the electronic voting system 10.

  In step S101, the authentication server 200a executes an authentication initialization process. The authentication initialization process generates authentication transaction data for generating an authentication coin having an ID (also referred to as a voter ID) distributed in advance to the voters as an authentication ID, and generates a block including the generated authentication transaction data. At this stage, the owner of the authentication coin is a voter identified by the voter ID (see FIG. 8).

  In step S102, the voting server 300a executes voting initialization processing. In the voting initialization process, voting transaction data for generating the same number of voting coins as the number of voters is generated, and a block including the generated voting transaction data is generated. At this stage, the owner of all the voting coins is the voting server 300a (see (a) of FIG. 9). The ID of the voting coin is a character string or a value that can uniquely identify each voting coin, and is all different. The ID of the voting coin may be a character string or a value selected at random. When all the IDs of the voting coins are different character strings or values, it is possible to confirm whether or not the same voting coin is not used twice when referring to the block chain.

  In step S103, the voting server 300a generates voting transaction data for providing the voting coin generated in step S102 to the authentication server 200c, and generates a block including the generated voting transaction data. Further, the generated voting transaction data is transmitted to the authentication server 200c. In addition, although the case where the provision destination of voting coins is the authentication server 200c will be described as an example, the provision destination of voting coins may be another authentication server 200a or 200b. At this stage, the information indicating the owner of the voting coin provided to the authentication server 200c is changed to the authentication server 200c (see FIG. 9B).

  In step S104, the authentication server 200c performs a synchronization process with the other authentication servers 200a and 200b. In the synchronization process, the authentication server 200c transmits the received voting transaction data to the other authentication servers 200a and 200b by the synchronization unit 215. The synchronization unit 215 of the authentication servers 200a and 200b stores the voting transaction data received from the synchronization unit 215 of the authentication server 200c.

<Voting process>
10 and 11 are sequence diagrams showing the voting process of the electronic voting system 10 in the present embodiment. 12 and 13 are explanatory diagrams showing the authentication coin and the owner of the voting coin during the voting process in the present embodiment, respectively.

  The voting process shown in FIG. 10 and FIG. 11 is a process executed once when one voter makes one vote, and is executed as many times as the number of voters in one election. The

  In step S201, the voting terminal 100a accesses the authentication server 200a. This access is, for example, Web access to a Web site provided by the authentication server 200a, and HTTP (Hypertext Transfer Protocol) or HTTPS (HTTP over SSL (Secure Sockets Layer) / TLS (Transport Layer) or the like. Can be used.

  In step S202, the authentication server 200a generates screen data of an authentication screen for acquiring the voter's voter ID in response to the access in step S201, and transmits the screen data to the voting terminal 100a.

  In step S203, the voting terminal 100a displays an authentication screen based on the screen data transmitted in step S202, and receives input of authentication information including the voter's voter ID. The voter visually recognizes the authentication screen displayed on the voting terminal 100a, and inputs the voter ID distributed in advance to the voting terminal 100a. The voter may manually input the voter ID, or may input the voter ID by reading the barcode or the two-dimensional code on which the voter ID is recorded by the voting terminal 100a.

  In step S204, the voting terminal 100a generates authentication transaction data using the voter ID input in step S203 as an authentication ID.

  In step S205, the voting terminal 100a transmits the authentication transaction data generated in step S204 to the authentication server 200a. Here, a case where authentication transaction data is transmitted to the authentication server 200a will be described as an example, but the authentication transaction data may be transmitted to other authentication servers 200b and 200c. The authentication server 200a receives the transmitted authentication transaction data.

  In step S206, the authentication server 200a verifies the authentication transaction data received from the voting terminal 100a in step S205. In verification of authentication transaction data, a block chain of authentication transaction data stored in the storage unit 216 is referred to, and a voter ID included in the authentication transaction data received from the voting terminal 100a is not already stored in the block chain It is determined whether or not. If it is determined that the voter ID is not already stored in the blockchain, the verification transaction data is successfully verified. If it is determined that the voter ID is already stored, the verification transaction data is verified. Suppose it failed.

  If verification of the authentication transaction data fails in step S206, the authentication server 200a performs error processing (not shown). In the error process, for example, an error message is notified to the voting terminal 100a. The error message may include a message such as “not voter” or “cannot use the same voter ID because it has already been authenticated”. Further, in error processing, subsequent voting processing such as transmission of voting data by the voting terminal 100a is prohibited.

  If the verification of the authentication transaction data is successful in step S206, the process proceeds to step S207.

  In step S207, the authentication server 200a transmits a copy of the authentication transaction data to the other authentication servers 200b and 200c. The authentication servers 200b and 200c verify the received authentication transaction data.

  In step S208, the authentication servers 200a, 200b, and 200c execute a consensus algorithm. By executing the consensus algorithm, it is verified that the received authentication transaction data is a legitimate transaction. The authentication servers 200a, 200b, and 200c generate a block that includes verified authentication transaction data. As a result, a block including an authenticated voter ID is generated, so that even if authentication transaction data including the same voter ID is subsequently received, the same voter ID can be used by referring to the block chain. Can be judged. At this stage, the owner of the authentication coin having the voter ID of the voter who has been authenticated is changed to the authentication server 200a (see FIG. 12).

  In step S209, the authentication server 200a generates voting transaction data that provides voting coins to the voting terminal 100a that has transmitted the authentication transaction data in step S205, and transmits the generated voting transaction data to the voting terminal 100a and the voting server 300a. .

  In step S210, the authentication server 200a transmits a copy of the generated voting transaction data to the other authentication servers 200b and 200c, and synchronizes the voting transaction data. The authentication servers 200a, 200b, and 200c record the voting coins related to the generated voting transaction data as used.

  In step S211, the voting server 300a verifies the voting transaction data received from the authentication server 200a in step S209. In the verification of the voting transaction data, the block chain of the voting transaction data stored in the storage unit 318 is referred to, and the voting ID included in the voting transaction data received from the authentication server 200a is not already stored in the block chain. It is determined whether or not. If it is determined that the voting ID is not already stored in the blockchain, the verification of the voting transaction data is successful. If it is determined that the voting transaction data is already stored, the verification of the voting transaction data is performed. Suppose it failed.

  If the verification of voting transaction data fails in step S211, the voting server 300a performs error processing (not shown). In the error process, for example, an error message is notified to the voting terminal 100a. The error message may include a message such as “The same ID cannot be used because it has already been voted”. Further, in error processing, subsequent voting processing such as transmission of voting data by the voting terminal 100a is prohibited.

  In step S212, the voting server 300a transmits a copy of the voting transaction data to the other voting servers 300b and 300c. The voting servers 300b and 300c verify the received voting transaction data.

  In step S213, the voting servers 300a, 300b, and 300c execute a consensus algorithm. By executing the consensus algorithm, it is verified that the received voting transaction data is a valid transaction. The voting servers 300a, 300b, and 300c generate a block that includes verified voting transaction data. At this stage, the owner of the voting coin provided to the voter who has successfully verified the authentication transaction data in step S206 is changed to the voting terminal 100a (see (a) of FIG. 13).

  In step S221, the voting terminal 100a accesses the voting server 300a. This access is, for example, Web access to a Web site provided by the voting server 300a, and HTTP or HTTPS can be used.

  In step S222, the voting server 300a generates screen data of a voting screen for voting by a voter in response to the access in step S221, and transmits the screen data to the voting terminal 100a. At this time, the voting server 300a refers to the candidate DB 312 and generates screen data including a list of candidates. This voting screen is a screen that the voter browses to select candidates who are voting destinations.

  In step S223, the voting terminal 100a displays a voting screen based on the screen data transmitted in step S222, and receives input of information indicating a voting destination candidate. The voter visually recognizes the voting screen displayed on the voting terminal 100a, and inputs the voting information that is information indicating the voting candidate. The voter may input the voting information by operating the screen displayed on the display device, or may input the voting information by manually inputting information such as the names of the candidates for the vote. . When receiving the input of voting information indicating a voting candidate from the voter, the voting terminal 100a generates voting transaction data including the voting information. This is voting transaction data that provides voting coins to candidates for voting. The voting terminal 100a transmits the generated voting transaction data to the voting server 300a.

  In step S224, the voting server 300a verifies the voting transaction data received from the voting terminal 100a in step S223. In the verification of voting transaction data, the block chain of voting transaction data stored in the storage unit 318 is referred to, and the voting ID included in the voting transaction data received from the voting terminal 100a is not already stored in the block chain It is determined whether or not. If it is determined that the voting ID is not already stored in the blockchain, the verification of the voting transaction data is successful. If it is determined that the voting transaction data is already stored, the verification of the voting transaction data is performed. Suppose it failed.

  If the verification of the voting transaction data fails in step S224, the voting server 300a performs error processing (not shown). In the error process, for example, an error message is notified to the voting terminal 100a. The error message may include a message such as “Same vote ID cannot be used because it has already been voted”.

  If the voting transaction data is successfully verified in step S224, the process proceeds to step S225.

  In step S225, the voting server 300a transmits a copy of the voting transaction data to the other voting servers 300b and 300c. The voting servers 300b and 300c verify the received voting transaction data and store them in the storage unit 318.

  In step S226, the voting servers 300a, 300b, and 300c execute a consensus algorithm. By executing the consensus algorithm, it is verified that the received voting transaction data is a valid transaction. When the received voting transaction data is verified as a legitimate transaction, a block including the verified voting transaction data is generated. As a result, a block including voted vote IDs is generated, and even if voting transaction data including the same vote ID is received thereafter, the same vote ID is used by referring to the block chain. Can be judged. At this stage, the owner of the voting coin used for voting by the voter is changed to the candidate X who is the candidate for the vote (see FIG. 13B).

  Note that the execution of the consensus algorithm in step S226 may not be performed every time, but only when a predetermined condition is satisfied. The predetermined condition is, for example, a condition that the voting transaction data included in the block satisfies the anonymization standard. This will be described later.

  First, the criteria for anonymization will be described.

  14 and 15 are explanatory diagrams of criteria for anonymization by the voting server 300a in the embodiment.

  Here, k-anonymization k = 2 and l-diversity l = 3 will be described as an example of anonymization criteria.

  FIG. 14 shows voting transaction data recorded in the storage unit 318 at a certain point in time and not yet included in the block chain. This voting transaction data indicates that the voting coin whose voting ID is 101 is provided to the candidate X, that is, the voter votes for the candidate X.

  When the block generation unit 316 generates a block including the plurality of voting transaction data when the plurality of voting transaction data does not satisfy the anonymization standard, the voter's voting destination can be specified. A Service-to-Self who can refer to both the block chain storing authentication transaction data and the block chain storing voting transaction data can identify a voter from the block chain storing authentication transaction data, and at the same time This is because the voting destination can be identified from the block chain storing the voting transaction data.

  Therefore, when a block including one vote transaction data shown in FIG. 14 is included in the block chain, a voter and a vote destination of the voter can be specified.

  FIG. 15 shows a state in which seven pieces of voting transaction data recorded in the storage unit 318 and not yet included in the block chain are stored. At this time, it is shown that the voting transaction data with the voting IDs 101 to 107 votes three for the candidate X, two for the candidate Y, and two for the candidate Z. The seven voting transaction data satisfy the anonymization criteria k-anonymization k = 2 and l-diversity l = 3.

  Therefore, even if the voter is identified by referring to the block chain storing the authentication transaction data, there are a plurality of voting coins in the block chain storing the voting transaction data at the same time. The voter cannot be identified. Therefore, it is impossible to narrow down which voter voted to which candidate, that is, the voter's vote destination cannot be specified.

  FIG. 16 is a flowchart showing processing relating to whether or not the consensus algorithm can be executed in the present embodiment. A series of processing shown in FIG. 16 is processing included in step SA in FIG. Note that the series of processes shown in FIG. 16 may be executed by at least one of the voting servers 300a, 300b, and 300c.

  As shown in FIG. 16, in step S231, the anonymization unit 315 is the voting transaction data recorded in the storage unit 318, and the voting transaction data not yet included in the block chain is a predetermined anonymization. It is determined whether or not the above criteria are satisfied.

  If it is determined in step S231 that the voting transaction data satisfies the anonymization standard (Yes in step S231), a consensus algorithm by the voting servers 300a, 300b, and 300c is executed in step S226.

  On the other hand, when it is determined that the voting transaction data does not satisfy the anonymization standard (No in step S231), the voting process is finished without executing the consensus algorithm. In this case, in the voting process performed for a voter different from the voter in the voting process, if it is determined that the anonymization standard is satisfied (Yes in step S231), the consensus algorithm is executed, and the block Block generation is performed by the generation unit 316.

  By doing so, a plurality of voting transaction data satisfying the anonymization standard are included in one block. Therefore, even when the contents of one block are disclosed, it is not specified which voter voted for which candidate, that is, there is an advantage that it is concealed.

<End processing>
FIG. 17 is a flowchart showing voting end processing of the electronic voting system 10 in the present embodiment. The series of processes shown in FIG. 17 may be executed by at least one of the voting servers 300a, 300b, and 300c.

  As illustrated in FIG. 17, in step S301, the block generation unit 316 determines whether or not the voting period has expired. If it is determined that the voting period has been exceeded (Yes in step S301), the process proceeds to step S302. If it is determined that the voting period has not been exceeded (No in step S301), step S301 is executed again. That is, the block generation unit 316 waits in step S301 until the voting period is exceeded.

  In step S302, a block including voting transaction data recorded in the storage unit 318 and not yet included in the block chain is generated, and the generated block is connected to the block chain. At this time, the voting transaction data recorded in the storage unit 318 is generated even if the voting transaction data not yet included in the block chain does not satisfy the criteria for anonymization. It may be connected to the block chain.

  In step S303, the voting servers 300a, 300b, and 300c execute a consensus algorithm. The contents of this process are the same as in step S226.

  By doing in this way, the voting server 300a etc. can connect all the voting transaction data to a block chain.

<Publication processing of voting results>
FIG. 18 is a sequence diagram illustrating a voting result disclosure process by the voting server 300a according to the embodiment.

  A series of processes shown in FIG. 18 is a process performed when the terminal 110 accesses the voting server 300a for publishing the voting result. This access is, for example, Web access to a Web site provided by the voting server 300a, and HTTP or HTTPS can be used. Note that the terminal 110 accessing the voting server 300a may be the voting terminal 100a or another terminal.

  Here, the case where the voting server 300a receives the access will be described as an example, but the same applies to the case where the other voting server 300b or 300c receives the access.

  In step S401, the screen data generation unit 311 of the voting server 300a determines whether or not the current time is within a period of allowing the voting result to be disclosed. A period during which voting results are allowed to be disclosed is also referred to as a disclosure period. The public period is, for example, a period after the end of the voting period, that is, a period after the time when voting is closed. If it is determined in step S401 that it is within the publication period (Yes in step S401), the process proceeds to step S402. If not (No in step S401), the process proceeds to step S411.

  In step S <b> 402, the screen data generation unit 311 acquires a block chain in which the voting transaction data stored in the storage unit 318 is stored.

  In step S403, the screen data generation unit 311 generates screen data of a screen indicating the voting result based on the information included in the block chain acquired in step S402. Then, the screen data generation unit 311 transmits the generated screen data to the terminal, and causes the terminal to display a screen indicating the voting result.

  In step S411, the screen data generation unit 311 performs error processing. In the error processing, for example, an error message is notified to the terminal. The error message may include a message such as “The voting result cannot be published because it is not yet a publication period”.

  Hereinafter, an example of the screen of the voting terminal 100a used for voting in the electronic voting system 10 and the screen of the terminal used for publishing the voting result will be described.

  FIG. 19 is a schematic diagram showing a voting terminal 100a used for voting in the electronic voting system 10 according to the present embodiment.

  The voting terminal 100a shown in FIG. 19 displays a screen for selecting a voting candidate and presents it to the voter.

  The screen shown in FIG. 19 includes an image 401 that shows a message prompting the voter to vote. In addition, an image 402 indicating a candidate's name and face photo, and a button image 403 indicating voting for the candidate are included. When the voter performs an operation on the image 403, that is, the voting button, the input unit 112 receives the voting content that the voting is performed on the candidate associated with the voting button.

  FIG. 20 is a schematic diagram showing a terminal 110 used for publishing a voting result in the electronic voting system 10 according to the present embodiment.

  The terminal 110 shown in FIG. 20 displays a screen for publishing the voting result and presents it to the voter.

  The screen shown in FIG. 20 includes an image 411 indicating a message indicating that the content displayed on the screen is a voting result. Further, an image 412 indicating the name and face photograph of the candidate and an image 413 indicating the number of votes obtained by the candidate are included. Further, the candidate image 412 with the largest number of votes is surrounded by a frame image 414 indicating that it has been won.

  The terminal 110 can present the voting result through such a screen.

1.6 Effects of the Embodiment The electronic voting system according to the present embodiment uses data including independent IDs for authentication of being a valid voter and for voting performed after authentication. Thereby, for example, even when the result of the authentication and the content of the vote are made public after the election, it is possible to prevent the voter who has voted for the content of the vote from being specified. Further, by storing the data indicating the authentication and the data indicating the voting contents in the individual block chains, it is possible to suppress alteration of each data. Therefore, the electronic voting system enables secret voting.

  In addition, the electronic voting system stores data including the contents of voting by the voter in the block chain. Therefore, the electronic voting system enables secret voting while suppressing falsification of the contents of the vote voted by the voting car.

  Also, the electronic voting system can cause the voter to input the contents of the vote based on the voter being authenticated by the authentication server. Therefore, the electronic voting system enables secret voting while restricting an unauthenticated voter to input the contents of the vote.

  Further, the electronic voting system suppresses the generation of blocks until a plurality of voting contents by the voter are collected and the concealment standard is satisfied. If a plurality of voting contents that do not satisfy the anonymization standard are stored in one block, depending on the voting contents included in the block, information such as the coincidence of the generation time of the block may be used. In some cases, collation is possible and secret voting is not realized. Therefore, the electronic voting system enables secret voting with higher secrecy by concealing the contents of voting in block units.

  In addition, the electronic voting system can avoid remaining in a state where voting contents are not stored in the block when the voting period ends without the concealment criteria being satisfied. Therefore, the electronic voting system makes it possible to perform secret voting with higher secrecy by avoiding the voting contents remaining without being preserved while making the voting contents concealed in units of blocks.

  In addition, the electronic voting system can easily determine whether or not the ID used for the voter authentication has already been used, that is, whether or not there is double use, by using the block chain technology. Therefore, the electronic voting system enables secret voting while easily suppressing double use of IDs used for authentication.

  In addition, the electronic voting system stores data indicating that the voter is authenticated in the block chain. Therefore, the electronic voting system enables secret voting while suppressing falsification that the voter is authenticated.

  In addition, the electronic voting system can easily determine whether or not the ID used for voting has already been used, that is, whether or not there is double use, by using the block chain technology. Therefore, the electronic voting system enables secret voting while easily suppressing double use of IDs used for voting.

2. Other Modifications Although the present invention has been described based on the above embodiments, the present invention is of course not limited to the above embodiments. The following cases are also included in the present invention.

  (1) In the above embodiment, the authentication server and the voting server are described as separate devices. However, the authentication server and the voting server may be the same device.

  (2) In the above embodiment, authentication and voting are realized by providing authentication coins and voting coins. However, coins are used as an example of virtual transaction objects, and virtual transaction objects are coins. It is not limited.

  (3) In the above embodiment, a block is generated when it is determined that the criteria for anonymization are satisfied, but the criteria for anonymization are not satisfied even if the number of votes exceeds a certain percentage of voters May generate a block. Thereby, even if the voting results are significantly biased, falsification of the voting results can be prevented by generating blocks.

  (4) In the above embodiment, voting coins are provided from the authentication server to the voting terminal. However, a voting transaction for voting coins to the voting terminal may be transmitted to the voting server. The voting server may receive a voting transaction from the authentication server and verify the voting transaction. Thereby, provision of voting coins to the voting terminal can be managed by the block chain.

  (5) In the above embodiment, the voting result is disclosed based on access from the voting terminal. However, the present invention is not limited to this, and any terminal that can access the voting server may be used. Further, the voting server may disclose a block chain including a voting transaction.

  (6) In the above embodiment, electronic voting for elections has been described as an example. However, the present invention is not limited to this and may be applied to voting and questionnaires. For example, it is possible to prevent falsification of resolutions and questionnaire results by using them for resolutions and questionnaires at a general meeting of shareholders.

  (7) Each device in the above embodiment is specifically a computer system including a microprocessor, a ROM, a RAM, a hard disk unit, a display unit, a keyboard, a mouse, and the like. A computer program is recorded in the RAM or hard disk unit. Each device achieves its functions by the microprocessor operating according to the computer program. Here, the computer program is configured by combining a plurality of instruction codes indicating instructions for the computer in order to achieve a predetermined function.

  (8) A part or all of the constituent elements of each device in the above embodiment may be configured by one system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on a single chip, and specifically, a computer system including a microprocessor, ROM, RAM, and the like. . A computer program is recorded in the RAM. The system LSI achieves its functions by the microprocessor operating according to the computer program.

  In addition, each part of the components constituting each of the above devices may be individually made into one chip, or may be made into one chip so as to include a part or all of them.

  Although the system LSI is used here, it may be called IC, LSI, super LSI, or ultra LSI depending on the degree of integration. Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  (9) A part or all of the constituent elements constituting each of the above devices may be constituted by an IC card or a single module that can be attached to and detached from each device. The IC card or the module is a computer system including a microprocessor, a ROM, a RAM, and the like. The IC card or the module may include the super multifunctional LSI described above. The IC card or the module achieves its function by the microprocessor operating according to the computer program. This IC card or this module may have tamper resistance.

  (10) The present invention may be the method described above. Further, the present invention may be a computer program that realizes these methods by a computer, or may be a digital signal composed of the computer program.

  The present invention also provides a computer-readable recording medium such as a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a BD (Blu-ray ( (Registered trademark) Disc), or recorded in a semiconductor memory or the like. The digital signal may be recorded on these recording media.

  In the present invention, the computer program or the digital signal may be transmitted via an electric communication line, a wireless or wired communication line, a network represented by the Internet, a data broadcast, or the like.

  The present invention may be a computer system including a microprocessor and a memory, wherein the memory records the computer program, and the microprocessor operates according to the computer program.

  In addition, the program or the digital signal is recorded on the recording medium and transferred, or the program or the digital signal is transferred via the network or the like, and executed by another independent computer system. It is good.

  (11) The above embodiment and the above modifications may be combined.

  The electronic voting system of the present embodiment can be described as follows, but is not limited to this description.

  (A) An electronic voting system comprising a voting terminal, a plurality of authentication servers, and a plurality of voting servers, wherein the voting terminal includes a first transaction generating unit that generates a blockchain transaction, The transaction generation unit transmits an authentication transaction from the voter's ID to the authentication server, generates a second voting transaction from the first voting transaction to which the voting right is transferred from the authentication server, and transmits to the voting server. The plurality of authentication servers perform block generation, a first transaction verification unit that verifies an authentication transaction when receiving the authentication transaction from the voting terminal, a second transaction generation unit that generates a block chain transaction, and A first block generation unit that receives the authentication transaction, the transaction verification unit verifies whether two or more IDs included in the authentication transaction exist in the block chain; If it is above, it is determined that the second transaction generation unit uses the first voting from the third voting transaction received from the voting server when the verification of the authentication transaction is successful in the transaction verification unit. A transaction is generated and transmitted to the voting terminal, and the plurality of voting servers generate a block transaction with a second transaction verification unit that verifies the transaction upon receipt of the second voting transaction from the voting terminal. And a second block generation unit for generating a block, and the second transaction verification unit receives the second voting transaction from the voting terminal and receives the second voting transaction. It is verified whether or not two or more voting rights included in the transaction exist in the blockchain. If there are two or more voting rights, it is determined that the voting right is used twice. Create a voting transaction and send it to the authentication server Electronic voting system which is characterized in that.

  (B) The plurality of voting servers further includes an anonymization unit that determines whether a predetermined anonymization criterion is satisfied when generating a block of a block chain, and the anonymization unit includes a plurality of anonymization units, The electronic voting according to (a), wherein when the second voting transaction is determined to satisfy a predetermined anonymization standard, the second block generation unit is requested to generate a block. system.

  (C) If the anonymization unit of the plurality of voting servers further determines that the voting period has passed even if the criteria for anonymization are not satisfied, the second block generation unit requests block generation. The electronic voting system according to (b), characterized in that:

  Thereby, it is authenticated whether it is a voter between the voting terminal and the authentication server, and in the case of the voter, the authentication server transfers the voting right transferred from the voting server to the voting terminal. The voting terminal can vote using the assigned voting right. By verifying whether the voting right is used twice in the voting server, illegal voting can be prevented even if there is no voter information. Further, the voting server can prevent falsification of the voting result by using the block chain for the voting transaction. Furthermore, by using anonymization for block generation, even if there is an unauthorized person who can refer to the block chain of the authentication transaction, the voting transaction at the same time as the authentication transaction is anonymized and the block is generated. The content can be prevented from being narrowed down, and a safe electronic voting system can be constructed.

  As described above, the electronic voting system according to one or more aspects has been described based on the embodiment, but the present invention is not limited to this embodiment. Unless it deviates from the gist of the present invention, various modifications conceived by those skilled in the art have been made in this embodiment, and forms constructed by combining components in different embodiments are also within the scope of one or more aspects. May be included.

  The electronic voting system according to the present invention enables secret voting.

10 Electronic voting system 100a, 101a, 102a, 100b, 101b, 102b, 100c, 101c, 102c Voting terminal 110 Terminal 111 Display unit 112 Input unit 113, 213, 314 Transaction data generation unit 114, 217, 319 Communication unit 200a, 200b , 200c Authentication server 211, 311 Screen data generation unit 212, 313 Transaction data verification unit 212A Authentication processing unit 214, 316 Block generation unit 215, 317 Synchronization unit 216, 318 Storage unit 300a, 300b, 300c Voting server 312 Candidate DB
315 Anonymization unit 401, 402, 403, 411, 412, 413, 414 Image B1, B2, B3 Block D1 Transaction data N Network P1, P2 Address P3 Electronic signature

Claims (11)

An electronic voting system comprising a terminal, a plurality of authentication servers, and a plurality of voting servers,
Each of the plurality of authentication servers includes:
An authentication processing unit that receives authentication data including a first ID associated with a voter and authentication information of the voter from the terminal, and authenticates the voter using the received authentication data;
A first storage unit storing a first block chain including first transaction data indicating that the voter has been authenticated by the authentication processing unit;
A first synchronization unit that synchronizes the first block chain stored in the first storage unit with one or more authentication servers other than the authentication server among the plurality of authentication servers;
Each of the plurality of voting servers is
Voting data including a second ID associated with a vote voted by the voter, the second ID being independent of the first ID, and voting information indicating the voting content of the vote from the terminal A voting processor to receive,
A second storage unit storing a second block chain including the voting information included in the voting data received by the voting processing unit as second transaction data;
A second synchronization unit that synchronizes the second block chain stored in the second storage unit with one or more voting servers other than the voting server among the plurality of voting servers;
The terminal
A data generation unit that generates the authentication data and transmits the generated authentication data to one authentication server of the plurality of authentication servers;
The data generation unit further includes:
By transmitting the authentication data to the authentication server, the voting data is generated after successful authentication by the one authentication server, and the generated voting data is sent to one voting server among the plurality of voting servers. Send electronic voting system. Each of the plurality of voting servers further
When receiving the voting data from the terminal, a second transaction data generating unit that generates second transaction data indicating the voting content included in the received voting data;
A second block generating unit configured to generate a second block including one or more second transaction data generated by the second transaction data generating unit, and to connect the generated second block to the second block chain; The electronic voting system according to claim 1. The second transaction data generation unit
Generate a third block including third transaction data indicating that the authentication processing unit can authenticate each of a plurality of voters, and connect the generated third block to the second block chain. And
Fourth transaction data indicating that the voter has been authenticated by one authentication server of the plurality of authentication servers, so that the terminal is ready to receive the vote content input by the voter. The electronic voting system according to claim 2, further comprising: generating a fourth block including: and connecting the generated fourth block to the second block chain. Each of the plurality of voting servers further
It is determined whether one or more of the second transaction data generated by the second transaction data generation unit satisfies a predetermined anonymity criterion, and when the second block is satisfied, the second block The electronic voting system according to claim 2, further comprising an anonymization unit that causes the generation unit to generate the second block and connect the second block to the second block chain. Even if the anonymization unit determines that one or more of the second transaction data does not satisfy the standard, the second block generation unit is over a predetermined voting period. The electronic voting system according to claim 4, wherein the second block is generated and connected to the second block chain. The authentication processing unit, when the first ID included in the received authentication data is already included in the first block chain, fails authentication and prohibits the terminal from transmitting the voting data. Item 6. The electronic voting system according to any one of Items 1 to 5. Each of the plurality of authentication servers further
A first data generation unit for generating first transaction data indicating that the authentication of the terminal is successful when the authentication of the terminal is successful;
A first block generation unit that generates the first block including the first transaction data generated by the first data generation unit and connects the generated first block to the first block chain. 7. The electronic voting system according to any one of 6 above. The voting processor
The electronic voting according to any one of claims 1 to 7, wherein the received voting data is discarded when the second ID included in the received voting data is already included in the second block chain. system. An electronic voting system comprising a plurality of authentication servers and a plurality of voting servers,
Each of the plurality of authentication servers includes:
An authentication processing unit that receives authentication data including a first ID associated with a voter and authentication information of the voter from the terminal, and authenticates the voter using the received authentication data;
A first storage unit storing a first block chain including first transaction data indicating that the voter has been authenticated by the authentication processing unit;
A first synchronization unit that synchronizes the first block chain stored in the first storage unit with one or more authentication servers other than the authentication server among the plurality of authentication servers;
Each of the plurality of voting servers is
Voting data including a second ID associated with a vote voted by the voter, the second ID being independent of the first ID, and voting information indicating the voting content of the vote from the terminal A voting processor to receive,
A second storage unit storing a second block chain including the voting information included in the voting data received by the voting processing unit as second transaction data;
An electronic voting system comprising: a second synchronization unit that synchronizes the second block chain stored in the second storage unit with one or more voting servers other than the voting server among the plurality of voting servers. A method for controlling one voting server among a plurality of voting servers in an electronic voting system,
Voting including a second ID linked to a vote voted by a voter, which is independent of the first ID linked to the voter, and voting information indicating the vote content of the vote Receive data from the device,
Storing a second block chain including the voting information included in the received voting data as second transaction data;
Synchronizing the stored second block chain with one or more voting servers excluding the one voting server among the plurality of authentication servers,
When receiving the voting data from the terminal, generate second transaction data indicating the voting content included in the received voting data,
Generating a second block including the generated one or more second transaction data, connecting the generated second block to the second block chain;
It is determined whether the one or more generated second transaction data satisfies a predetermined anonymity criterion, and when the criterion is satisfied, the second block is generated and the second block is generated. Control method connected to the chain. A method for controlling an electronic voting system comprising a terminal, a plurality of authentication servers, and a plurality of voting servers,
By each of the plurality of authentication servers,
Receiving the authentication data including the first ID associated with the voter and the authentication information of the voter from the terminal, and authenticating the voter using the received authentication data;
Storing a first blockchain including first transaction data indicating that the voter has been authenticated;
Synchronizing the stored first block chain with one or more authentication servers excluding the authentication server among the plurality of authentication servers,
By each of the plurality of voting servers,
Voting data including a second ID associated with a vote voted by the voter, the second ID being independent of the first ID, and voting information indicating the voting content of the vote from the terminal Receive
Storing a second block chain including the voting information included in the received voting data as second transaction data;
Synchronizing the stored second block chain with one or more voting servers excluding the voting server among the plurality of voting servers,
By the terminal
Generating the authentication data, transmitting the generated authentication data to one of the plurality of authentication servers,
By transmitting the authentication data to the authentication server, the voting data is generated after successful authentication by the one authentication server, and the generated voting data is sent to one voting server among the plurality of voting servers. Control method to send.

Images