JPH06195361A - Electronic voting device - Google Patents

Abstract

PURPOSE:To provide the electronic voting device which can enable voting with out signature in an electronic network and further can prevent illegal voting by providing a key certifying means for an election manager while allocating signature certificate keys and signature secret keys to voting persons. CONSTITUTION:This non-signature electronic voting system is composed of a preparation phase, tag vote generation phase, voting phase and result open phase. First of all, an election managing center 100 sets a quorum for signature and presents the quorum for signature on an electronic bulletin board 102. The voting person reads the information written on the bulletin board 102 by using a bulletin board reading means 301, prepares a tag vote (t) by using a tag vote preparing means 310, simultaneously prepares a voting person signature secret key (d) and holds it by a signature key holder 312. The center 100 transmits a blind signature D to the elector preparing the tag vote by using a blind signature transmitting means 205. A signature preparing means 306 prepares a signature sentence T of the tag vote (t) to be certified by the open key of the center while using the signature D sent from the center 100 and the quorum for certificate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows only voters to vote anonymously once on an electronic network, and against voter totaling without letting other voters know what they voted for. It is an object of the present invention to propose a device capable of detecting that the same voter voted for two or more options in a system in which an objection can be opened, and the detection mechanism is not misused by a third party.

[0002]

2. Description of the Related Art The conventional electronic voting method is Ohta's method. This is JP-A-1-1771.
64 and 1988 IEICE Spring National Convention A-
294, "Electronic Voting Scheme Using a Single Election Administrator". In this method, the voter obtains the signature of the center for the voting contents converted by random numbers, then creates the signature of the center for the original voting contents by removing the random number component on the voter side, and gives it to the center anonymously. The secret ballot is realized by sending it. Each voter confirms that his / her vote has been accepted and totaled in the list of voting contents announced by the center. With this method, you can get the signature of the center only for the vote contents that reflect your opinion, so if the center does not count the vote contents, you do not have to open your objection and open the objection. Don't

In order to solve this problem, even if an objection is made, in order for the voter to make an objection without disclosing the content of his / her vote, only the ballot form that does not depend on the content of the vote must be signed beforehand. Japanese Patent Application No. 4-108069 discloses a method of sending the contents of a vote that reflects one's opinion on a signed ballot to the center. As an example, a method is described in which each voter obtains a signed ballot consisting of a positive vote, a negative vote, and a voting tag in a registered form, and one of the votes is cast anonymously along with the voting tag. In addition, an electronic voting system, which is designed to prevent an illegal voter from voting for two or more opinions, is Japanese Patent Application No. 4-
No. 222580. As an example, the vote tag is a signature verification key generated by a voter, and each voter obtains a signed ballot consisting of a positive vote, a negative vote and a vote tag signed with a corresponding signature private key in a registered form, A method of voting one of the votes anonymously along with a voting tag is described.

In addition, A-188 "Practical and safe secret voting system" was announced at the 1992 Autumn Meeting of the Institute of Electronics, Information and Communication Engineers. This is a method in which voters perform anonymous communication twice in order to pursue fairness.

[0005]

Problems to be Solved by the Invention Japanese Patent Application No. 4-10806
In No. 9 and Japanese Patent Application No. 4-222580, there is a problem that the amount of information on the ballot sheet increases in proportion to the number of voting options. For example, in the case of a two-valued vote for or against, the ballot consists of a yes, no, and tag votes, but a three-valued vote: yes, no, and hold.・ As you have to use negative votes, hold votes, and tag votes, the amount of communication and processing will increase as the number of options increases. Furthermore, if the options are not fixed in advance, ballots cannot be created, and there is the problem that it is not possible to respond to free-form voting, questionnaires, and opinions.

The present invention proposes an electronic voting apparatus which allows a voter to efficiently realize an anonymous communication once even if the number of options increases or the options are not fixed in advance.

[0007]

The electronic voting apparatus of the first invention is a key generation means for a voter to create a signature verification key and a signature private key, and an election management for the signature verification key created by the voter. Authentication method to obtain the blind signature of the voter, a signature means to sign the vote contents using the signature private key created by the voter, the vote contents signed by the voter, and the signature verification signed by the election manager It is characterized by having a voting means for sending the key anonymously to the election manager and a counting means for counting only valid voting texts.

In the electronic voting device of the second invention, the voter obtains a blind signature of the election manager with respect to the key generation means by which the voter creates the signature verification key and the signature private key, and the signature verification key created by the voter. Anonymous by encrypting the key authentication means, the signature means that uses the signature private key created by the voter to sign the vote content, the vote content signed by the voter, and the signature verification key signed by the election manager. It is characterized by having a voting means for sending to the election manager and a counting means for counting only valid voting text.

In the electronic voting device of the third invention, a voter elects a key generation means for creating a signature verification key and a signature secret key, and a signature verification key created by the voter and a bit string depending on the content of the vote. A key authentication means for obtaining the blind signature of the administrator, a signature means for signing the voting contents using the signature private key created by the voter, and voting contents with the voter's signature,
It is characterized by having a voting means for sending the signature verification key with the signature of the election manager to the election manager in secret, and a totaling means for totalizing only valid voting sentences.

In the electronic voting device according to the fourth aspect of the invention, the voter elects the key generation means for the voter to create the signature verification key and the signature private key, and the signature verification key created by the voter and the bit string depending on the content of the vote. A key authentication means for obtaining the blind signature of the administrator, a signature means for signing the voting contents using the signature private key created by the voter, and voting contents with the voter's signature,
It is characterized by having a voting means for encrypting the signature verification key with the signature of the election manager and sending it to the election manager in secret, and aggregating means for summing up only valid voting sentences.

An electronic voting device according to a fifth aspect of the present invention is the electronic voting device according to claim 1 or 3, further comprising publishing means for converting the voting text sent by the election manager anonymously by a one-way function and publishing it. It is characterized by

[0012]

EXAMPLES Examples of the first, second, third, fourth and fifth inventions will now be described with reference to FIGS.

As shown in FIG. 2, the electronic voting apparatus of the present invention is
m voter subsystems 101 (1) -101 (m)
And one election management center 100 are connected to each other through a secure communication channel (for example, a data line) 105, and a bulletin board that is writable only by the election management center 100 and is readable by all voter subsystems. An example of implementation in the anonymous electronic voting system when the bulletin board 102 exists will be described. For the sake of simplicity, the election management center will be called the center, and the voter subsystem will be called the voter.

This voting system comprises a preparation phase, a tag vote generation phase, a voting phase and a result announcement phase.

The first and third inventions relate to a tag vote generation phase, the second and fourth inventions relate to a voting phase, and the fifth invention relates to a result publication phase.

First, the preparation phase of the first invention will be described with reference to FIG.

As a preparation for implementing this anonymous electronic voting system, the center 100 sets a constant for signature,
The verification constants are posted on the electronic bulletin board 102. For example, assume that the RSA cryptosystem is used as the signature system. Therefore,
Let n _{c be} the product of two prime numbers p _c and q _c , and let e _c and d _c be e
_It is an integer that satisfies _c · d _c = 1 mod (p _c −1) (q _c −1). At this time, the center sets e _c and n _c as verification constants (step 11). These constants are written in the electronic bulletin board 102 (step 12). Since the verification constants e _c and n _c will be frequently used in the future, the constant holding means 201 can be easily written and accessed (step 13). On the other hand, d _c is stored in its own secret information holding means 202 (step 14).

Next, the center 100 defines rules regarding voting. First, clarify the agenda for voting. Next, a tag vote format and a vote content format are determined as vote formats. For example, consider the following tag vote format. At this time, e and n

[0019]

A tag form is a combination of the numbers that is smaller than n _c as a number. For example, the output of the function h is set to 64 bits, e is set to 10 bits, n is set to 512 bits, and n _c is set to 587 bits in advance.

The following are possible voting content formats. Connected voting content x and random number y

[0022]

And the

[0024]

Concatenation of

[0026]

[0027] At this time, n
It shall be smaller. The voting content x may be a choice number given in advance, or may be a text in free form replaced with an ASCII character string (step 1
5).

Next, the names of subsystems (hereinafter referred to as voters) who have the right to vote are listed (step 16). Set and announce the deadline for ballot creation and voting (step 17) and signal the start of the tag vote creation phase (step 18).

The above is the preparation phase.

Next, the tag vote creating phase and the voting phase will be described. Both of these phases are in the election management center 10.
Since 0 follows the same procedure for each voter, the description will be continued by taking the procedure for a specific voter subsystem 101 (i) as an example.

As shown in FIG. 1, in the anonymous electronic voting system, the center 100 writes a fixed number and voting rules in the electronic bulletin board 102, a secure communication channel 103, and a voter 101.
(I) is composed of a safe communication channel 104 (i) for reading the contents written on the electronic bulletin board 102 and a safe communication channel 105 (i) for communicating between the voter and the center.

First, referring to FIG. 1, the voter 101
The tag vote creating phase of (i) will be described. Voter 101
(I) is a bulletin board 10 using the bulletin board reading means 301.
The contents written in 2 are read out and the constants e _c and n _c are stored in the constant holding means 302, while the tag form t conforming to the read format is created by the tag form creating means 310. That is, first, a 512-bit number n that is the product of two prime numbers p and q is determined, and a 10-bit number e that is coprime to (p-1) (q-1) is determined. With this

[0033]

A tag form t is a combination of the above. Ie

[0035]

It is assumed that Further, at the same time, d that is e · d = 1 mod (p−1) (q−1) is obtained and held as a voter signature private key. The output of the random number generator 303 is used as the random number component necessary for the format when creating the tag form.

Next, the tag vote converter 304 uses the output r of the random number generator 303 and the constants e _c and n _c ,

[0038]

Calculate and output s. Further, the output r of the random number generator 303 at this time is stored in the random number holder 309. The communication means 305 with the name s is the safety channel 10.
5 (i) to the center 100.

The center 100 receives the s from the legitimate voters received by the tag slip receiving means 206. The blind signature generator 204 includes a secret holding unit 201 and a constant holding unit 2.
Using d _c and n _c read from 02,

[0041]

Calculate and output The blind signature transmitting means 205 transmits D to the voter 101 (i).

The center declares that it will shift to the voting phase if the signatures are sent to all the voters who have created the tag form. The above is the tag vote setting phase.

Next, the voting phase will be described.

The signature creating means 306 uses D received from the center 100 by the blind signature receiving means 311 and e _c and n _c read from the constant holding means 302.

[0046]

It is verified whether or not is satisfied. If confirmed, T = D / r mod n _c is calculated using the integer r read from the random number holder 309 and n _c and e _c read from the constant holding unit 302.

The T is the public key e _c , n _{c of the} center.
It is the signature text of the tag form t that can be verified by. That is,

[0049]

Is becoming Obtaining the signature without showing the tag slip t itself to the center is called a blind signature, and the series of tag slip converters 304, blind signature generators 204, and signature creation means 306 are tag slip authentication means. The tag form is also the signature verification key of the voter, and is also a key authentication means.

Next, the voting text generator 307 creates a voting text. First, according to the vote content format, a vote v reflecting the vote content x of oneself is generated as follows.

[0052]

Where y is the output of generator 303. Next, v is signed using the signature key d read from the signature key holder. That is, v ′ = v ^d mod n is calculated. The anonymous transmission means 308 transmits the pair v = (v ′, T) of this signature and the tag signature obtained by the blind signature to the center 100 without adding the sender name.

The center 100 reads T out of the received V

[0055]

Calculate α is equal to t if the voter is not cheating. If α is a predetermined tag format, verify whether the same tag tag has been used before. If not, then verify the vote. That is, the signature verification keys e and n are extracted from the tag form, and β = (v ′) ^e mod n is calculated. β is equal to v if the voter is not cheating. If β has a predetermined voting content format, x is extracted from this and tabulated.

When everyone has voted, the center publishes the results. That is, a list of all tag votes and voting texts is posted on the bulletin board. Each voter can view the list to see if their votes have been aggregated. If it is not totaled, it is possible to point out the total omission of the center by publishing the tag votes that have not been totaled, and at this time, other voters do not know what they voted for.

Next, an embodiment of the second invention will be described with reference to FIG. The preparation phase is performed in the same manner as the preparation phase of the embodiment of the first invention, but in step 11,
Center further generate an RSA encryption key _{n 2, e 2, d 2} , is added at writing the d ₂ in their constant holding means 201 in step 13 with posting the public key e _2, n ₂ in step 12 .

Also, the tag form preparation phase is performed in the same manner as in the first embodiment of the invention, but the reading and storing of e ₂ and n ₂ are added in the bulletin board reading means 401.

The voting phase is also the same as that of the first embodiment of the invention, but in the voting phase, the voting text encryptor 407 is input with the output V = (v ', T) of the voting text creator.
Put. In this voting text encryptor, the voting text V is encrypted as follows. Using n ₂ and e ₂ read from the constant holding means 302,

[0061]

The anonymous transmission means 408 calculates V ′ =
(V ', T') is sent to the center 100 without adding the sender name.

In the center 100, the acceptance slip verification means 417 reads T'of the received V '.

[0064]

Calculate α is equal to t if the voter is not cheating. If α is a predetermined tag format, verify whether the same tag tag has been used before. If not, then verify the vote. That is, the signature verification keys e and n are extracted from the tag form, and β = (v ′) ^e mod n is calculated. β is equal to v if the voter is not cheating. If β has a predetermined voting content format, x is extracted from this and tabulated.

As the publicizing means, V'that remains encrypted is used.
You can check whether or not each person's voting text is totaled by posting.

As a method of encrypting the voting text in the voting text encryptor 407, v is encrypted in addition to the above method.
There are methods such as encrypting v ', or encrypting both the voting text and the tag vote.

Next, an embodiment of the third invention will be described with reference to FIG.

The preparation phase is performed in the same manner as the preparation phase of the first embodiment of the invention, but in step 15, the tag slip format is determined as follows. At this time, e and n and voting content x

[0070]

A tag vote is a concatenation of numbers that is smaller than n _c as a number.

The tag form creating phase is also the same as that of the first embodiment of the invention, but the tag form creating means 610 is used.

[0073]

Is set as a tag vote. Where x is the voter's opinion.

In this way, each voter incorporates his / her opinion when the tag vote is generated, so that his / her opinion cannot be changed during the voting phase.

Next, an embodiment of the fourth invention will be described with reference to FIG.

The preparatory phase is performed in the same manner as the preparatory phase of the embodiment of the second invention, but in step 15, the tag slip format is determined as follows. At this time, e and n and voting content x

[0078]

A tag vote is a concatenation of numbers that is smaller than n _c as a number.

Also, the tag form creating phase is performed in the same manner as in the embodiment of the second invention, but the tag form creating means 710 is used.

[0081]

Is set as a tag form. Where x is the voter's opinion.

Next, an embodiment of the fifth invention will be described with reference to FIG. This relates to the result publication phase.

Next, the result announcement phase will be described with reference to FIG. It is assumed that the preparation phase, the tag vote setting phase, and the voting phase have been completed as in the embodiment of the first invention or the embodiment of the third invention, and that the acceptance vote is accepted through the acceptance vote verifying unit 207. It is assumed that it is stored in the vote holding unit 811. Further, each voter is supposed to hold his / her own voting text in the voting text holding means 902.

Here, the RSA encryption function is used as the one-way function.

In the center 100, the one-way function generating means 802 first generates the RSA encryption keys n ₂ and e ₂ . Next, in the acceptance slip conversion unit 801, all received receipts and their tags are cryptographically converted with (n ₂ , e ₂ ). That is, for the acceptance slip V = (v ′, T),

[0087]

It is assumed that The converted acceptance form v ′ is published by the acceptance form publishing means 208. At the same time, the encryption keys (n ₂ , e ₂ ) are also announced.

Each voter 101 (i) reads the converted acceptance vote list and the encryption key (n ₂ , e ₂ ) by the acceptance vote list read-out means 911, and the votes and tags of its vote are verified by the verification means 912. Make sure it is in the list. That is, using (n ₂ , e ₂ ) the own voting text V held in the voting text holding means 902,

[0090]

Then, it is confirmed whether or not this is included in the converted acceptance slip list.

If it cannot be confirmed, objection means 91
Use 3 to challenge. This will be described in detail later. The center publishes the unconverted acceptance vote and the aggregated results if no objection is made by any voter.

On the other hand, if the verification means 912 does not accept the vote of its own, the objection means 913 publishes its tag vote, and the fact that it is a legitimate tag vote and its converted sentences are aggregated. Indicates that not.
If this claim is confirmed, it will be processed if the opponent's vote has not been accepted.

By thus protesting, it is possible to prove that one's vote was not accepted, without clarifying which opinion the challenger actually voted for. Furthermore, since the entire voting result remains encrypted when the objection is made, it is distinguished from the objection to the voting result, and the objector is not dissatisfied with the voting result as in the conventional method. Will be revealed.

Referring to FIG. 4, the system described in any of the embodiments has a terminal unit (TMU) 401 such as a personal computer having a communication processing function, a read-only storage unit (ROM) 402, and a random number unit. An access storage device (RAm) 403, a random number generator (RNG) 404,
Signal processor (SP) 406, TMU 401,
ROM402, RAM403, RNG404 and SP
It is composed of a common bus 405 that connects 406 to each other.

The RNG 404 generates a random number according to a command from the SP 406. This is used when the center 100 sets a constant, and is also used as a random number generator for each voter 101 (i). In the case of the center 100, the RAM 407 serves as the constant holding means 202 or the secret information holding means 201. The secret information may be stored in the RAM from the TMU as needed. Voter subsystem 1 in ROM407
In the case of 01 (i), the constant holding means 302 and the random number holder 3
09 and so on. The above operation is realized based on the program stored in the ROM. The RAM 403 is used to temporarily store the intermediate calculation result and the like during the execution of these steps.

The systems 100 and 101 (i) may be data processing devices such as general-purpose electronic computers or IC cards.

[0098]

As described in detail above, according to the present invention, a voter can open an objection to fraudulent counting without letting other voters know what they voted for. , In a bearer electronic voting device that can detect that the same voter votes for two or more options, and that this detection mechanism is not abused by a third party, the processing amount and communication amount are constant regardless of the number of options, An efficient electronic voting device smaller than the minimum value (when the number of options is 2) of the conventional method can be realized. This electronic voting device does not require predetermination of options and can be easily applied to a free-filling questionnaire.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic voting device of the first invention.

FIG. 2 is a diagram showing an anonymous electronic voting system.

FIG. 3 is a diagram showing an example of a preparation phase.

FIG. 4 is an example of a system used in the embodiments of the first to fifth inventions.

FIG. 5 is a block diagram showing a position embodiment of the electronic voting device of the second invention.

FIG. 6 is a block diagram showing an embodiment of an electronic voting device of a third invention.

FIG. 7 is a block diagram showing an embodiment of an electronic voting device of a fourth invention.

FIG. 8 is a block diagram showing an embodiment of an electronic voting device of the fifth invention.

[Explanation of symbols]

 100 Election Management Center 101 (i) Voter Subsystem 102 Electronic Bulletin Board

Claims (5)

[Claims] 1. A key generation means for a voter to create a signature verification key and a signature private key, a key authentication means for obtaining a blind signature of an election manager for a signature verification key created by the voter, and a voter A signature means for signing the voting contents using the created signature private key, voting contents with the voter's signature, and voting means for sending the signature verification key with the signature of the election manager to the election manager in secret. An electronic voting device having a counting means for counting only valid voting text. 2. A key generation means for a voter to create a signature verification key and a signature private key, a key authentication means for obtaining a blind signature of an election manager for a signature verification key created by the voter, and a voter A vote to sign the voting contents using the created signature private key, the voting contents with the voter's signature, and the signature verification key with the signature of the election manager, which is sent anonymously to the election manager. An electronic voting device comprising means and a counting means for counting only valid voting text. 3. A key generation means for a voter to create a signature verification key and a signature private key, and a key to obtain a blind signature of an election manager for a bit string depending on the signature verification key and the content of the vote created by the voter. The signing means for signing the content of the vote using the authentication means, the signature private key created by the voter, the content of the vote with the voter's signature, and the signature verification key with the signature of the election manager in secret An electronic voting device characterized in that it has a voting means for sending to, and a counting means for counting only valid voting sentences. 4. A key generation means for a voter to create a signature verification key and a signature private key, and a key for obtaining a blind signature of an election manager for a bit string depending on the signature verification key and the content of a vote created by the voter. An authentication method, a signature method that uses the signature private key created by the voter to sign the content of the vote, the content of the vote signed by the voter, and the signature verification key signed by the election manager that is encrypted and anonymous. An electronic voting device characterized by having a voting means for sending to an election manager and a counting means for counting only valid voting text. 5. The electronic voting device according to claim 1 or 3, further comprising a publishing means for converting a voting text sent by an election manager anonymously by a one-way function and publishing it. .