An anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption

Abstract

The present invention discloses an anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption, and belongs to the field of blockchain application technology. The method includes the following steps: the voting initiator initializes a smart contract; the voter obtains encrypted public parameters through the smart contract and generates a homomorphic encryption key; the voter obtains the homomorphic encryption public keys of all voters in the system and calculates the encrypted public key; the decision content is encrypted using the encrypted public key, a non-interactive zero-knowledge proof is generated for the encrypted decision content and signed, and the final ballot is obtained and stored on the blockchain; the voter generates a secret share and uploads it to the smart contract; the voting initiator and all voters obtain the secret share and all legal ballots through the smart contract, and calculate the final voting result; when an abnormal voter fails to upload the secret share, the abnormal recovery stage is entered. The present invention solves the anonymity problem of secure voting after introducing voter weights in weighted decision-making scenarios.

Description

Technical Field

[0001] The present invention belongs to the technical field of blockchain application, and in particular relates to an anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption. Background Art

[0002] With the increasing development of Internet technology, electronic voting has gradually become an important means of decision-making in modern society with its high efficiency and convenience and has been widely used. In summary, the primary concern in the design of electronic voting systems is its security, including filtering illegal voters, achieving ballot integrity and confidentiality, and ensuring the correct counting of ballots. To this end, traditional electronic voting schemes usually use homomorphic encryption, blind signatures, and hybrid network technologies to achieve voting security requirements. However, these traditional methods all rely on centralized third-party system architectures, making it difficult to achieve open and transparent verifiability and protect voter privacy, and the final voting results depend to a certain extent on the honesty of the third party. Therefore, the establishment of a decentralized electronic voting system has gained more and more attention.

[0003] Blockchain technology is usually regarded as a secure distributed ledger maintained by multiple nodes. It has the characteristics of decentralization and trustlessness, and can effectively solve the design problems of traditional electronic voting systems. Specifically, the use of blockchain can ensure the transparency of the voting process and the immutability of data, thereby making the correctness of voting results verifiable. Due to the openness and transparency of blockchain, it inevitably exacerbates the problem of voting privacy protection, especially in anonymous electronic voting systems. Therefore, the relationship between the voter's identity and the ballot should be protected.

[0004] In addition, the electronic voting system needs to support different voting scenarios in practical applications. Although the current blockchain electronic voting solution has a good performance in terms of security, it cannot be effectively extended to the electronic voting scenario with weighted decision-making. Often, the voter's weight information in the weighted decision-making scenario will expose the voter's ballot content. The identity of the corresponding voter can be confirmed based on the weight of the ballot content. Therefore, it is a major challenge to achieve anonymity in secure voting under the premise of introducing voting weights. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption, which solves the anonymity problem of secure voting after introducing voter weights in weighted decision-making scenarios.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption includes the following steps:

[0008] Step 1, system initialization phase: the voting initiator announces the voting activity, and the voter registers with the voting initiator; the voting initiator initializes the smart contract and uploads the voting activity information, encrypted public parameters and the list of legal voters to the smart contract;

[0009] Step 2, key negotiation phase: Voters obtain encryption public parameters through the smart contract, generate homomorphic encryption keys, and upload them to the smart contract;

[0010] Step 3, voting stage: The voter obtains the homomorphic encryption public keys of all voters in the system through the smart contract, and calculates the encrypted public key; the voter uses the encrypted public key to encrypt the decision content, generates a non-interactive zero-knowledge proof for the encrypted decision content and signs it to obtain the final ballot; the voter uploads the final ballot to the smart contract; the final ballot is saved on the blockchain after the smart contract verifies the digital signature and zero-knowledge proof is valid;

[0011] Step 4, vote counting phase: Voters generate secret shares and upload them to the smart contract; when all voters in the legal voter list have completed uploading secret shares, the voting initiator and all voters obtain the secret shares and all legal votes through the smart contract, and calculate the final voting results; when there are abnormal voters who have not uploaded secret shares, the abnormal recovery phase begins;

[0012] Step 5, abnormal recovery phase: except for abnormal voters, the remaining voters discard abnormal ballots that have not uploaded secret shares, and upload abnormal recovery shares to the smart contract; when all the remaining voters have completed uploading, any entity in the system obtains the abnormal recovery share through the smart contract and calculates the final voting result after recovery.

[0013] The beneficial effects of the present invention are:

[0014] The ballots are correct and cannot be tampered with: the voting activities initiated by the voting initiator and the encrypted ballots submitted by the voters are uploaded to the blockchain and accompanied by user signatures to ensure that the voting activities and encrypted ballots after being uploaded to the chain are open and transparent; at the same time, relying on the tamper-proof characteristics of the blockchain, it is ensured that the ballots on the chain cannot be tampered with, so that the ballots cannot be illegally modified or deleted.

[0015] Ballot confidentiality: Use homomorphic encryption algorithms and encryption and decryption processes suitable for voting activities to ensure that the content of a user's single ballot cannot be decrypted; ballots are encrypted during the voting process, and no one can manipulate the voting results by obtaining the intermediate ballot content and intermediate ballot results.

[0016] Anonymity of ballots: Based on the voter weight information introduced in the weighted decision-making scenario, the ballot content is aggregated by using a homomorphic encryption algorithm, and only the final aggregated result is decrypted to obtain the voting activity result, ensuring that the result of a single ballot will never be decrypted from beginning to end, thereby ensuring that the user's ballot content will never be exposed, and it is even more impossible to infer the user's ballot content through the content of a single ballot and the voter weight information, thereby ensuring the anonymity of the user's voting.

[0017] System robustness: Due to the characteristics of homomorphic encryption and decentralization without a third-party central agency, it is difficult to decrypt the voting results in a conventional voting scheme if the voter does not support the final result of the ballot decryption. The present invention introduces an abnormal recovery method. When the user's ballot is illegal and the user refuses to submit the decryption secret share, the abnormal recovery method can be used. When only legitimate users are left, the results of all legitimate ballots can still be decrypted to ensure the normal operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of an anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption in the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 1 This paper provides a specific implementation process of an anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption. Using this method, users can implement weighted decision-making voting under anonymous conditions. Based on the homomorphic encryption algorithm and zero-knowledge proof method of the system, users can generate encrypted ballots and prove the legitimacy of their content in combination with their own voting weights. The homomorphic encryption properties of the encryption algorithm can be used to correctly count ballots based on ciphertext, ensuring that the content of a single ballot is always kept confidential, thereby achieving voting anonymity. Specifically, the anonymous weighted decision-making implementation process in scenarios where voters are assigned different voting weights includes the following steps:

[0021] Step 1, system initialization phase: the voting initiator announces the voting activity, and the voter registers with the voting initiator; the voting initiator initializes the smart contract and uploads the voting activity information, encrypted public parameters and the list of legal voters to the smart contract;

[0022] Step 2, key negotiation phase: Voters obtain encryption public parameters through the smart contract, generate homomorphic encryption keys, and upload them to the smart contract;

[0023] Step 3, voting stage: The voter obtains the homomorphic encryption public keys of all voters in the system through the smart contract, and calculates the encrypted public key; the voter uses the encrypted public key to encrypt the decision content, generates a non-interactive zero-knowledge proof for the encrypted decision content and signs it to obtain the final ballot; the voter uploads the final ballot to the smart contract; the final ballot is saved on the blockchain after the smart contract verifies the digital signature and zero-knowledge proof is valid;

[0024] Step 4, vote counting phase: Voters generate secret shares and upload them to the smart contract; when all voters in the legal voter list have completed uploading secret shares, the voting initiator and all voters obtain the secret shares and all legal votes through the smart contract, and calculate the final voting results; when there are abnormal voters who have not uploaded secret shares, the abnormal recovery phase begins;

[0025] Step 5, abnormal recovery phase: except for abnormal voters, the remaining voters discard abnormal ballots that have not uploaded secret shares, and upload abnormal recovery shares to the smart contract; when all the remaining voters have completed uploading, any entity in the system obtains the abnormal recovery share through the smart contract and calculates the final voting result after recovery.

[0026] Furthermore, the system initialization phase of step 1 includes the following steps:

[0027] Step 1.1: The voter generates a pair of public and private keys for signing , send the identity to the voting initiator With public key , request registration;

[0028] Step 1.2: The voting initiator initiates a decision event through a smart contract, and uploads the voting activity information, encrypted public parameters, and a list of legal voters to the smart contract; the voting activity information includes the decision content and the start and end time of the vote; the encrypted public parameters are the ElGamal encryption system parameters ,in for Cyclic group of order The legal voter list includes the identity ID, weight, and and the public key used for signing .

[0029] Furthermore, the blockchain smart contract initialized in step 1 includes: a creation voting contract used by the voting initiator to upload voting parameters, a key negotiation contract for the voter to upload the ballot encryption public key, a voting contract for the voter to submit the ballot and verify the legitimacy of the ballot, a counting contract for restoring the ballot using the decrypted secret share and publishing it, and an abnormal recovery contract for restoring abnormal ballots.

[0030] Furthermore, the key negotiation phase in step 2 includes the following steps:

[0031] Step 2.1: Voters obtain ElGamal encryption system parameters through the smart contract ;

[0032] Step 2.2: The voter randomly selects a homomorphic encryption private key , and calculate the corresponding homomorphic encryption public key ;

[0033] Step 2.3: The voter encrypts the homomorphic public key Sign and upload to the smart contract.

[0034] Furthermore, the voting phase in step 3 includes the following steps:

[0035] Step 3.1: Voters obtain the homomorphic encrypted public keys of all voters in the system through the smart contract , and calculate the encryption public key ;

[0036] Step 3.2: The voters determine their decision content ; Decision intention From the collection , representing "in favor", "abstain" and "against" respectively; is the weight of said voter;

[0037] Step 3.3: The voter selects a random integer , and use encryption and public key Compute encrypted decision content ,in are the parameters of the ElGamal encryption system, For decision-making content;

[0038] Step 3.4: The voter generates a non-interactive zero-knowledge proof of the encrypted decision content , the non-interactive zero-knowledge proof To prove the content of the decision Within three items;

[0039] Step 3.5: The voter uses the private key for signing The content of the decision on the encryption and non-interactive zero-knowledge proofs Sign and generate digital signature and final votes ;

[0040] Step 3.6: The voter will submit the final ballot Upload to the smart contract; the smart contract verifies the digital signature And non-interactive zero-knowledge proof The validity of the final ballot will be verified Save on the blockchain, otherwise discarded.

[0041] Furthermore, the vote counting stage in step 4 includes the following steps:

[0042] Step 4.1. Voters Obtain all legal votes through the smart contract ,in The encrypted decision content of all legal ballots is multiplied by the number of voters who have voted to obtain the aggregated encrypted decision content. ,in Representative voter number;

[0043] Step 4.2: The voters Calculate the secret share based on the aggregated vote encryption result ,in , ,in homomorphically encrypt the private key of the voter, To encrypt the public key, The public key multiplication result is homomorphically encrypted for the voter who performs the voting process. Use the private key for signing The secret share Signature Get Digital Signature , and set its voting activity parameters , Secret Share And digital signature Upload to the smart contract;

[0044] Step 4.3: When all voters have uploaded their secret shares, any entity in the system obtains all votes and decrypts the secret shares through the smart contract, and obtains the aggregated encrypted decision content as described in step 4.1; the entity calculates the decrypted aggregated decision content , by combining the voting result range enumeration, the final voting result is obtained .

[0045] Furthermore, the abnormal recovery phase in step 5 includes the following steps:

[0046] Step 5.1: The remaining voters discard the votes of users who have not submitted secret shares. , recalculate the encrypted result of the ballot to be restored ,in , For the The encrypted decision content of each voter, Representative voter number;

[0047] Step 5.2: The remaining voters calculate the abnormal recovery share ,in homomorphically encrypt the private key of the voter, is a random integer selected by the voter, To execute the voting process and upload the secret share of the voter homomorphically encrypted public key multiplication result, use the private key used for signing to sign the abnormal recovery share to obtain a digital signature , and set its voting activity parameters , abnormal recovery share And digital signature Upload to the smart contract;

[0048] Step 5.3: When all remaining voters have completed uploading the abnormal recovery share, any entity in the system obtains the abnormal recovery share through the smart contract and calculates the new decrypted aggregate decision content. , by combining the voting result range enumeration, the final voting result is obtained .

[0049] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption, characterized in that: The steps include: Step 1, system initialization phase: the voting initiator announces the voting activity, and the voter registers with the voting initiator; the voting initiator initializes the smart contract and uploads the voting activity information, encrypted public parameters and the list of legal voters to the smart contract; Step 2, key negotiation phase: Voters obtain encryption public parameters through the smart contract, generate homomorphic encryption keys, and upload them to the smart contract; Step 3, voting stage: The voter obtains the homomorphic encryption public keys of all voters in the system through the smart contract, and calculates the encrypted public key; the voter uses the encrypted public key to encrypt the decision content, generates a non-interactive zero-knowledge proof for the encrypted decision content and signs it to obtain the final ballot; the voter uploads the final ballot to the smart contract; The final ballot is stored on the blockchain after the smart contract verifies the digital signature and zero-knowledge proof is valid; Step 4, vote counting phase: Voters generate secret shares and upload them to the smart contract; when all voters in the legal voter list have completed uploading secret shares, the voting initiator and all voters obtain the secret shares and all legal votes through the smart contract, and calculate the final voting results; when there are abnormal voters who have not uploaded secret shares, the abnormal recovery phase begins; Step 5, abnormal recovery phase: except for abnormal voters, the remaining voters discard abnormal ballots that have not uploaded secret shares, and upload abnormal recovery shares to the smart contract; when all the remaining voters have completed uploading, any entity in the system obtains the abnormal recovery share through the smart contract and calculates the final voting result after recovery.

2. According to claim 1, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: The step 1 comprises: Step 1.1: The voter generates a pair of public and private keys for signing , send the identity to the voting initiator With public key , request registration; Step 1.2: The voting initiator initiates a decision event through a smart contract, and uploads the voting activity information, encrypted public parameters, and a list of legal voters to the smart contract; the voting activity information includes the decision content and the start and end time of the vote; the encrypted public parameters are the ElGamal encryption system parameters ,in for Cyclic group of order The generator of .

3. According to claim 2, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: In step 1.2, the list of legal voters includes the identity ID, weight, and and the public key used for signing .

4. According to claim 3, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: The step 2 comprises: Step 2.1: Voters obtain ElGamal encryption system parameters through the smart contract ; Step 2.2: The voter randomly selects a homomorphic encryption private key , and calculate the corresponding homomorphic encryption public key ; Step 2.3: The voter encrypts the homomorphic public key Sign and upload to the smart contract.

5. According to claim 4, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: Step 3 includes: Step 3.1: Voters obtain the homomorphic encrypted public keys of all voters in the system through the smart contract , and calculate the encryption public key ; Step 3.2: The voters determine their decision content ;in Indicate decision-making intention. is the weight of said voter; Step 3.3: The voter selects a random integer , and use encryption and public key Compute encrypted decision content ,in are the parameters of the ElGamal encryption system, For decision-making content; Step 3.4: The voter generates a non-interactive zero-knowledge proof of the encrypted decision content. ; Step 3.5: The voter uses the private key for signing The content of the decision on the encryption and non-interactive zero-knowledge proofs Sign and generate digital signature and final votes ; Step 3.6: The voter will submit the final ballot Uploaded to said smart contract.

6. According to claim 5, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: Decision intention in step 3.2 From the collection , representing "in favor", "abstention" and "against" respectively.

7. According to claim 5, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: The non-interactive zero-knowledge proof in step 3.4 To prove the content of the decision Within three items.

8. According to claim 5, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: The step 3.6 also includes the smart contract verifying the digital signature And non-interactive zero-knowledge proof The validity of the final ballot will be verified Save on the blockchain, otherwise discarded.

9. According to claim 5, the anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption is characterized in that: Step 4 includes: Step 4.

1. Voters Obtain all legal votes through the smart contract ,in The encrypted decision content of all legal ballots is multiplied by the number of voters who perform the voting process, and the aggregated encrypted decision content is obtained. ,in Representative voter number; Step 4.2: The voters Calculate the secret share based on the aggregated encryption decision content ,in , ,in homomorphically encrypt the private key of the voter, To encrypt the public key, The public key multiplication result is homomorphically encrypted for the voter who performs the voting process. Use the private key for signing The secret share Signature Get Digital Signature , and set its voting activity parameters , Secret Share And digital signature Upload to the smart contract; Step 4.3: When all voters have uploaded their secret shares, any entity in the system obtains all votes and decrypts the secret shares through the smart contract, and obtains the aggregated encrypted decision content as described in step 4.1; the entity calculates the decrypted aggregated decision content , by combining the voting result range enumeration, the final voting result is obtained .

10. The anonymous weighted decision-making electronic voting method based on blockchain and homomorphic encryption according to claim 9 is characterized in that: Step 5 includes: Step 5.1: The remaining voters discard the votes of users who have not submitted secret shares. , recalculate the encrypted result of the ballot to be restored ,in , For the The encrypted decision content of each voter, Representative voter number; Step 5.2: The remaining voters calculate the abnormal recovery share ,in homomorphically encrypt the private key of the voter, is a random integer selected by the voter, To execute the voting process and upload the secret share of the voter homomorphically encrypted public key multiplication result, use the private key used for signing to sign the abnormal recovery share to obtain a digital signature , and set its voting activity parameters , abnormal recovery share And digital signature Upload to the smart contract; Step 5.3: When all remaining voters have completed uploading the abnormal recovery share, any entity in the system obtains the abnormal recovery share through the smart contract and calculates the new decrypted aggregate decision content. , by combining the voting result range enumeration, the final voting result is obtained .

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