# Privacy-Preserving E-Voting System Supporting Score Voting Using Blockchain
###### Abstract  
With the advancement of cyber threats, blockchain technology has evolved to have a significant role in providing secure and reliable decentralized applications. One of these applications is a remote voting system that allow voters to participate in elections remotely. This work proposes a privacy-preserving e-voting system supporting score voting using blockchain technology. The main challenge with score voting compared to the regular yes/no voting approach is that a voter is allowed to assign a score from a defined range for each candidate. To preserve privacy, votes shall be encrypted before submission to the Blockchain, however, a malicious voter can modify the score value before encrypting it to manipulate the elections result for the favor of a certain candidate. To address this challenge, the proposed scheme allows voters to first prove that the submitted score lies in the predefined range before the vote is added to the Blockchain to ensure fairness of the election. The performance of our scheme is evaluated against a set of comprehensive experiments designed to determine optimal bounds for workload and transaction send rates and measure the impact of exceeding these bounds on critical performance metrics. The results of these simulations and their implications therefore indicate that the proposed scheme is secure while being able to handle up to 10,000 transactions at a time. s _applied_  
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Footnote †: This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/py/4.0/](https://creativecommons.org/licenses/py/4.0/)]([https://creativecommons.org/licenses/py/4.0/](https://creativecommons.org/licenses/py/4.0/))). Recently, cryptographic primitives such as ElGamal encryption schemes, blind signatures, ring signatures, and homomorphic encryption have been implemented within contemporary online voting systems to guarantee voter privacy and anonymity, ballot secrecy, and the verifiability of election results. Despite these measures, however, security incidents have still occurred in online election systems. In 2015, the New South Wales (NSW) Electoral Commission admitted that up to 66,000 election votes had been compromised on the online iVote website [6], where the compromised votes could have been exposed or tampered with unnoticed. The Pentagon refuses to endorse electronic voting; and in May 2020, the FBI and NIST, among other federal agencies, released a warning to the states that the return of marked ballots online was a \"high risk\" venture [7]. Voatz, perhaps currently the most widespread e-voting system in use in the United States, was found to have \"concerning\" security issues, leading to the notification of the DHS of these security issues [8]. Blockchain technology and the concept of decentralized applications (DApps) lend special potential to the field of remote e-voting. Namely, its ability to provide accountability through verification and security and robustness through immutability and their distributed nature enable an election to take place with minimal interaction of a third party during the process, thus preserving election integrity and removing the potential for bias. In simpler terms, a blockchain is merely a novel data structure consisting of interconnected blocks called nodes. Each node contains an archive of a transaction that must be committed by the network of peer devices, called miners, via a consensus algorithm. The addition of smart contracts to blockchain enabled the shift of blockchain utilization from solely for cryptocurrency to DApps as well. Smart contracts are simply programs that contain the business logic for the application and are stored on-chain [9; 10; 11]; it is these contracts that enable the application to execute and enforce without the need for a central third party.