Blockchain-Based E-Voting Mechanisms: A Survey and a Proposal ^†

Abstract

Advancements in blockchain technology and network technology are bringing in a new era in electronic voting systems. These systems are characterized by enhanced security, efficiency, and accessibility. In this paper, we compose a comparative analysis of blockchain-based electronic voting (e-voting) systems using blockchain technology, cryptographic techniques, counting methods, and security requirements. The core of the analysis involves a detailed examination of blockchain-based electronic voting systems, focusing on the variations in architecture, cryptographic techniques, vote counting methods, and security. We also introduce a novel blockchain-based e-voting system, which integrates advanced methodologies, including the Borda count and Condorcet method, into e-voting systems for improved accuracy and representation in vote tallying. The system’s design features a flexible and amendable blockchain structure, ensuring robustness and security. Practical implementation on a Raspberry Pi 3 Model B+ demonstrates the system’s feasibility and adaptability in diverse environments. Our study of the evolution of e-voting systems and the incorporation of blockchain technology contributes to the development of secure, transparent, and efficient solutions for modern democratic governance.

1. Introduction

Electronic voting (e-voting) systems represent a significant technological advancement in modernizing the electoral process. E-voting systems are characterized by their use of electronic mechanisms not only for casting, but also for accurately counting votes. The diversity in these systems shows in their varying architectures, counting styles, and security protocols. However, despite their advancements, these systems face a myriad of challenges, including security vulnerabilities, scalability issues, and a lack of transparency and reliability in the vote tallying process. These challenges highlight the need for innovative solutions to enhance the integrity, efficiency, and trustworthiness of e-voting systems.

This paper explores the integration of innovative technologies and methodologies within e-voting frameworks to address these issues. We focus on the role of blockchain technology, which presents a promising avenue of study for reinforcing the security and transparency of e-voting systems. Blockchain is composed of an immutable decentralized ledger which allows e-voting systems more security and transparency through the ledger’s auditability. We study the diverse ways in which blockchain can alleviate the existing flaws in e-voting architectures and create a more secure, transparent, and efficient voting process. We extend the study to incorporate advanced counting methodologies, innovative architectural designs, and robust cryptographic security measures, all aimed at enhancing the electoral process.

Additionally, we scrutinize the architectural designs of several blockchain-based e-voting systems to analyze their operational efficacy in resource-constrained environments. We determine that the systems which employ lightweight protocols requiring less computational power and storage are optimized for energy and network efficiency, and those that implement data aggregation techniques to reduce the amount of data needed can conserve bandwidth and storage on IoT devices.

Counting styles in e-voting systems are another area of focus. Traditional counting methods face challenges in accuracy and speed, which are critical in electoral contexts. This paper delves into advanced counting methodologies like the Borda count and Condorcet method, utilizing their potential to provide a more accurate and representative election outcomes. The integration of these methodologies into e-voting systems can significantly streamline the vote tallying process and enhance the reliability of election results. In Section 5, we further explain how these different counting methodologies can be used in different situations and how this can bolster the voting process.

Our contribution in this paper is two-fold: First, we surveyed blockchain-based e-voting mechanisms that have not yet been compared in other survey papers and scrutinized each design to see if the design was able to be used in resource constrained environments. Second, we propose a novel approach to integrating blockchain technology with advanced voting methodologies. Our unique methodology includes the simultaneous use of the Borda count and Condorcet method in parallel branchchains. Our novel voting methodology ensures cross-verification of results to enhance accuracy and robustness. Our innovative design approach not only addresses the traditional challenges faced by e-voting systems but also introduces a new dimension of reliability and efficiency in vote tallying.

The remainder of this paper is organized as follows. In Section 2, we give an overview of existing survey papers on blockchain-based e-voting systems. Next, in Section 3, we perform a comparative analysis of various blockchain based e-voting designs. In Section 4, we describe the background technologies used in our proposed design. In Section 5, we present our novel design of a new e-voting system based on an amendable and correctable blockchain which utilizes Borda count and Condorcet method in parallel chains for vote tallying. In Section 6, we discuss our implementation of our design and some results. Finally, in Section 7, we conclude the paper and discuss future work.

2. Related Work

In this section, we briefly review the recent works in related surveys on existing blockchain-based voting systems.

Jafar et al. [1] explore the integration of blockchain technology in electronic voting systems, examining its potential to enhance the accuracy, security, and convenience of e-voting processes. The paper discusses the progression of e-voting, addressing how blockchain can resolve prevalent issues. It also discusses various current implementations of blockchain in e-voting, highlighting both general e-voting challenges and specific technical hurdles in blockchain applications. Common e-voting challenges discussed include secure digital identity management, ensuring anonymous vote-casting, personalized ballot processing, and enabling voters to verify their own ballot casting. Moreover, the paper explores technical difficulties such as high initial setup costs, escalating security concerns, prevention of evidence tampering, and balancing transparency with voter privacy. Another significant issue is the existing lack of transparency and trust in e-voting systems. By integrating blockchain technology, many of these longstanding issues in traditional e-voting systems can be largely mitigated. Nonetheless, this work identifies unique challenges that emerge with blockchain-based e-voting systems. These include scalability and processing overheads, constraints due to scalability, block size limitations, and sensitivity to varying demands in voter participation. These challenges underscore the complexity of implementing blockchain in e-voting systems and highlight the need for ongoing research and development in this evolving field.

Abuidris et al. [2] offer an in-depth look on various companies that use blockchain-based e-voting systems. A system called Follow My Vote [3] aims to offer a secure online voting platform based on blockchain. The system allows voters to audit the ballot box and see election progress in real-time. They also use a webcam and user ID for remote, secure voting, which enables voters to confirm their votes. Agora [4] proposes a blockchain-based digital voting platform which features immediate recording of votes on multiple blockchain layers and offers tamper-proof results and full auditability while being able to maintain voter privacy. Voatz [5] offers a smartphone-based voting system for public elections using blockchain where voters verify their identity through the application using a photo of themselves and their ID, along with either a fingerprint or other biometric evidence. Polyas [6] incorporates blockchain into its e-voting system which is widely used in Germany and is currently expanding to North America and European nations. Luxoft [7] is a global IT service provider that developed an e-voting system for its elections in Switzerland. This work also offers a discussion of some current trends in blockchain-based e-voting systems and protocols, including the quantum blockchain voting protocol, bearable new e-voting protocol, verify-your-vote protocol, blockchain-based e-voting without a trusted third party, end-to-end privacy voting protocol, and others. Of these techniques, the quantum blockchain voting protocol discussed in [8] presents an advancement in security using three different quantum techniques. The system discussed in [9] uses a secret sharing scheme and homomorphic encryption scheme which allows for voting to be trusted without a third party and provides transparent voting while maintaining voter anonymity. Abuidris et al. also examine the pros and cons on various other blockchain-based e-voting protocols.

Fatih et al. [10] presents an in-depth exploration of blockchain structure, examining various types of blockchains, including public, private, and consortium. The paper highlights the unique characteristics of these blockchains and various cryptography techniques like hashing, which transforms any input data into a fixed mathematical algorithm which is non-reversible, which secures the blockchain by transforming input data into a fixed, non-reversible mathematical output. The importance of Merkle trees in summarizing transactional data and facilitating transaction verification is emphasized. The paper also explores public-key encryption, where private keys authenticate transactions. The paper then compares different consensus mechanisms focusing on aspects like identity management, energy efficiency, adversary tolerance, and scalability.

The study by Elfattal et al. [11] examines the global shift from traditional voting methods to electronic voting systems. The paper highlights the theoretical advantages of Electronic Voting Machines (EVMs), like ease of use, expedited vote counting, and improved accuracy. The paper also discuses the challenges and deficiencies these machines have faced, including issues in vote counting accuracy and transparency, which have spurred further research and development to enhance the reliability of EVMs. The paper offers a comprehensive analysis involving data from Scopus encompassing the United States, India, China, the United Kingdom, and Germany. The analysis of the data reveals how different nations have engaged with electronic voting, noting the trends in research interest and technological adoption. A finding of the study shows that since the 2000 presidential elections and the implementation of the Help America Vote Act, the U.S dominates the e-voting volume of publications, nearly doubling India’s contributions. This work provides a comprehensive view of the e-voting landscape and highlights the advancements in e-voting while shedding light on the need for maintaining the integrity, security, and transparency of these systems in global context.

The survey paper by McCorry et al. [12] explores the dynamics of various e-voting systems, dissecting them into three categories: centralized, centralized remote, and decentralized voting. The paper presents the defining characteristics of these voting types, and provides practical examples offering a perspective on their real-world applications. The paper examines secure voting practices and emphasizes identifying and addressing vulnerabilities existing in the tallying process. This is relevant in the evolution of electronic voting trends and the shift towards electronic voting using the Direct Recording Electronic machines. The paper shifts its focus towards presenting a high-level vision of the future of e-voting and the challenges and opportunities inherent in implementing these systems, especially on a national scale. In addition, they implement the Open Vote network protocol (OV-net), a self-tallying decentralized, two-round voting scheme. The OV-net is implemented on the Ethereum blockchain using two smart contracts, with one handling the voting process and the other managing cryptographic functions. A thorough analysis is conducted on the implemented system, encompassing cost and timing analysis. The paper also outlines the limitations of the implementation which includes vulnerability to coercion and vote proving also the requirement of an Ethereum account and deposit. This requirement poses a significant barrier to entry, potentially limiting the accessibility of the system and barring wider adoption.

3. Comparative Analysis

In this section, we perform a comparative analysis of various blockchain-based e-voting designs. In

Table 1. Comparison of blockchain-based e-voting system.

	Blockchain Type	Cryptography	Counting	Anonymity	Auditability	Verifiability	Uniqueness	Fairness	Resource Constraint
[14]	public	public key	third party	✓	✓	✓	✓
[15]	private	public key	self-tallying	✓	✓	✓	✓
[16]		ECDSA, Ed25519, digital signature		✓	✓	✓	✓		✓
[17]	public	zk proofs	self-tallying	✓	✓	✓	✓	✓
[18]		post-quantum	self-tallying		✓	✓	✓
[19]	public	ECDSA		✓	✓	✓	✓
[20]		SHA-256, RSA	third party		✓	✓	✓		∼
[21]	private	digital signatures	hybrid		✓	✓	✓
[22]	public		third party		✓	✓	✓
[23]	public	public key	self-tallying		✓		✓
[24]	hybrid	public key	self-tallying	✓	✓	✓	✓	✓
[25]	public	blind signatures	self-tallying	✓	✓	✓	✓	✓
[26]	public	RSA	hybrid		✓	✓	✓		∼
[27]	consortium	zk proofs	self-tallying	✓	✓	✓	✓	✓
[28]	private		self-tallying				✓
[29]	private	blind signatures	third party	✓		✓	✓	✓
[30]	public	ECC, ring signatures	self-tallying	✓	✓	✓	✓
[31]	public	public key, ECC, digital signatures	self-tallying	✓	✓	✓	✓
[32]	public	public key, OTPs, digital signatures	self-tallying	✓	✓	✓	✓	✓
[33]	private	zk proofs, homomorphic encryption		✓	✓	✓	✓	✓
[34]		ECC, ring signatures	hybrid	✓	✓		✓
[35]	hybrid	public-key cryptography, blind signatures	self-tallying	✓	✓	✓	✓
[36]	hybrid		hybrid				✓
[37]	private	RSA, blind signatures	hybrid	✓	✓	✓	✓
[38]	private	public-key cryptography, digital signatures, ABAC	hybrid	✓	✓	✓	✓	✓
[39]		zk proofs, digital signatures	hybrid	✓	✓		✓
[40]	hybrid	non-interactive zk proofs, ring signatures	third party	✓	✓	✓	✓	✓
[41]	hybrid	pk encryption, digital signatures, SHA-256	self-tallying	✓	✓	✓	✓	✓	✓

For columns Blockchain Type, Cryptography, and Counting, a blank space means that the paper does not mention this feature, while in security requirement columns, a blank space means that the requirement is not satisfied or not discussed, a checkmark indicates the system fulfills the feature, and the tilde means it could be suitable with implementation.

, we evaluate the presented designs based on blockchain type, cryptography, how the votes are counted, and security requirements. We build upon the methodology established in our previous work [13] to evaluate various new blockchain-based e-voting mechanisms.

3.1. Blockchain Type

Presently, there are primarily four distinct categories of blockchain networks: public, private, hybrid, and consortium blockchains.

• Public blockchain, often referred to as permissionless blockchain, forms the backbone of numerous cryptocurrencies. It is an open network blockchain where anyone with an internet connection can participate.
• Private blockchain, also known as permissioned blockchain, operates within a limited scope, typically under the control of a single organization.
• Hybrid blockchain uses both public and private models. It usually contains an open operation with an owner or overseer of the blockchain, who retains authority to grant or deny user access.
• Consortium blockchain, similar to hybrid blockchain, involves collaboration among several organizations. It is also referred to federated blockchain and represents a decentralized network that is managed jointly by multiple entities.

3.2. Cryptography Techniques

Common cryptographic techniques used in electronic voting systems include zero-knowledge (zk) proofs, public-key encryption, homomorphic encryption, blind signatures, and ring signatures. Additionally, hashing algorithms, such as SHA-256, are a staple in nearly all blockchain networks.

3.3. Counting Type

There are two distinct types of counting structures employed by blockchain-based e-voting systems. Some systems utilize a self-tallying counting system, while others may employ one trusted third party to be in charge of the vote tallying. Another type of counting method is one that uses both self-tallying and third party tallying either in tandem or sequentially, we designate it as a hybrid counting system.

3.4. Security Requirements

We utilize the security requirement model from [2,42,43] and we analyze the following security requirements.

• Voter Anonymity: It is essential that there is no feasible way to trace how the voters cast their votes. Anonymity can be maintained by using cryptographic techniques, zero-knowledge proofs, secure multi-party computation methods, and other techniques.
• Election Auditability: The voting process must be fully auditable once the results are declared.
• Vote Verifiability: Every voter in the election should have the ability to confirm that their vote has been recorded and counted correctly in the election.
• Vote Uniqueness: The system must ensure that each voter can cast only one vote, preventing duplicate voting.
• Election Fairness: The system should avoid revealing real-time results which could potentially influence subsequent voting decisions.

3.5. Trends in Blockchain-Based E-Voting

Referring to Table 1, our analysis of blockchain-based e-voting research has surmised several trends. Public blockchains are predominantly favored for e-voting systems, followed by private and hybrid types. Public blockchains offer transparency and wider accessibility, essential elements in voting systems. A variety of cryptographic methods are used, with public-key cryptography being the most prevalent. Public-key cryptography is often complemented with other techniques, including ECDSA, digital signature requirements, zero-knowledge proofs, RSA and Elliptic Curve Cryptography. This diversity in cryptographic techniques suggests a focus on ensuring security and voter privacy. Regarding vote counting, there is a balance between third-party counting systems, self-tallying, and hybrid methods. While self-tallying systems are notably popular, offering a degree of automation and decentralization, hybrid systems provide a more controlled environment, potentially enhancing the integrity of vote counting. Voter anonymity is prioritized in most systems, aligning with the blockchain’s ability to offer anonymity alongside traceability. This feature proves critical in preserving the confidentiality of votes. Auditability and verifiability are almost universally integrated, indicating a trend towards creating systems where election results can be independently verified and audited, bolstering the trust in the electoral process. The uniqueness of votes is a standard feature, ensuring one person, one vote. However, fairness, representing equal access and representation, is less emphasized, indicating an area for future development. We also discover some emerging technologies in this study. The use of post-quantum cryptography and the incorporation of advanced cryptographic techniques like zero-knowledge proofs and ring signatures indicate a proactive approach to future-proofing against challenges, such as those posed by quantum computing. These trends reflect the dynamic and evolving nature of blockchain-based e-voting systems and emphasizing security, transparency, and the integrity of the voting process. The diversity in the approaches taken by various systems suggests ongoing experimenting to find the optimal balance these critical features.

3.6. Use in Resource-Constrained Environments

Adapting these systems for use in environments with limited resources is a crucial aspect of the analysis presented in this survey. As detailed in Table 1, Chaabane et al. [41] specifically discusses their system’s capability to operate in environments with low power or limited hardware, such as sensor networks. They highlight the efficiency of using low-power ARM architectures and implement their approach using a Raspberry Pi 4, which is recognized for its compact size and energy efficiency. While Woda et al. [16], Uma et al. [20], and Chaudhary et al. [26] do not provide explicit power consumption evaluations, their proposed solutions, utilizing 5G networks or fog computing, suggest potential for deployment in resource-constrained settings. Woda et al. discuss enhancing energy efficiency by transitioning from Proof of Work to signature-based algorithms for transaction validation. Uma et al. introduce a system designed around fog computing, aimed at optimizing performance in resource constrained scenarios. Chaudhary et al. explore the benefits of 5G networks in reducing latency and improving communication efficiency, indicating adaptability to resource constrained environments with adjustments. Although further exploration and practical application are necessary, the studies surveyed imply that many of these methodologies could be effectively employed in sensor networks or other resource restricted environments.

4. Background

In this section, we give an overview of the background technologies used in the proposed scheme to be introduced in the next section. Specifically, we will discuss the smart marker scheme which enables the creation and merging of branchchains in a blockchain system, the Borda counting methodology and the Condorcet method for voting.

4.1. Smart Markers

In our prior work [44], we introduced smart markers for blockchain, which can enable multiway branching and merging in the blockchain system to support one-to-many or many-to-one node dependency. Unlike traditional blockchains which retains only the longest branch and prunes all other branches, a blockchain that uses smart markers can keep every branch. The structure of smart markers are designed to be similar to the structure of regular blocks while following three essential criteria: recognizability, which means that smart markers contain unique header information indicating branching/merging points; compatibility, which means that smart markers are able to be seamlessly integrated along with regular blocks in the chain; and authenticity, which means that smart markers ensure validity through hashing to prevent tampering. Smart markers differ in two ways from standard blockchain blocks. As seen in Figure 1, smart markers have a fixed size and they do not contain any transaction data. Instead, smart markers contain a digital signature in the body of the block for authentication purposes. The headers of smart markers, like regular blocks, reference the previous block’s cryptographic hash. Smart markers allow the blockchain to branch into what is called branchchains. The branchchain is enclosed within a pair of smart markers. In each branchchain there is a branching marker, which indicates the branching point of the chain, and a merging marker which indicates the merging point of the branchchain. Smart markers also are used to allow the branchchains to be stored linearly as can be seen in Figure 2. All additional data needed to identify the smart markers are stored in the block header, including a type field in the header to indicate the type of block, in which 0 stands for a regular block, 1 for a branching marker block, and 2 for a merging marker block. For more details about the design and operation of smart markers, please refer to [44].

4.2. Borda Count and Condorcet Method

The Borda count and the Condorcet method [45,46] are two of the most widely studied and used counting methodologies. The Borda count method is a voting system that is used to rank a list of candidates based on the preferences of voters. This positional voting method bases where the position of a candidate on a voter’s ballot contributes to their final score. In the Borda count method, voters first rank all candidates in order of preference. For example, in a race with three candidates, A, B, and C, a voter might rank them B > A > C, C > B > A, etc. In this system, voters must rank all candidates. After the ranking portion is completed, points are assigned to each position on a voter’s ballot. The most commonly used method is to give the bottom-ranked candidate 0 points, the next rank up 1 point, and so on until the top-ranked candidate. Once the voting process concludes and all ballots are evaluated, the points for each candidate are tallied. The candidate with the highest aggregate point total across all ballots is declared the winner. This method aims to identify a consensus candidate who garners broad support across the electorate, rather than a majority candidate.

The Condorcet method is a voting system which elects the candidate that would win by a majority of votes in a series of hypothetical head-to-head match-ups against each other candidate. In this method, voters rank all candidates in order of preference. The essential step in this method lies in pairwise comparisons, where each candidate is pitted against every other candidate in head-to-head contests in turn. In each head-to-head contest, the candidate who is preferred by the majority of voters is declared the winner of that pairing. For each match-up, a candidate is awarded a point if they are ranked higher than the opponent on the voter’s ballot; this candidate is considered the winner of that match-up. The candidate with the most points at the end of the head-to-head match-ups is the final winner of the method. However, the Condorcet method in some cases can result in a situation where there may be no clear majority winner. To resolve this voting paradox, or Condorcet cycle [47], various methods can be employed. The method can either be finalized by using the ranked pairs method [48], where the most decisive pairwise contest is locked first and then it continues ignoring any pairings that would create a cycle. Or, it could be finalized using the Schulze method [49], which identifies the strongest path between each pair of candidates and then selects the candidate who has the strongest paths against all the others.

5. Design

In this section, we outline our innovative blockchain-based e-voting scheme. Our methodology efficiently resolves the Condorcet cycles paradox in scalable e-voting systems on the blockchain. The objective of our design is to elevate the standards of blockchain-based voting systems. One takeaway from reviewing the existing approaches of blockchain-based e-voting systems is that they did not take into account the type of voting style that may be used in their system. We take inspiration from Dasgupta and Maskin [50], who proposed one voting mechanism that combines the Condorcet method and Borda counting method, reducing susceptibility to strategic voting. The simultaneous use of these two algorithms within a single e-voting system in parallel branchchains ensures accuracy and robustness.

5.1. Design Overview

The Borda counting method is adept at identifying broadly supported candidates, even if they are not the top preference for many. The Condorcet method excels in identifying options that would win in one-on-one match-ups against all other candidates. By combining these methods, we leverage their respective strengths while mitigating their weaknesses. The Borda count is vulnerable to tactical voting, where voters may rank a less preferred candidate higher to prevent a least-favored candidate from winning. Additionally, it may not always identify the Condorcet winner, the candidate who would win against all others in head-to-head contests. The Condorcet method, on the other hand, can lead to a Condorcet cycle, where no clear winner emerges due to circular preferences.

If one methodology results in a tie or unclear outcome, the other method can be used as a tiebreaker or secondary check to ensure a decisive result. This can enhance the legitimacy of the result for the electorate or decision-makers.

The advantages of our methodology are threefold:

• By combining the two methodologies, we ensure mitigatin the individual weaknesses of each method.
• Using both algorithms allow for a tiebreaker or secondary check to ensure a decisive result, enhancing the legitimacy of the election outcome.
• Using smart markers in our design facilitates branchchains and ensures that each voting session is conducted independently while being easily integrated and verified, maintaining the integrity and transparency of the election process.

In

Table 2. Candidates and voter preferences.

Voter	1st Preference	2nd Preference	3rd Preference
Voter 1	A	B	C
Voter 2	A	B	C
Voter 3	A	B	C
Voter 4	B	A	C
Voter 5	B	C	A
Voter 6	C	A	B
Voter 7	C	A	B
Voter 8	C	A	B
Voter 9	C	B	A

, we give an example of voting that would lead to a Condorcet cycle. In this example, there are three candidates, A, B, and C, and there are nine total voters, whose preferences are as shown in Table 2. In the case when tallying B against C, candidate B gets 5 votes, where C gets 4, giving B the win over C. Between candidate C and A, C wins with 5 votes over candidate A’s 4. In the case between A and B, A wins 6 votes over candidate B’s 3 votes. However, now a cycle exists where A wins over B, B wins over C, and C wins over A. This example exists in any voting mechanism where there are at least three candidates and is known as the Gibbard–Satterthwaite Impossibility Theorem [51,52].

Our design incorporates our previous work’s novel branching structure in blockchain technology [53]. We introduce a new voting blockchain, termed the Borda–Condorcet chain, implemented using smart markers. These smart markers facilitate the formation of branchchains [54], allowing simultaneous voting sessions across branches for rapid and precise results. A different voting method is employed in each different branchchain, which allows mutual verification to ensure correct results of vote counting. For example, in our prototype implementation used for evaluation purposes, one branchchain uses the Borda count method and the other uses the Condorcet method. We note that our system is not limited by these two methods alone and can be easily adapted to employ more of other methodologies.

During voting, results are recorded as new blocks in the respective branchchain. If the Condorcet method yields a cycle (indicating no clear winner), the result is marked as a tie. In our prototype implementation, we choose the Condorcet method as the preferred method. That is, the winner yielded by the Condorcet method will be taken for decision-making. However, if this method fails to identify a winner due to a cycle, the Borda count winner is chosen instead. The voting process concludes with the addition of a merging smart marker to each branchchain, signaling the end of the voting session. Figure 3 depicts the Borda–Condorcet chain structure, with each branchchain defined by a pair of smart markers (i.e., a branching marker and a merging marker), efficiently identifiable and indexable through their unique digital signatures. Figure 2 illustrates the chain’s linear storage formatting, which reduces the storage needs compared to traditional blockchain architectures. Our novel voting blockchain structure maintains voting integrity through a tamper-resistant ledger and hashing cryptography, ensuring voter anonymity and vote uniqueness. Smart markers allow each branchchain to operate independently, safeguarding election fairness by preventing potential biases between chains.

5.2. Discussion

In addition to the accuracy and robustness of e-voting systems, privacy protection is also crucial, given the transparent and immutable nature of blockchain technology. Even though we focus on the e-voting mechanisms in this paper, various cryptographic and non-cryptographic methodologies can be combined with our proposed solution. Zero-knowledge roofs (ZKPs) [55,56,57] are a prominent solution, enabling parties to verify transactions without revealing any additional information. To enhance e-voting systems, ZKPs can be adopted in multiple steps. For example, election authorities (EAs) can register services and generate key pairs with ZKPs for proof of correct constructions. Issuing anonymous voting credentials [58] through these EAs while using ZKPs to verify that the voting is valid without revealing the vote’s content can be an effective design decision and applying ZKPs throughout the entire voting process will harden the security of the design. Strategies such as mixing services blend multiple transactions to obscure origins and destinations [59], and a blockchain-empowered data sharing system such as blockshare [60] should also be compatible with our design. Blockshare’s blockchain functionalities can manage the sharing of voter credentials, voting data, and other sensitive information securely and verifiably.

Combining a blockchain-based e-voting system with a blockchain data query solution such as [61,62] can enhance both the transparency and privacy of the voting process, ensuring the integrity of the data while providing efficient ways to access and analyze voting records. During the voting process, voters cast their votes using our blockchain-based e-voting system. Election officials and authorized parties use the blockchain data query solution to retrieve and verify vote counts. Data analytics tools can also conduct the analysis and generate reports with the help of blockchain data query solutions.

6. Implementation

To evaluate our innovative blockchain-based electronic voting system, we implemented a prototype using a Raspberry Pi 3 Model B+, made by the Raspberry Pi Foundation located in Pencoed, United Kingdom. This device features a Broadcom BCM2837B0, Cortex-A53 (ARMv8) 64-bit SoC clocked at 1.4 GHz, and is equipped with 1 GB LPDDR2 SDRAM. It supports 2.4 GHz and 5 GHz IEEE 802.11.b/g/n/ac wireless LAN, as well as Bluetooth 4.2. Our test involved simulating a voting process with 10,000 randomly generated votes cast for three different candidates. To measure the maximum power in Watts used, we used a Mecheer power meter plug model PM01-US, sourced from https://www.amazon.com/Electricity-Monitor-Electrical-Consumption-Voltage/dp/B0BR7Y5PYW?th=1 (accessed on 1 January 2024). This meter has a voltage error rate of 1% and a current error rate of 2%.

The initial step in our process was to establish a genesis block in the blockchain. We then utilized smart markers and the multiprocessing capabilities of the Raspberry Pi to simultaneously execute two different voting algorithms: the Borda count and the Condorcet method. To facilitate user interaction and manage the voting procedures efficiently, we employed Flask, a lightweight web framework, enabling seamless communication and data handling via a web interface. Using multiprocessing capabilities as each new round of voting initializes, we split the chain into two branchchains which store the results of each voting methodology that is executed concurrently. Smart markers delineate the start and end of each voting session within the branchchains, maximizing computational efficiency and ensuring timely processing of votes. As part of the blockchain framework, new blocks are added to each predetermined branchchain to record the results of each voting method and are linked to their predecessors using cryptographic hashes. The Flask application includes endpoints for submitting votes and viewing the entire blockchain. Multiprocessing is used to execute the Borda count and Condorcet method algorithms concurrently, utilizing the multi-core capabilities of the Raspberry Pi.

Experimental Analysis and Observations

The experimental analysis of our blockchain-based electronic voting system focused on evaluating its performance, scalability, power efficiency, and security. The voting process was simulated with 10,000 randomly generated votes for three candidates to assess the system’s ability to handle substantial voting data. We employed the multiprocessing capabilities of the Raspberry Pi to concurrently execute the Borda count and Condorcet method algorithms, demonstrating the system’s efficiency in processing votes. The concurrent execution ensured optimal utilization of the multi-core processor, with processing time scaling proportionally to the number of votes.

The novel branching blockchain structure proves to be highly scalable, maintaining consistent performance even with increased voting loads. Each branchchain operated independently, allowing simultaneous processing of the different voting methodologies. Smart markers ensure precise and rapid results while preserving data integrity. The measured power consumption shows that our system is suitable for all environments and is available for use in resource-constrained environments as well.

Security and data integrity were paramount in our design. Though any consensus method will work with our methodology, we employed Practical Byzantine Fault Tolerance (PBFT) protocol, ensuring robustness against faulty nodes and maintaining the integrity of the voting results. Each block’s cryptographic hash linked to its predecessor creates a tamper-proof ledger. The branching structure allows verification of each branchchain independently, enhancing election fairness and preventing biases. In cases where the Condorcet method resulted in a tie, the Borda count served as a secondary check, ensuring a decisive outcome.

In

Table 3. Time required to mine two blocks in tandem (one per branchchain).

Votes per Block	Time per Block (s)
100	0.02184
1000	0.06666
10,000	0.56661
100,000	6.39104
200,000	12.99719

, we list the average time to append the blocks to their branchchains. In

Table 4. Highest power consumed when mining two blocks in tandem (one per branchchain).

Votes per Block	Power Consumption per Block (Watt)
100	4.4
1000	4.1
10,000	4.1
100,000	4.7
200,000	4.8

, we list the maximum power consumption in Watts viewed on the power meter plug.

Our findings indicate that the computational demands for hash calculations and execution of the voting algorithms are relatively modest. The multiprocessing module is efficiently used in the Raspberry Pi 3’s multi-core processor and we expect enhanced performance on more robust hardware.

Analyzing the data presented in Table 3, it can be seen that the time required for mining two blocks concurrently in the system scales proportionally with the increase in votes per block. The overall time includes the branching of the blockchain and simultaneous execution of the Borda count and Condorcet method, and culminates in the generation of two new blocks, representing the collective voting data and final results for each branchchain in the Borda–Condorcet chain. The scalability of the system, as demonstrated by these results, indicates its effective functionality even in resource-constrained contexts.

Table 4 shows the system’s power efficiency, with the highest power consumption recorded as 4.8 Watts, from the base power consumption of 2.5 Watts, even at the upper limit of 200,000 votes per block. This efficiency in power usage further confirms the suitability of our system for use in limited-resource environments.

These results show that our blockchain-based e-voting system is not only compatible but also optimally designed for deployment in resource-constrained environments, such as sensor networks. The system’s scalability and low computational demands manifest its potential for broader application and integration in diverse electoral settings.

7. Conclusions

We present a comprehensive exploration and innovative approach to enhancing electronic voting (e-voting) systems using blockchain technology. Our extensive analysis covers existing blockchain-based e-voting systems, emphasizing the importance of the integration of advanced counting methodologies, robust cryptographic security measures, and innovative architectural designs. The paper’s additional contribution lies in proposing a novel e-voting system that combines the strengths of the Borda count and the Condorcet method for vote tallying, implemented on a branching blockchain structure.

Our comparative analysis of various blockchain-based e-voting systems studies critical trends in blockchain types, cryptographic techniques, and counting methods. This analysis underscores the importance of voter anonymity, election auditability, vote verifiability, uniqueness, and fairness in designing e-voting systems. Our innovative design, termed the Borda–Condorcet chain, leverages smart markers to facilitate multiple voting methodologies, ensuring a robust and fair electoral process.

The implementation of our system on a Raspberry Pi 3 Model B+ showcases its feasibility in low-resource environments, manifesting its potential for widespread adoption in diverse settings. The adaptability and scalability of our system makes it a viable and promising solution for secure, transparent, and reliable e-voting.

Our work marks a significant stride towards modernizing electoral processes through blockchain technology. The ongoing evolution of blockchain technology and its application in e-voting systems will continue to be a dynamic and critical area of research, offering profound implications for the future of democratic governance. While our designed system has addressed several challenges faced by current e-voting systems, we envision that future research directions should focus on further enhancing security and privacy features, such as exploring the possible integration with post-quantum cryptographic techniques, and extending the accessibility and usability of such systems to ensure a more inclusive and democratic electoral process for wider adoption worldwide.