A vast number of e-voting schemes including mix-net-based e-voting, homomorphic e-voting, blind signature-based e-voting, blockchain-based e-voting, post-quantum e-voting, and hybrid e-voting have been proposed in the literature for better security and practical implementation. In this paper, we review various e-voting approaches to date. We first compare the structures, advantages, and disadvantages of the different e-voting approaches. We then summarise the security properties of the e-voting approaches in terms of their functional requirements and security requirements. In addition, we provide a comprehensive review of various types of e-voting approaches in terms of their security properties, underlying tools, distinctive features, and weaknesses. We also discuss some practical considerations in the design of e-voting systems. Subsequently, some potential research directions are suggested based on our observations.

Although e-voting scheme and e-cheque scheme are two different applications, they have similarities in the scheme definitions and security properties. This inspires us to establish a relationship between the two schemes by formalising a generic transformation from e-voting to e-cheque scheme. Firstly, we define the scheme definitions and security models for both e-voting scheme and e-cheque scheme. Subsequently, we demonstrate a generic transformation framework from e-voting to e-cheque with asymptotic complexity of O(n) and design a formal proof to show that a secure e-voting scheme can be transformed into a secure e-cheque scheme. As a proof of concept, we apply our newly proposed transformation technique to the e-voting scheme proposed by Li et al. and obtain a concrete e-cheque scheme.

This paper illustrates how a transformation technique can be used to demonstrate the relationship among e-voting, e-auction, e-cheque, and e-cash, even though they serve distinct purposes. Initially, we examine the definitions of e-cheque and e-cash schemes, along with their respective security models. Subsequently, we develop a systematic framework to transform e-cheque into e-cash, supported by formal proof demonstrating the security of the conversion. As a corollary, we further exemplify this integration with a generic transformation framework to obtain e-cash from e-voting directly by combining an existing transformation of e-voting into e-cheque and the transformation of e-cheque into e-cash which we established earlier. We apply our transformation framework to Li et al.’s transformed e-cheque scheme and Li et al.’s e-voting scheme to obtain a concrete, secure e-cash scheme that is IND-CCEA, IND-CIA, and EUF-CIA as an instance. Finally, we examine how our result contributes to the integration and relationship between e-voting, e-auction, e-cheque, and e-cash systems.

Ensuring both cast-as-intended (CAI) verifiability and coercion-resistance in e-voting remains a critical challenge. The e-voting scheme proposed by Finogina and Herranz in 2023 represents the first notable advancement in reconciling these conflicting requirements. CAI verifiability allows voters to confirm that their intended vote has been correctly recorded, even without a secure channel to the election committee, while coercion-resistance prevents external influence and vote-selling. However, essential security properties such as confidentiality, anonymity, unforgeability, and double-voting prevention fall outside the scope of Finogina and Herranz’s e-voting scheme, leaving significant gaps in its security guarantees. To address this limitation, we propose a novel e-voting scheme that simultaneously achieves CAI verifiability, coercion-resistance, confidentiality, anonymity, unforgeability, and double-voting prevention while maintaining an asymptotic complexity of ????(n) . To the best of our knowledge, no existing scheme satisfies all these properties concurrently. Moreover, we establish that anonymity inherently implies CAI verifiability in e-voting schemes, a result of independent interest. By strengthening security and privacy guarantees, our work bridges existing gaps and provides a comprehensive security model that serves as a foundation for the design of future e-voting systems.