# PVPBC: Privacy and Verifiability Preserving E-Voting Based on Permissioned Blockchain
## 2 Related Work
Some leading examples of live systems include, Follow My Vote ([[https://followmyvote.com/](https://followmyvote.com/)]([https://followmyvote.com/](https://followmyvote.com/)), accessed on 18 January 2023) and Democracy.Earth ([[https://www.democracy.ea](https://www.democracy.ea)]([https://www.democracy.ea](https://www.democracy.ea)), accessed on 18 January 2023). Typically, these proposals view the act of casting a vote as a transaction which should be documented on a blockchain or DL. A systematic review of the literature on blockchain-based solutions for e-voting and an analysis of the techniques reviewed is given in [23]. Blockchain is reviewed from a security perspective in [24]. The authors perform their analysis at three levels: the process, data and infrastructure levels and emphasize the need to consider these levels in light of urgent business and industrial concerns. Occasionally, the act of casting a vote is analogous to transferring a vote \"coin\" to a specific candidate. Nevertheless, these proposals often fail to tackle concerns related to electronic voting. These concerns include, but are not limited to, ballot secrecy, E2E verifiability, resistance to coercion, confirmation of accurate casting and recording of votes, voter eligibility, and the guarantee that all ballots cast before the end of the election will be counted. In addition, these actions could have unfavorable consequences, such as disclosing real-time running totals or voter turnout during the election, or linking a monetary value to a vote. Limited levels of technical details are available for some of these systems. The technical details of the schemes that are available are difficult to review and to independently assess. On the other hand, the VMV voting system introduced in [3] also uses the Selene voting scheme as the underlying voting system and employs blockchain to preserve verifiability. However, VMV sacrifices the voter-privacy property as the EA has full control of the voter's identity. VMV was added as a verifiability layer on the already-available legacy system. A solution for the integrity and verifiability problems is commonly sought by applying the DL concept. Adoption of a permissionless DL on public, peer-to-peer networks gives rise to a number of security and performance issues which have not been addressed in these solutions. Firstly, inconsistency in the DL, which might result as the necessary and sufficient conditions for independent consistency verification, is not well-defined or understood. Secondly, due consideration is not given to information propagation delay, which is an on-going concern in public networks that maintain DLs [25; 26]. Potential solutions exist in the form of modern machine-learning approaches that aim to minimize variation in propagation times [27; 28] and deep-learning-based traffic-classification schemes [29] which seek to utilize network resources better. The net result of these issues is that votes might be absent from the DL at the end of an election. Finally, performance issues, which are related to transaction costs, are high when a public DL is used. In summary, we compare the shortcomings and strengths of state-of-the-art e-voting systems in Table 1 under the headings Eligibility (EI), Privacy (Pr), Verifiability (Vr) and Usability (Us), in order to establish the need for PVPBC.