Digital Liquid Democracy: Delegative End-to-end Verifiable E-voting

This project will model, design, analyze, and implement a novel secure, transparent end-to-end verifiable e-voting system that can enable liquid democracy. With the advancement of digital technology, developing a secure and transparent e-voting system becomes increasingly important to the UK society. In 2015, UK Digital Democracy Commission recommends that "By 2020, secure online voting should be an option for all voters". The outcomes of this project will push forward e-voting development in both theoretical and practical aspects. It can provide valuable expertise input to the UK Parliament to accelerate UK's e-voting adoption progress.

Conventionally, no voter behavioral characteristics were taken into account in the analysis of e-voting verifiability. However, the correctness of the election result when the election authorities are adversarial is impossible to verify unless the humans that participate in the protocol follow a suitable behavior. This means that the voters, beyond the ballot-casting procedure, are supposed to carry out additional steps that may find to be counterintuitive. This project will initiate the study of e-voting ceremony, which expands a security protocol with out-of-band channels, and the human users are considered as separate nodes of the system that should be taken into account when performing the security analysis. The statistical data of Estonian i-vote users collected from the legally-binding national elections and European Parliament elections will be used in our study.

The state-of-the-art end-to-end verifiable e-voting systems [1,2] in the standard model can only support basic vote tally schemes due to its technical limitation - homomorphic tally. This drawback prevents those systems from wider adoption in the real world. To address this drawback, this project will construct a universally verifiable ballot mixing mechanism (i.e., mix-net) in the standard model. Its key component is a zero-knowledge shuffle proof/argument that allows the mixing server to show the correctness of its ballot shuffling operation without violating voter privacy. Following the paradigm of [1], we need a non-interactive zero-knowledge shuffle proof with perfect soundness in the common reference string model. Unfortunately, none of the existing candidates satisfy this requirement. This project will, therefore, construct such a candidate to fill the missing puzzle piece.

Liquid democracy is a hybrid of direct democracy and representative democracy, where voters can either vote directly on issues, or they can delegate their votes to representatives who vote on their behalf. Due to its advantages, liquid democracy has received high attentions since the spread of its concept; however, there is no good implementation available in practice yet. The ultimate goal of this project is to fill this gap and develop the world's first provably secure candidate for digital liquid democracy. To enable vote delegation for liquid democracy, advanced blockchain technologies, such as cryptonote and zerocash, will be adopted.


[1] Aggelos Kiayias, Thomas Zacharias, and Bingsheng Zhang. DEMOS-2: scalable E2E verifiable elections without random oracles. In Proceedings of CCS 2015.
[2] Aggelos Kiayias, Thomas Zacharias, and Bingsheng Zhang. End-to-end verifiable elections in the standard model. In Proceedings of EUROCRYPT 2015.

In general, the project has two main impact areas: knowledge and society. In terms of the knowledge perspective, the current project strives to advance the state-of-the-art of both theory and practice of the end-to-end verifiable e-voting. The initiation of e-voting ceremony modeling and analysis will raise academic awareness of human aspect in security critical systems and bring new insight to the research community. In addition, each component of the resulting e-voting system will be of independent interest in their corresponding fields. With regard to the social impact, our impact plan has been developed with a view to maximizing the impact of the project's results to deliver two key impact objectives as follows.

(i) influencing Estonian e-voting development
Estonia is a pioneer in adopting Internet voting systems in legally-binding national elections in the world. Along with paper voting, Internet voting has been an option to Estonian citizen since 2006. In their recent elections, over one-third of the votes are cast via Internet voting. Although there was no serious real-life attack to the system, the Estonian electronic voting system is the lack of transparency and verifiability. The Estonian e-voting committee is, therefore, keen to upgrade the existing out-dated system.
The PI, Dr. Zhang, has a long history of collaboration with Estonian e-voting development team. One of this project collaborators is Cybernetica AS, which is in charge of the design, development, and deploy of the next generation Estonian e-voting system. Dr. Zhang was also invited to the workshop called "E-enabled elections in Estonia: Forum on research and development" to participate the discussion of the next generation Estonian i-voting architecture (IVXV) in November 2015.
Dr. Jan Willemson from Cybernetica AS is one of the chief designers of the Estonian IVXV system. He will actively participate in this project and incorporate some of the findings of this project to the Estonian IVXV system design. The outcome of this project will have a direct impact on Estonian i-voting system development. This collaboration will largely enhance security guarantee of the next generation Estonian Internet voting system. The success of this project will foster a long-term collaboration with the Estonian e-voting committee, providing sustainable benefits to the progress of Estonian E-government.

(ii) accelerating UK's e-voting adoption.
UK Digital Democracy Commission has expressed strong interest in adopting Internet voting to UK's national elections. While it is widely agreed to introduce e-voting to this country, the process of UK's e-voting adoption is still very slow. While preparing the proposal, we have engaged with Cat Smith, MP for Lancaster & Fleetwood in arranging a meeting to discuss this subject. During this meeting, Dr. Zhang aims to understand the barriers that preventing the UK from moving forward in the direction of e-voting and will attempt to investigate these issues relevant to his research coverage.
At the end of this project, we will deploy the developed e-voting system at Lancaster University. The system will be integrated with Lancaster University's authentication system and will be available to the university students as well as the public for any legally binding polls. Meanwhile, we will try to seize an opportunity to use our system in the exit polls of some local elections during the meeting with Cat Smith, MP. This will increase the public familiarity and confidence to e-voting systems.
The PI, Dr. Zhang is currently a member of the Council of WebRoots Democracy, a voluntary organization campaigning for the introduction of an online voting option in UK elections. WebRoots Democracy is currently establishing a new Advisory Council made up of members from across the tech industry, academia, civil society, and politics. The outcome of this project will provide valuable input to WebRoots Democracy.