Decentralized Voting: A Self-tallying Voting System Using a Smart Contract on the Ethereum Blockchain

Electronic online voting has been piloted in various countries in the recent past. These experiments show that further research is required, to improve the security guarantees of such systems, in terms of vote confidentiality and integrity and validity verification. In this paper we argue that blockchain technology, combined with modern cryptography can provide the transparency, integrity and confidentiality required from reliable online voting. Furthermore, we present a decentralized online voting system implemented as a smart contract on the Ethereum blockchain. The system has no hardwired restrictions on possible vote assignments to candidates, protects voter confidentiality by using a homomorphic encryption system and stores proofs for each element of a vote. To the best of our knowledge, our proposed system is the first decentralized ranked choice online voting system in existence. The underlying Ethereum platform enforces the correct execution of the voting protocol. We also present a security and performance analysis, showing the feasibility of our proposed protocol for real-world voting applications at large scale.