Provotum: A Blockchain-based and End-to-end Verifiable Remote Electronic Voting System

Abstract

While the existence of Public Bulletin Boards (PBB) is often formulated as an assumption in related work on Remote Electronic Voting (REV) systems, this work here on Provotum focuses on the practical design and architecture of such a PBB, including its distributed execution. Further, Provotum leverages a public permissioned Blockchain (BC) as a PBB, where only authorized entities can sign blocks, while the general public can verify all BC data. Therefore, Provotum defines a new and fully decentralized BC-based REV system, which deploys a permissioned BC as a PBB and allows for the explicit distribution of trust across different permissioned BC nodes. Provotum is operated in a fully distributed fashion by using Smart Contracts (SC), Distributed Key Generation (DKG), Homomorphic Encryption (HE), and Cooperative Decryption (CD), as well as employing client-side encryption, which enables ballot secrecy, while the BC forms an audit trail, enabling public and End-to-end Verifiability (E2E-V).