Distributed, End-to-end Verifiable, and Privacy-Preserving Internet Voting Systems
This addresses the need for secure, verifiable, and private internet voting systems for democratic processes, though it builds incrementally on prior distributed and verifiable voting approaches.
The authors tackled the problem of single points-of-failure in e-voting systems by designing and implementing the D-DEMOS suite, which includes distributed, privacy-preserving, and end-to-end verifiable systems, and demonstrated their ability to handle large-scale elections with preliminary use in national-level exit-polls and adoption by a union of over half a million members.
E-voting systems are a powerful technology for improving democracy. Unfortunately, prior voting systems have single points-of-failure, which may compromise availability, privacy, or integrity of the election results. We present the design, implementation, security analysis, and evaluation of the D-DEMOS suite of distributed, privacy-preserving, and end-to-end verifiable e-voting systems. We present two systems: one asynchronous and one with minimal timing assumptions but better performance. Our systems include a distributed vote collection subsystem that does not require cryptographic operations on behalf of the voter. We also include a distributed, replicated and fault-tolerant Bulletin Board component, that stores all necessary election-related information, and allows any party to read and verify the complete election process. Finally, we incorporate trustees, who control result production while guaranteeing privacy and end-to-end-verifiability as long as their strong majority is honest. Our suite of e-voting systems are the first whose voting operation is human verifiable, i.e., a voter can vote over the web, even when her web client stack is potentially unsafe, without sacrificing her privacy, and still be assured her vote was recorded as cast. Additionally, a voter can outsource election auditing to third parties, still without sacrificing privacy. We provide a model and security analysis of the systems, implement complete prototypes, measure their performance experimentally, and demonstrate their ability to handle large-scale elections. Finally, we demonstrate the performance trade-offs between the two versions of the system. A preliminary version of our system was used to conduct exit-polls at three voting sites for two national-level elections and is being adopted for use by the largest civil union of workers in Greece, consisting of over a half million members.