Receipt-Freeness and Coercion Resistance in Remote E-Voting Systems

Abstract: Remote electronic voting (E-voting) is a more convenient and efficient methodology when compared with traditional voting systems. It allows voters to vote for candidates remotely, however, remote E-voting systems have not yet been widely deployed in practical elections due to several potential security issues, such as vote-privacy, robustness and verifiability. Attackers' targets can be either voting machines or voters. In this paper, we mainly focus on three important security properties related to voters: receipt-freeness, vote-selling resistance, and voter-coercion resistance. In such scenarios, voters are willing or forced to cooperate with attackers. We provide a survey of existing remote E-voting systems, to see whether or not they are able to satisfy these three properties to avoid corresponding attacks. Furthermore, we identify and summarise what mechanisms they use in order to satisfy these three security properties

Ballot secrecy: Security definition, sufficient conditions, and analysis of Helios

We propose a definition of ballot secrecy as an indistinguishability game in the computational model of cryptography. Our definition improves upon earlier definitions to ensure ballot secrecy is preserved in the presence of an adversary that controls ballot collection. We also propose a definition of ballot independence as an adaptation of an indistinguishability game for asymmetric encryption. We prove relations between our definitions. In particular, we prove ballot independence is sufficient for ballot secrecy in voting systems with zero-knowledge tallying proofs. Moreover, we prove that building systems from non-malleable asymmetric encryption schemes suffices for ballot secrecy, thereby eliminating the expense of ballot-secrecy proofs for a class of encryption-based voting systems. We demonstrate applicability of our results by analysing the Helios voting system and its mixnet variant. Our analysis reveals that Helios does not satisfy ballot secrecy in the presence of an adversary that controls ballot collection. The vulnerability cannot be detected by earlier definitions of ballot secrecy, because they do not consider such adversaries. We adopt non-malleable ballots as a fix and prove that the fixed system satisfies ballot secrecy

Enhancing and Implementing Fully Transparent Internet Voting

Voting over the internet has been the focus of significant research with the potential to solve many problems. Current implementations typically suffer from a lack of transparency, where the connection between vote casting and result tallying is seen as a black box by voters. A new protocol was recently proposed that allows full transparency, never obfuscating any step of the process, and splits authority between mutually-constraining conflicting parties. Achieving such transparency brings with it challenging issues. In this paper we propose an efficient algorithm for generating unique, anonymous identifiers (voting locations) that is based on the Chinese Remainder Theorem, we extend the functionality of an election to allow for races with multiple winners, and we introduce a prototype of this voting system implemented as a multiplatform web application

Blockchain, consensus, and cryptography in electronic voting

Motivated by the recent trends to conduct electronic elections using blockchain technologies, we review the vast literature on cryptographic voting and assess the status of the field. We analyze the security requirements for voting systems and describe the major ideas behind the most influential cryptographic protocols for electronic voting. We focus on the great importance of consensus in the elimination of trusted third parties. Finally, we examine whether recent blockchain innovations can satisfy the strict requirements set for the security of electronic voting