key: 2017-verifiability-Helios-mixnet
type: inproceedings
title: Verifiability of Helios Mixnet
authors:
  - Ben Smyth
year: 2018
doi: 10.1007/978-3-662-58820-8_17
booktitle: "Voting'18: 3rd Workshop on Advances in Secure Electronic Voting"
series: LNCS
volume: "10958"
pages: 247--261
publisher: Springer
description: This manuscript analyses individual and universal verifiability of Helios's mixnet variant.
keywords: >-
  voting, election system, electronic voting, e-voting, Helios, mixnet, verifiability, individual
  verifiability, universal verifiability
abstract: >-
  We study game-based definitions of individual and universal verifiability by Smyth, Frink &
  Clarkson. We prove that building voting systems from El Gamal coupled with proofs of correct key
  generation suffices for individual verifiability. We also prove that it suffices for an aspect of
  universal verifiability. Thereby eliminating the expense of individual-verifiability proofs and
  simplifying universal-verifiability proofs for a class of encryption-based voting systems. We use
  the definitions of individual and universal verifiability to analyse the mixnet variant of Helios.
  Our analysis reveals that universal verifiability is not satisfied by implementations using the
  weak Fiat-Shamir transformation. Moreover, we prove that individual and universal verifiability
  are satisfied when statements are included in hashes (i.e., when using the Fiat-Shamir
  transformation, rather than the weak Fiat-Shamir transformation).
links:
  - file: Smyth18-Verifiability-Helios-Mixnet.LNCS.pdf
    text: Conference paper
  - file: Smyth18-Verifiability-Helios-Mixnet.pdf
    text: Extended version
    alt:
      url: https://eprint.iacr.org/2018/017
      text: Cryptology ePrint Archive version