key: 2024-tally-then-decrypt
type: misc
title: Championing tally-then-decrypt secrecy
authors:
  - Ben Smyth
year: 2024
description: >-
  This manuscript shows that verifiable voting systems require a security notion beyond individual-
  and universal-verifiability plus cast-as-intended
keywords: voting, privacy, secrecy, anonymity, election system, electronic voting, e-voting
abstract: >-
  Ballot secrecy is achievable with varying degrees of information leakage: At one extreme,
  <i>winner-only secrecy</i> reveals just the winning candidate. At the other, <i>secrecy by
  anonymity</i> reveals anonymised votes. I champion <i>tally-then-decrypt secrecy</i> for
  delivering on traditional privacy expectations, wherein an election reveals nothing more than a
  frequency distribution of voters' votes. The gulf between anonymised votes and vote frequency
  distributions is witnessed by mixnets revealing the contents of every individual ballot (i.e.,
  anonymised votes), whilst homomorphically combining ballots reveals only a frequency distribution.
links:
  - file: Smyth24-Tally-then-Decrypt.pdf
    text: Draft