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What and Who

Proving Pret a Voter Receipt Free in the Computational Models

Dr. Dalia Daoud Suleiman Khader
University of Luxembourg
SWS Colloquium, Post Doc Application Talk
AG 1, AG 2, AG 3, AG 4, AG 5, SWS, RG1  
Expert Audience
English

Date, Time and Location

Friday, 28 March 2014
12:00
60 Minutes
E1 5
0.29
Saarbrücken

Abstract

Pret a Voter is a supervised, end-to-end verifiable voting scheme. Informal analyses indicate that, subject to certain assumptions, Pret a Voter is receipt free,
i.e. a voter has no way to construct a proof to a coercer of how she voted. In this paper we propose a variant of Pret a Voter and prove receipt freeness of this
scheme using computational methods. Our proof shows that if there exists an adversary that breaks receipt freeness of the scheme then there exists an adversary
that breaks the IND-CCA2 security of the Naor-Yung encryption scheme.
We propose a security model that defines receipt freeness based on the indistinguishability of receipts. We show that in order to simulate the game we require
an IND-CCA2 encryption scheme to create the ballots and receipts. We show that, within our model, a non-malleable onion is sufficient to guarantee receipt freeness.
Most of the existing Pret a Voter schemes do not employ IND-CCA2 encryption in the construction of the ballots, but they avoid such attacks by various additional
mechanisms such as pre-commitment of ballot material to the bulletin board, digitally signed ballots etc. Our use of the Naor-Yung transformation provides the
IND-CCA2 security required.

Contact

Prof. Dr. Michal Backes
0681 302-3249
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Tags, Category, Keywords and additional notes

SWS Colloquium, Post Doc Application Talk, Prof. Dr. Michael Backes

Stephanie Feyahn, 03/24/2014 09:34 -- Created document.