Pretty Good Democracy for a variety of voting schemes


August 1, 2011


Vanessa Teague


University of Melbourne


Code voting seeks to address the issues of privacy and integrity for Remote Internet Voting. It sidesteps many of the inherent vulnerabilities of the Internet and client platforms but it does not provide end-to-end verification that votes are counted as cast. In this paper, we propose a simple technique to enhance the verifiability of code voting by ensuring that the Vote Server can only access the acknowledgement codes if the vote code is correctly registered by a threshold set of Trustees. The mechanism adds an extra level of verifiability in registering and counting the vote. Voter-verification is simple and direct: the voters need only check that the acknowledgement code returned to them agrees with the value on their code sheet. To ensure receipt-freeness we propose the use of a single acknowledgement code per code sheet, rather than individual acknowledgement codes for each candidate as with usual code voting.

I will first present Pretty Good Democracy for voting schemes in which the voter selects a single candidate, then show how it can be extended to more expressive voting schemes such as Borda, approval voting and STV.

(Joint work with Peter Ryan, University of Luxembourg, and James Heather, University of Surrey.)


Vanessa Teague

Dr Vanessa Teague is a researcher at the University of Melbourne. After completing her PhD thesis at Stanford on cryptographic protocols for rational participants, she returned to Australia and focused on end-to-end verifiable protocols for secure electronic voting, particularly those suitable for the obscure and complicated voting system used in Aus. She is co-chair of this year’s USENIX/ACCURATE Electronic Voting Technologies workshop and Workshop on Trustworthy Elections (EVT/WOTE 2011). She has also recently made a hobby of public criticism of insecure electronic voting protocols that are unsuitable for use in Australian elections but were used anyway.