Voter Verifiable and Single Transferable Electronic Voting for Elections with Electoral Barriers

Yucel O., BAYKAL N.

9th European Conference on e-Government, London, Canada, 29 - 30 June 2009, pp.703-710 identifier

  • Publication Type: Conference Paper / Full Text
  • City: London
  • Country: Canada
  • Page Numbers: pp.703-710
  • Middle East Technical University Affiliated: Yes


"Voter verifiability" is a notion offered by some electronic voting schemes, which develops into an important issue of democracy in the electronic world. The idea is to endow each voter with the facility of verifying that his vote is counted correctly. The check mechanism for the correct count of the vote can be provided by means of a voting receipt. On the other hand, whenever one has a receipt that serves to check the correct casting and tallying of the vote, it can also be used as the proof for the content of the vote. This may lead to voter coercion and ballot-selling, which in turn injures democracy. Hence, previous versions of the electronic voting schemes have avoided giving receipts to the voters, and introduced the concept of receipt-freeness as an integral part of the voting system. Nonetheless, e-voting can only be made to work if voters trust in the system, and receipts are useful in building this trust. "Pret a Voter" is an e-voting scheme proposed by Chaum, Ryan et al, which provides voter verifiability without any threat of voter coercion and ballot-selling; because, the receipt does not tell anything about the content of the vote to anybody except for the voter himself. The last version, "Pret a Voter: All-In-One" scheme proposed in 2007 also solves the problem of handling the Single Transferable Voting (STV) elections efficiently. We focus on STV elections and propose a protocol modification for the elections; in which political parties, whose votes remain below a certain barrier, are eliminated. Our proposal prevents the loss of votes used for the eliminated parties and distributes them securely to the second or higher choices of their voters. This protocol is then applied to the Pret a Voter: All-In-One scheme, which we suitably modify to enhance the security of its ballot-construction phase. We finally adapt the STV protocol to Turkish parliamentary elections, by taking into consideration the present details of the tallying strategy within each election region.