Development of world’s first end-to-end verifiable voting system

Research by Professor Steve Schneider and Dr Chris Culnane, Department of Computer Science, University of Surrey

An accredited Global Uncertainties project funded by the Engineering and Physical Sciences Research Council (EP/G025797/1)

While various ‘e-voting’ systems have been piloted around the world, researchers in Surrey’s Department of Computing led by Professor Steve Schneider, with Dr Chris Culnane as lead system architect, have developed the world’s first end-to-end verifiable electronic voting system. This was successfully deployed in the State of Victoria election in Australia in November 2014.

The Victorian election constituted a number of world firsts:

  • First time an end-to-end verifiable electronic voting system was deployed in a state-wide statutory political election worldwide
  • First time blind voters have been able to cast a fully secret vote in a verifiable way
  • First time a verifiable voting system has been used to collect remote votes in a political election

Based on open source code, the verifiable voting system is a secure and trustworthy electronic voting system which protects against fraud, and fosters greater trust in the electoral process, by allowing voters to check that their votes have been accurately recorded. The system also encrypts receipts so that votes remain completely secret.

The system features a printed ballot form with the candidates listed in a randomised order (ie different on different ballot forms). The voter makes their selection and then destroys the list of candidates, retaining and casting their marked preference list for verifiable tallying.

An early prototype based on the ‘Pret a Voter’ design, was developed in 2007 at Surrey, winning ‘best system design’ at VoComp 2007.  More recently in 2011 the team was approached by the State of Victoria and spent three years refining the system to meet the needs of the Victorian election in 2014.

The State of Victoria has a proud history of innovation in voting systems, having introduced the secret ballot and deployed the world’s first secret ballot election in 1856. It had already run electronic voting systems at its 2006 and 2010 elections but was seeking a verifiable system to give better assurances of the integrity of the ballot.

With voting compulsory in Australia, the election authorities are obliged to make every effort to enable people to vote, so better accessibility for blind, partially sighted and motor impaired voters was a key requirement. Elections also need to cater for the broad range of languages spoken by Victoria’s citizens, as well as expatriate Australians living in other countries around the world. In addition, since Victorian elections are based on the single transferable vote, the ballot is very complex, with voters required to rank a list of around 40 candidates in their preferred order.

Surrey’s verifiable voting system was able to meet these needs and provide a chain of links all the way from the initial casting of the vote right through to the tallying, reassuring voters that their vote has been cast as they intended. By incorporating an audio interface, the system enabled blind and partially-sighted voters to cast a fully secret vote in a verifiable way.

The verifiable voting system was deployed for the last two weeks of November 2014 for ‘early voting’ at 24 voting centres in Victoria, where it was offered to particular target groups of voters (the blind, partially-sighted and motor impaired). It was also made available to all voters at the Australia Centre in London.

In this controlled deployment, the verifiable voting system ran perfectly with no need for rebooting throughout the two-week period. A total of 1,121 votes were cast, with a very low level of spoilt ballots (1.9 per cent, compared with 4.3 per cent for paper voting). A survey of voters in the London election found that 75 per cent preferred the electronic system to paper voting.

In separate tests, the system proved to be capable of handling a million votes and was able to respond to individual voters within 10 seconds, and accept 800 votes in a 10 second period.

Following the success of the verifiable voting system at the Victorian election, Professor Schneider and his team are looking at opportunities for commercialisation and roll-out of the system.