Demonstration of the Version 1 Prototype

of Prêt à VoterSteve Schneider, Chris

CulnaneUniversity of Surrey

SecVote, Bertinoro 3rd September 2010

Prêt à Voter Prototype Version 1

• Entry in VoComp 2007• Starting point system for the Trustworthy Voting Systems (TVS)

project (Surrey, Birmingham, Luxembourg) 2009-2013• Used for focus groups• Original versions for STV (USSU, VoComp) • More recent version for FPTP

• Hardware: off the shelf (laptop; printer/scanners)

• Version 2 to be produced during the TVS project…

A brief guide to voting with Prêt à Voter

1. Alice1. Alice

2. Bob2. Bob

3. Crystal3. Crystal

4. Diane4. Diane

5. Elaine5. Elaine

Casting a vote

• Place X against desired candidate.• Separate left hand side.• Destroy left hand side.• Cast (scan) vote and get signed.• Take receipt home.

6QakL5sR6QakL5sRsignedsigned

Bulletin Board publishes the ballots cast.

Public bulletin boardof votes cast.

x

x

x

x

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Voter’s receipt

• Voter receipts prevent election officials from discarding or altering votes.

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Auditing ballot forms

• A voter might have the following concern:– Suspect ballot forms.– What if the encrypted order doesn’t match the printed order?

• This should not happen if the ballot forms are correctly constructed. But how can the voter be satisfied of this?

1. Alice1. Alice

2. Bob2. Bob

3. Crystal3. Crystal

4. Diane4. Diane

5. Elaine5. Elaine

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A vote for Crystal would A vote for Crystal would be counted for Alicebe counted for Alice

Auditing the ballot forms

• To audit a ballot form – a voter can have it decrypted without voting, and check that the result matches the printed candidate order.

• In principle the crypto can be checked (randomness exposed)• We introduce the option to audit as part of the voting process. • Voters can do this with as many forms as they like (in principle!)

This gives them confidence that the ballot forms are correctly constructed.

1. Alice1. Alice

2. Bob2. Bob

3. Crystal3. Crystal

4. Diane4. Diane

5. Elaine5. Elaine

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A Ballot Form

System Demo• To Vote

– Mark X against your chosen candidate– Remove and destroy the left-hand side– Scan the right hand side– Obtain your (newly printed) receipt. [Also enables check of scan.]

• To Audit– Do not mark any X– Remove the left-hand side but do not discard it– Scan the right hand side - the blank ballot triggers an audit– Check that the order produced matches the order left-hand side

• To Check the receipt (and eventually the result) with your laptop– Log into the bulletin board. For this demo it is at:

• SSID: clone (no password, no encryption)• Go to http://192.168.2.99/pav/receiptlookup.php

– Submit your serial number and compare against your receipt