Heliosweb-based

truly verifiable votingBen Adida

Harvard University

MSR Voting Technology Workshop19 March 2010

“Web Based????”- many elections are happening

on the web already, whether we like it or not.

- online elections are the least auditable of all:you can’t even watch the ballot box.

- opportunity for a clear win:improve auditability of elections that willhappen online no matter what.

- risk: people will think web-based votingis okay for all eelections.

Low-Coercion

- web-based elections assumelow coercion already.

- If the voting public is a subset of the population, there may be inherent limits to coercion.

- e.g. university voting

Technical Concepts

- Probabilistic Encryption & Threshold Decryption.posting ciphertexts safely on a web site

- Homomorphic Tallying.no write-ins, proofs of correct plaintext

- Benaloh Challenge.cast or audit, authenticate only upon cast

- In-Browser Encryption.plaintext only in user’s browser

"AUDIT"

Alice

EncryptedBallot

Alice

DecryptedBallot

Alice

"CAST"

SignedEncryptedBallot

Alice

http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg

SignedEncryptedBallot

DecryptedBallot

EncryptedBallot

VERIFICATION

"Obama"

Helios System Details

- Python & JavaScript logic & crypto

- Free/Open-Source stack

- Deployed on Google App Engine

- Deployed on Apache/Python/PostgreSQL

- Customizableauthentication, look-and-feel, translations

So, does it work?

- Université catholique de Louvain25,000 eligible voters - 5000 votesUniversity president electionHelios 2.0, optimizedcustomized for UCL (French, improved UI)

- Princeton University undergraduate government5000 eligible voters - 1500 votesauthentication integration with CASHelios 3.0a

Université catholiquede Louvain

[de Marneffe, Pereira, Quisquater]

8

9

10

11

12

most fun tidbit

in the first round,the leader was

short of winningby 2 votes out of 5000.

most interesting lesson

spurious claimsare easily countered

Princeton

15

16

FROM TO 2010 2011 2012 2013

2009-12-14 17:00:002009-12-14 18:00:00 44 68 80 74

2009-12-14 18:00:002009-12-14 19:00:00 26 36 47 43

2009-12-14 19:00:002009-12-14 20:00:00 13 10 16 27

2009-12-14 20:00:002009-12-14 21:00:00 11 21 21 22

2009-12-14 21:00:002009-12-14 22:00:00 6 14 17 18

2009-12-14 22:00:002009-12-14 23:00:00 4 5 9 9

2009-12-14 23:00:002009-12-15 00:00:00 3 1 8 7

2009-12-15 00:00:002009-12-15 01:00:00 0 6 6 6

2009-12-15 01:00:002009-12-15 02:00:00 5 14 6 11

2009-12-15 02:00:002009-12-15 03:00:00 10 15 2 8

2009-12-15 03:00:002009-12-15 04:00:00 3 5 7 5

2009-12-15 04:00:002009-12-15 05:00:00 9 5 5 0

2009-12-15 05:00:002009-12-15 06:00:00 2 1 6 2

2009-12-15 06:00:002009-12-15 07:00:00 2 3 1 5

2009-12-15 07:00:002009-12-15 08:00:00 1 6 2 3

2009-12-15 08:00:002009-12-15 09:00:00 0 1 0 0

2009-12-15 09:00:002009-12-15 10:00:00 0 0 0 0

2009-12-15 10:00:002009-12-15 11:00:00 0 0 0 0

2009-12-15 11:00:002009-12-15 12:00:00 0 0 0 0

2009-12-15 12:00:002009-12-15 13:00:00 0 0 0 0

2009-12-15 13:00:002009-12-15 14:00:00 0 2 1 0

2009-12-15 14:00:002009-12-15 15:00:00 1 2 0 0

2009-12-15 15:00:002009-12-15 16:00:00 0 1 0 0

2009-12-15 16:00:002009-12-15 17:00:00 3 0 1 1

2009-12-15 17:00:002009-12-15 18:00:00 1 0 0 1

2009-12-15 18:00:002009-12-15 19:00:00 1 1 2 1

2009-12-15 19:00:002009-12-15 20:00:00 25 27 4 15

2009-12-15 20:00:002009-12-15 21:00:00 6 5 1 12

2009-12-15 21:00:002009-12-15 22:00:00 0 13 2 3

2009-12-15 22:00:002009-12-15 23:00:00 3 0 1 4

2009-12-15 23:00:002009-12-16 00:00:00 0 2 2 2

2009-12-16 00:00:002009-12-16 01:00:00 1 4 0 1

2009-12-16 01:00:002009-12-16 02:00:00 2 5 4 1

2009-12-16 02:00:002009-12-16 03:00:00 1 3 4 5

2009-12-16 03:00:002009-12-16 04:00:00 0 0 0 0

2009-12-16 04:00:002009-12-16 05:00:00 0 0 0 0

2009-12-16 05:00:002009-12-16 06:00:00 0 0 0 0

2009-12-16 06:00:002009-12-16 07:00:00 0 0 0 0

2009-12-16 07:00:002009-12-16 08:00:00 0 0 0 0

2009-12-16 08:00:002009-12-16 09:00:00 0 0 0 0

2009-12-16 09:00:002009-12-16 10:00:00 0 0 0 0

2009-12-16 10:00:002009-12-16 11:00:00 0 0 0 0

2009-12-16 11:00:002009-12-16 12:00:00 0 0 0 0

2009-12-16 12:00:002009-12-16 13:00:00 0 0 0 0

2009-12-16 13:00:002009-12-16 14:00:00 0 0 0 0

2009-12-16 14:00:002009-12-16 15:00:00 0 0 0 0

2009-12-16 15:00:002009-12-16 16:00:00 0 0 0 0

2009-12-16 16:00:002009-12-16 17:00:00 0 0 0 0

2009-12-16 17:00:002009-12-16 18:00:00 0 0 0 0 0

20

40

60

80

Princeton Winter 2009 Runoff Election, # votes cast per class per hour

2010 2011 2012 2013

most interesting lesson

voting is error-prone ;true verifiability can help recover

vote herehttp://tinyurl.com/mshelios

Open Problems

- Java!

- additional ways of ensuring that thesame booth code is run by all.

- giving a choice to voters to do a trueinteractive proof of the vote they actually cast.

- STV?

- Deep Issue: is enforced privacy over?

Questions?ben_adida@harvard.edu

http://heliosvoting.org/