Masked Ballot Voting for Receipt-Free Online Elections

Sam Heinith, David Humphrey,

and Maggie Watkins

Why Online Voting?

- Quick election results- No paper ballot recounts- Less costly for the voter than mail-in elections - No long lines to vote - Faster than mailing in absentee ballots

Requirements For Secure Online Voting

• Universally Verifiable

• Receipt Free

• Individually Verifiable

• Untappable Channels• Anonymous Channels

How Masked Ballot Voting for Receipt-Free Online Elections

Works

- Three stages to an electionstage 1: Registrationstage 2: Votingstage 3: Unmasking

- SecurityElGamal Encryption ensures a vote

cannot be linked to a voter (secret ballots)

During an Election

Bulletin Board

Registrar/AuthorityVoter

Private

Public

Bulletin Board

Registrar/Authority

m, d

V, 〚 m 〛Store

Private Key

Publish Public Key

Voter

Stage 1: Registration

Public

Privatem = unique mask

d = security verifier

〚 m 〛 = encrypted maskV = unique voter ID

Voter

Bulletin Board

Registrar/Authority

〚 vote - m 〛 , p

Public

Stage 2: Voting

〚 vote - m 〛 = masked and encrypted vote

p = proof of plaintext knowledge

Private

Voter

Bulletin Board

Registrar/Authority

V, 〚 vote 〛

Election

Results

Unencrypted Unencrypted Results to be Results to be

countedcounted

vote

Public

Stage 3: Unmasking

〚 vote 〛 = encrypted vote

Read from BB Private

ElGamal Encryption- The Masked Ballot Voting scheme depends on a homomorphic encryption system because the masking and unmasking happens while the vote is still encrypted.

- ElGamal is a Homomorphic encryption system.

A homomorphic encryption system allows for performing operations on the cyphertext that predictably change the plaintext. 

Example of homomorphic property of ElGamal:

〚 vote - m 〛 = 〚 vote 〛 - 〚 m 〛

Decrypts to: vote - m

Assumptions

•Authority is not corrupt

•Authority has plenty of processing power

•Voters have little processing power

•Untappable channel during registration

•Voting is an atomic process

Sources

Wen, Roland, and Richard Buckland. "Masked Ballot Voting for Receipt-Free Online Elections." Lecture Notes in Computer Science, vol. 5767 (2009): pp. 18-36.

Schneier, Bruce. Applied Cryptography: Protocols, Algorithms, and Source Code in C. New York: Wiley, 1996. Print. (sited over 8,000 times according to Google Scholar)

Download Our Code!http://code.google.com/p/

maskedballotvoting/

Demonstration

http://maskedballotvoting.googlecode.com/files/client.jar

Questions?