secure voting
DESCRIPTION
A short and sweet version of my voting talk for the Harvard College Fund meeting. The talk started with Stuart Shieber and ended with Greg Morrisett. I haven't included their slides here, as I'm not sure what license they'd like to use.TRANSCRIPT
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School of Engineering and Applied SciencesHarvard University
Voters, Computers, and Trust: Designing Verifiable Elections
Stuart M. ShieberBen Adida
Greg MorrisettCenter for Research on Computation and Society
October 18, 2008
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Secure Voting
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• Voting is particularly challenging:requires secrecy and public auditability.
• Computer science enablesqualitatively novel solutions.
• Cryptography can reconcileseemingly contradictory requirements.
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"That's for me and a button to know."
Joe, the plumber.
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“When I finally sawthe results of our tests,
I thought I was going to throw up.”
Sec. of State, Ohio, last week.
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
http://www.cs.uiowa.edu/~jones/voting/pictures/9
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Fashionable Voting
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Voting is a fundamentally difficult problem.
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1 person, 1 vote
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Enforced Privacyto ensure each voter
votes in his/herown interest
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http://www.cs.uiowa.edu/~jones/voting/pictures/ 14
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http://www.cs.uiowa.edu/~jones/voting/pictures/
1892 - Australian Ballot
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The Ballot Handoff
Alice the Voter
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McCain
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The Ballot Handoff
Alice the Voter
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McCain
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The Ballot Handoff
Alice the Voter
16
McCain
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The Ballot Handoff
Alice the Voter
16
McCain
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The Ballot Handoff
Alice the Voter
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McCain
ObamaObamaObama
McCainMcCain
McCain
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The Ballot Handoff
Alice the Voter
16
McCain
ObamaObamaObama
McCainMcCain
Black Box
McCain
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Chain of Custody
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Chain of Custody
Vendor
/*
* source
* code
*/
if (...
1
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
Polling Location
3
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
Polling Location
3
4
Alice
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
Polling Location
3
4
Alice
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
Polling Location
3
Ballot Box Collection
5
4
Alice
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
Polling Location
3
Ballot Box Collection
5
Results
.....6
4
Alice
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Chain of Custody
VotingMachine
2
Vendor
/*
* source
* code
*/
if (...
1
Polling Location
3
Ballot Box Collection
5
Results
.....6
4
Alice
Black Box19
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Computers have only obscured the process.
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Computers have only obscured the process.
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What aboutcomputer science?
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Cryptographysolving problems that initially
appear to have conflicting requirements.
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Public-Key Encryption
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Customer
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Public-Key Encryption
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Customer
public key
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Public-Key Encryption
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Customer
public key
enc(cc number)
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Bulletin Board
Public Ballots
Bob:McCain
Carol:Obama
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Bulletin Board
Public Ballots
Bob:McCain
Carol:Obama
Alice
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Bulletin Board
Public Ballots
Alice:Obama
Bob:McCain
Carol:Obama
Alice
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Bulletin Board
Public Ballots
Alice:Obama
Bob:McCain
Carol:Obama
Tally
Obama....2McCain....1
Alice
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Encrypted Public BallotsBulletin Board
Alice:Rice
Bob:Clinton
Carol:Rice
Tally
Obama....2McCain....1
Alice
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Encrypted Public BallotsBulletin Board
Alice:Rice
Bob:Clinton
Carol:Rice
Tally
Obama....2McCain....1
Alice
Alice verifies her vote
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Encrypted Public BallotsBulletin Board
Alice:Rice
Bob:Clinton
Carol:Rice
Tally
Obama....2McCain....1
Alice
Alice verifies her vote Everyone verifies the tally
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How can we verify operations on
encrypted data?
Mathematical Proofs.
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Zero-Knowledge Proof
Vote For:
Obama
President:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MouseVote For: Obama
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Zero-Knowledge Proof
Vote For:
Obama
President:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MouseVote For: Obama
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Zero-Knowledge Proof
This last envelope likely contains “Obama”
Vote For:
Obama
President:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MouseVote For: Obama
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Zero-Knowledge Proof
Open envelopes don’t proveanything after the fact.
President:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MouseVote For: Obama
President:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MousePresident:
Mickey MouseVote For:
Paul
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McCain