1. e-Voting
A Risk to Democracy
Ulrich Wiesner
www.ulrichwiesner.de
Copenhagen, 17 June 2010

2. 20 years ago...
• Copenhagen Meeting on the Human
Dimensions of the CSCE, 5-29 June 1990
• Adopting as general standard:
– Rule of law
– Free, fair, periodical elections
– ...
– Presence of domestic and international observers
in elections

3. Topics
• Situation in Germany
• Requirements for democratic elections
• Issues
• Can cryptography fix it?

4. Convention on International Trade in
Endangered Species, 2010
Testing the Conference E-Voting
• "Could everyone please vote 'Yes' now?“
– 128 Yes, 7 No, 2 Abstain
• "Is Doha the capital of Qatar?“
– 134 Yes, 2 No, 1 Abstain (Cameroon, Croatia, China)
– 135 Yes, 2 Abstain (Nigeria, Azerbaijan)
Source: The Economist, 24 March 2010, http://www.economist.com/blogs/babbage/2010/03/electronic_voting

5. Why eVoting?
Inappropriate Reasons Better Reasons
• Because it’s cheaper (?) • Multi-vote elections
• Because we’ve already (cumulative voting)
spent the money on the • Complex voting schemes
equipment • Multiple races or high
• Because it saves 1 hr of election frequencies
counting
• „Media attention for
Cologne“

6. e-Voting: what is the issue?
• Paper based election: white • eVoting: black box
box
• Ballot box is passive device
• No processing: Output is input • Voting computer is active
• Manipulations need to be device
conducted under the • Output might be input
public’s eyes
• Processing not observable

7. Fraud and errors not observable
• PowerVote • PowerFraud
Raised as issue
•by Commission on Electronic Voting in IE (2003)
•by Korthals Altes commission in NL (2007)
•by Federal Constitutional Court in DE (2009)
Resulted in banning of e-Voting in all three countries

8. eVoting in Germany
Nedap Voting machines
– 1999 – 2008
– 2M votes in 2005
– 2’000 of 80’000 polling
stations
Digital Pen
– Introduction in Hamburg
abandoned in 2007
– No plans for internet
Circle size represents number of polling
voting stations using computers

9. Nedap Voting Computer

10. Digital Pen
• 2D dot pattern, 90 dpi
• Dots are offset in 4 directions (up,
down, left, right)
• Pattern of 6x6 dots provide
coordinates for pen,
• Addresses* 436 squares of 2x2mm2
e.g. 20’000x20’000 km2
• *)Anoto refers to 60M km2

11. Certification Process until 2009
• Federal Voting Machine Act (unconstitutional)
– Evaluation of sample device by Federal Institute
for Physics and Technology
– Certification of model by Federal Ministry of
Interior
– Permission for use in a specific election by Federal
Ministry of Interior
– No evaluation of individual devices

12. Principles of Elections
• Verifiability, transparency and secrecy (procedure)
ensure that elections are free, fair and general (values)
se
cre
t
free
equal
general
in public auditable

13. Constitutional Implementation (Germany)
Section 38 (1)
Members of the German Bundestag shall be elected in
general, direct, free, equal, and secret elections. […]
Section 20 (1)
The Federal Republic of Germany is a democratic and
social federal state.

14. Election Scrutiny
• Complaint to scrutiny
committee of
Bundestag
– Filed Nov 2005
– Rejected Dec 2006
• Complaint to Federal
Constitutional court
– Filed Feb 2007
– Hearing Oct 2008
– Judgement Mar 2009

15. German Federal Constitutional Court
(2 BvC 3/07 – March 2009)
1. The fundamental decision for the principles of
democracy, republic and conduct of law require
elections to be conducted in a transparent
manner.
2. All relevant steps need to be verifiable by the
public (unless other constitutional principles
require something else)
3. If voting technology is used, all relevant steps of
the election and the determination of the result
need to be verifiable by any citizen and without
any specialist knowledge .
http://www.bundesverfassungsgericht.de/entscheidungen/rs20090303_2bvc000307en.html

16. Cryptography
Conflicting goals: Secrecy of vote and
transparency/auditability
In e-Voting, you can’t have both

17. Approach
• What all proposals have in common:
– Ballots have a unique id (random/serial number)
– Voters receive a receipt which contains their vote
in an encrypted form
– All encrypted votes are published
– Voter can verify that his vote is on the list

18. Cryptography and Elections
• Proposals:
– Prêt-à-Voter (P A Ryan, D Chaum, S A Schneider, 2005)
– ThreeBallot (R L Rivest, 2006)
– Scratch & Vote (B Adida, R Rivest, 2006 )
– Punchscan (D Chaum, 2006)
– Scantegrity (D Chaum, 2007)
– Bingo-Voting (J M Bohli, J Müller-Quade, S Röhrich, 2007)
– VoteBox (D Wallach et al, 2007)
– Scantegrity 2 (D Chaum, R Rivest et al, 2008)

19. Scantegrity 2
• Goal: provide additional security to optical
scanning systems
123456 123456 123456
123456 123456 123456
1AC Candidate A Candidate A Candidate A
W46 Candidate B Candidate B Candidate B
J3C Candidate C Candidate C J3C Candidate C
#123456 #123456 #123456
prepare hide vote
David Chaum et al., 2007
D. Chaum, R. Rivest, et al., 2008

20. Bingo Voting
• Preparation Phase
– For each voter, prepare
a random number for
every candidate
(“dummy votes”)
– Commit to
candidate/number pairs
– Commitments are
shuffled and published
on bulletin board
Jens-Matthias Bohli, Jörn Müller-Quade, Bulletin Board
Stefan Röhrich, 2007

21. Bingo Voting Vote for
Candidate A
• Voting Phase
– Voter selects candidate
– Fresh random number is
generated (“Bingo”) and
presented to voter
– Machine will print receipt
with
• fresh random number next
to chosen candidate
• Dummy votes next to other
candidates Bingo Voting
Receipt #365345
– Voter verifies that fresh
random number is next to Candidate A Candidate B Candidate C Candidate D
Candidate A 7274005338
Candidate B 4331957287
the chosen candidate 6590639838
9833598816
2520374482
8363113427
7212101090
1256726340
0886217910
1929824271 Candidate C 0683785432
• Voter takes receipt home 0493602852
1282600713
4765268594
4819451232
6198852851
7628033922
2108748691
6588916051
3676093186
9837776014
5298189700
0499224103
Candidate D 6875191193
for later verification 9878973891
3001529408
4331957287
6730909097
2907441205
9453541167
6875191193
9292058742
1796122212 4044134963 9799374379 4839552381
• Receipt does not allow the 9478710903
0139099844
9424374180
1707764919
0683785432
1129607005
6737547570
7873063572
voter to proof his vote 3381155817
4714748971
8367481777
6882788475
5985589286
2959387527
7767137671
6576688585
... ... ... ...
Bulletin Board

22. Bingo Voting
• With his vote for
Candidate A, the voter
reduces the number of
remaining dummy votes
for all other voters by 1
• At the end of the
election, the result can
be determined (and
verified) by counting
the un-used dummy
votes.

23. Bingo Voting
• Post Voting Phase
– Publish results
– Publish all receipts
– List all unused dummy votes and corresponding
commitments
– Prove that every unopened commitment was
used on one receipt
• Makes use of Randomized Partial Checking

24. Cryptography - Issues
• Implementation
• Usability
• Verifiability
• Complexity

25. Summary
• Transparency and Verifiability!
– Fundamental feature
– Legitimates elected body
• Trade offs not acceptable:
– Secrecy vs. transparency/verifiability
– Verifiability vs. election efficiency
wahlcomputer@ulrichwiesner.de