Kickoff Meeting „ E-Voting Seminar“

1. Kickoff Meeting „E-Voting Seminar“ An Introduction toCryptographicVoting Systems Prof. Andreas Steffen Hochschule für Technik Rapperswil andreas.steffen@hsr.ch

2. Cryptographic Voting Systems Summary of my talk: • Due to repeatedfailures and detectedvulnerabilities in bothelectro-mechanical and electronicvotingmachines, votershavesomehow lost faiththattheoutcome of a poll alwaysrepresentsthetrue will of theelectorate. • Even moreuncertainiselectronicvotingoverthe Internet whichispotentiallyprone to coercion and vote-selling (thisdoesn‘tseem to be an issue in Switzerland). • Manual counting of paperballotsis not really an option in the21stcentury and is not freefromtamperingeither. • Modern cryptographicvotingsystemsallowtrueend-to-endverification of thecompletevotingprocessbyanyindividualvoter, withoutsacrificingsecrecy and privacy.

3. Losing Trust in Electronic Voting Systems 2006 - The Morning Call: Voter smashes DRE in Allentown with metal cat 2006 - Princeton study on Diebold DRE: Hack the vote? No problem March 3 2009 - Germany: Bundesverfassungsgericht bansunverifiableE-voting 2006 - Dutch ES3B voting machines: Hacked to play chess

4. E-Voting in myhometown Schlieren Hidden PIN „Internet-basedvotingdoes not havetobemoresecure as voting per snailmail“ Justice Department of theCanton of Zurich

5. [In]Security Features ??? ProtectionfromMan-in-the-Middleattacks

6. E-Voting Website

7. Voter Login

8. Ballot (PHP Form)

9. E-Voting in myhometown Schlieren PIN

10. VoterAuthentication

11. Transmission Receipt

12. Conclusion So what? „Youare not allowed to know. Theexacttransactionprocessingiskeptsecretdue to securityreasons“Justice Department of theCanton of Zurich

13. Traditional Chain-of-Custody Security Software Verification Sealing Tallying Verification by proxy only Source: Ben Adida, Ph.D. Thesis 2006

14. Desirable: End-to-End Verification by Voter Secrecy? Privacy? Source: Ben Adida, Ph.D. Thesis 2006

15. End-to-End Auditable Voting System (E2E) • Any voter can verify that his or her ballot is included unmodified in a collection of ballots. • Any voter (and typically any independent party additionally) can verify [with high probability] that the collection of ballots produces the correct final tally. • No voter can demonstrate how he or she voted to any third party (thus preventing vote-selling and coercion). Source: Wikipedia

16. Solution: Cryptographic Voting Systems ThresholdDecryption Mixnet A B A B C C ElGamal /Paillier Tamper-ProofBulletin Board HomomorphicTallying Source: Ben Adida, Ph.D. Thesis 2006

17. Proposed E2E Systems • Punchscan by David Chaum. • Prêt à Voter by Peter Ryan. • Scratch & Vote by Ben Adida and Ron Rivest. • ThreeBallot by Ron Rivest (paper-based without cryptography) • Scantegrity II by David Chaum, Ron Rivest, Peter Ryan et al.(add-on to optical scan voting systems using Invisible Ink) • Helios by Ben Adida (http://www.heliosvoting.org/)

18. Scratch & Vote Ballot Perforation Encryptpk(256, r1) Encryptpk(20 , r2) Encryptpk(228, r3) Obama Randomized candidate list None McCain 2D barcode ElGamal or Paillier Public Key Encryption r1 r2 r3 Random Key Scratch surface Source: Ben Adida, Ph.D. Thesis 2006

19. Homomorphic Counters 256 00...01 00...00 00...00 One vote for Obama 228 00...00 00...01 00...00 One vote for McCain 20 00...00 00...00 00...01 One vote for None Obama McCain None 00...10 00...01 00...00 Tallying Counter Multiplication of all encrypted votes with Tallying Counter accumulates votes in the candidates‘ counters in encrypted form. Total number of registered U.S. voters < 228 (28 bits) 1024 bit Paillier Public Key Cryptosystem could handle 35 candidates Source: Ben Adida, Ph.D. Thesis 2006

20. Vote Audit Pre-Voting Verification I McCain None Obama Obama None McCain Valerie the Voter Source: Ben Adida, Ph.D. Thesis 2006

21. None Obama McCain Vote Audit Pre-Voting Verification II McCain None Obama Obama None McCain r1 r2 r3 Valerie the Voter Source: Ben Adida, Ph.D. Thesis 2006

22. Casting the Ballot I McCain  Obama None Valerie the Voter Source: Ben Adida, Ph.D. Thesis 2006

23. Casting the Ballot II McCain  Obama Ed the Election Official None Valerie the Voter Source: Ben Adida, Ph.D. Thesis 2006

24. Optical Scanner Keep as a receipt Casting the Ballot III  Ed the Election Official Valerie the Voter Source: Ben Adida, Ph.D. Thesis 2006

25. Post-Voting Verification Web Bulletin Board Valerie Vanessa Victor     Valerie the Voter Source: Ben Adida, Ph.D. Thesis 2006

26. Obama McCain None 00...10 00...01 00...00 Threshold decryption with shared private key Democrats Homomorphic Addition Republicans 0101101...11100100011 Independents Encrypted tallying counter Tally and Decryption of Final Result Web Bulletin Board Valerie Vanessa Victor    Source: Ben Adida, Ph.D. Thesis 2006

27. Conclusion • Modern Cryptographic Voting Systems allow true end-to-end verification of the whole voting process by anyone while maintaining a very high level of secrecy. • Due to the advanced mathematical principles they are based on, Cryptographic Voting Systems are not easy to understand and are therefore not readily accepted by authorities and the electorate. • But let‘s give Cryptographic Voting Systems a chance!They can give democracy a new meaning in the 21st century!