![But Secrecy is Important.
Secret Ballot implemented in Chile in 1958.
“the secrecy of the ballot [...] has
...](https://image.slidesharecdn.com/2009-05-17-voting-security-overview-090525185641-phpapp01/85/voting-security-overview-51-320.jpg?cb=1243277827)
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Voting Security Overview
- 1. (Electronic) Voting Security Ben Adida Harvard University Workshop on Electronic Voting IDC Herzliya 17 May 2009
- 2. The Point of An Election
- 3. The Point of An Election “The People have spoken.... the bastards!” Dick Tuck 1966 Concession Speech
- 4. The Point of An Election “The People have spoken.... the bastards!” Dick Tuck 1966 Concession Speech Provide enough evidence to convince the loser.
- 5. quot;That's for me and a button to know.quot; Joe, the plumber.
- 6. 5
- 7. 5
- 8. 5
- 9. 5
- 10. 5
- 11. 5
- 12. 5
- 13. 6
- 14. 6
- 15. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 16. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 17. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 18. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 19. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 20. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 21. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/7
- 22. Fashionable Voting 8
- 23. Fashionable Voting 8
- 24. Voting is a fundamentally difficult problem. 9
- 25. Wooten got the news from his wife, Roxanne, who went to City Hall on Wednesday to see the election results. quot;She saw my name with zero votes by it. She came home and asked me if I had voted for myself or not.quot; 10
- 26. 14 12
- 27. 14 12 1 person, 1 vote
- 28. Enforced Privacy to ensure each voter votes in his/her own interest 12
- 29. http://www.cs.uiowa.edu/~jones/voting/pictures/ 13
- 30. 1892 - Australian Ballot http://www.cs.uiowa.edu/~jones/voting/pictures/ 14
- 31. The Ballot Handoff McCain Alice the Voter 17
- 32. The Ballot Handoff McCain Alice the Voter 17
- 33. The Ballot Handoff McCain Alice the Voter 17
- 34. The Ballot Handoff McCain Alice the Voter 17
- 35. The Ballot Handoff McCain Obama Obama Obama McCain McCain McCain Alice the Voter 17
- 36. The Ballot Handoff McCain Obama Obama Obama McCain McCain McCain Alice the Voter Black Box 17
- 37. Chain of Custody 18
- 38. Chain of Custody /* 1 * source * code */ if (... Vendor 18
- 39. Chain of Custody /* 1 * source * code Voting 2 */ Machine if (... Vendor 18
- 40. Chain of Custody /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 18
- 41. Chain of Custody /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice 18
- 42. Chain of Custody /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice 18
- 43. Chain of Custody /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice 5 Ballot Box Collection 18
- 44. Chain of Custody /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice Results 5 6 ..... Ballot Box Collection 18
- 45. Chain of Custody /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice Results 5 6 ..... Ballot Box Collection Black Box 18
- 46. The Cost of Secrecy
- 47. The Cost of Secrecy
- 48. The Cost of Secrecy
- 49. The Cost of Secrecy
- 50. The Cost of Secrecy
- 51. But Secrecy is Important. Secret Ballot implemented in Chile in 1958. “the secrecy of the ballot [...] has first-order implications for resource allocation, political outcomes, and social efficiency.” [BalandRobinson 2004]
- 52. Because we care about a meaningful result, we’ve made auditing very difficult. 21
- 53. We are left chasing evidence of correctness. Meanwhile we destroy evidence on purpose. 22
- 54. Obtaining Evidence /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice Results 5 6 ..... Ballot Box Collection 23
- 55. Obtaining Evidence /* 1 * source * code Polling Voting */ 3 2 Location Machine if (... Vendor - source code audit - Logic & Accuracy - Parallel Testing - Voter-Verified Paper Audit Trail
- 56. Obtaining Evidence Polling Location 3 - Multiple poll watchers competing affiliations - No personal 4 Alice electronic devices at the polling station - Logging all events
- 57. Obtaining Evidence - redundant counts - ballot box seals - statistical auditing by partial recounts Results 5 6 ..... Ballot Box Collection
- 58. Fragmented, Adversarial and Indirect - each piece of evidence covers a small segment of the chain. - attacker knows the checks, and can try to sneak in where the chain is not covered. - to maintain security and for practical purposes, the evidence is very indirect.
- 59. The Effect of DREs - More to audit - Errors can have disproportionate effects - Software is not just for speed/efficiency, it becomes central for integrity.
- 60. Software Independence an undetected mistake in the system does not cause an undetectable error in the tally.
- 61. Can we get more direct, more end-to-end evidence?
- 62. Secret Ballot vs. Verifiability Voting System convince Alice Carl the Coercer 31
- 63. Secret Ballot vs. Verifiability Voting System convince Alice Carl the Coercer [Chaum81], [Benaloh85], [PIK93], [BenalohTuinstra92], [SK94], [Neff2001], [FS2001], [Chaum2004], [Neff2004], [Ryan2004], [Chaum2005] Punchscan, Scantegrity I & II, Civitas, ThreeBallot, Prêt-à-Voter, Scratch & Vote, ... 31
- 64. Public Ballots Bulletin Board Bob: McCain Carol: Obama 32
- 65. Public Ballots Bulletin Board Bob: McCain Carol: Obama Alice 32
- 66. Public Ballots Bulletin Board Alice: Bob: Obama McCain Carol: Obama Alice 32
- 67. Public Ballots Bulletin Board Alice: Bob: Obama McCain Carol: Obama Tally Obama....2 McCain....1 Alice 32
- 68. Encrypted Public Ballots Bulletin Board Alice: Bob: Rice Clinton Carol: Rice Tally Obama....2 McCain....1 Alice 33
- 69. Encrypted Public Ballots Bulletin Board Alice: Bob: Rice Clinton Carol: Ali Rice ce ver Tally ifies he rv Obama....2 ote McCain....1 Alice 33
- 70. Encrypted Public Ballots Bulletin Board Alice: Bob: Rice Clinton Carol: Ali ce Rice ta lly ver e thTally ifies rifies ve he rv eryone ote E v Obama....2 McCain....1 Alice 33
- 71. End-to-End Verification
- 72. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Polling Location
- 73. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Ballot Box / Polling Bulletin Board Location Alice
- 74. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Ballot Box / Results Polling Bulletin Board Location ..... Alice
- 75. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Ballot Box / Results Polling Bulletin Board Location ..... 1 Alice Receipt
- 76. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Ballot Box / Results Polling Bulletin Board Location ..... 1 2 Alice Receipt
- 77. Open-Audit Elections
- 78. Evidence-Based Elections
- 79. Questions? ben_adida@harvard.edu