Open-Audit Voting

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My open-audit voting talk given at Université Catholique de Louvain, on Feb 3rd, 2009.

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  • REALLY easy to verify



    “The County Election” by George Caleb Bingham


  • We choose secrecy. The secrecy implemented here is *very* good.




  • TAKE YOUR TIME WITH THIS!
    explain all details of every step
  • We give up on audit-ability and transparency












  • INSIST on EVERYONE!!!!
  • CHANGE VALERIE TO ALICE










  • AN OPPORTUNITY --> no observable process for online elections.
  • REACHING MORE PEOPLE.






  • GENERATION, too, is distributed.




























  • Open-Audit Voting

    1. 1. Open-Audit Voting How to let anyone verify an election Ben Adida Harvard University Université Catholique de Louvain 3 February 2009 Saturday, February 14, 2009
    2. 2. The Point of An Election Saturday, February 14, 2009
    3. 3. The Point of An Election “The People have spoken.... the bastards!” Dick Tuck 1966 Concession Speech Saturday, February 14, 2009
    4. 4. The Point of An Election “The People have spoken.... the bastards!” Dick Tuck 1966 Concession Speech Provide enough evidence to convince the loser. Saturday, February 14, 2009
    5. 5. Saturday, February 14, 2009
    6. 6. quot;That's for me and a button to know.quot; Joe, the plumber. Saturday, February 14, 2009
    7. 7. 5 Saturday, February 14, 2009
    8. 8. 5 Saturday, February 14, 2009
    9. 9. 5 Saturday, February 14, 2009
    10. 10. 5 Saturday, February 14, 2009
    11. 11. 5 Saturday, February 14, 2009
    12. 12. 5 Saturday, February 14, 2009
    13. 13. 5 Saturday, February 14, 2009
    14. 14. 6 Saturday, February 14, 2009
    15. 15. 6 Saturday, February 14, 2009
    16. 16. “When I finally saw the results of our tests, I thought I was going to throw up.” Secretary of State of Ohio, two weeks before 2008 US Presidential Elections Saturday, February 14, 2009
    17. 17. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    18. 18. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    19. 19. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    20. 20. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    21. 21. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    22. 22. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    23. 23. Fashionable Voting http://www.cs.uiowa.edu/~jones/voting/pictures/8 Saturday, February 14, 2009
    24. 24. Fashionable Voting 9 Saturday, February 14, 2009
    25. 25. Fashionable Voting 9 Saturday, February 14, 2009
    26. 26. Voting is a fundamentally difficult problem. 10 Saturday, February 14, 2009
    27. 27. 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; 11 Saturday, February 14, 2009
    28. 28. 12 Saturday, February 14, 2009
    29. 29. 14 12 12 Saturday, February 14, 2009
    30. 30. 14 12 1 person, 1 vote 12 Saturday, February 14, 2009
    31. 31. Enforced Privacy to ensure each voter votes in his/her own interest 13 Saturday, February 14, 2009
    32. 32. http://www.cs.uiowa.edu/~jones/voting/pictures/ 14 Saturday, February 14, 2009
    33. 33. 1892 - Australian Ballot http://www.cs.uiowa.edu/~jones/voting/pictures/ 15 Saturday, February 14, 2009
    34. 34. The Ballot Handoff McCain Alice the Voter 16 Saturday, February 14, 2009
    35. 35. The Ballot Handoff McCain Alice the Voter 16 Saturday, February 14, 2009
    36. 36. The Ballot Handoff McCain Alice the Voter 16 Saturday, February 14, 2009
    37. 37. The Ballot Handoff McCain Alice the Voter 16 Saturday, February 14, 2009
    38. 38. The Ballot Handoff McCain Obama Obama Obama McCain McCain McCain Alice the Voter 16 Saturday, February 14, 2009
    39. 39. The Ballot Handoff McCain Obama Obama Obama McCain McCain McCain Alice the Voter Black Box 16 Saturday, February 14, 2009
    40. 40. Saturday, February 14, 2009
    41. 41. Saturday, February 14, 2009
    42. 42. Chain of Custody 19 Saturday, February 14, 2009
    43. 43. Chain of Custody 1 /* * source * code */ if (... Vendor 19 Saturday, February 14, 2009
    44. 44. Chain of Custody 1 /* * source * code Voting */ 2 Machine if (... Vendor 19 Saturday, February 14, 2009
    45. 45. Chain of Custody 1 /* * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 19 Saturday, February 14, 2009
    46. 46. Chain of Custody 1 /* * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice 19 Saturday, February 14, 2009
    47. 47. Chain of Custody 1 /* * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice 19 Saturday, February 14, 2009
    48. 48. Chain of Custody 1 /* * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice 5 Ballot Box Collection 19 Saturday, February 14, 2009
    49. 49. Chain of Custody 1 /* * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice Results 5 6 ..... Ballot Box Collection 19 Saturday, February 14, 2009
    50. 50. Chain of Custody 1 /* * source * code Polling Voting */ 3 2 Location Machine if (... Vendor 4 Alice Results 5 6 ..... Ballot Box Collection Black Box 19 Saturday, February 14, 2009
    51. 51. The Cost of Secrecy Saturday, February 14, 2009
    52. 52. The Cost of Secrecy Saturday, February 14, 2009
    53. 53. The Cost of Secrecy Saturday, February 14, 2009
    54. 54. The Cost of Secrecy Saturday, February 14, 2009
    55. 55. The Cost of Secrecy Saturday, February 14, 2009
    56. 56. 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] Saturday, February 14, 2009
    57. 57. Computers have obscured the process. 22 Saturday, February 14, 2009
    58. 58. Computers have obscured the process. What about computer science? 22 Saturday, February 14, 2009
    59. 59. Cryptography solving problems that initially appear to have conflicting requirements. 23 Saturday, February 14, 2009
    60. 60. Public-Key Encryption Customer 24 Saturday, February 14, 2009
    61. 61. Public-Key Encryption public key Customer 24 Saturday, February 14, 2009
    62. 62. Public-Key Encryption public key enc(cc number) Customer 24 Saturday, February 14, 2009
    63. 63. Secret Ballot vs. Verifiability Voting System convince Alice Carl the Coercer 25 Saturday, February 14, 2009
    64. 64. 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, ... 25 Saturday, February 14, 2009
    65. 65. Public Ballots Bulletin Board Bob: McCain Carol: Obama 26 Saturday, February 14, 2009
    66. 66. Public Ballots Bulletin Board Bob: McCain Carol: Obama Alice 26 Saturday, February 14, 2009
    67. 67. Public Ballots Bulletin Board Alice: Bob: Obama McCain Carol: Obama Alice 26 Saturday, February 14, 2009
    68. 68. Public Ballots Bulletin Board Alice: Bob: Obama McCain Carol: Obama Tally Obama....2 McCain....1 Alice 26 Saturday, February 14, 2009
    69. 69. Encrypted Public Ballots Bulletin Board Alice: Bob: Rice Clinton Carol: Rice Tally Obama....2 McCain....1 Alice 27 Saturday, February 14, 2009
    70. 70. Encrypted Public Ballots Bulletin Board Alice: Bob: Rice Clinton Carol: Ali Rice ce ver Tally i fies he rv Obama....2 ote McCain....1 Alice 27 Saturday, February 14, 2009
    71. 71. Encrypted Public Ballots Bulletin Board Alice: Bob: Rice Clinton Carol: lly Ali ta Rice ce e thTally ver es rifi i fies e ve he n ryo rv ve Obama....2 E ote McCain....1 Alice 27 Saturday, February 14, 2009
    72. 72. End-to-End Verification Saturday, February 14, 2009
    73. 73. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Polling Location Saturday, February 14, 2009
    74. 74. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Ballot Box / Bulletin Board Polling Location Alice Saturday, February 14, 2009
    75. 75. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Results Ballot Box / Bulletin Board Polling ..... Location Alice Saturday, February 14, 2009
    76. 76. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Results Ballot Box / Bulletin Board Polling ..... Location 1 Alice Receipt Saturday, February 14, 2009
    77. 77. End-to-End Verification /* * source * code Voting */ Machine if (... Vendor Results Ballot Box / Bulletin Board Polling ..... Location 1 2 Alice Receipt Saturday, February 14, 2009
    78. 78. How can we verify operations on encrypted data? Mathematical Proofs. 29 Saturday, February 14, 2009
    79. 79. Zero-Knowledge Proof 30 Saturday, February 14, 2009
    80. 80. Zero-Knowledge Proof President: President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse Vote For: Mickey Mouse Obama Vote For: Obama 30 Saturday, February 14, 2009
    81. 81. Zero-Knowledge Proof President: President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse Vote For: Mickey Mouse Obama Vote For: Obama 30 Saturday, February 14, 2009
    82. 82. Zero-Knowledge Proof President: President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse President: Mickey Mouse Vote For: Mickey Mouse Obama Vote For: Obama This last envelope likely contains “Obama” 30 Saturday, February 14, 2009
    83. 83. Zero-Knowledge Proof President: President: President: President: Mickey Mouse Mickey Mouse President: President: Mickey Mouse Mickey Mouse President: President: Mickey Mouse Mickey Mouse President: President: Mickey Mouse Mickey Mouse President: President: Mickey Mouse Mickey Mouse Vote For: Vote For: Mickey Mouse Mickey Mouse McCain Obama Paul Open envelopes don’t prove anything after the fact. 31 Saturday, February 14, 2009
    84. 84. Helios Saturday, February 14, 2009
    85. 85. “And there are cryptographic techniques that can be used to achieve software independence so that even if there's a bug in the software, you'll detect if there's a problem. But those are not ready for prime time in my opinion.” Avi Rubin, 7/9/2008 Saturday, February 14, 2009
    86. 86. “But with cryptography, you’re just moving the black box. Few people really understand it or trust it.” California Sec. of State, 7/30/2008 (paraphrased) Saturday, February 14, 2009
    87. 87. Simplify Low-Coercion Elections Web-based Saturday, February 14, 2009
    88. 88. Technical Concepts Saturday, February 14, 2009
    89. 89. Technical Concepts - Probabilistic Encryption & Threshold Decryption. posting ciphertexts safely on a bulletin board Saturday, February 14, 2009
    90. 90. Technical Concepts - Probabilistic Encryption & Threshold Decryption. posting ciphertexts safely on a bulletin board - Homomorphic Tallying. no write-ins, proofs of correct plaintext Saturday, February 14, 2009
    91. 91. Technical Concepts - Probabilistic Encryption & Threshold Decryption. posting ciphertexts safely on a bulletin board - Homomorphic Tallying. no write-ins, proofs of correct plaintext - Benaloh Challenge. cast or audit, authenticate only upon cast Saturday, February 14, 2009
    92. 92. Technical Concepts - Probabilistic Encryption & Threshold Decryption. posting ciphertexts safely on a bulletin board - Homomorphic Tallying. no write-ins, proofs of correct plaintext - Benaloh Challenge. cast or audit, authenticate only upon cast - In-Browser Encryption. plaintext only in user’s browser Saturday, February 14, 2009
    93. 93. Probabilistic Encryption & Threshold Decryption Saturday, February 14, 2009
    94. 94. Public-Key Encryption Saturday, February 14, 2009
    95. 95. Public-Key Encryption Keypair consists of a public key pk and a secret key sk . Saturday, February 14, 2009
    96. 96. Public-Key Encryption Keypair consists of a public key pk and a secret key sk . Enc pk quot;Obamaquot; 8b5637 Saturday, February 14, 2009
    97. 97. Public-Key Encryption Keypair consists of a public key pk and a secret key sk . Enc pk quot;Obamaquot; 8b5637 Enc pk quot;McCainquot; c5de34 Saturday, February 14, 2009
    98. 98. Public-Key Encryption Keypair consists of a public key pk and a secret key sk . Enc pk quot;Obamaquot; 8b5637 Enc pk quot;McCainquot; c5de34 Enc pk quot;Obamaquot; a4b395 Saturday, February 14, 2009
    99. 99. Threshold Decryption Secret key is shared amongst multiple parties: all (or at least a quorum) need to cooperate to decrypt. 8b5637 Saturday, February 14, 2009
    100. 100. Threshold Decryption Secret key is shared amongst multiple parties: all (or at least a quorum) need to cooperate to decrypt. Dec sk1 b739cb 8b5637 Saturday, February 14, 2009
    101. 101. Threshold Decryption Secret key is shared amongst multiple parties: all (or at least a quorum) need to cooperate to decrypt. Dec sk1 b739cb Dec sk2 261ad7 8b5637 Saturday, February 14, 2009
    102. 102. Threshold Decryption Secret key is shared amongst multiple parties: all (or at least a quorum) need to cooperate to decrypt. Dec sk1 b739cb Dec sk2 261ad7 8b5637 Dec sk3 7231bc Saturday, February 14, 2009
    103. 103. Threshold Decryption Secret key is shared amongst multiple parties: all (or at least a quorum) need to cooperate to decrypt. Dec sk1 b739cb Dec sk2 261ad7 8b5637 Dec sk3 7231bc Dec sk4 8239ba Saturday, February 14, 2009
    104. 104. Threshold Decryption Secret key is shared amongst multiple parties: all (or at least a quorum) need to cooperate to decrypt. Dec sk1 b739cb Dec sk2 261ad7 8b5637 quot;Obamaquot; Dec sk3 7231bc Dec sk4 8239ba Saturday, February 14, 2009
    105. 105. Homomorphic Tallying Saturday, February 14, 2009
    106. 106. Homomorphic Property First: r’th residuosity [Benaloh85] Also: Paillier Cryptosystem [P99] 41 Saturday, February 14, 2009
    107. 107. Homomorphic Property Enc(m1 ) × Enc(m2 ) = Enc(m1 + m2 ) First: r’th residuosity [Benaloh85] Also: Paillier Cryptosystem [P99] 41 Saturday, February 14, 2009
    108. 108. Homomorphic Property Enc(m1 ) × Enc(m2 ) = Enc(m1 + m2 ) First: r’th residuosity [Benaloh85] Also: Paillier Cryptosystem [P99] 41 Saturday, February 14, 2009
    109. 109. Homomorphic Property Enc(m1 ) × Enc(m2 ) = Enc(m1 + m2 ) then we can simply add votes “under cover” of encryption! First: r’th residuosity [Benaloh85] Also: Paillier Cryptosystem [P99] 41 Saturday, February 14, 2009
    110. 110. Homomorphic Tally Vote for None Adam 0001 0000 0000 0000 Vote for Vote for Vote for Bob Obama 0000 0001 0000 0000 Vote for McCain 0000 0000 0001 0000 Vote for Charlie 0000 0000 0000 0001 Vote for David 0003 0001 0008 0002 0004 0006 0005 Sample Tally [B+2001, P1999] 42 Saturday, February 14, 2009
    111. 111. Benaloh Casting Protocol Saturday, February 14, 2009
    112. 112. http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    113. 113. Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    114. 114. quot;Obamaquot; Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    115. 115. quot;Obamaquot; Encrypted Ballot Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    116. 116. quot;Obamaquot; Encrypted Ballot Alice Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    117. 117. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    118. 118. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; Decrypted Ballot Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    119. 119. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; Decrypted Ballot Alice Encrypted Decrypted Ballot Ballot VERIFICATION http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    120. 120. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; Decrypted Ballot Alice Encrypted Decrypted Ballot Ballot VERIFICATION http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    121. 121. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; Decrypted Ballot Alice Encrypted Decrypted Ballot Ballot VERIFICATION http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    122. 122. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; Decrypted Ballot Alice Alice Encrypted Decrypted Ballot Ballot VERIFICATION http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    123. 123. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; quot;CASTquot; Decrypted Ballot Alice Alice Encrypted Decrypted Ballot Ballot VERIFICATION http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    124. 124. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; quot;CASTquot; Decrypted Signed Ballot Encrypted Ballot Alice Alice Encrypted Decrypted Ballot Ballot VERIFICATION http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    125. 125. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; quot;CASTquot; Decrypted Signed Ballot Encrypted Ballot Alice Alice Encrypted Decrypted Ballot Ballot VERIFICATION Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    126. 126. quot;Obamaquot; Encrypted Ballot Alice quot;AUDITquot; quot;CASTquot; Decrypted Signed Ballot Encrypted Ballot Alice Alice Encrypted Decrypted Ballot Ballot Signed Encrypted Ballot VERIFICATION Alice http://en.wikipedia.org/wiki/Image:Barcode-scanner.jpg Saturday, February 14, 2009
    127. 127. Web Browser Tricks Saturday, February 14, 2009
    128. 128. Single-Page Web App <a href=“javascript:doStuff();”> next page </a> Saturday, February 14, 2009
    129. 129. LiveConnect Saturday, February 14, 2009
    130. 130. LiveConnect var p = new java.math.BigInteger(“13”,10); Saturday, February 14, 2009
    131. 131. LiveConnect var p = new java.math.BigInteger(“13”,10); var p = lc_applet.newBigInteger(“13”,10); Saturday, February 14, 2009
    132. 132. LiveConnect var p = new java.math.BigInteger(“13”,10); var p = lc_applet.newBigInteger(“13”,10); var GEN = new java.security.SecureRandom(); Saturday, February 14, 2009
    133. 133. LiveConnect var p = new java.math.BigInteger(“13”,10); var p = lc_applet.newBigInteger(“13”,10); var GEN = new java.security.SecureRandom(); var GEN = lc_applet.newSecureRandom(); Saturday, February 14, 2009
    134. 134. Data URIs Saturday, February 14, 2009
    135. 135. Data URIs window.open(“data:text/plain,” + content); Saturday, February 14, 2009
    136. 136. Data URIs window.open(“data:text/plain,” + content); w = window.open(quot;quot;); w.document.open(quot;text/plainquot;); w.document.write(content); w.document.close(); Saturday, February 14, 2009
    137. 137. window.postMessage() Saturday, February 14, 2009
    138. 138. window.postMessage() w = window.open(HELIOS_API_URL); w.postMessage(“election 123”, helios_host); Saturday, February 14, 2009
    139. 139. window.postMessage() w = window.open(HELIOS_API_URL); w.postMessage(“election 123”, helios_host); window.addEventListener(“message”, ...); window.opener.postMessage(election_data); Saturday, February 14, 2009
    140. 140. Helios System Details Saturday, February 14, 2009
    141. 141. Helios System Details - Python & JavaScript logic & crypto Saturday, February 14, 2009
    142. 142. Helios System Details - Python & JavaScript logic & crypto - Free/Open-Source stack Saturday, February 14, 2009
    143. 143. Helios System Details - Python & JavaScript logic & crypto - Free/Open-Source stack - Deployed on Google App Engine Saturday, February 14, 2009
    144. 144. Helios System Details - Python & JavaScript logic & crypto - Free/Open-Source stack - Deployed on Google App Engine - Deployed on Apache/Python/PostgreSQL at UCL! Saturday, February 14, 2009
    145. 145. Helios System Details - Python & JavaScript logic & crypto - Free/Open-Source stack - Deployed on Google App Engine - Deployed on Apache/Python/PostgreSQL at UCL! - Customizable authentication, look-and-feel, translations Saturday, February 14, 2009
    146. 146. Demo Saturday, February 14, 2009
    147. 147. Is Open-Audit Voting Too Difficult to Understand? Saturday, February 14, 2009
    148. 148. Is Open-Audit Voting Too Difficult to Understand? - It’s more difficult than counting paper ballots. Saturday, February 14, 2009
    149. 149. Is Open-Audit Voting Too Difficult to Understand? - It’s more difficult than counting paper ballots. - Simplicity hides a lack of auditability: how can you trust that a ballot box was not tampered with? Saturday, February 14, 2009
    150. 150. Is Open-Audit Voting Too Difficult to Understand? - It’s more difficult than counting paper ballots. - Simplicity hides a lack of auditability: how can you trust that a ballot box was not tampered with? - With open-audit, anyone can learn the math and write their own program. Saturday, February 14, 2009
    151. 151. Is Open-Audit Voting Too Difficult to Understand? - It’s more difficult than counting paper ballots. - Simplicity hides a lack of auditability: how can you trust that a ballot box was not tampered with? - With open-audit, anyone can learn the math and write their own program. - If there’s fraud, there’s evidence! All you need is one person to point it out. Saturday, February 14, 2009
    152. 152. Questions? Ben Adida ben@adida.net Harvard University Université Catholique de Louvain 3 February 2009 53 Saturday, February 14, 2009

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