1. A remote voting system based on Prêt à Voter coded by David Lundin Johannes Clos

2. Design goals End-to-end verifiable (if...)‏ Offload authentication to host organization Easy to set up, maintain and use Use publicly available mix servers (when...)‏

3. Limitations Unsupervised voting  No coercion resistance  No guarantee of response from server Someone has to authenticate users  We use host organization (could use our server)‏ Some parts not quite complete  Threshold decryption  SSL certificates (time/money)‏

4. Operational overview

5. Election setup phase Create election on EE  Don't declare voters! Retrieve shared secret Retrieve signed applet Integrate host auth

6. Client authentication phase Voter logs on normally  Host serves applet  PHP script gets authentication information

7. Voting phase Vote using applet Applet encrypts vote  ElGamal encryption  Ciphertexts à la [Hea07]  Packaged as XML  Committed to  Audit or vote  Vote sent back to host Host signs XML  Sent back to ee.com  Signed receipt given

8. Auditing

9. Voting and auditing Voting applet  constructs XML  reveals XML and hash  offers vote or audit Voter then can either  audit, and uncover details of encryptions  vote, and get signed hash Audit gives confidence in applet's fairness

10. Decryption/tallying after polls close Use mix nets  PRC to audit mixes  Anyone can audit  Public mix servers Votes decrypted  Threshold decryption  CP proofs  Anyone can check  Lazily decrypt (STV)‏ Anyone can tally

11. Auditing the mix nets A mix net  re-encrypts votes  randomly shuffles Twice, with PRC Links chosen by hash of output Can be re-run

12. Conclusion Pretty much plug-and-play Any organization hosting a web site can use End-to-end verifiable ...on various seemingly unavoidable assumptions