Themis: An On-Site Voting System with Systematic Cast-as-intended Verification and Partial Accountability

Receives the paper ballot's QRCodes from the booth terminal; (also checks the signatures and well-formedness) 2 Sends the e-Ballot for display on the screen and in the chain. 3 On signed confirmation, shows SD elec and SD paper on card. Bougon et al. Themis Electronic Ballot (concept) e-Ballot contains : proof that X , A, B are integers between 0..n -1 Voter audit request: either A or B, chose secretly in the voting booth ⇒ ignored by the smartcard, the terminals and the server Smartcard and e-Ballot audit: ⇒ e-Ballot created in the voting booth and added to the chain + screen ⇒ before confirmation, Voter must see his ballot on the screen ⇒ SmartCard provides the random used to encrypt the audited A or B Auditors: see and check A or B plus random, for each ballot in the chain. Ballot manipulation detected with probability 1/2 (on each ballot)