Securing optical-scan voting

Abstract

This paper presents a method for adding end-to-end verifiability to any optical-scan vote counting system. A serial number and set of letters, paired with every candidate, are printed on each optical-scan ballot. The letter printed next to the candidate(s) chosen by the voter is posted to a bulletin board, and these letters are used as input to Punchscan's verifiable tallying method. The letters do not reveal which candidate was chosen by the voter. The method can be used as an independent verification mechanism that provides assurance that each vote is included in the final tally unmodified - a property not guaranteed by a manual recount. We also provide a proof-of-concept process that allows the election authority to settle disputes after the polls close while preserving ballot secrecy. © 2010 Springer-Verlag.