To Du or Not to Du: A Security Analysis of Du-Vote

Du-Vote is a recently presented remote electronic voting scheme. Its goal is to be malware tolerant, i.e. provide security even in the case where the platform used for voting has been compromised by dedicated malware. For this it uses an additional hardware token, similar to tokens distributed in the context of online banking. The token is software closed and does not have any communication means other than a numerical keyboard and a small display. Du-Vote aims at providing vote privacy as long as either the vote platform or the vote server is honest. For verifiability, the security guarantees are aimed higher, indeed even if the token's software has been changed, and the platform and the server are colluding, attempts to change the election outcome should be detected with high probability. In this paper we provide an extensive security analysis of Du-Vote and show several attacks on both privacy as well as verifiability. We also propose changes to the system that would avoid many of these attacks.