Assessing the usability of open verifiable e-voting systems: a trial with the system Prêt à Voter
Résumé
─ E-voting systems – the combination of vote-casting, ballot transmission and counting, auditing and monitoring systems – have been gaining much attention from the international community as a suitable solution for preventing errors issued from human reliability on vote counting. Whilst many reports have said about currently available pilots and proposals are sensible, some fundamental issues remain unresolved such as the fact that most of systems are unverifiable by voters, candidates and returning officers. In most proposals, votes disappear into the machine so that it is impossible to audit votes without removing the secrecy of votes. In more recent years, an electronic voting system called Prêt à Voter has been developed to allow verification of individual casts and audit elections. Prêt à Voter combines paper trail for recounts and a sophisticated cryptography mechanism to ensure secrecy of votes and vote verification. However, as any other e-voting system, the user adoption and the user acceptance of Prêt à Voter not only depend on how technically sound the system is but also how voters perceive the system as trusted. Despite the fact Prêt à Voter has been designed to make the voting process as simpler as possible the introduction of online encrypted vote verification is an unnatural concept for most voters and may affect user's opinion. This paper reports some observed user behavior faced to the introduction of new voting system including cryptographically vote verification. In particular, this paper presents the results of a large scale trial with the system Prêt à Voter. We describe some usability problems related to user behaviour that may affect the reliability of E-voting procedures and (by the means of questionnaires specifically designed to assess of user acceptance and user adoption) we collected voters' opinions about their experience using individual vote verification. These results are compared with other studies with similar electronic voting systems, which allow us to draw out some recommendations for assessing the usability of E-voting systems.