SINGLE TRANSFERABLE VOTE ANALOGUE OF DESMEDT-KUROSAWA VOTING PROTOCOL

During Information Security Conference 2005, Yvo Desmedt and Kaoru Kurosawa presented an electronic voting scheme that allows to point the winner, without revealing the final tally - that is, no information is disclosed except for the name of the winner(s). In particular, even the number of votes for every single candidate remains hidden. It can be important in practice, since these numbers can reveal sensitive information about voters' preferences in some scenarios, especially in closed, small communities. In some sense, this scheme meets stronger privacy requirements than any voting protocol before. The main contribution of our paper is a version of Desmedt-Kurosawa scheme that supports Single Transferable Vote (STV) used among others in Republic of Ireland and Australia. The presented solution has the main properties of Desmedt-Kurosawa scheme, however we had to solve several subtle problems in order to implement the idea of SVT that is much more complicated than the regular voting. For example, we have even to hide the number of rounds that does not need to be constant. As in the original scheme, every step can be publicly verified.