A Distributed Polling with Probabilistic Privacy

In this paper, we present PDP, a distributed polling protocol that enables a set of participants to gather their opinion on a common interest without revealing their point of view. PDP does not rely on any centralized authority or on heavyweight cryptography. PDP is an overlay-based protocol where a subset of participants may use a simple sharing scheme to express their votes. In a system of M participants arranged in groups of size N where at least 2k-1 participants are honest, PDP bounds the probability for a given participant to have its vote recovered with certainty by a coalition of B dishonest participants by π(B/N)^(k+1), where π is the proportion of participants splitting their votes, and k a privacy parameter. PDP bounds the impact of dishonest participants on the global outcome by 2(kα + BN), where represents the number of dishonest nodes using the sharing scheme.