Limiting user’s sybil attack in resource sharing

Abstract

In this work, we discuss the sybil attack to a sharing economic system where each participant contributes its own resource for all to share. We are interested in the robustness of the market equilibrium mechanism in withstanding such an attack, in terms of the incentive ratio to measure how much one could gain by splitting its identity and reconstructing its communication connections with others. On one hand, weshow that no player can increase more than 2 times of their original share from the market equilibrium solution, by characterizing the worst case under which strategic agent can obtain the maximum utility gain after manipulation. On the other hand, such a bound of 2 is proved to be tight by constructing a proper instance, for which this bound is reached.