Toward an Optimal Redundancy Strategy for Distributed Computations

Abstract

Volunteer distributed computations utilize spare processor cycles of personal computers that are connected to the Internet. The related computation integrity concerns are commonly addressed by assigning tasks redundantly. Aside from the additional computational costs, a significant disadvantage of redundancy is its vulnerability to colluding adversaries. This paper presents a tunable redundancy-based task distribution strategy that increases resistance to collusion while significantly decreasing the associated computational costs. Specifically, our strategy guarantees a desired cheating detection probability regardless of the number of copies of a specific task controlled by the adversary. Though not the first distribution scheme with these properties, the proposed method improves upon existing strategies in that it requires fewer computational resources. More importantly, the strategy provides a practical lower bound for the number of redundantly assigned tasks required to achieve a given detection probability