The impact of social cloud reputation and structure on rational computation

Abstract

Rational computation means secure multi-party computation in the presence of rational parties, who care about maximizing their utility. Here the notion of utility denotes payoffs when parties take certain actions in the computation. Therefore rational parties may carefully choose their actions before they interact with others. Traditionally, the main tasks of rational computation is to encourage parties to exchange information with their opponents, even if they do not trust each other. Exchanging information is similar to the action of cooperation towards the view of game theory. Therefore, measures should be taken to encourage parties to cooperate with others in rational computation. In this paper, we assume that rational parties who participate in the computation protocol form a social cloud. Parties in the social cloud may interact within several rounds and in each round, some desirable properties such as reputation may be generated. Parties who have good reputation means they are likely to cooperate with others. The structure of social cloud is not static. Instead, it evolutes when parties complete one round of computation. We mainly discuss the impact of social cloud structure on rational computation. Simulation results show that when the community structure reach to a proper value, parties are more likely to cooperate in the computation protocol. In addition, rational parties can gain optimal utilities.