Reputation propagation and agreement in mobile ad-hoc networks

Several reputation systems have been proposed for mobile ad-hoc networks in order to stimulate cooperation among mobile nodes. However, whether or not the mobile nodes will agree on the reputation of other nodes is not studied. In this paper, we present a formal specification and analysis of a general class of mechanisms to locally update the reputation of mobile nodes. Given an initial assessment of the reputation of other mobile nodes, we formally show that under mild conditions, the mobile nodes will achieve reputation agreement. Our analysis captures reputation propagation using graph connectivity and makes use of a recent theoretical result [A. Jadbabaie, et. al., IEEE Control and Decision Conference, 2001]. We also evaluate the convergence speed of two reputation propagation mechanisms through simulations. Our simulations show that the speed of reputation propagation is an important factor for the convergence speed of reputation agreement.