Assessing security threat scenarios for utility-based reputation model in grids

Trust and reputation models play an important role in enabling trusted computations over large-scale distributed grids. Many models have been recently proposed and implemented within trust management systems. Nevertheless, the existing approaches usually assess performance of models in terms of resource management while less attention is paid to the analysis of security threat scenarios for such models. In this paper, we assess the most important and critical security threats for a utility-based reputation model in grids. The existing model is extended to address these threat scenarios. With simulations that were run using data collected from the EGEE Grid-Observatory project, we analyse efficiency of the utility-based reputation model against these threats.