Building a reputation-based bootstrapping mechanism for newcomers in collaborative alert systems

Today trust is a key factor in distributed and collaborative environments aimed to model participating entities’ behavior, and to foresee and predict their expected actions in the future. Yet, prior to the first interaction of a new party in the system, trust and reputation models face a great challenge: how to assign an accurate initial reputation score to a newcomer? The answer needs to tackle two well-known problems, namely, cold-start and reputation bootstrapping. Cold-start is a common issue to any information system when it boots for the very first time, while reputation bootstrapping especially affects highly distributed scenarios, where mobile entities travel across domains and collaborate with a number of them. In this paper, we focus on the two problems and, in order to address them, we present a novel reputation bootstrapping mechanism for a newcomer in a collaborative alert system aimed at detecting distributed threats. The experiments conducted show the accuracy of our proposal as well as its robustness in the presence of ill-intentioned entities. c © 2013 Published by Elsevier Ltd.