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

•Novel reputation management system facing cold-start and bootstrapping problems.•Reputation bootstrapping model aimed at assigning an initial reputation to newcomers.•Trust model applied to collaborative networks aimed at detecting distributed threats.•Addressing bootstrapping of mobile IDSs in highly distributed environments.•Experiments confirm better accuracy and resilience in the presence of malicious IDSs.

Today trust is a key factor in distributed and collaborative environments aimed to model participating entitiesʼ behavior, and to foresee their further actions. Yet, prior to the first interaction of a newcomer in the system trust and reputation models face a great challenge: how to assign an accurate initial reputation to a newcomer? The answer needs to tackle two well-known problems: cold-start and reputation bootstrapping. Cold-start is a common issue to any system when newcomers boot for the 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, which are addressed through a novel reputation bootstrapping mechanism for newcomers in a collaborative alert system aimed at detecting distributed threats. Experiments confirm the accuracy of our proposal as well as its robustness in the presence of ill-intentioned entities.