In this paper we propose an approach to P2P security where servents can keep track, and share with others, information about the reputation of their peers. Reputation sharing is based on a distributed polling algorithm by which resource requestors can assess the reliability of perspective providers before initiating the download. The approach nicely complements the existing P2P protocols and has a limited impact on current implementations. Furthermore, it keeps the current level of anonymity of requestors and providers, as well as that of the parties sharing their view on others' reputations.