Incentive mechanisms in peer-to-peer networks

In the last few years, peer-to-peer systems became well known to the general public by allowing fast and simple exchange of resources between users. The complexity of these systems resides in the absence of a central authority and the fact that each user can act both as a client and as a server. Thus, a need for self-regulation arises in order to guarantee that every user contributes to the system. This paper describes our work developing incentive mechanisms, which enable the correct operation of peer-to-peer systems, imposing a balance between demand for resources and the existing offer. All incentive mechanisms take into account the attacks these systems are subject to, as well as the system´s structure, so that they do not pose an unnecessary burden, slowing down the system excessively. We explore concepts such as reputation and currency, which are used in other systems and, most importantly, in our everyday life, enabling a coherent scheme to detect untrustworthy users and reward truthful peers with faster access to the resources. Our work is part of a larger project called GINGER, an acronym for Grid In a Non-Grid Environment, a peer-to- peer infrastructure intended to ease the sharing of computer resources between users.