Running on Karma - P2P reputation and currency systems

Peer-to-peer (P2P) systems allow users to share resources with little centralized control. Malicious users can abuse the system by contributing polluted resources. Moreover, selfish users may just connect for their own benefits without donating any resources. The concepts of reputation and currency give possible approaches to address these problems. However, to implement these ideas is non-trivial, due to the nonexistence of a single trusted party. Existing works circumvent this by placing trust assumption on certain nodes of an overlay network. This work presents a new reputation system and a new currency system. Our designs axe simple thanks to the full use of the trust assumption.