Securing reputation data in peer-to-peer networks

Alice, a peer in a peer-to-peer (P2P) network can evaluate the reputation of another peer, Bob, either based on her own experiences (with Bob) or based on the evaluation (of Bob) by others (say Carol and David). If Alice uses her own experiences only, she will get cheated atleast once for every malicious peer she identifies. If Alice uses third party experiences (Carol and David), she can reduce the number of times she gets cheated. Besides, Alice will have to verify the third party information receives from other peers. The verification (if at all possible) is likely to be both network and computation intensive. In the propose solution, the reputation holder (Bob) stores its reputation data and protects it from the other peers. The reputation data is stored in a cryptographic chain in order to protect the reputation data from the reputation holder itself. Bob cannot modify the chain because the head and tail of the chain are public information and all recommendations are digitally signed. We show that the proposed solution reduces the number of malicious transaction experienced by a peer (Alice), along with a reduction in network traffic.