| Peer-to-Peer (P2P) model has become the mainstream of the applications in current and future Internet. Being effective in utilizing and managing globally distributed information over Internet, however, most current P2P systems do not provide protection to their users against the increasing threat from selfish peers or malicious adversaries. Anonymous and trustworthy computing hereby has continuously gained importance because it meets the users' demands of privacy, fairness, trust, and reliability. In order to construct anonymous and trustworthy P2P systems, we must address several crucial challenges including (1) reliably and efficiently anonymizing the P2P network; (2) authenticating users' identities; (3) enabling trust management in anonymous environments. Most existing approaches achieve anonymity via fixed paths, which are unreliable and inefficient in dynamic P2P systems. We propose two non-path based protocols to anonymize P2P systems. The results of trace driven simulations show that our proposed protocols are reliable, scalable and effective, and significantly reduce cryptographic overhead. The second issue is that the current authentication approaches face a dilemma in anonymous environments: authenticating other users needs their real identities; while the anonymity requires those users to hide their real identities. We propose a Zero-knowledge based protocol to allow users authenticate with each other without exposing their real identities. We show the effectiveness of our proposed protocol by simulation studies and prototype implementation. We solve the third issue by constructing a reputation based trust management architecture. We particularly focus on the feedback quality problem. In shorting of trusted authority centers in P2P systems, the feedback quality are easily wrecked by the dishonest feedback from malicious peers, which further degrades the computation accuracy of users' reputation. Our proposed architecture effectively alleviates the damage on computing reputation caused by the feedback cheating. We believe that widely employing above proposed approaches will make P2P systems more secure and reliable. We also extend our study to other distributed systems and propose a privacy-preserving authentication protocol for RFID systems.; Keywords: Peer-to-Peer, Anonymity, Privacy-Preserving, Authentication, Key Updating, Secret Sharing, Random Walk, Selected Flooding, Trustworthy Computing, Feedback Quality, Trust Management, Trace Driven Simulation, Zero-Knowledge Proof, Man-in-middle-attack... |
