Computer Security: Chapter 8 - Trust in P2P Systems

8. Trust in P2P Systems Prof. Bharat Bhargava Center for Education and Research in Information Assurance and Security (CERIAS) and Department of Computer Sciences Purdue University http://www.cs.purdue.edu/people/bb bb@cs.purdue.edu Collaborators in the RAID Lab (http://raidlab.cs.purdue.edu): Mr. Ahmet Burak Can (Ph.D. Student) 1 Trust in P2P Systems Outline 1) Introduction 1.1) Mitigating Attacks in P2P Systems 1.2) Assumptions for Peer Interactions 2) Contexts of Trust in P2P Systems 3) Definitions for the Proposed Solution 4) Trust Metrics 5) Trust­based Decisions 6) Interaction Evaluation by Peers 7) Recommendation Evaluation by Peers 8) Simulation Experiments 8.1) Attacker Models for Simulation: Individual attackers/ Collaborators / Pseudospoofers 8.2) Experimental Results 2 1) Introduction 1.1) Mitigating Attacks in P2P Systems Mitigating attacks in a malicious P2P environment Use trust relationships among peers to mitigate attacks in a malicious P2P environment Algorithms are needed to establish trust among peers Research tasks: Propose trust metrics that reflect all aspects of trust. Develop distributed algorithms to manage trust relationships among peers and help them to make decisions using trust metrics Define methods to evaluate interactions and trust information exchanged among peers (recommendations) 3 1.2) Assumptions for Peer Interactions Peers use no a priori information to establish trust No pre­existing trust relationships among peers A peer must contribute and behave well to gain and preserve trust of another peer Malicious behavior of Peer 1 against Peer 2 can easily destroy trust of Peer 2 in Peer 1 Trust metrics should have sufficient precision Required to rank peers accurately (according their trustworthiness) 4 2) Contexts of Trust in P2P Systems Two contexts of trust — w.r.t. performing 2 different tasks: 1) Providing services to other peers 2) Giving recommendations to other peers . These contexts considered separately A peer might simultaneously be a good service provider and a bad recommender (or vice versa) 5 ... - tailieumienphi.vn