International OPEN ACCESS Journal Of Modern Engineering Research (IJMER) | IJMER | ISSN: 2249–6645 | www.ijmer.com | Vol. 4 | Iss. 5| May. 2014 | 42| Making Trust Relationship For Peer To Peer System With Secure Protocol Miss. I. Jancy 1 , Mr. S. Balamurugan 2 1, 2 (PG Student, Assistant Professor, Sri ManakulaVinayagar Engineering College, Pondicherry-605106) I. Introduction Open nature of peer-to-peer systems exposes them to malicious activity. Building trust relationships among peers can mitigate attacks of malicious peers. This paper presents distributed algorithms that enable a peer to reason about trust worthiness of other peers based on past interactions and recommendations. Peers create their own trust network in their proximity by using local information available and do not try to learn global trust information. Two contexts of trust, service, and recommendation contexts are defined to measure trustworthiness in providing services and giving recommendations. Interactions and recommendations are evaluated based on importance, recentness, and peer satisfaction parameters. Additionally, recommender‟s trustworthiness and confidence about a recommendation are considered while evaluating recommendations. Simulation experiments on a file sharing application show that the proposed model can mitigate attacks on 16 different malicious behavior models. In the experiments, good peers were able to form trust relationships in their proximity and isolate malicious peers. Peer to Peer (P2P) systems rely on collaboration of peers to accomplish tasks. Ease of performing malicious activity is a threat for security of P2P systems. Creating long-term trust relationships among peers can provide a more secure environment by reducing risk and uncertainty in future P2P interactions. And Therefore, classic peer-to-peer unaware viruses could inadvertently be transmitted via a peer-to- peer network. Viruses could also take advantage of the regular use of a peer-to-peer network. For example, viruses could specifically attempt to copy themselves to or infect files within the shared peer-to-peer space. A peer sharing files is called an uploader. A peer downloading a file is called a downloader. The set of peers who downloaded a file from a peer are called downloaders of the peer. An ongoing download/ upload operation is called a session. Simulation parameters aregenerated based on results of several empirical studies [6], [7] to make observations realistic. A file search request reaches up to 40 percent of the network and returns online uploaders only. A file is downloaded from one uploader to simplify integrity checking. All peers are assumed to have antivirus software so they can detect infected files Four different cases are studied to understand effects of trust calculation methods under attack conditions: No trust. Trust information is not used for uploader selection. An uploader is selected according to its bandwidth. This method is the base case to understand if trust is helpful to mitigate attacks. Abstract: In the peer-to-peer systems exposes them to malicious activity. Building trust relationships among peers can mitigate attacks of malicious peers. This paper presents distributed algorithms that enable a peer to reason about trust worthiness of other peers based on past interactions and recommendations. Peers create their own trust network in their proximity by using local information available and do not try to learn global trust information. Two contexts of trust, service, and recommendation contexts are defined to measure trustworthiness in providing services and giving recommendations. So, neighbouring node will give the recommendation to peer. Based on the recommendation only Peer decides whether the node is good (or) malicious. Find the node is malicious node means peer will not interact with malicious node. Isolate the malicious node from the network. Find the node is good means peer interact with good peer. Peer stores a separate history of interactions for each Acquaintance. This paper also discuss the malicious threats, privacy concerns, and security risks of three commonpeer-to-peer network systems that are gaining popularity today. The malicious threats discussed willinclude how malicious threats can harness existing peer-to-peer networks, and how peer-to-peernetworking provides an additional (potentially unprotected) vector of delivery for malicious code. Index Terms: Peer-to-peer systems, trust management, reputation, security.