Research And Realization Of Credit Mechanism In P2P Network

Because of its distributed characteristic and making resources being more fully utilized, P2P (Peer-to-Peer) technology can be used to improve many applications. But in current P2P network, free-riding phenomenon has become a serious problem, especially in P2P file-sharing network, because of lacking centralized control. It finally comes to be an important fact of restricting development of P2P file-sharing systems.So far, A number of solutions have been proposed to address the free-riding problem in peer-to-peer file sharing systems. The solutions are either imperfect–they allow some users to cheat the system with malicious behavior, or expensive–they require human intervention, or require servers. Terefore, we design a credit model to describe the contribution and consumption of peers in order to avoid those weaknesses. Subsequently, on the basis of this credit model, we design various of maintenance information to record peers'histories, which includes: credit information, trade records information, and interested peer list infomation. Meanwhile, we design several strategies for synchronizing peers'maintenance information, to ensure that peer in P2P file-sharing system has sound knowledge of its interested peers.Then, we put forward an automatic audit mechanism on the basis of above-mentioned model and strategies. The automatic audit mechanism is initiated for auditing three kinds of maintenance information by certain probability, and it's purpose is to allow any peer in P2P file-sharing system can automatically detect malicious behavior of its interested peers(such as: exaggerated credit, conspiracy, blame transfer). Peer continuously initiated the audit to gradually identify malicious peers and exclude them from P2P file-sharing system, so that P2P file-sharing system will be healty and has lasting vitality.We realize this credit mechanism in a P2P file-sharing system, and simulate it to analyse its performance and validity.