Debt-based file exchange mechanism in peer-to-peer networks

The self-interest of peers degrades the system usability of P2P file sharing networks. Debt-based files exchange network constructs an incentive mechanism which induces cooperative and equivalent file exchange where creditor's rights between neighbors play as light weight cash in file download. Creditor's rights need only be maintained between neighbors, so maintenance cost is low and the mechanism is scalable for large networks. Number of files shared can be seen as a peer's strategy selection. The game among rational peers exists a Nash equilibrium and the approximate algorithm of strategy selection gradually converges. Simulations indicate the effectiveness of incentive mechanism and steady performance in dynamic networks.