OnionCoin : peer-to-peer anonymous messaging with incentive system

The "free-riders" issue happens in many peer-to-peer system, and this issue severely damages the liveness of the system especially for the system that heavily relies on coordination of multiple peers. Many peer-to-peer system assumes that the peers are willing to volunteer their resources to support functionality of the system, such as content storage and traffic relay. However, the assumption is hardly true in real Internet world, in which most of the users are trying to maximize their profit playing to take advantages from the system without providing corresponding services to others in the system. The notable decentralized anonymous network, TOR, also does not have any explicit incentives for the peer to host Onion Router as infrastructures relaying secure traffics to protect the other peers' anonymity. Therefore, eventually the behaving users lose their faith in the system due to the unfairness, and the system may cease to properly run. OnionCoin(OC) is the first decentralized peer-to-peer anonymous messaging system based on Onion Routing with the integration of currency system attempting to resolve such issues in Onion Routing based systems. A peer in OC will have to "pay" for using the anonymous messaging service, and will "gain" by helping other peers. The purpose of this currency system is to record the transactions of "pay" and "gain" in order to provide incentives for peers to participate more in the system. Several protocols are designed so that the introduction of the currency system does not compromise any existing protection in Onion Routing on the anonymity of the communicating parties.Science, Faculty ofComputer Science, Department ofGraduat