Rearch Of Privacy Protection And Anonymous Communication In Peer-to-Peer Systems

While encrypting comunication can hide the content of the transaction, the attacker call still invade the user's privacy by flow analysis. Anonymous communication technology is an important method to protect user's privacy. By hiding the participators'identities, or the linkability between sender and receiver, anonymous communication system can guard user's privacy from invasion.The study of anonymous communication techniques was surveyed. Base on this,a calable protocol called C-EDR was given, which can be applied to peer-to-peer systems.In C-EDR, all users join a crowds group. Each user use the address and public key of a mix node(a special kind of node in group) to construct their own destination routing. While communicating with other user, the sender first gain the receiver's destination routing, then message was passed to a randomly chosen group member, that member can either submit the message to the mix which was used to build the destination routing, or forward it to another user again. Finaly, mix get the message and pass it to it's real receiver.In this way, sender and receiver are hided. Even there are collaboration members in the system, the sender anonymity can still be promised. On the other hand, all users were responsible for forwarding message, which greatly relieve the mixs'load, letting the system get a good expansibility.C-EDR's safety and performance were analysed and proved. Compared to other systems, in C-EDR, user's expected load does't increase while the scale of system increasing, so does the expected length of path which the messages goes through, mix node's load is also better than traditional mix network.