Reputation

Reputation and Trust in Peer-to-Peer Networks

This article deals with the problems and solutions of trusting strangers in a network. In a Network where you are transacting with identities you don't know, you have a problem when you need to know whether you really get what you want or not. To solve this problem you need a system which can tell you how suitable a peer is for your needs. Such a system can be called Trustsystem or Reputationsystem.

Example Scenarios

Filesharing: Peer A is part of a filesharing network and wants to get some data. Peer A searches and finds a couple of peers providing that data. Peer A needs to select a transaction partner. Which one to choose depends on the P2P network used. Usually things like speed or distance make up that decision. When it is important to get reliable data then the reputation of the providing peer is an important point.

"Expert"network: Peer A is part of a network that provides answers to questions by having experts taking part in it. Peer A has a question and some "experts" can answer it. It would be very nice, if Peer A could somehow know, how credible those experts are.

Network protection: A P2P network is usually open to everyone, so it is also open for malicious users who want to damage the network. They can do that depending on the architecture by flooding, providing wrong data, manipulating searches and so on. For the network to keep going well it needs to protect itself somehow. Restricting users depending on their reputation is a way to do so.