Privacy preserving online reputation systems

Reputation systems evolve as a mechanism to build trust in dynamic electronic societies. However, they are also a danger to privacy because they monitor a user's behavior. At the same time reputation systems offer the possibility to limit the information a user has to give away during a transaction to ensure accountablity. Privacy preserving reputation systems solve the conflict between anonymity and accountability. This paper examines privacy problems of current reputation systems and classifies them with respect; to the location of stored information. Requirements for reputation systems that provide privacy protection are derived from this analysis. As result a new privacy preserving online reputation system is presented that uses locally stored coins to represent reputation information.