A privacy preserving reputation system for mobile information dissemination networks

In a mobile information dissemination network mobile users, equipped with wireless devices, exchange information in a spontaneous manner whenever they come into communication range. Users have to specify what kind of information they are looking for and what kind of information they can offer A priori there is no relation between users, literally spoken, they don't know each other and confidence in newly collected information might be low. This work presents two reputation schemes, a simple and an extended version, for mobile information dissemination networks that, based on user ratings, increase a user's confidence in some information source. As reputation systems collect sensitive personal information and monitor users' behavior, privacy is an essential requirement - especially in a mobile scenario - that is neglected by many existing approaches. Using cryptographic group signatures and the concept of an observer, our extended reputation scheme guarantees high user privacy.