Privacy, Liveliness and Fairness for Reputation

In various Internet applications, reputation systems are typical means to collect experiences users make with each other. We present a reputation system that balances the security and privacy requirements of all users involed. Our system provides privacy in the form of information theoretic relationship anonymity w.r.t. users and the reputation provider. Furthermore, it preserves liveliness, i. e., all past ratings can influence the current reputation profile of a user. In addition, mutual ratings are forced to be simultaneous and self rating is prevented, which enforces fairness. What is more, without performing mock interactions —even if all users are colluding— users cannot forge ratings. As far as we know, this is the first protocol proposed that fulfills all these properties simultaneously.