Sybil-Free Pseudonyms, Privacy and Trust: Identity Management in the Internet of Services

We propose an identity management system that supports role-based pseudonyms that are bound to a given set of services (service contexts) and support the use of reputation systems. Our proposal offers a solution for the problem of providing privacy protection and reputation mechanisms concurrently. The trust information used to evaluate the reputation of users is dynamic and associated to their pseudonyms. In particular, our solution does not require the support or assistance from central authorities during the operation phase. Moreover, the presented scheme provides inherent detection and mitigation of Sybil attacks. Finally, we present an attacker model and evaluate the security and privacy properties and robustness of our solution.