TY - CONF AU - Blömer, Johannes AU - Bobolz, Jan AU - Porzenheim, Laurens Alexander ID - 43458 TI - A Generic Construction of an Anonymous Reputation System and Instantiations from Lattices ER - TY - GEN AU - Porzenheim, Laurens Alexander ID - 10306 TI - Post-Quantum Secure Group Signatures ER - TY - CONF AB - We present CLARC (Cryptographic Library for Anonymous Reputation and Credentials), an anonymous credentials system (ACS) combined with an anonymous reputation system. Using CLARC, users can receive attribute-based credentials from issuers. They can efficiently prove that their credentials satisfy complex (access) policies in a privacy-preserving way. This implements anonymous access control with complex policies. Furthermore, CLARC is the first ACS that is combined with an anonymous reputation system where users can anonymously rate services. A user who gets access to a service via a credential, also anonymously receives a review token to rate the service. If a user creates more than a single rating, this can be detected by anyone, preventing users from spamming ratings to sway public opinion. To evaluate feasibility of our construction, we present an open-source prototype implementation. AU - Bemmann, Kai AU - Blömer, Johannes AU - Bobolz, Jan AU - Bröcher, Henrik AU - Diemert, Denis Pascal AU - Eidens, Fabian AU - Eilers, Lukas AU - Haltermann, Jan Frederik AU - Juhnke, Jakob AU - Otour, Burhan AU - Porzenheim, Laurens Alexander AU - Pukrop, Simon AU - Schilling, Erik AU - Schlichtig, Michael AU - Stienemeier, Marcel ID - 3265 SN - 978-1-4503-6448-5 T2 - Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES '18 TI - Fully-Featured Anonymous Credentials with Reputation System ER -