[{"abstract":[{"text":"In this paper, we introduce updatable anonymous credential systems (UACS) and use them to construct a new privacy-preserving incentive system. In a UACS, a user holding a credential certifying some attributes can interact with the corresponding issuer to update his attributes. During this, the issuer knows which update function is run, but does not learn the user's previous attributes. Hence the update process preserves anonymity of the user. One example for a class of update functions are additive updates of integer attributes, where the issuer increments an unknown integer attribute value v by some known value k. This kind of update is motivated by an application of UACS to incentive systems. Users in an incentive system can anonymously accumulate points, e.g. in a shop at checkout, and spend them later, e.g. for a discount.","lang":"eng"}],"file":[{"file_size":838949,"file_name":"full_eprinted_v2.pdf","access_level":"closed","file_id":"13907","date_updated":"2019-10-18T08:07:49Z","date_created":"2019-10-18T08:07:49Z","creator":"jbobolz","relation":"main_file","content_type":"application/pdf"}],"publication":"Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS '19","ddc":["006"],"language":[{"iso":"eng"}],"year":"2019","title":"Updatable Anonymous Credentials and Applications to Incentive Systems","date_created":"2019-10-18T08:09:44Z","status":"public","type":"conference","file_date_updated":"2019-10-18T08:07:49Z","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Project Area C","_id":"4"},{"name":"SFB 901 - Subproject C1","_id":"13"}],"_id":"13904","user_id":"25078","series_title":"Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS '19","department":[{"_id":"7"},{"_id":"64"}],"citation":{"apa":"Blömer, J., Bobolz, J., Diemert, D. P., &#38; Eidens, F. (2019). Updatable Anonymous Credentials and Applications to Incentive Systems. <i>Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19</i>. 26th ACM Conference on Computer and Communications Security, London. <a href=\"https://doi.org/10.1145/3319535.3354223\">https://doi.org/10.1145/3319535.3354223</a>","mla":"Blömer, Johannes, et al. “Updatable Anonymous Credentials and Applications to Incentive Systems.” <i>Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19</i>, 2019, doi:<a href=\"https://doi.org/10.1145/3319535.3354223\">10.1145/3319535.3354223</a>.","short":"J. Blömer, J. Bobolz, D.P. Diemert, F. Eidens, in: Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19, 2019.","bibtex":"@inproceedings{Blömer_Bobolz_Diemert_Eidens_2019, series={Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19}, title={Updatable Anonymous Credentials and Applications to Incentive Systems}, DOI={<a href=\"https://doi.org/10.1145/3319535.3354223\">10.1145/3319535.3354223</a>}, booktitle={Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19}, author={Blömer, Johannes and Bobolz, Jan and Diemert, Denis Pascal and Eidens, Fabian}, year={2019}, collection={Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19} }","ama":"Blömer J, Bobolz J, Diemert DP, Eidens F. Updatable Anonymous Credentials and Applications to Incentive Systems. In: <i>Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19</i>. Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19. ; 2019. doi:<a href=\"https://doi.org/10.1145/3319535.3354223\">10.1145/3319535.3354223</a>","chicago":"Blömer, Johannes, Jan Bobolz, Denis Pascal Diemert, and Fabian Eidens. “Updatable Anonymous Credentials and Applications to Incentive Systems.” In <i>Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19</i>. Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS ’19, 2019. <a href=\"https://doi.org/10.1145/3319535.3354223\">https://doi.org/10.1145/3319535.3354223</a>.","ieee":"J. Blömer, J. Bobolz, D. P. Diemert, and F. Eidens, “Updatable Anonymous Credentials and Applications to Incentive Systems,” presented at the 26th ACM Conference on Computer and Communications Security, London, 2019, doi: <a href=\"https://doi.org/10.1145/3319535.3354223\">10.1145/3319535.3354223</a>."},"has_accepted_license":"1","main_file_link":[{"open_access":"1","url":"https://eprint.iacr.org/2019/169.pdf"}],"conference":{"location":"London","end_date":"2019-11-15","start_date":"2019-11-11","name":"26th ACM Conference on Computer and Communications Security"},"doi":"10.1145/3319535.3354223","oa":"1","date_updated":"2023-01-10T10:25:27Z","author":[{"first_name":"Johannes","last_name":"Blömer","full_name":"Blömer, Johannes","id":"23"},{"full_name":"Bobolz, Jan","id":"27207","last_name":"Bobolz","first_name":"Jan"},{"first_name":"Denis Pascal","full_name":"Diemert, Denis Pascal","id":"44071","last_name":"Diemert"},{"first_name":"Fabian","id":"25078","full_name":"Eidens, Fabian","last_name":"Eidens"}]},{"publication":"Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES '18","abstract":[{"text":"We present CLARC (Cryptographic Library for Anonymous Reputation and Credentials), an anonymous credentials system (ACS) combined with an anonymous reputation system.\r\n\r\nUsing 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.\r\n\r\nFurthermore, 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.\r\n\r\nTo evaluate feasibility of our construction, we present an open-source prototype implementation.","lang":"eng"}],"file":[{"relation":"main_file","content_type":"application/pdf","file_size":920843,"file_name":"react_acs.pdf","file_id":"5428","access_level":"closed","date_updated":"2018-11-08T10:17:39Z","date_created":"2018-11-08T10:17:39Z","creator":"feidens"}],"ddc":["000"],"language":[{"iso":"eng"}],"quality_controlled":"1","year":"2018","publisher":"ACM","date_created":"2018-06-14T11:19:29Z","title":"Fully-Featured Anonymous Credentials with Reputation System","type":"conference","status":"public","_id":"3265","project":[{"name":"SFB 901","_id":"1"},{"name":"SFB 901 - Project Area C","_id":"4"},{"name":"SFB 901 - Subproject C1","_id":"13"},{"_id":"44","name":"KogniHome - die mitdenkende Wohnung"}],"department":[{"_id":"64"}],"user_id":"25078","file_date_updated":"2018-11-08T10:17:39Z","publication_identifier":{"isbn":["978-1-4503-6448-5"]},"has_accepted_license":"1","publication_status":"accepted","related_material":{"link":[{"url":"https://github.com/upbcuk","relation":"software"}]},"place":"New York, NY, USA","citation":{"ama":"Bemmann K, Blömer J, Bobolz J, et al. Fully-Featured Anonymous Credentials with Reputation System. In: <i>Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18</i>. New York, NY, USA: ACM. doi:<a href=\"https://doi.org/10.1145/3230833.3234517\">10.1145/3230833.3234517</a>","ieee":"K. Bemmann <i>et al.</i>, “Fully-Featured Anonymous Credentials with Reputation System,” in <i>Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18</i>, Hamburg, Germany.","chicago":"Bemmann, Kai, Johannes Blömer, Jan Bobolz, Henrik Bröcher, Denis Pascal Diemert, Fabian Eidens, Lukas Eilers, et al. “Fully-Featured Anonymous Credentials with Reputation System.” In <i>Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18</i>. New York, NY, USA: ACM, n.d. <a href=\"https://doi.org/10.1145/3230833.3234517\">https://doi.org/10.1145/3230833.3234517</a>.","apa":"Bemmann, K., Blömer, J., Bobolz, J., Bröcher, H., Diemert, D. P., Eidens, F., … Stienemeier, M. (n.d.). Fully-Featured Anonymous Credentials with Reputation System. In <i>Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18</i>. New York, NY, USA: ACM. <a href=\"https://doi.org/10.1145/3230833.3234517\">https://doi.org/10.1145/3230833.3234517</a>","bibtex":"@inproceedings{Bemmann_Blömer_Bobolz_Bröcher_Diemert_Eidens_Eilers_Haltermann_Juhnke_Otour_et al., place={New York, NY, USA}, title={Fully-Featured Anonymous Credentials with Reputation System}, DOI={<a href=\"https://doi.org/10.1145/3230833.3234517\">10.1145/3230833.3234517</a>}, booktitle={Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18}, publisher={ACM}, author={Bemmann, Kai and Blömer, Johannes and Bobolz, Jan and Bröcher, Henrik and Diemert, Denis Pascal and Eidens, Fabian and Eilers, Lukas and Haltermann, Jan Frederik and Juhnke, Jakob and Otour, Burhan and et al.} }","mla":"Bemmann, Kai, et al. “Fully-Featured Anonymous Credentials with Reputation System.” <i>Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18</i>, ACM, doi:<a href=\"https://doi.org/10.1145/3230833.3234517\">10.1145/3230833.3234517</a>.","short":"K. Bemmann, J. Blömer, J. Bobolz, H. Bröcher, D.P. Diemert, F. Eidens, L. Eilers, J.F. Haltermann, J. Juhnke, B. Otour, L.A. Porzenheim, S. Pukrop, E. Schilling, M. Schlichtig, M. Stienemeier, in: Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES ’18, ACM, New York, NY, USA, n.d."},"oa":"1","date_updated":"2022-01-06T06:59:07Z","author":[{"first_name":"Kai","full_name":"Bemmann, Kai","last_name":"Bemmann"},{"full_name":"Blömer, Johannes","id":"23","last_name":"Blömer","first_name":"Johannes"},{"last_name":"Bobolz","full_name":"Bobolz, Jan","id":"27207","first_name":"Jan"},{"first_name":"Henrik","full_name":"Bröcher, Henrik","id":"41047","last_name":"Bröcher"},{"first_name":"Denis Pascal","last_name":"Diemert","full_name":"Diemert, Denis Pascal","id":"44071"},{"first_name":"Fabian","id":"25078","full_name":"Eidens, Fabian","last_name":"Eidens"},{"last_name":"Eilers","full_name":"Eilers, Lukas","first_name":"Lukas"},{"first_name":"Jan Frederik","last_name":"Haltermann","full_name":"Haltermann, Jan Frederik","id":"44413"},{"first_name":"Jakob","last_name":"Juhnke","full_name":"Juhnke, Jakob","id":"48090"},{"full_name":"Otour, Burhan","last_name":"Otour","first_name":"Burhan"},{"full_name":"Porzenheim, Laurens Alexander","id":"47434","last_name":"Porzenheim","first_name":"Laurens Alexander"},{"last_name":"Pukrop","full_name":"Pukrop, Simon","first_name":"Simon"},{"first_name":"Erik","last_name":"Schilling","full_name":"Schilling, Erik"},{"last_name":"Schlichtig","id":"32312","full_name":"Schlichtig, Michael","first_name":"Michael"},{"last_name":"Stienemeier","full_name":"Stienemeier, Marcel","first_name":"Marcel"}],"conference":{"end_date":"2018-08-30","location":"Hamburg, Germany","name":"ARES 2018 - SECPID","start_date":"2018-08-27"},"doi":"10.1145/3230833.3234517","main_file_link":[{"open_access":"1","url":"https://eprint.iacr.org/2018/835"}]}]