Cryptology ePrint Archive: Report 2018/835

Fully-Featured Anonymous Credentials with Reputation System

Kai Bemmann and Johannes Blömer and Jan Bobolz and Henrik Bröcher and Denis Diemert and Fabian Eidens and Lukas Eilers and Jan Haltermann and Jakob Juhnke and Burhan Otour and Laurens Porzenheim and Simon Pukrop and Erik Schilling and Michael Schlichtig and Marcel Stienemeier

Abstract: We present $\mathsf{CLARC}$ (Cryptographic Library for Anonymous Reputation and Credentials), an anonymous credentials system (ACS) combined with an anonymous reputation system.

Using $\mathsf{CLARC}$, 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, $\mathsf{CLARC}$ 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.

Category / Keywords: Anonymous Credential System, Authentication, Privacy, Proofs of Partial Knowledge, Reputation System, Revocation

Original Publication (in the same form): Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES 2018

Date: received 5 Sep 2018, last revised 5 Sep 2018

Contact author: feidens at mail uni-paderborn de

Available format(s): PDF | BibTeX Citation

Version: 20180906:204845 (All versions of this report)

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