Benchmarking Privacy-ABC Technologies - An Evaluation of Storage and Communication Efficiency

Privacy-enhancing attribute-based credentials (Privacy-ABC) technologies represent a particular category of security mechanisms that enable privacy-friendly identity management systems. In order to provide privacy for users and strong authentication for service providers, they rely on a number of different cryptographic building blocks, which increase their complexity. Hence, efficiency of these technologies becomes an important challenge and a factor that can determine their suitability for deployment in different platforms and services. In this paper, we focus on the storage and communication efficiency. We used a common framework to compare two prominent examples of Privacy-ABC technologies, U-Prove and Idemix, and evaluate the cost of a number of advanced Privacy-ABC features on the chosen efficiency aspects. Our results suggest that for storage, Idemix is more efficient than U-prove, since a single credential provides multiple-presentation unlink ability. In terms of communication efficiency, Idemix is more efficient for issuance, whereas U-Prove is more efficient for presentation of credentials. Independently of these two technologies, revocation and inspection represent a strong, constant impact on the efficiency of presentation.