Efficient U-Prove Implementation for Anonymous Credentials on Smart Cards

In this paper we discuss an efficient implementation of anonymous credentials on smart cards. In general, privacy-preserving protocols are computationally intensive and require the use of advanced cryptography. Implementing such protocols for smart cards involves a trade-off between the requirements of the protocol and the capabilities of the smart card. In this context we concentrate on the implementation of Microsoft’s U-Prove technology on the MULTOS smart card platform. Our implementation aims at making the smart card independent of any other resources, either computational or storage. In contrast, Microsoft suggests an alternative approach based on device-protected tokens which only uses the smart card as a security add-on. Given our very good performance results we argue that our approach should be considered in favour of Microsoft’s one. Furthermore we provide a brief comparison between Java Card and MULTOS which illustrates our choice to implement this technology on the latter more flexible and low-level platform rather than the former.