Multi-Issuer Attribute-based Anonymous Credential with Traceability and Revocation

Attribute-based anonymous credential schemes allow users to obtain credentials from the issuer and prove the possession of their attributes interactively and anonymously with service providers. So far, most existing schemes only consider single-issuer, where some of them are extended to be traceable or revocable. In the reality, anonymous credential schemes under multi-issuer are more practical, since users could query for credentials from different issuers and use some of them simultaneously, which is more efficient than showing them individually. Although there are also multi-issuer schemes where users obtain credentials from different issuers and show an aggregated credential to service providers, however, these schemes lack practical properties, for example, revocation of invalid users. In this paper, we propose a multi-issuer attribute-based anonymous credential with traceability and revocation, which provides traceability of invalid users, and revocation of the specific users. Users receive credentials from multiple issuers and show an aggregated credential of selective disclosures of attributes. We provide the security model of our scheme of anonymity and unforgeability. Finally, we discuss the computational complexity, which shows the practicality and efficiency of our scheme.