Privacy-Enhancing Decentralized Anonymous Credential in Smart Grids

Decentralized Anonymous Credential (DAC) has posed enormous potential in smart grids for protecting user privacy (e.g. preventing user's daily life from being sketched out). However, the existing DAC protocols still compromise user privacy for a full list of attributes are disclosed during showing credentials. In this paper, to construct a privacy-enhancing decentralized anonymous credential (PEDAC) protocol, we first design a more efficient range proof to hide user's attributes. Specifically, we are inspired by Camenisch et al. (ASIACRYPT 2008), but replace their adopted Boneh-Boyen signature scheme with the Chinese standard 5M2 signature scheme (incorporated in the ISO/IEC 14888-3) to propose pairing-free set membership and range proof protocols. These protocols can be executed non-interactively upon the Fiat-Shamir heuristic (INDOCRYPT 2012), and then be used to construct our PEDAC protocol. By compared with the protocols of Camenisch et al. (ASIACRYPT 2008) and Poelstra et al. (FC 2018), our proposed range proofs are with less communication and computation costs and hence more practical for constructing PEDAC protocols in smart grids.