Short Revocable Group Signatures with Compact Revocation Lists from SPS-EQ (preliminary version)

Abstract

Group signature schemes offer privacy-enhancing user authentication by enabling a user to anonymously prove membership in a group. However, revoking the membership of anonymous users is challenging, and thus various revocable group signature schemes have been proposed. Existing schemes that rely on zero-knowledge proofs often suffer from long signature sizes and large revocation lists, resulting in poor efficiency and scalability. In this paper, we propose a revocable group signature scheme where both the revocation list size and the signature length are reduced by using randomizable SPS-EQ and set commitments without requiring zero-knowledge proofs. Compared to the previous scheme, signature size in our proposed scheme is reduced to 58%. Our implementation on a PC confirms the efficiency and practicality of the proposed scheme.