Revocable ring signatures with CCA-anonymity from standard lattices

Abstract

Ring signatures are significant cryptographic primitives used for anonymous authentication due to their anonymity and spontaneity. However, in some scenarios, they may offer excessive anonymity to the signer. Revocable ring signatures aim to preserve the desirable properties of ring signatures while incorporating the accountability aspect of group signatures, leading a better trade-off between anonymity and accountability. Nevertheless, most revocable ring signature schemes only provide relatively weak CPA-Anonymity. In this paper, we present an instantiation of CCA-Anonymity from standard lattices, and prove its security under the random oracle model. Our construction achieves stronger anonymity and revocability, while relying on weaker assumptions than existing schemes from module lattices. Moreover, it boasts smaller sizes when the ring is large.