A CCA-Full-Anonymous Group Signature with Verifiable Controllable Linkability in the Standard Model

Group signatures allow users to anonymously sign messages on behalf of a group. In this paper, we construct a group signature with verifiable controllable linkability in a generic way, where a linking authority (LA) can link two signatures to determine whether they are generated by the same unknown signer or not. Our core building block is a structure-preserving public key encryption with equality test, where public keys, plaintexts, and ciphertexts are all group elements, encryption, decryption, and test algorithms only consist of group and pairing operations. Due to its structure-preserving property, our scheme is easy to combine with non-interactive zero-knowledge proofs on bilinear groups and hence make this combination more efficient than the most CCA-full-anonymous GSS-VCL constructions in the standard model.