Secure and Efficient Fully Dynamic Lattice-based Group Signature Scheme

Group signature is an interesting primitive of cryptography, enabling each group member to sign messages on behalf of the entire group anonymously. In the literature, most lattice-based group signatures are designed for static settings, hindering their practical efficiency and effectiveness. A practically feasible group signature scheme should prioritize user-friendliness and provide flexibility in the processes of user enrollment and revocation, maintaining an appropriate signature size. Keeping these considerations in mind, we have developed a variant of a lattice-based fully dynamic group signature scheme. Our scheme does not rely on a trapdoor function, which reduces its operational complexity. In our scheme, we have employed an updatable Merkle tree accumulator based on shortest integer solution (SIS) hardness to ensure the security of a user’s identity and to enable timely updates to user information as required. For explicit standard parameter size, we have presented our signature size under different security levels and compared our results with the existing similar schemes.