Revocable Group Signature Scheme Using Ideal Lattices

M. H. Abhilash ； B. B. Amberker

《International Journal of Electronics and Information Engineering》 13卷4期 (2021/12) Pp. 149-169

https://doi.org/10.6636/IJEIE.202112_13(4).03

摘要

Group signature scheme is a cryptographic primitive that allows its registered group members to generate signatures on behalf of the whole group without revealing their identity. An important feature of a group signature scheme is revocation, which allows an authorized entity called group manager to remove users from the group. In 2018, Ling et al. [19] proposed partial dynamic group signature scheme using ideal lattices, where signature size is independent of number of users N in the group. This scheme supports joining of new users at any time but it does not support revocation. We present a partial dynamic group signature scheme using ideal lattice which supports revocation. In our scheme number of users are fixed in the group setup stage, hence it does not support joining of new users after group formation. The revocation method used is called Verifier Local Revocation (VLR). In VLR based schemes the signature verification cost is proportional to the number of revoked users. It is observed that the number of revoked users increases with time in many applications, making the verification process costly. So to overcome this an improvement to the VLR revocation method is proposed using time bound signing keys which reduces the verification cost. And the security the proposed scheme is proved based on the hardness of Ring Short Integer Solution (RSIS) and Ring Learning With Errors (RLWE) assumptions in random oracle model.

關鍵字

Group Signature Scheme ； Ideal Lattice ； Lattice Based Cryptography ； Revocation