An efficient full dynamic group signature scheme over ring

The group signature scheme is an important primitive in cryptography,it allows members in a group to generate signatures anonymously on behalf of the whole group.In view of the practical application of such schemes,it is necessary to allow users’registration and revocation when necessary,which makes the construction of dynamic group signature schemes become a significant direction.On the basis of(Ling et al.,Lattice-based group signatures:achieving full dynamicity with ease,2017),we present the first full dynamic group signature scheme over ring,and under the premise of ensuring security,the efficiency of the scheme is improved mainly from the following three aspects:the size of keys,the dynamic construction of a Merkle hash tree that used to record the information of registered users,and the reuse of the leaves in this tree.In addition,the public and secret keys of both group manager and trace manager are generated by a trusted third party,which prevents the situation that the two managers generate their respective public key and secret key maliciously.Compared with the counterpart of the scheme in(Ling et al.,Lattice-based group signatures:achieving full dynamicity with ease,2017)over ring,the expected space complexity of the Merkle tree used in our work down almost by half,and the computational complexity of its update has been reduced by a notch because of the dynamic construction of the hash tree.