An Improved Identity-Based Group Signature Scheme

In a group signature scheme, a group member signs messages anonymously on behalf of the group. However, in the case of a dispute, the actual group signer´s identity can be revealed by a designated entity. In this paper, we propose a new identity-based group signature scheme using bilinear maps. The group signature scheme is well suited for large groups, i. e., the length of the group´ s public key and the length of signatures are independent on the size of the group. Our signature scheme is based on bilinear maps. Furthermore, a group member can sign many messages using the same key pair. Cryptanalysis shows that the proposed group signature scheme is secure under the computational Diffie Hellman problem called CDHP assumption. And it is also more efficient than previous ones satisfying these requirements.