Efficient Group Signatures from Bilinear Pairing

Abstract

This paper presents two types of group signature schemes from bilinear pairings: the mini type and the improved type. The size of the group public keys and the length of the signatures in both schemes are constant. An on-line third party is introduced to help the schemes to realize the “join” of group members, the “opening” of group signatures, and the immediate “revocation” of group membership. It is shown that the introduction of this party makes our schemes much more simple and efficient than the previous schemes of this kind. The mini group signature is in fact only a BLS short signature. Unfortunately, it has a drawback of key escrow. A dishonest group manager can forge any group signature at his will. To avoid this drawback, we put forward an improved scheme, which is also very simple and efficient, and satisfies all the security requirements of a group signature scheme.KeywordsGroup signatureDigital signatureGDH groupBilinear pairing