Short group signatures with efficient concurrent join

Abstract

Group signature schemes are fundamental cryptographic tools. A group signature scheme allows members of a group to anonymously sign messages. To counter misuse, the anonymity can be revoked by the group manager. The group joining operation is a critical component of group signature scheme, the framing attack can be prevented by group joining processes. This paper presents an efficient group signature scheme with a simple joining protocol that is based on a “single message and signature response” interaction between the prospective user and the group manager. The security of our group signature is based on the Discrete Logarithm assumption and Decisional Linear Diffie-Hellman assumption. The formal security proof of our scheme is given in the random oracle model. Our scheme is also a very efficient short group signature scheme with efficient concurrent join.