An improved group signatures scheme based on discrete logarithm problem

A group signature scheme allows a group member to sign a message anonymously on behalf of the group. In case of a dispute, the group manager can reveal the actual identity of signer. In this paper, we propose an efficient group signature scheme, which divide the document M into m blocks and add some redundant bits to each message block, to avoid the conspiracy attack. The security of the proposed scheme is based on the difficulty of computing the discrete logarithm modulo for a composite number. The size of the group signature and the verification time of the group signature are equivalent to that of an individual signature.