A New Threshold Signature Scheme to Withstand the Conspiracy Attack

Aiming at the weakness of existing schemes, a new threshold signature scheme to withstand the conspiracy attack is proposed in this paper. In this scheme, any subset of t or more than t members of the group can execute a valid threshold signature on behalf of the whole but can´t construct legal group signature through giving two specific equations contained each other, so this scheme can not only withstand conspiracy attacks effectively, but also provide traceability under the premise of group signature anonymity. In addition, a new conspiracy attack method is designed, which was adopted to test the existing schemes and the new scheme of this paper, the result shows new scheme has higher security than existing ones.