Weaknesses of Some Threshold Group Signature Schemes
几个门限群签名方案的弱点

Threshold group signature is an important kind of signatures, but all of the exi sting threshold group schemes have weaknesses. Several properties are proposed t o define a good threshold group scheme. Then, the weaknesses of three threshold group schemes are analyzed. The most serious weakness is that part of members ca n conspire to get system secret parameters and then forge a valid signature. In the worst situation, the total system is broken.