Abstract: The threshold signature can be classified into the two categories, solutions with the assistance of a trusted party and solutions without the assistance of a trusted party. In some special cases, as an authority which can be trusted by all members does not always exist, a threshhold signature scheme without a trusted party seems more attractive. A new traceability threshhold signature scheme without a trusted party is proposed based on Wang-Li scheme after analyzing WLC threshhold signature scheme. The security of this scheme is analyzed. The results show that the proposed scheme can not only resist conspiracy attacks and forgery attacks, but also provide anonymity and tracebility simultaneously. Besides, it can realize the unknow ability of groups secret by constructing a secure distributed key generation protocol.

Key words: threshhold signature, trusted party, identifier tracing, conspiracy attack

摘要： 在很多特定的应用环境之中，一个可以被所有成员信任的可信中心并不存在。因此在分析有可信中心的WLC门限签名的基础上基于王—李方案思想提出了一个无可信中心的门限签名。另外在对张文芳等具有可追查性的抗合谋攻击的门限签名的分析下，对方案的安全性进行了分析。结果表明，该方案可抵抗合谋攻击和伪造签名攻击，并且在确保匿名性的前提下实现签名者身份的可追查性，同时通过分布式密钥生成协议保证了群私钥的不可知性。

关键词: 门限签名, 可信中心, 可追查, 合谋攻击