Abstract: Consider the following situations：Two companies A and B want to communicate with each other via the Internet.Company A demands that only enough members in A can generate a valid signature on behalf of the company，and the signature can only be verified by the designated receiver.Motivated by this consideration，this paper puts forward a new identity based Chameleon threshold signature which doesn’t need a trusted dealer to distribute the private key.Only the designated receiver can verify the validity of the signature，and he can not prove the validity of the signature to others.It is undeniable，and when dispute occurs，the signers can prove the signature to be forged without exposure of the original signature.

Key words: trusted dealer, Chameleon, threshold signature, bilinear paring

摘要： 考虑如下情况，有两个公司A，B通过网络进行通信，为了能安全地生成签名，公司A要求有足够多的A内成员参与时才能生成有效的签名，并且只有指定的接收者才能对签名进行验证。针对以上问题，使用一种新的基于身份的卡梅隆Hash函数，结合分布式密钥生成技术，提出了一种新的无可信中心的基于身份的卡梅隆门限签名方案。此方案不需要可信中心来分发签名密钥，只有指定的接收方可以验证签名的正确性，且指定的接收方不能向第三方证明签名是否有效；具有不可否认性，在争议发生时可以在不暴露原始签名的条件下鉴别伪造的签名。

关键词: 可信中心, 卡梅隆, 门限签名, 双线性映射