中文摘要：

该文分析了曹晨磊等人（2014）提出的层次身份基认证密钥协商方案的安全性,指出该方案无法抵抗基本假冒攻击。文中具体描述了对该方案实施基本假冒攻击的过程,分析了原安全性证明的疏漏和方案无法抵抗该攻击的原因。然后,在BONEH等人（2005）层次身份基加密方案基础上提出了一种改进方案。最后,在BJM模型中,给出了所提方案的安全性证明。复杂度分析表明所提方案在效率上同原方案基本相当。

英文摘要：

The security of hierarchical identity based authenticated key agreement scheme which was proposed by CAO et al. （2014） is cryptanalyzed. First, it is pointed out that the scheme is not completely secure against the basic impersonation attack. Then, the process and the reasons of the attack are described. Finally, an improvement scheme to mend the security leaks is proposed based on the hierarchical identity based encryption （BONEH et al. 2005）. The security proof of the proposal is presented in the BJM model. The computation efficiency of the proposed scheme is nearly equivalent to the CAO et al.＇s.