安全和效率是影响无证书认证组密钥协商协议能否在Ad Hoc网络中得到实际应用的两个关键因素。本项目以提高安全性和效率为目标对Ad Hoc网络安全组通信面临的密钥管理难题展开研究。首先研究协议中存在的几类攻击行为，建立基于eCK模型的无证书认证组密钥协商协议安全模型，为后续设计具有强安全特性的组密钥协商协议奠定基础；其次，综合考虑节点在能量、计算能力、地理位置等方面的约束，建立基于资源感知的Huffman会话密钥树，提高协议运行效率；第三，利用椭圆曲线密码实现无配对的无证书认证组密钥的协商和身份认证，基于Huffman密钥树优化通信轮数，降低计算量和通信量，提高组密钥协商效率。通过本项目研究，解决资源受限条件下组密钥建立以及组成员变动带来的密钥更新效率问题，为Ad Hoc网络中资源受限节点安全组通信提供技术支撑。

Security and efficiency are two key factors to deciding whether the certificateless authenticated group key agreement protocol can be applied in Ad Hoc Networks. Considering the key management problems in securing group communications of Ad Hoc networks, this project studies the above two key factors. First, through analyzing the attacker behaviors in certificateless authenticated group key agreement protocols, this project will establish a security model for certificateless authenticated group key agreement protocols, which will be the foundation for designing the authenticated group key agreement protocol later. Second, through studying the key tree structure considering the difference of users’ energy, computation ability, and location, this project will establish the Huffman key tree based on resource-aware, which will improve the efficiency of the protocol. Third, this project will utilize ECC to achieve the certificateless group key agreement and authentication without pairing. The number of the key negotiation round can be optimized by adopting the Huffman key tree, which will decrease the computation and communication overheads, and therefore improve the group key negotiation efficiency. The aim of the project is to improve the efficiency of key establishment and rekeying for dynamic groups with restrained resources, and provide the technical support for securing the group communication in Ad Hoc networks.