An Improved Key Agreement Protocol Based on Key Association Set for Dynamic Peer Group

Secure group communication is a research hotspot. The Tree-based Group Diffie-Hellman Protocol is a fairly good key management scheme for dynamic peer group communications. Through analyzing TGDH protocol, the authors have found out that a deficiency exists with its communication mode. A lot of redundant messages are used to complete group re-keying so that more communication bandwidth will be consumed in TGDH. This paper aims to solve the deficiency and improve TGDH through designing a preparatory algorithm of finding a Key Association Set. A new re-keying protocol is also designed by using the algorithm. Theoretical analysis shows that our protocol effectively decreases the communication and storage overload of TGDH, with the communication bandwidth descending from O (nlogn) to O (n) and the key storage descending from O (n) to O (logn). The simulation result also shows the improved protocol has a better communication performance.