How to get Group key efficiently in mobile ad hoc networks?

Securing Group communications in mobile ad-hoc networks (MANETs) continues attracting researchers´ attentions due to its importance in many critical applications. Yet, the nature lacking a key management center makes it a challenge in terms of group key management problem in MANETs. Although recent advances in certificateless public key cryptography (CL-PKC) shed light on lightweight group key management issues, most of them depend on the bilinear pairing during their operations, which were not suitable for resource constrained nodes in MANETs due to the heavy computation overhead. This paper proposes a Huffman-tree-based pairing free authenticated certificateless group key agreement protocol (HPF-CLGKA) to establishing the group key efficiently. Neither pairing operation nor the signature for authentication is used during the protocol execution, which will cut down the computation overheads greatly. Moreover, the Huffman key tree further minimizes the negotiation rounds and therefore reduces computation and communication costs. Through these measures, group key establishment and rekeying efficiencies are greatly improved.