Research On Group Key Management For MANET

With the rapid development of Mobile Ad hoc Network(MANET) and multicastcommunication techniques, the security of multicast key for MANET has attractedmore and more attention. How to realize a secure, efficient and facile group keymanagement for MANET via insecure wireless network is a challenge for research,Some typical scheme for group key management can't be used in MANET directly.there are some problems existing in group key management for MANET asfollowing:Firstly, because the character of MANET is no central node for distributing andmanaging CA, and no node can be trusted by all other nodes in networks, how togenerate group key and distribute it to all members of group, securely and efficiently,fault torrent and distributed as well, is the most field be worth researching. For alarge-scale Ad hoe networks, because the number of nodes is numerous and mobile, itis easy to gernerate network split and un-synchronization, A cluster-based structurenetwork is often used to manage the route and member of group, but the roamproblem caused by hostility nodes who roam from one cluster to another frequently,will immerse network performance deteriorated deeply. How to provide security andusability of group key when some nodes roaming is an important challenge.Secondly, most of typical scheme for MANET multicast reking are based inbalanceable key tree, the most import problem of multicast reking is providingforward security when member leaves and backward security when member join, then,how to improve efficient of multicast reking, decrease the cost of reking, is the coreproblem of balanceable key tree for MANET multicast reking.Thirdly, Huffman key tree is used for providing the most efficent of grouprekeying theoretically, who can realize the least average cost of group rekeying. Butin fact, because the probability of leaving member can't be predicted accurately, andthe Huffman tree is a static tree, How to provide an dynamitic and adaptive Huffmankey tree, is another important field of multicast rekeying. For solution of above three problem, this paper is focus on group keymanagement in MANET as follows: (1) research on generation and distribution ofgroup key for MANET; (2) research on balanceable key tree for group rekeying;(3) research on Huffman tree for group rekeying.(1) research on generation and distribution of group key: First we use secretshare and Id-based key technique to estabilish Id-based key system in MANET, inwhich system every node has an pair of key, the public key of nodes is his ID. Thenwe propose a fault-torrent and distributed group key generation and distributionscheme, by this scheme, we propose a group key management for cluster-based Adhoc network.(2) research on balanceable key tree for group rekeying: Because most ofrekeying cost is caused by leaving member, we propose an M-dimension spheremulticast rekeying scheme, in this scheme, cooperation of brother nodes can improvethe efficient of rekeying cost when leaving member. Then we propose an batchrekeying scheme by M-dimension sphere.(3) research on Huffman tree for group rekeying: For solving the problem thatHuffman key tree can't be adjusted dynamically but be statically established inscheme by now, in this paper we propose an adaptive Huffman key tree scheme formulticast rekeying, in our scheme, we can adjust the structure Huffman key treeadaptively with the frequent of users join in or leave from multicast group before now,because that the frequent denote the probability of this group member who shouldjoin in or leave from group in future. By the analysis, we prove that our scheme canprovide the security of multicast rekeying, as well as can ensure the condition that theaverage cost of rekeying is minimum value, even when adjusting Huffman key treedynamically.