Efficient Key Management Schemes For Ad Hoc Network

Ad Hoc network, which is also called self-organized network, becomes the first choice of digital battlefield communication because of its properties such as dispense with spanning network establishment, speediness extensibility and resisting damage. Protecting the Ad Hoc network becomes extremely important for the openness of wireless channel and the particularity of Ad Hoc network in military application. Key management is the key problem of Ad Hoc network. In traditional network, key management is done by key distribution center or certification authentication center. But in Ad Hoc network, the computation of each node is distributed, there is no such trusted organization, so it is very difficult to realize such centralized key management mechanism. Meanwhile, bringing in such organization also brings in potential security threat. Once the organization is successfully attacked by adversaries, the whole network will be in a state of paralysis. So we should find more suitable ways to manage the key.We mainly study on secure, efficient key management schemes of Ad Hoc network in this paper. We start with the structure and characteristics of Ad Hoc network, analyzing the types of attackers in the network, then we research on the security threaten and relative security requirements. Based on this, we point out main research problems on security of Ad Hoc network, then sum up present research results of key management in Ad Hoc network, thoroughly analyze the advantages and disadvantages of these schemes. After that, using the new theory and techniques in cryptology, such as ID-based cryptosystem, verifiable secret sharing, paring in elliptic curves, combined these tools with the research results on Ad Hoc key management, we put forward some secure and efficient key management schemes. Our works are as follows:Firstly, we propose a new Ad Hoc networks key management scheme based on the intractability of discrete logarithm problem and Diffie-Hellman key agreement algorithm. The advantage of our scheme is that it is compact, and the quantity and time of interactive message is reduced during the key agreement by broadcasting, so the efficiency is improved.Secondly, we construct a non-interactive Ad Hoc networks key management scheme based on Chinese Remainder Theorem and ElGamal public key cryptosystem. The scheme aims at solving the disadvantage of frequent key agreement when refreshing the key in previous schemes. In our scheme, each legal node only need hold a self-select secret key, then for a long period he can get the refreshed group key after decipher. In this way, not only the disadvantage of mass interactive agreement in previous schemes is avoided, but also improved the efficiency of key management, this makes our scheme more applicable and expansible.Thirdly, we put forward an ID-based key distribution and rekey protocol, using bilinear paring in elliptic curve, ID-based cryptosystem and Pedersen-VSS distributed key generation protocol. First, the scheme solves the aptness of giving away system private key and node private key when new node joins in or old node leaves the network in ID-based cryptosystem. Second, the scheme solves the disadvantage that any group contains equal to or more than threshold nodes can reconstruct the system secret key and other node's secret key. Third, our scheme strengthens robustness, discrimination and error tolerance of Ad Hoc networks. At last, the scheme improves efficiency of protection and refreshing the system private key and node private key in previous schemes. With the premise of fulfilling the properties and security requirements of Ad Hoc networks, our scheme is more applicable and expansible by solving the above problems.