Research On Distributed Key Management Scheme For Mobile Ad Hoc Networks

With the rapid development of mobile computing and wireless communications technology, performance of mobile devices has been greatly improved, such as computing, storage, communications and so on. Thus, mobile Ad hoc networks are becoming the research hotspot in next-generation wireless communications technology. Mobile Ad hoc Networks are self-organized, multi-hop network through wireless communication, one of the most difference from traditional networks is that it does not depend on any fixed infrastructure; there are no base stations, access points or remote servers. Mobile Ad hoc networks can be, at any time and any place, the convenience of fast networking makes it have been widely used in military, emergency, remote areas, personal communications, and so on.Mobile Ad hoc networks do not have any infrastructure, the network topology changes dynamically, the terminal node’s storage capacity, computing power and energy are limited, the bandwidth of wireless transmission are limited, and they have poor communication quality. These characteristics make the network is vulnerable to variety of attacks from external malicious nodes, such as eavesdropping, spoofing, message retransmission, messages destruction, etc. At the same time, the internal node is also very easy to be captured by malicious node, thus there exist attacks inside the network. Key management is an important and critical security technology of mobile Ad hoc network. Key management schemes for the traditional wired network are not suitable for mobile Ad hoc networks because of the special characteristics of Mobile Ad hoc Networks. Therefore, it is necessary to design some special key management schemes for mobile Ad hoc network.At present, research on key management scheme for mobile Ad hoc networks have achieved certain outcomes at home and abroad, where researchers mostly focus on study of the key management scheme in the standard model and further try to design key management scheme which meeting the theoretical requirements in every respect. However, in different environments, there are different requirements in the quality of channel, node performance, and security needs, and therefore the availability of the key management scheme design under the standard model for Ad hoc network is not strong. In this paper, we make further study of distributed key management in mobile Ad hoc networks. On the one hand, we analyze the existing schemes, avoid their shortcomings, reduce the computational and communication complexity as much as possible, and enhance their security; On the other hand, according to requirements of some specific applications, we try to design some special Ad hoc network models and key management framework. Specifically, there are following aspects of the work:First, for the specific applications which require a trusted third party such as notaries, we proposed an asymmetric key management framework for mobile Ad hoc network. In this framework, nodes in network are asymmetric, where there are some special nodes, which can achieve some special network services. According to this framework, we designed a new secret sharing scheme to share the master private key. In addition, we designed a limited verifier signature scheme in mobile Ad hoc Networks based on the structure of the node’s key configuration.Second, for matters such as approval step by step, we proposed a hierarchical key management model for mobile Ad hoc networks. In this model, it needs different levels of the nodes to provide network services. According to the model, we designed a hierarchical secret sharing scheme for different levels of nodes sharing the master private key, and designed a scheme to sign and distribute a certificate.Third, we designed a simple distributed digital signature scheme based on Euler’s theorem, and further applied it to the key management scheme for Ad hoc network combined with the Shamir secret sharing. In signature validation phrase, nodes only need to compute modular multiplications, thus it reduces the computational overhead, and enhance the availability.Fourth, the traditional distributed key management of mobile Ad hoc network based on Shamir secret sharing needs a trust center to generate the share of the master private for network nodes in the network initialization. To solve this problem, we designed a key management scheme for mobile Ad hoc network without a trusted center. In initial phase, some server nodes of the network directly select their respective shares of master private key without a trusted center, and then generate and distribute shares of mater private key for other server nodes in networks. Compared with the existing key management schemes without a trusted center for Ad hoc network, our scheme reduces the communication and computation complexities.