The Research On Key Management Algorithm In Wireless Ad Hoc Network

Wireless Ad hoc network is a novel decentralized wireless network with no pre-existing fixed infrastructure, limited computing resource and dynamic topology. It plays an important role in emergency network deployment. Due to its inherent characteristics, wireless Ad hoc network is vulnerable to attacks. And security scheme for traditional wired network can not be resistant to those attacks. As a result, a security scheme for wireless Ad hoc network should be redesigned. The core issue of this security scheme is the design and implementation of a secure and efficient key management algorithm which can protect network against attacks.In this thesis, by adopting elliptic curve cryptosystem (ECC) combined public key technology, verifiable secret sharing technology, two-tier architecture network technology, and so on, we propose a novel key management scheme and algorithm based on two-tier architecture network. The main creative point of this scheme is the server nodes security management layer. In this layer, we distribute private-key seed matrix shadow to server nodes in backbone network instead of all nodes in network. It not only solves the problem of single point failure, but also increases the network efficiency. A centralized group key agreement is applied in the lower layer of network, and a distributed group key agreement is applied in the upper layer of network. So it gains the advantages of two key agreement modes to increase network flexibility and group key updating efficiency. And there is an identity authentication mechanism in group key agreement to keep network from active attacks.The key management algorithm based on the new scheme includes several sub algorithms, such as key generation, group key agreement, key update, nodes joining operation and nodes existing operation. These sub-algorithms link to each other and are regarded as an integrated key management algorithm in wireless Ad hoc network. The algorithm can manage the key from generation to revocation. There are active malicious nodes recognizing mechanisms in most of the sub-algorithms. The update of pair key and private seed matrix shadow can increase the network security. It can dynamically adjust the threshold parameter not only to the variable network size, but also to the dynamic change of network structure. Additionally, the analysis and experimental data show that the proposed scheme not only provides better network security, but also improves the efficiency compared with the previous scheme in Ad hoc network.