In recent years, Mobile Ad-hoc Networks have received an immense attention in both industry and academia as they provide dynamic networking services. Such networks are rapidly deployable in the future, so secure wireless environment will be obligatory. In mobile ad hoc networks, due to unreliable wireless media, lack of fixed infrastructure and host mobility, providing secure communications is a big challenge. Because a temporary device recurrently joins or leaves a network, the authentication and security technology should be equipped for the malicious devices used in third-party attacks. Usually, symmetric and asymmetric cryptographic techniques are used for secure communications in wired and wireless networks but they have their advantages and disadvantages. In fact, any cryptographic means is ineffective if its key management is fragile. Key management is one of the vital aspects for security in mobile ad hoc networks. In mobile ad hoc networks, the processing load and complexity for key management are strongly subject to restriction by the node's available resources like energy and the dynamic nature of network topology. In this paper, Adaptive Group Key Management technique is proposed which uses symmetric key management. The proposed technique diagnoses compromised nodes in their regions by a secure key initially generated by the base stations (BSs). BSs carry out an initial key generation and trust is developed among mobile stations / nodes by another key known as group key. Simulations are done to observe the network performance and the results are very outstanding.

Mobile Ad-Hoc Networks (MANET) Group key management Security Intrusion detection Cryptography Trust Key Management Symmetric key