Mobile ad hoc network is a wireless network without the support of network infrastructure. Security is one of the main challenge in ad hoc network due to dynamic topology and mobility of nodes. In this paper, we present a new composite key management scheme based on a combination of techniques such as hierarchical clustering, partially distributed key management, offline certification authority and mobile agent. In this method, network is hierarchically structured into clusters based on node’s trust value. The information about node revocation and PKG service nodes are exchanged in the network using mobile agents. The cluster head maintains public keys of its members which overcomes the storage problem in PKI where each node maintains public key of other nodes in network and avoids centralized CA to generate keys, thus enhances security.

Composite Key management Certification authority Trust evaluation