Providing a reliable and secure communication in Mobile Adhoc Network (MANET) is a highly challenging and demanding task in recent days. For this purpose, different techniques are developed in the traditional works, but it lacks with the drawbacks of difficult key revocation, reduced security, increased delay, and bandwidth usage. To solve these problems, this paper motives to develop a routing technique, namely, Identity Based Key Management (IBKM) for providing a secure communication in MANET. Here, the group polynomial equation is generated at first for generating a unique ID to each node in the network. Then, the neighboring nodes of the source and destination are identified and registered in the network table. After that, the routing path between these nodes are validated in order to enable a reliable communication. The node pairing is performed and the public key is distributed to the nodes that are successfully paired. Sequentially, the signature of the packet is generated and verified, if both generated and received signature are same, the packet is received; otherwise, the misbehavior node is identified and blocked. To evaluate the results of the proposed mechanism, various performance measures such as malicious node detection probability, average message overhead, Packet Delivery Ratio (PDR), end-to-end delay, throughput, and routing overhead are used. Here, the results are evaluated with respect to various malicious node ratio, speed (m/s), and simulation time (s). Also, the existing Dynamic Source Routing (DSR) and Cooperative Bait Detection Scheme (CBDS) are compared with the proposed mechanism for proving the efficiency. From the results, it is analyzed that the PDR and throughput of the network is increased with the reduced message overhead and delay. Also, the proposed mechanism uses the identity based key management technique, which efficiently detects the malicious nodes in the network. © 2018 International Journal of Intelligent Engineering and Systems.