MANET is an autonomous wireless network without any centralized authority, consisting of a dynamic topology with a multi-hop scenario. Clustering provides centralized authority within MANET and makes the network stable up to some extent. Security is one of the most challenging aspects, directly proportional to load and overhead over the network. The model being proposed uses a cluster-based technique and modified secure routing protocol, which minimizes the network’s load and overhead, improving the network’s security and performance. Two major factors are used as contribution level and stability factor for the choice of cluster head, which minimizes the method of re-selection for cluster head. The node addition using authentication and the Modified Secure Routing Protocol increases the security of the network. The Modified Secure Routing Protocol, based on limited and efficient use of the certificates with encryption and decryption of packets, minimizes the overhead and load over the network. Hence, it provides more efficiency and security.