Mobile ad hoc networks have attracted much attention due to their mobility and easy deployment. However, the wireless and dynamic nature of network renders them more vulnerable to various types of security attacks than the wired networks. The major challenge is to guarantee secure network services. The Clustering Problem in MANETs consists of selecting the most suitable nodes of MANET topology as clusterheads, and ensuring that regular nodes are connected to clusterheads such that the lifetime of the network is maximized. In this paper, Enhanced balanced clustering algorithm with distributed self-organization (EDSBCA) is proposed for cluster formation. Elliptic Curve Digital Signature algorithm (EC-DSA) based authentication scheme is implemented in clustering of MANET for securing the nodes in cluster. Extensive results demonstrate that the scheme is effective and efficient to guarantee security in mobile ad hoc networks.