Mobile Ad-Hoc Networks (MANETs) use anonymous routing protocols that hide node identifies and/or routes from outside observers in order to provide anonymity protection. In this attack, an adversary captures few nodes, replicates them and then deploys arbitrary number of replicas throughout the network. It is very hard to distinguish between non-compromised nodes a clone node since a clone has the same security and code information of original node. Hence cloned nodes can launch a variety of other attacks. The detection of cloning attacks is therefore a fundamental problem. The main objective of this method is to prevent clone attacks in MANETs while routing. A clone attack is launched by a malicious node by copying the configuration of a legitimate active node of current operating network. Polynomial bivariate keys are used for preventing clone attacks while routing by validating the next hop until the data reaches the destination. A polynomial key based authentication layer in AODV is used to demonstrate the clone attack prevention in the MANET.