Mobile ad-hoc networks (MANETs) are self-organizing wireless networks of movable nodes. It can be established with no needs of preexist network infrastructure for managing a routing between each node within the network. MANETs are highly vulnerable to various types of adversary’s malicious attacks or security threats. Among numerous security attacks, sinkhole attack is one of the severe security threats in ad-hoc networks that can be easily performed by exploiting vulnerability of on-demand routing protocols such as ad-hoc on demand distance vector (AODV) and others. We implemented a prevention mechanism for sinkhole attacks, which imposed by malicious node, by modifying AODV protocol with Identity base cryptography (IBC).IBC is a cryptographic scheme that is recently being applied since 2001, which allows nodes to communicate securely based on their identity. In this thesis, we implemented prevention mechanism by enhancing AODV protocol with identity based signature (IBS) scheme. It shows high ability to prevent sinkhole attack. Unlike the existing sinkhole attack prevention techniques that rely on the cooperation of mobile nodes and sequence number to announce a presence of intrusion, usage IBS scheme enables each mobile node to protect itself from an intruder. Implementation of the prevention mechanism has been carried out by using the Network Simulation version 2(NS-2). An Xgraph used to analyze outcome results of simulation. Postanalysis result proves that the prevention method implemented maximizes network performance by effectively preventing sinkhole attack against mobile ad-hoc networks as well as minimizing packet dropping of route controlling messages.