MANET (Mobile Ad-hoc NETwork) is the self configuring type of network in which mobile nodes can join or leave the network when they want; it is a decentralized type of network. Due to these unique properties of the MANET, it is much vulnerable to security attacks. ALARM protocol (Anonymous Location Aided Routing in MANET) is used in MANET to achieve the key security objectives, i.e. confidentiality, authentication, authorization, integrity. ALARM protocol is based on certain assumptions, such as, location of the mobile nodes, time at each node, range of mobile nodes etc.