In the last two decades, research in various aspects of mobile ad-hoc networks, MANETs, has been very active, motivated mainly by military, disaster relief and law enforcement scenarios. More recently, location information has become increasingly available; partially prompted by the emerging trend to incorporate location or position sensing into personal handheld devices. An evolutionary natural step is to adopt such position-based operation in MANETs. This results in what we call position-based MANETs. In such settings, devices are equipped with position-sensing capabilities and rely on position information in their operation. The main distinguishing feature of the envisaged position-based MANET environment is the communication paradigm based not on permanent or semi-permanent identities, addresses or pseudonyms, but on instantaneous node locations or positions. In some application settings, such as: military, law enforcement and search-and-rescue, node identities are not nearly as important as node positions. Such settings have certain characteristics in common. First, node position is very important: knowledge of the physical, as opposed to logical or relative topology, makes it possible to avoid wasteful communication and focus on nodes located within a specific area. Thus, the emphasis is not on the longterm node identity, but rather on current node position. Second, critical environments face security and privacy attacks. Security attacks aim to distribute false location and network ing control information, e.g., routing control messages, or impede the propagation of genuine information. The goal of privacy attacks is to track nodes as they move. Third, when the operating environment is hostile, as is the case in military and law enforcement settings, node identities must not be revealed. We use the term hostile to mean that communication is being monitored by adversarial entities that are not part of the MANET. The need to hide node identities becomes more pressing if we further assume that MANET nodes do not trust each other, due to a suspicious environment where nodes can be compromised. In such an environment, it is natural for node movements to be obscured, such that tracking a given node is impossible or, at least, very difficult. While we do not claim that such suspicious and hostile location-based MANET environments are commonplace, they do occur and require high security and privacy guarantees. While doing all these;there is a challenge for nodes to maintain anonymity protection from outside observers or malicious attackers. Full anonymity protection can be achieved only when ;sources,destinations and routes all are protected. In this work, to offer better anonymity protection, we propose an Anonymous Position-based Security Aware Routing Protocol (APSAR). Experimental results exhibit consistency with the theoretical analysis, and show that APSAR achieves better route anonymity protection compared to other anonymous routing protocols. Also, APSAR achieves comparable routing efficiency to the GPSR geographical routing protocol. The work in this thesis addresses a number of security and privacy issues arising in position-based MANETs. models. We address the problem of position based security aware routing in consideration with better anonymity protection .