In this new era of mobile communication, with the technological advancements, we have found out new alternatives to the traditional infrastructure-based networks, a MANET. A Mobile Ad hoc Network (MANET) is the cooperative engagement of mobile nodes without the required intervention of any centralized access point or existing infrastructure. However, this infrastructure-less nature of MANET makes it difficult in designing a foolproof security protocol. A number of protocols have been proposed in the literature for secure routing, but, most of these are either proactive or reactive in approch with their own limitations. In this book, we proposed a secure hybrid ad hoc routing protocol, called Secure Zone Routing Protocol (SZRP), which aims at addressing the above limitations by combining the best properties of both proactive and reactive approaches. The book details the design of the protocol and analyses its robustness in the presence of multiple possible security attacks that involves impersonation, modification, fabrication and replay of packets caused either by an external advisory or an internal compromised node within the network.