Compared to wired networks, mobile ad hoc networks are much more vulnerable to security attacks. This is mainly due to its features of open medium, dynamic topology, cooperative algorithms, lack of centralized monitoring and management point. In this book, the author first reviews security and privacy issues in mobile ad hoc networks, and then proposes the study of algorithms and protocols for key management and (anonymous) secure routing in large ad hoc networks. More specifically, in terms of key management, the author investigates scalable key management protocols for large ad hoc networks by exploiting hierarchical network structures and cryptographical techniques. As to anonymous secure routing, the author first formally defines a set of requirements on privacy and security of an anonymous secure routing protocol, and then presents a few protocols that are designed to satisfy those requirements.