Future communication networks aim to build an intelligent and efficient living environment by connecting a variety of heterogeneous networks to fulfill complicated tasks. These communication networks bring significant challenges in building secure and reliable communication networks to address the numerous threat and privacy concerns. New research technologies are essential to preserve privacy, prevent attacks, and achieve the requisite reliability. This book studies and presents recent advances reflecting the state-ofthe- art research achievements in novel cryptographic algorithms, intrusion detection mechanisms, privacy preserving techniques and reliable system protocols. It is ideal for personnel in computer communication and networking industries as well as academic staff and collegial, master, Ph.D. students in computer science, computer engineering, cyber security, information insurance and telecommunication systems. The book is organized into four parts. Part I presents to two novel schemes to preserve privacy in wireless ad hoc networks. In Part II, three creative approaches to detect instructions, service violations, and vulnerabilities in various networked systems. Part III introduces four interesting algorithms to improve security. One chapter evaluates a set of encryption tools in cloud computing. The other chapter designs encryption algorithm for low-energy devices. How to construct secrecy is also discussed in this part. Finally, reliable system design mechanisms are demonstrated in Part IV. Three different routing protocols are presented to improve the reliability and robustness in the communication.Aprediction scheme is proposed to ensure Quality of Service in IEEE 802.11.