Book excerpt: This book highlights research on secure communication of 5G and the Internet of Things (IoT) Networks, along with related areas to ensure secure and Internet-compatible IoT systems. The authors not only discuss 5G and IoT security and privacy challenges, but also energy efficient approaches to improving the ecosystems through communication. The book addresses the secure communication and privacy of the 5G and IoT technologies, while also revealing the impact of IoT technologies on several scenarios in smart city design. Intended as a comprehensive introduction, the book offers in-depth analysis and provides scientists, engineers and professionals the latest techniques, frameworks and strategies used in 5G and IoT technologies.