"The text discusses theories like quantum-safe cryptography, zero trust networking, blockchain-based trust management, architectures like heterogeneous networks, software-defined networking, edge computing, and applications like secure Internet of Things, smart cities, critical infrastructure protection, and secure telemedicine. It further covers deep and light algorithms for detecting fake intrusion in 6G networks, and quantum security in 6G communication systems. It is primarily written for senior undergraduates, graduate students, and academic researchers in the fields including electrical engineering, electronics and communications engineering, computer science, and engineering"--