This document discusses the key concepts of cyber security. It begins by defining cyber security as the practice of defending computers, servers, mobile devices, electronic systems, networks, and data from malicious attacks. The document then explains the three key concepts that form the foundation of cyber security, known as the CIA Triad: confidentiality, integrity, and availability. It provides examples of how each concept is implemented. The document also distinguishes between cyber security and information security, and lists some common categories of cyber security like network security, application security, and information security. It concludes by discussing types of cyber threats, common cyber attacks, and elements of an effective cyber security checklist.