The document discusses cyber security. It begins by explaining how computer usage has grown significantly since the 1970s and how cyber security systems aim to protect computers and networks from threats like theft, damage, disruption and information disclosure. It then describes several key elements of cyber security including data security, application security, mobile security, network security, endpoint security, cloud security, database/infrastructure security and business continuity/disaster recovery. The document emphasizes that cyber threats can cause damages and data issues, so cyber security is important to implement. It provides examples of common cyber threats like phishing, malware attacks and backdoors. Finally, it offers tips for building effective cyber security systems and strategies.