What are the five pillars of security?

What are the five pillars of security depends on context, but most commonly in information security and cybersecurity, the five pillars are confidentiality, integrity, availability, authentication, and non-repudiation, sometimes referred to as CIA triad plus two more. Confidentiality ensures information is accessible only to authorized users, protected by encryption and access controls. Integrity ensures information is not altered unauthorized, protected by hashing and checksums. Availability ensures systems and data are accessible when needed, protected by redundancy and backups. Authentication verifies identity of users, protected by passwords, MFA, and biometrics. Non-repudiation ensures actions cannot be denied, protected by logs and digital signatures. In physical security and general security management, five pillars are often described as physical security, personnel security, information security, operational security, and cyber security. Another framework for national security lists military, economic, energy, environmental, and cyber security. For personal safety, some teach five pillars as awareness, avoidance, deterrence, detection, and defense. Choose framework relevant to your domain, but CIA plus authentication and non-repudiation is most widely taught in cybersecurity training.