Security is the set of protections and controls that reduce the risk of unauthorized access, disruption, or misuse of systems, data, and services. In cyber security, it includes technical safeguards such as access control, patching, encryption, monitoring, backups, and network segmentation, as well as administrative measures like policies, training, and incident response planning.
Security matters because digital systems are constantly exposed to threats such as phishing, malware, credential theft, and service disruption. Strong security helps limit how far an attacker can move, protects sensitive information, and supports business continuity. In practice, it appears in defenses like multi-factor authentication and logging, and in attacks as the target of weak passwords, unpatched software, or poorly configured cloud services. In maturity models, security is often measured alongside infrastructure and skills because all three need to work together.