What aspect of security focuses on ensuring systems are reliable and operational?

The focus on ensuring systems are reliable and operational is centered around the concept of availability. Availability refers to the guarantee that systems and data are accessible and usable when needed by authorized users. In security, this entails minimizing downtime and ensuring that services remain functional in both normal conditions and during incidents, such as attacks or hardware failures.

A significant part of availability involves implementing measures like redundancy, failover systems, and regular maintenance to ensure that systems can withstand various forms of disruption. This can also include strategies for disaster recovery and business continuity planning, ensuring that operations can continue smoothly and data remains accessible even after adverse events.

Confidentiality, while crucial in protecting sensitive information from unauthorized access, does not specifically focus on the operational reliability of systems. Integrity is about ensuring that data is accurate and has not been tampered with, which, while important for security, does not address availability directly. Accountability relates to ensuring that actions can be traced back to the individual responsible, which is vital for enforcing policies but does not impact system operation in the same way availability does.