Air gap

An air gap is a cybersecurity strategy that involves the complete physical isolation of a computer network or device from all external, untrusted networks, including the internet. This is achieved by ensuring there are no direct wired, wireless, or optical connections between the isolated system and any other network. As a result, an air-gapped system is effectively immune to remote cyberattacks, malware propagation, and unauthorized data exfiltration originating from outside its physical perimeter.

Air gaps are considered essential in environments where data confidentiality, integrity, and availability are critical. Common use cases include military and government classified networks, industrial control systems (ICS), operational technology (OT) in critical infrastructure, and research facilities handling sensitive intellectual property. While data transfer to or from an air-gapped system remains possible, it requires manual, physical processes—such as using removable media—that are themselves subject to strict security protocols to maintain the integrity of the isolation.