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

Air gaps are essential in environments where data security is critical, such as military and government classified networks, industrial control systems (ICS), operational technology in critical infrastructure, and research facilities handling sensitive information. While data transfer to or from an air-gapped system is possible, it requires manual physical processes subject to strict security protocols, ensuring the isolation remains effective against evolving cyber threats.