Air-gapping or air-gap stands for air gap and is a security concept for computers and networks. Air-gapped computers or networks are neither directly connected to the Internet nor to other computers, systems or networks that are connected to the Internet. Physically, they are completely separate and isolated from the Internet.
If the air-gapped concept is consistently maintained, it is very difficult or impossible for attackers to gain access to the air-gapped computer via the Internet.
The Air-Gap concept is used wherever the highest security requirements are needed. For example, in military computer systems and networks, in the financial sector, in industrial control systems, and in many systems that have a direct impact on society, such as nuclear power plants, hospitals, or electric utilities. In an air-gap system, only computers that are on the air-gap network can communicate with each other. Attacks on Air-Gap systems can only occur through direct interfaces into which the malware is injected. For example, attacks can be carried out via USB sticks.