توضیحات:

In espionage, agents under non-official cover (NOC) are operatives who assume covert roles in organizations without official ties to the government for which they work. Such agents or operations are typically abbreviated in espionage lingo as a NOC (pronounced knock). These agents are also known as "illegals" (see Clandestine HUMINT operational techniques). Non-official cover is contrasted with official cover, where an agent assumes the position at an otherwise benign department of their government, such as the diplomatic service. This provides the agent with official diplomatic immunity, thus protecting them from the steep punishments normally meted out to captured spies.