Terrorist cell

A clandestine cell structure is a method for organizing a group of people like resistance fighters or terrorists in such a way that it can more effectively resist penetration by an opposing organization (such as a law enforcement organization). In a cell structure, each small group of people in the cell know the identities of only the people in their cell. Thus, a cell member who is apprehended and interrogated will not know the identities of the higher-ranking individuals in the organization; unless the cell member happens to be a member who necessarily knows and communicates with higher-ranking individuals in the organization. Depending on the group's philosophy, its operational area, the communications technologies available and the nature of the mission, it can range from a strict hierarchy to an extremely distributed organization.

It is also a method used by criminal organizations, undercover operatives, and unconventional warfare units led by special forces. Historically, clandestine organizations have avoided electronic communications, as signals intelligence is a strength of conventional militaries and counterintelligence organizations.

In the context of tradecraft, covert and clandestine are not synonymous. As noted in the definition (which has been used by NATO since World War II) in a covert operation the identity of the sponsor is concealed, but in a clandestine operation, the operation itself is concealed. At least insofar as someone or something that is known to exist by at least two individuals can be "concealed". Put differently, clandestine means "hidden", and covert means "deniable". The adversary is aware that a covert activity is happening, but theoretically and hypothetically does not know who is doing it and certainly not the sponsorship. Separating action from "sponsorship" is a technicality hopefully (for the "sponsor") providing sufficient distance from the action so that the sponsor can claim ignorance in the event the "covert" plot is discovered. Clandestine activities, however, if successful, are completely unknown to the adversary, and their function, such as espionage, would be neutralized if there was any awareness of the activity. Such "neutralization" of the intended goal, actions or results does not grant the sponsor deniability of responsibility, blame and guilt and is not a legal, ethical or moral defense if negative consequences have resulted from the operation. Espionage is espionage regardless of whether or not the intelligence and information provided to the sponsor - friend or foe - is of benefit or use or not. Even if the information was intentionally misleading, fake or inaccurate the crime is in passing it to a foreign government.

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Wikipedia