Need to know
The term
"need to know", when used by government and other organizations, describes the restriction of data which is considered very sensitive. Under need-to-know restrictions, even if one has all the necessary official approvals to access certain information, one would not be given access to such information, or read into a clandestine operation, unless one has a specific
need to know; that is, access to the information must be necessary for the conduct of one's official duties. As with most security mechanisms, the aim is to make it difficult for unauthorized access to occur, without inconveniencing legitimate access. Need-to-know also aims to discourage "browsing" of sensitive material by limiting access to the smallest possible number of people. The Battle of Normandy in 1944 is an example of a need-to-know restriction. Though thousands of military personnel were involved in planning the invasion, only a small number of them knew the entire scope of the operation; the rest were only informed of data needed to complete a small part of the plan. The same is true of the Trinity project, the first test of a nuclear weapon in 1945.