Need to know

The term "need to know" (alternatively spelled need-to-know), when used by governments and other organizations (particularly those related to military[1] or intelligence[2]), describes the restriction of data which is considered very confidential and sensitive.

Need-to-know also aims to discourage "browsing" of sensitive material by limiting access to the smallest possible number of people.

Oppenheimer went and talked to the security and got special permission so I could give a nice lecture about what we were doing, and they were all excited: "We're fighting a war!

They understood everything; they invented several of the programs that we used.The discretionary access control mechanisms of some operating systems can be used to enforce need to know.

The term is also used in the concept of graphical user interface design where computers are controlling complex equipment such as airplanes.

In this usage, when many different pieces of data are dynamically competing for finite user interface space, safety-related messages are given priority.