The Need-to-Know Rule
The need-to-know rule means that a person who does not need to know concrete information for his work may not know it and vice versa, a person who needs this information for his work must know it, in its entirety (the need to share rule). The need-to-know rule is applied by the so-called compartmentalization, i.e. horizontal as well as vertical division of knowledge, accesses and responsibilities.
Source: Petr Zeman - lectures, trainings and public speeches