classified information

A typical classified document. Page 13 of a U.S. National Security Agency report on the USS Liberty incident, partially declassified and released to the public in July 2004. The original overall classification of the page, "top secret", and the Special Intelligence code word "umbra", are shown at top and bottom. The classification of individual paragraphs and reference titles is shown in parentheses—there are six different levels on this page alone. Notations with leader lines at top and bottom cite statutory authority for not declassifying certain sections.

Classified information is confidential material that a government, corporation, or non-governmental organisation deems to be sensitive information, which must be protected from unauthorized disclosure and that requires special handling and dissemination controls. Access is restricted by law, regulation, or corporate policies to particular groups of individuals with both the necessary security clearance and a need to know.