Classifications? What Do They Mean?
There are three classifications: confidential, secret, and top secret. The definitions are essentially the same, just the magnitude changes. "Confidential" information is the lowest classification. Information is deemed confidential if its release "could cause damage to national security or foreign relations." The Department of Defense (DoD) classifies information as "secret" when its release "could cause serious damage to national security or foreign relations." Information classified as "top secret" when its release "could cause exceptionally grave damage to national security or foreign relations."
People are cleared for access to classified information if their jobs require it. The department conducts a clearance investigation to ensure an individual is trustworthy and reliable. According to the Defense Security Service, a personnel security investigation looks at an individual for the qualities of trustworthiness, honesty, loyalty, and reliability. In addition, investigators examine a person's character and finances.
Service members, DoD civilians, and contractor employees receive clearances for classified information. The higher an individual's access to classified information, the more thorough the investigation. The Defense Security Service and other federal agencies conduct national agency checks and local national agency checks on individuals for confidential and secret clearances. Investigators conduct single-scope background investigations for individuals needing a top-secret clearance. Individuals are periodically reinvestigated to maintain their clearances. Secret clearances are updated every ten years and top secret every five.
"For official use only" may be a familiar label you've seen on some
documents. It isn't actually a security classification; rather, it's a lesser
form of control. The protective marking signifies that information in the document
qualifies for exemption from public release under the Freedom of Information
Act (FOIA). This includes information protected under the Privacy Act of 1974.