Levels of US Top Secret

Levels of classification over Top Secret:

  1. Sensitive Compartmented Information" (SCI)
  2. SCIF data or information that can only be read inside of a Special Compartmentalized Information Facility. 
  3. Special Access Programs (SAP)
  4. SCI Access" or SAP approval

    In the military, all classified information is divided into one of three categories:

    CONFIDENTIAL: Applied to information or material the unauthorized disclosure of which could be reasonably expected to cause damage to the national security.

    SECRET: Applied to information or material the unauthorized disclosure of which reasonably could be expected to cause serious damage to the nation
    al security.

    TOP SECRET: Applied to information or material the unauthorized disclosure of which reasonably could be expected to cause exceptionally grave damage to the national security.

ref: http://usmilitary.about.com/cs/generalinfo/a/security.htm