32 CFR 149.3 - Definitions.
Classified National Security Information (CNSI). Information that has been determined pursuant to Executive Order 12958 (60 FR 19825, 3 CFR 1995 Comp., p. 333) or any predecessor order to require protection against unauthorized disclosure and is marked to indicate its classified status when in documentary form.
Restricted Data (RD). All data concerning design, manufacture or utilization of atomic weapons; the production of special nuclear material; or the use of special nuclear material in the production of energy, but shall not include data declassified or removed from the RD category pursuant to section 102 of the Atomic Energy Act of 1954, as amended.
Sensitive but Unclassified. Any information, the loss, misuse, or unauthorized access to or modification of which could adversely affect the national interest or the conduct of federal programs, or the privacy to which individuals are entitled under 5 U.S.C. 552a, but which has not been specifically authorized under criteria established by an Executive Order or an Act of Congress to be kept secret in the interest of national defense or foreign policy.
Technical Surveillance Countermeasures (TSCM). Techniques and measures to detect and nullify a wide variety of technologies that are used to obtain unauthorized access to classified national security information, restricted data, and/or sensitive but unclassified information.