In black bag operations, Federal Bureau of Investigation (FBI) agents illegally entered offices of targeted individuals and organizations, and photographed information found in their records. This practice was used by the FBI from 1942 until 1967. In July 1966, FBI Director J. Edgar Hoover ordered the practice discontinued. The use of "black bag jobs" by the FBI was declared unconstitutional by the United States Supreme Court on 19 June 1972 in the Plamondon case, United States v. U.S. District Court, 407 U.S. 297. The FBI still carries out numerous "black bag" entry-and-search missions, in which the search is covert and the target of the investigation is not informed that the search took place. If the investigation involves a criminal matter a judicial warrant is required; in national security cases the operation must be approved by a secret body called the Foreign Intelligence Surveillance Court.
The British, Israeli, Russian, and other intelligence agencies are known to use black-bag operations to steal secrets. When the technique is used to obtain codes it may be called Black-bag cryptanalysis.