Black Chamber

The Black Chamber, officially the Cable and Telegraph Section and also known as the Cipher Bureau,[clarification needed] was the first peacetime cryptanalytic organization in the United States, operating from 1917 to 1929.

Until World War I, the only codes and cypher organizations created by the U.S. government were short-lived agencies of the United States Armed Forces, such as the U.S. Army's Military Intelligence (MI-8).

According to intelligence historian James Bamford, the Black Chamber secured the cooperation of American telegraph companies such as Western Union in illegally turning over the cable traffic of foreign embassies and consulates.

However, these companies eventually withdrew their support, possibly due to the Radio Act of 1927, which broadened criminal offenses related to breaching the confidentiality of telegraph messages.

[7] In 1929, the State Department withdrew its share of the funding while the Army, undergoing unit reorganizations, transferred the Black Chamber to the Signal Corps, which opted to rebuild the organization for their own purposes and dismissed Yardley and all of his employees.