Black Chamber
Encyclopedia
The Cipher Bureau otherwise known as The Black Chamber was the United States' first peacetime cryptanalytic organization, and a forerunner of the National Security Agency
National Security Agency
The National Security Agency/Central Security Service is a cryptologic intelligence agency of the United States Department of Defense responsible for the collection and analysis of foreign communications and foreign signals intelligence, as well as protecting U.S...

. The only prior codes and cypher organizations maintained by the US government had been some intermittent, and always abandoned, attempts by Armed Forces branches prior to World War I.

History

Headed by Herbert O. Yardley (1889–1958), it was founded in May 1919 following World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. Yardley had commanded the Army cryptographic section of Military Intelligence (MI-8) during World War I. MI-8 was disbanded after the war. Jointly funded by the Army and the State Department, the Cipher Bureau was disguised as a New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

 commercial code company; it actually produced and sold such codes for business use. Its true mission, however, was to break the communications (chiefly diplomatic) of other nations. Its most notable known success was during the Washington Naval Conference
Washington Naval Conference
The Washington Naval Conference also called the Washington Arms Conference, was a military conference called by President Warren G. Harding and held in Washington from 12 November 1921 to 6 February 1922. Conducted outside the auspices of the League of Nations, it was attended by nine nations...

 during which it aided American negotiators considerably by providing them with the decrypted traffic of many of the Conference delegations, most notably the Japanese
Empire of Japan
The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...

.

In 1929, the State Department withdrew its share of the funding, the Army declined to bear the entire load, and the Black Chamber closed down the Cipher Bureau. In his much later memoirs, then new Secretary of State
United States Secretary of State
The United States Secretary of State is the head of the United States Department of State, concerned with foreign affairs. The Secretary is a member of the Cabinet and the highest-ranking cabinet secretary both in line of succession and order of precedence...

 Henry L. Stimson
Henry L. Stimson
Henry Lewis Stimson was an American statesman, lawyer and Republican Party politician and spokesman on foreign policy. He twice served as Secretary of War 1911–1913 under Republican William Howard Taft and 1940–1945, under Democrat Franklin D. Roosevelt. In the latter role he was a leading hawk...

 said that: "Gentlemen do not read each other's mail." His views on the worth of cryptanalysis had changed by the time he became Secretary of War
United States Secretary of War
The Secretary of War was a member of the United States President's Cabinet, beginning with George Washington's administration. A similar position, called either "Secretary at War" or "Secretary of War," was appointed to serve the Congress of the Confederation under the Articles of Confederation...

 during World War II, before and during which he, and the entire US command structure, relied heavily on decrypted enemy communications.

In 1931, and in need of money, Yardley wrote a book about the Cipher Bureau, entitled The American Black Chamber.

The term "Black Chamber" predates Yardley's use of it in the title of his book. The first in a long line of cabinet noir
Cabinet noir
Cabinet noir was the name given in France to the office where the letters of suspected persons were opened and read by public officials before being forwarded to their destination...

s
was established by King Henry IV of France in 1590 as part of the Poste aux Lettres. Its mission was to open, read and reseal letters, and great expertise was developed in the restoration of broken seals. In the knowledge that mail was being opened, correspondents began to develop systems to encrypt and decrypt their letters, the breaking of these codes giving birth to modern systematic scientific code breaking. The Black Chambers survived through to the Twentieth Century in a variety of guises and inspired similar organisations in other countries, such as the "Secret Office" of the British Post Office, and it is within this historical framework that Yardley uses the term.

It was also used at about that time in Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 (see article on Marian Rejewski
Marian Rejewski
Marian Adam Rejewski was a Polish mathematician and cryptologist who in 1932 solved the plugboard-equipped Enigma machine, the main cipher device used by Germany...

).
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