MI History- The United States Army Security Agency

United States Army Security Agency
and its Predecessors

From 1945 to 1977, the United States Army Security Agency (USASA) served as the organization responsible for all Army signals intelligence (SIGINT) and communications security (COMSEC). However, the origins of its functions can be traced to World War I and the Cipher Bureau of the Military Intelligence Section, War Department General Staff.

At the outbreak of World War I, the Army had no effective organization for intelligence at all, apart from a system of military attaches. A gifted Regular Army officer, Major Ralph Van Deman, quickly set up the Military Intelligence Section within the Army's General Staff.

Recognizing that his organization needed experience in both cryptanalysts and code compilation, Major Van Deman engaged the services of a young code clerk in the State Department, Herbert C Yardley. Yardley was hastily commissioned and become the chief of the Cipher Bureau.

By the time the war ended, the Cipher Bureau had been redesignated as MI-8 and had shown itself to be so useful that its activities survived Army demobilization. Although the responsibility for Army code and cipher compilation was transferred to the Signal Corps in 1920, MI- 8's code and cipher solution section continued on as a covert cryptanalytic agency jointly funded by the War and State Departments.

Under Yardley's expert guidance, this element, known as the cipher bureau, scored a number of significant triumphs in the 1920's, especially in managing to break the Japanese diplomatic code in time to strengthen the United States' negotiating position at the Washington Peace Conference.

The cipher bureau was finally discontinued in 1929 because of two interacting factors. The Army had come to the conclusion that Yardley's small operation, with its aging staff, was not well suited to meeting the War Department's future needs, especially in training another generation of Army cryptanalysts. At the same time, a new Secretary of State, Henry L. Stimson, decided that cryptanalysts of foreign diplomatic communications was unethical. As a result of all this, State Department support of Yardley's cipher bureau was terminated and Army cryptanalytic activities were transferred to a new signal intelligence service controlled by the Signal Corps rather than by the Military Intelligence Division. Yardley was offered a position with the new organization, but the Civil Service pay scale could not match his previous income, and he refused. Instead, he went on to write a sensational expose of the cipher bureau's operations entitled "The American Black Chamber".

The U.S. Army Signal Intelligence Service (SIS) which took over the Army's cryptanalytic function had the rare good fortune to be headed by a cryptologic genius, William F. Friedman. Friedman had received his initial cryptologic training at the privately-funded Riverbank Laboratories before World War I. He had gone on to serve as a cryptologic officer with the American Expeditionary Force in France before accepting civilian employment as a code-compiler for the Signal Corps at the end of the war.

Friedman was perfectly qualified for his job. By the time the United States entered World War II, Friedman and his small organization had not only devised new electro-mechanical cipher machines of unparalleled security for U.S. communications, but had succeeded in breaking the "PURPLE" cipher system that carried the most secret Japanese diplomatic messages.

American involvement in World War II caused an enormous expansion of U.S. SIGINT and COMSEC operations. The SIS grew in size; moved from its cramped quarters in the Munitions Building, Washington, D.C., to Arlington Hall Station in what was then the Virginia countryside; and was repeatedly redesignated, finally becoming the U.S. Army Signal Security Agency (SSA) in 1943. Operational control over the SSA was reassigned to the Military Intelligence Division in 1944.

By the end of the war, the SSA controlled a worldwide network of intercept stations through its 2d Signal Service Battalion, and Arlington Hall's success at breaking the main Japanese military and diplomatic systems was furnishing the Army with an unparalleled stream of invaluable intelligence.

On 15 September 1945, the U.S. Army Security Agency (ASA) was set up to conduct all Army SIGINT and COMSEC operations under the command of the Director of Military Intelligence. The new agency had a sweeping charter. During World War II, the SSA had directed only a part of the Army SIGINT effort. Theater commanders retained control over their own tactical radio intelligence efforts. ASA, in contrast, exercised control over all U. S. SIGINT and COMSEC operations through a verticalized command structure. ASA was a separate specialized entity within the rest of the Army, with complete control over personnel, training, research, development, and procurement as well as over operations.

Although it surrendered certain operational functions to the new Armed Forces Security Agency (AFSA) in 1949, ASA grew as a result of the Korean War, fielding tactical units on a large scale to support the Army's tactical commanders. ASA expanded its mission once again in 1955, acquiring direction the Army's electronic warfare (EW) program. Since its functions were no longer exclusively those of intelligence and security, ASA was withdrawn from G-2 control and resubordinated to the Army Chief of Staff as a field operating agency.

On 13 May 1961, the first contingent of ASA personnel arrived in South Vietnam to provide support to the U.S. Military Assistance Advisory Group and to train the South Vietnamese Army. With the introduction of U.S. tactical units in South Vietnam, ASA responded with the deployment of TOE direct support units. During the course of the Vietnam conflict, the agency experienced a period of rapid growth, reaching a strength of 30,000. Meanwhile, it had been given the noncommunications EW mission in 1963 and been raised to the status of a major Army field command in 1964.

However, the massive drawdown of the Army following the termination of the Vietnam conflict led to pressure to achieve economies by the consolidation of intelligence functions. Since the creation of ASA in 1945, a series of Army studies had validated ASA's separate identity and unique vertical command structure. Nevertheless, in 1975 the Army Chief of Staff accepted the recommendations of the Intelligence Organization and Stationing Study and agreed to a wholesale reorganization of Army intelligence that would create multi-discipline military intelligence organizations within the Army at both the tactical and departmental levels. As a result ASA was effectively dismembered. ASA's tactical units were resubordinated to the supported commanders, its functional responsibilities of training and research and development spun off to other Army major commands (MACOM), and its headquarters and fixed sites used as the nucleus of a new intelligence and security MACOM. On 1 January 1977, Headquarters, the U.S. Army Security Agency was redesignated as Headquarters, U.S. Army Intelligence and Security Command.