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Army Signal Corps Takes Control of Cryptography and Cryptanalysis. This Week in History, April 5, 1929

March 27, 2013

By Ruth Quinn

Fort Huachuca, Az. -- The business of solving codes and ciphers had been an active field in the U.S. government since World War I when Ralph Van Deman realized he needed a cipher bureau as part of his newly organized Military Intelligence Division. Van Deman picked a State Department code clerk and amateur cryptologist named Herbert Yardley to head up his newly created Codes and Ciphers division, or MI-8. Yardley was commissioned a lieutenant in 1917, and tasked with setting up MI-8. The fledgling Cipher Bureau had quite a few remarkable successes.

After the war, however, the business of cryptology took on a more sensitive nature. What was the role of such an invasive method of warfare during peacetime? Herbert Yardley believed it was critical, and he convinced the State and War Department Chiefs to set him up in a peacetime, strategic cryptologic operation so that that the United States could keep up with the rest of the world in decoding diplomatic messages. In a secret, bi-lateral agreement, the State Department and War Department jointly funded MI-8, which became known as The Black Chamber, with an initial budget of $100,000 per year. This all ended when Herbert Hoover, or more accurately, his new Secretary of State Henry L. Stimson, took over. Shocked at the impropriety of 'gentlemen reading one another's mail,' Stimson immediately withdrew all State Department funding and closed down the Black Chamber, leaving Yardley without a job, a family to feed, and a grudge to nurse.

Meanwhile, the Army had developed its own Code and Cipher section under the Signal Corps. Mr. William Friedman, who had served in a radio intelligence section during the War, was hired as the chief cryptographer for the Signal Corps. Friedman was charged with code and cipher development for the Army, and to plan for wartime signals intelligence operations. However, the budget crises of post war cutbacks combined with the passage of a law in 1927 making radio communications intercept illegal in America, brought the code and cipher effort nearly to a halt. To save the effort from extinction, in April 1929, the Secretary of War directed 'That the Signal Corps be charged with the duties pertaining to the solution of enemy codes and ciphers and the detection of secret inks in War, in addition to those duties with which they are now charged by the Army and to the interception of enemy radio and wire traffic in war.' The War Department was, in effect, tasking its Signal Corps to break the law. Needless to say, the Signal Corps maintained the utmost secrecy regarding these efforts.

Despite Mr. Stimson's outrage at the Black Chamber's work, and his direction that the State Department cease and desist all intercept and cryptography efforts, that decree never made it to the U.S. military. After the Black Chamber closed, all cryptographic work became the sole responsibility of the War Department, by both the Army and the Navy. In May 1929, all War Department operational functions pertaining to cryptography and cryptanalysis were brought together under the Army's Chief Signal Officer. Two months later, the Signals Intelligence Service (SIS) was officially organized with Mr. Friedman as its chief. He remained in this position until 1935 when an Army major was assigned as officer-in-charge.

In 1943, the SIS was redesignated the Signal Security Service and later the Signal Security Agency. Responsibility for the SSA was divided between the Military Intelligence Service (MIS) for operations, and the Signal Corps for administration. On 15 September 1945, the Signal Security Agency was reunited again under the Director of Military Intelligence as the Army Security Agency at Arlington Hall, Virginia.

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