Pre-1952 Historical Timeline

  • 1912 Nov 16 Herbert O. Yardley hired as Code Clerk, U.S. State Department
  • 1916 Colonel Parker Hitt, USA: published Manual for MilitaryCiphers
  • 1916 Jul 28 U.S. Navy Code and Signal Section established
  • 1917 Gilbert Vernam, AT&T, invented one-time tape teleprinter
  • 1917 Jan 16 Zimmermann Telegram sent
  • 1917 Mar 01 Zimmermann Telegram released to the U.S. press
  • 1917 Jun 10 Establishment of U.S. Army Code and Cipher Section, MI-8
  • 1917 Jun 29 Herbert O. Yardley commissioned First Lieutenant in U.S. Army
  • 1917 Jul 28 Captain Frank Moorman detailed to form U.S. Army Radio Intercept Section, AEF
  • 1917 Oct 29 First U.S. intercept in France in World War I
  • 1917 Dec 12 U.S. Army intercept station opened, Souilly, France
  • 1918 Apr 15 Arthur Scherbius offered prototype ENIGMA machine to German Navy
  • 1918 May William Friedman commissioned First Lieutenant, assigned to Radio Intelligence Section, France
  • 1919 May 19 Chief of the U.S. Department of State approved creation of Cipher Bureau (AKA Black Chamber)
  • 1919 Jul Agnes Driscoll employed by U.S. Navy
  • 1919 Oct 01 The Cipher Bureau began operations.
  • 1919 Nov 01 Great Britain: Government Code and Cipher School (GC&CS) established
  • 1920 William Friedman published The Index of Coincidence at Riverbank Laboratories
  • 1920 Dec 06 William Friedman hired as contract code compiler by U.S. Army
  • 1923 Chief of Naval Operations directed U.S. Navy to undertake intercept of foreign communications
  • 1924 U.S. established COMINT site in Shanghai
  • 1924 Jan 01 U.S. Navy established Radio Intelligence Office
  • 1924 Jan 01 Laurance Safford became Officer in Charge, Cryptographic Research, U.S. Navy.
  • 1924 Sep 30 Edward Hebern received a patent for a rotor-based electric code machine.
  • 1926 Feb 09 German Navy introduced the ENIGMA machine as "Radio Key C" for communications security
  • 1927 U.S. intercept station established, Peking
  • 1927 Swedish businessman Boris Hagelin introduced A-22 machine
  • 1928 U.S. Navy began Japanese kana intercept course
  • 1928 Jul 15 German Army introduced the ENIGMA machine for communications security
  • 1929 U.S. intercept station established, Guam
  • 1929 Mar U.S. intercept station in Shanghai decommissioned
  • 1929 May 10 U.S. Army decided to form Signal Intelligence Service; Friedman to be chief
  • 1929 Oct 31 The Cipher Bureau, headed by Herbert Yardley, closed
  • 1930 Apr 01 Frank B. Rowlett hired by William Friedman as cryptologist for U.S. Army Signal Intelligence Service
  • 1930 Apr 10 Abraham Sinkov hired by William Friedman as cryptologist for U.S. Army SIS
  • 1930 Apr 21 Solomon Kullback hired by William Friedman as cryptologist for U.S. Army SIS
  • 1930 May U.S. intercept station established, Olongapo, Philippines
  • 1930 May 13 John Hurt hired by William Friedman as Japanese linguist, U.S. Army SIS
  • 1931 Jan Intercept site established, Bar Harbor, Maine
  • 1931 Jun Herbert O. Yardley published The American Black Chamber
  • 1932 Mar Intercept site established, Astoria, Oregon
  • 1932 Dec Polish Cipher Bureau began deciphering German ENIGMA-based messages
  • 1935 Mar 11 U.S. Navy intercept reorganized and redesignated as OP-20-G
  • 1935 Apr U.S. Navy high frequency direction finding installed at Mare Island, California
  • 1935 Jul U.S. intercept site moved from Peking to Shanghai
  • 1937 Feb U.S. Army SIS produced first translation of Japanese diplomatic "RED" machine
  • 1937 Feb Great Britain: Air Ministry adopted TYPEX MK 1 cipher machine
  • 1938 Solomon Kullback published Statistical Methods in Cryptanalysis
  • 1938 Jun Japanese Ministry of Foreign Affairs introduced "PURPLE" cipher machine
  • 1939 Jan 01 U.S. Army Second Signal Service Company (later Battalion) created
  • 1939 Jun Japanese Navy introduced code system known to the U.S. as JN-25
  • 1939 Jul 24 UK-France-Poland tripartite meeting to discuss decryption of ENIGMA
  • 1939 Aug Astoria, Oregon intercept site relocated to Bainbridge Island, Washington
  • 1939 Sep U.S. Army SIS produced first translation of Japanese "PURPLE" machine
  • 1940 Aug U.S. Army approved exchange of cryptologic information with GC&CS
  • 1940 Sep 11 U.S. Army and Navy sign agreement on joint exploitation of Japanese "PURPLE" machine
  • 1940 Oct Cavite station moved to Corregidor
  • 1940 Oct Shanghai station decommissioned
  • 1941 Feb Sinkov-Currier mission to UK departed (in UK through Mar)
  • 1941 Mar Monitoring school established at Fort Monmouth
  • 1941 Jun 11 Herbert O. Yardley hired by Canada's National Research Council
  • 1941 Aug Commander Alistaire Denniston of GC&CS visited SIS
  • 1941 Sep DF station commission at Sitka, Alaska
  • 1941 Nov 22 Herbert O. Yardley dismissed by Canada's National Research Council
  • 1941 Dec 07 Japanese forces attack Pearl Harbor, Hawaii
  • 1942 U.S. Army Signal Intelligence Service redesignated Signal Security Service
  • 1942 U.S.-UK agreement on sharing naval communications intelligence
  • 1942 Jan First U.S.-Canada cryptologic exchange (captured French code)
  • 1942 Feb U.S. Navy Fleet Radio Unit, Melbourne (FRUMEL) established
  • 1942 Feb 01 German Navy introduced 4-rotor ENIGMA machine for U-boats
  • 1942 Feb 05 First evacuation of Station CAST (Corregidor) personnel
  • 1942 Mar 11 Second evacuation of Station CAST personnel
  • 1942 Mar 15 U.S. Navy began reading Japanese system JN-25
  • 1942 Apr 15 Central Bureau established in Australia to support Southwest Pacific operations
  • 1942 May DF station established at Kodiak, Alaska
  • 1942 Jun U.S. Army acquired Arlington Hall Station for the Signal Security Service
  • 1942 Jul Central Bureau moved to Brisbane
  • 1942 Jul Abraham Sinkov arrived at Central Bureau, Brisbane as Commander, 837th Detachment
  • 1942 Jul 08 FDR limits COMINT activities to Army, Navy, and FBI
  • 1942 Oct 05 U.S. Army SSA activated Vint Hill Farms
  • 1942 Nov COMINT station established on Guadalcanal
  • 1943 Feb 07 U.S. Navy OP-20-G moved to Nebraska Avenue
  • 1943 Mar German Navy adopted 4-rotor ENIGMA machine
  • 1943 Apr First break into Japanese Water Transport System
  • 1943 May GC&CS activated HEATH ROBINSON machine for cryptanalysis of German TUNNY machine
  • 1943 Aug Strategic intercept station at Amchitka, Alaska
  • 1943 Sep Intercept site established at Adak, Alaska
  • 1943 Dec Strategic DF station established at Tarawa
  • 1944 U.S. Army Air Corps established independent intercept operations
  • 1944 Feb Intercept and DF stations established at Kwajalein
  • 1944 Feb GC&CS activated COLOSSUS MK I for cryptanalysis of TUNNY; may be first computer
  • 1944 Apr 18 Army-Navy COMINT Coordinating Committee -- precursor of USIB -- first met
  • 1944 Nov DF station Tarawa decommissioned
  • 1944 Dec DF station Guadalcanal decommissioned
  • 1945 Feb DF station Amchitka decommissioned
  • 1945 Apr Intercept and DF stations established at Iwo Jima
  • 1945 Jul 03 Cryptographic Security Board established
  • 1945 Aug Strategic DF station established at Leyte
  • 1945 Sep 15 U.S. Army Signal Security Agency renamed Army Security Agency
  • 1948 Jun 23 Air Force Security Group activated
  • 1948 Oct 20 Air Force Security Group renamed Air Force Security Service
  • 1949 May 20 Armed Forces Security Agency established
  • 1952 Nov 04 National Security Agency established

Aug. 20, 2021

The Investigations

On 6 December 1941 a 14-part message was sent from Tokyo to the Japanese ambassador to the United States. The entire message was to be presented to President Roosevelt at approximately the same time as the attack on Pearl Harbor, breaking off relations between Japan and the United States. The fourteenth part of the message arrived somewhat later

Aug. 20, 2021

Pearl Harbor

Writing some 15 years after the Japanese attack, William F. Friedman said that the "Battle of Pearl Harbor is still being fought but the adversaries this time are all Americans."This statement is almost as true today as it was in the 1950s.On a par with theories about the Kennedy Assassination, the attack on Pearl Harbor continues to draw

Aug. 20, 2021

The International Agreements

The literature on cryptology in World War II initially emphasized the close cooperation between the United States and the United Kingdom during the war, with little attention to any disagreements or controversies. Some recent books have called more attention to conflicts occurring within this special relationship.The disputes center around two main

Aug. 20, 2021

Red and Purple

Embarrassed by Herbert Yardley's revelations in his 1931 book The American Black Chamber, the Japanese Foreign Ministry turned increasingly to machine systems to encipher its messages.The Foreign Ministry in 1935 adopted a device called the "Type A Machine" to protect its communications.When the U.S. Army's Signal Intelligence Service (SIS) first

Aug. 20, 2021

JN-25

In 1938, the Japanese Navy changed its operational code, replacing a system that had been in use since 1931. The U.S. Navy terminology for the superseded system had been the BLUE CODE, based on the color binding used for the American recoveries to the system; the new code was designed BLACK. The BLACK CODE introduced the use of an additive book to

Aug. 20, 2021

Army and Navy Get Their Act Together

Today, smooth cooperation among the military services is taken for granted. It was not always so.As early as January 1932, the Army and Navy recognized the benefits of cooperation in cryptanalysis, particularly in avoiding the costs of duplication of effort. A draft agreement between them was drawn up, pledging the two services to share information

Aug. 20, 2021

Pearl Harbor Review - Following the Fleets

One major contribution of U.S. Navy cryptologists in the period between the wars was to give American naval and civilian policy makers information derived from studies of Japanese Navy maneuvers. This capability required all the many skills and facilities the U.S. Navy had been developing since the inception of its cryptologic service after World

Aug. 20, 2021

COMINT Stations Overseas

As early as 1924, the Navy established intercept sites in China and Oahu to copy Japanese communications -- the Shanghai station, established in 1924 may have been the Navy's earliest shore-based intercept site, with Wailupe, Hawaii second in 1925, and then Peiping [Peking] in 1927. Some intercept activity was also carried on in Guam, and San

Aug. 20, 2021

Linguists

As both the Navy's OP-20-G and the Army's Signals Intelligence Service began to solve Japanese cryptosystems in the 1930s, they faced a second challenge, the underlying language itself.For a variety of linguistic and cultural reasons, the Japanese language has been difficult for westerners to master. A European missionary of the 16th century, one

Aug. 20, 2021

Early Japanese Systems

[NOTE: In the following discussion, please be careful not to confuse RED and RED BOOK]Like many countries around the world, the Japanese used a variety of cryptographic systems, often based on code books. As with many other countries, the Japanese shifted some but not all of their communications security to machine systems in the 1920s and 1930s,