1912 November 16

Herbert O. Yardley hired as Code Clerk, U.S. State Department


Colonel Parker Hitt, USA: published Manual for Military Ciphers

1916 July 28

U.S. Navy Code and Signal Section established


Gilbert Vernam, AT&T, invented one-time tape teleprinter

1917 January 16

Zimmermann Telegram sent

1917 March 1

Zimmermann Telegram released to the U.S. press

1917 June 10

Establishment of U.S. Army Code and Cipher Section, MI-8

1917 June 29

Herbert O. Yardley commissioned First Lieutenant in U.S. Army

1917 July 28

Captain Frank Moorman detailed to form U.S. Army Radio Intercept Section, AEF

1917 October 29

First U.S. intercept in France in World War I

1917 December 12

U.S. Army intercept station opened, Souilly, France

1918 April 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 July

Agnes Driscoll employed by U.S. Navy

1919 October 1

The Cipher Bureau began operations.

1919 November 1

Great Britain: Government Code and Cipher School (GC&CS) established


William Friedman published The Index of Coincidence at Riverbank Laboratories

1920 December 6

William Friedman hired as contract code compiler by U.S. Army


Chief of Naval Operations directed U.S. Navy to undertake intercept of foreign communications


U.S. established COMINT site in Shanghai

1924 January 1

U.S. Navy established Radio Intelligence Office

1924 January 1

Laurance Safford became Officer in Charge, Cryptographic Research, U.S. Navy.

1924 September 30

Edward Hebern received a patent for a rotor-based electric code machine.

1926 February 9

German Navy introduced the ENIGMA machine as "Radio Key C" for communications security


U.S. intercept station established, Peking


Swedish businessman Boris Hagelin introduced A-22 machine


U.S. Navy began Japanese kana intercept course

1928 July 15

German Army introduced the ENIGMA machine for communications security


U.S. intercept station established, Guam

1929 March

U.S. intercept station in Shanghai decommissioned

1929 May 10

U.S. Army decided to form Signal Intelligence Service; Friedman to be chief

1929 October 31

The Cipher Bureau, headed by Herbert Yardley, closed

1930 April 1

Frank B. Rowlett hired by William Friedman as cryptologist for U.S. Army Signal Intelligence Service

1930 April 10

Abraham Sinkov hired by William Friedman as cryptologist for U.S. Army SIS

1930 April 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 January

Intercept site established, Bar Harbor, Maine

1931 June

Herbert O. Yardley published The American Black Chamber

1932 March

Intercept site established, Astoria, Oregon

1932 December

Polish Cipher Bureau began deciphering German ENIGMA-based messages

1935 March 11

U.S. Navy intercept reorganized and redesignated as OP-20-G

1935 April

U.S. Navy high frequency direction finding installed at Mare Island, California

1935 July

U.S. intercept site moved from Peking to Shanghai

1937 February

U.S. Army SIS produced first translation of Japanese diplomatic "RED" machine

1937 February

Great Britain: Air Ministry adopted TYPEX MK 1 cipher machine


Solomon Kullback published Statistical Methods in Cryptanalysis

1938 June

Japanese Ministry of Foreign Affairs introduced "PURPLE" cipher machine

1939 January 1

U.S. Army Second Signal Service Company (later Battalion) created

1939 June

Japanese Navy introduced code system known to the U.S. as JN-25

1939 July 24

UK-France-Poland tripartment meeting to discuss decryption of ENIGMA

1939 August

Astoria, Oregon intercept site relocated to Bainbridge Island, Washington

1939 September

U.S. Army SIS produced first translation of Japanese "PURPLE" machine

1940 August

U.S. Army approved exchange of cryptologic information with GC&CS

1940 September 11

U.S. Army and Navy sign agreement on joint exploitation of Japanese "PURPLE" machine

1940 October

Cavite station moved to Corregidor

1940 October

Shanghai station decommissioned

1941 February

Sinkov-Currier mission to UK departed (in UK through March)

1941 March

Monitoring school established at Fort Monmouth

1941 June 11

Herbert O. Yardley hired by Canada's National Research Council

1941 August

Commander Alistaire Denniston of GC&CS visited SIS

1941 September

DF station commission at Sitka, Alaska

1941 November 22

Herbert O. Yardley dismissed by Canada's National Research Council

1941 December 7

Japanese forces attack Pearl Harbor, Hawaii


U.S. Army Signal Intelligence Service redesignated Signal Security Service


U.S.-UK agreement on sharing naval communications intelligence

1942 January

First U.S.-Canada cryptologic exchange (captured French code)

1942 February

U.S. Navy Fleet Radio Unit, Melbourne (FRUMEL) established

1942 February 1

German Navy introduced 4-rotor ENIGMA machine for U-boats

1942 February 5

First evacuation of Station CAST (Corregidor) personnel

1942 March 11

Second evacuation of Station CAST personnel

1942 March 15

U.S. Navy began reading Japanese system JN-25

1942 April 15

Central Bureau established in Australia to support Southwest Pacific operations

1942 May

DF station established at Kodiak, Alaska

1942 June

U.S. Army acquired Arlington Hall Station for the Signal Security Service

1942 July

Central Bureau moved to Brisbane

1942 July

Abraham Sinkov arrived at Central Bureau, Brisbane as Commander, 837th Detachment

1942 July 8

FDR limits COMINT activities to Army, Navy, and FBI

1942 October 5

U.S. Army SSA activated Vint Hill Farms

1942 November

COMINT station established on Guadalcanal

1943 February 7

U.S. Navy OP-20-G moved to Nebraska Avenue

1943 March

German Navy adopted 4-rotor ENIGMA machine

1943 April

First break into Japanese Water Transport System

1943 May

GC&CS activated HEATH ROBINSON machine for cryptanalysis of German TUNNY machine

1943 August

Strategic intercept station at Amchitka, Alaska

1943 September

Intercept site established at Adak, Alaska

1943 December

Strategic DF station established at Tarawa


U.S. Army Air Corps established independent intercept operations

1944 February

Intercept and DF stations established at Kwajalein

1944 February

GC&CS activated COLOSSUS MK I for cryptanalysis of TUNNY; may be first computer

1944 April 18

Army-Navy COMINT Coordinating Committee -- precursor of USIB -- first met

1944 November

DF station Tarawa decommissioned

1944 December

DF station Guadalcanal decommissioned

1945 February

DF station Amchitka decommissioned

1945 April

Intercept and DF stations established at Iwo Jima

1945 July 3

Cryptographic Security Board established

1945 August

Strategic DF station established at Leyte

1945 September 15

U.S. Army Signal Security Agency renamed Army Security Agency

1948 June 23

Air Force Security Group activated

1948 October 20

Air Force Security Group renamed Air Force Security Service

1949 May 20

Armed Forces Security Agency established

1952 November 4

National Security Agency established