Timeline of Cryptography - 1900 - 1949

1949

• c 1915 - William Friedman applies statistics to cryptanalysis (coincidence counting, etc.)
• 1917 - Gilbert Vernam develops first practical implementation of a teletype cipher, now known as a stream cipher and, later, with Joseph Mauborgne the one-time pad
• 1917 - Zimmermann telegram intercepted and decrypted, advancing U.S. entry into World War I
• 1919 - Weimar Germany Foreign Office adopts (a manual) one-time pad for some traffic
• 1919 - Edward Hebern invents/patents first rotor machine design—Damm, Scherbius and Koch follow with patents the same year
• 1921 - Washington Naval Conference - U.S. negotiating team aided by decryption of Japanese diplomatic telegrams
• c. 1924 - MI8 (Herbert Yardley, et al.) provide breaks of assorted traffic in support of US position at Washington Naval Conference
• c. 1932 - first break of German Army Enigma by Marian Rejewski in Poland
• 1929 - United States Secretary of State Henry L. Stimson shuts down State Department cryptanalysis "Black Chamber", saying "Gentlemen do not read each other's mail."
• 1931 - The American Black Chamber by Herbert O. Yardley is published, revealing much about American cryptography
• 1940 - Break of Japan's PURPLE machine cipher by SIS team
• December 7, 1941 - attack on Pearl Harbor; U.S. Navy base at Pearl Habor in Oahu is surprised by Japanese attack, despite U.S. breaking of Japanese codes. U.S. enters World War II
• June 1942 - Battle of Midway where U.S. partial break into Dec 41 edition of JN-25 leads to turning-point victory over Japan
• April 1943 - Admiral Yamamoto, architect of Pearl Harbor attack, is assassinated by U.S. forces who know his itinerary from decoded messages
• April 1943 - Max Newman, Wynn-Williams, and their team (including Alan Turing) at the secret Government Code and Cypher School ('Station X'), Bletchley Park, Bletchley, England, complete the "Heath Robinson". This is a specialized machine for cipher-breaking, not a general-purpose calculator or computer.
• December 1943 - The Colossus computer was built, by Thomas Flowers at The Post Office Research Laboratories in London, to crack the German Lorenz cipher (SZ42). Colossus was used at Bletchley Park during World War II - as a successor to April's 'Robinson's. Although 10 were eventually built, unfortunately they were destroyed immediately after they had finished their work - it was so advanced that there was to be no possibility of its design falling into the wrong hands.
• 1944 - Patent application filed on SIGABA code machine used by U.S. in World War II. Kept secret, it finally issues in 2001
• 1946 - VENONA's first break into Soviet espionage traffic from early 1940s
• 1948 - Claude Shannon writes a paper that establishes the mathematical basis of information theory
• 1949 - Shannon's Communication Theory of Secrecy Systems published in Bell Labs Technical Journal