| 
        
          | 
  
    |  | Timeline 1900-1970 AD |  
    |  
  
  | 1913 		the wheel cipher gets re-invented as a strip 
 1917
  William Frederick Friedman starts working as a cryptoanalyst at Riverbank Laboratories, which also works for the U.S. Government. Later he creates a school for military cryptoanalysis 
 - an AT&T-employee, Gilbert S. Vernam, invents a polyalphabetic cipher machine that works with random-keys
 
 1918		the Germans start using the ADFGVX-system, that later gets later by the French Georges Painvin
 
 - Arthur Scherbius patents a ciphering machine and tries to sell it to the German Military, but is rejected
 
 1919		Hugo Alexander Koch invents a rotor cipher machine
 
 1921		the Hebern Electric Code, a company producing electro-mechanical cipher machines, is founded
 
 1923		Arthur Scherbius founds an enterprise to construct and finally sell his
  Enigma machine for the German Military 
 late 1920's/30's	more and more it is criminals who use cryptology for their purposes (e.g. for smuggling). Elizabeth Smith Friedman deciphers the codes of rum-smugglers during prohibition regularly
 
 1929		Lester S. Hill publishes his book Cryptography in an Algebraic Alphabet, which contains enciphered parts
 
 1933-1945	the Germans make the Enigma machine its cryptographic main-tool, which is broken by the Poles Marian Rejewski, Gordon Welchman and Alan Turing's team at Bletchley Park in England in 1939
 
 1937		the Japanese invent their so called Purple machine with the help of Herbert O. Yardley. The machine works with telephone stepping relays. It is broken by a team of
  William Frederick Friedman. As the Japanese were unable to break the US codes, they imagined their own codes to be unbreakable as well - and were not careful enough. 
 1930's		the Sigaba machine is invented in the USA, either by W.F. Friedman or his colleague Frank Rowlett
 
 - at the same time the British develop the Typex machine, similar to the German Enigma machine
 
 1943		Colossus, a code breaking computer is put into action at Bletchley Park
 
 1943-1980	the cryptographic Venona Project, done by the NSA, is taking place for a longer period than any other program of that type
 
 1948		Shannon, one of the first modern cryptographers bringing mathematics into cryptography, publishes his book A Communications Theory of Secrecy Systems
 
 1960's		the Communications-Electronics Security Group (= CESG) is founded as a section of Government Communications Headquarters (= GCHQ)
 
 late 1960's	the IBM Watson Research Lab develops the Lucifer cipher
 
 1969		James Ellis develops a system of separate public-keys and private-keys
 
 
 
 
  
 |  |  |    
  |  |