Timeline BC

~ 1900 BC: Egyptian writers use non-standard Hieroglyphs in inscriptions of a royal tomb; supposedly this is not the first but the first documented example of written cryptography

1500 an enciphered formula for the production of pottery is done in Mesopotamia

parts of the Hebrew writing of Jeremiah's words are written down in "atbash", which is nothing else than a reverse alphabet and one of the first famous methods of enciphering

4th century Aeneas Tacticus invents a form of beacons, by introducing a sort of water-clock

487 the Spartans introduce the so called "skytale" for sending short secret messages to and from the battle field

170 Polybius develops a system to convert letters into numerical characters, an invention called the Polybius Chequerboard.

50-60 Julius Caesar develops an enciphering method, later called the Caesar Cipher, shifting each letter of the alphabet an amount which is fixed before. Like atbash this is a monoalphabetic substitution.

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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

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Martin Hellman

Martin Hellman was Whitfield Diffie's collegue in creating pubylic key cryptography in the 1970s.

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Leonard M. Adleman

Leonard M. Adleman was one of three persons in a team to invent the RSA public-key cryptosystem. The co-authors were Adi Shamir and Ron Rivest.

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to decipher/decode

to put the ciphers/codes back into the plaintext

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cryptoanalysis

the study of breaking others' codes to transform a message back into a legible form without knowing the key from the beginning

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plaintext

the original, legible text

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codes

an algorithm for bringing a legible message into an illegible form. There has to exist some sort of code book to encode/decode it.

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