1913 the wheel cipher gets re-invented as a strip
1917
- 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
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
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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some essential definitions in the field of cryptography are:
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"Few false ideas have more firmly gripped the minds of so many intelligent men than the one that, if they just tried, they could invent a cipher that no one could break." (David Kahn)
The variants of encryption systems are endless.
For deciphering there exists always the same game of trial and error (first guessing the encryption method, then the code). A help to do so is pruning. Once, after a more or less long or short period a code/cipher breaks. Monoalphabetic ciphers can be broken easily and of course are no longer used today but for games.
for further information on codes and ciphers etc. see:
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Ciphers as well as codes are transmitted openly. Everyone can see that they exist. Not so with steganograms.
Steganography is the art and science of communicating in a way which hides the existence of the secret part in that communication. During the Italian Renaissance and the time of the Elizabethan Age in England cryptography was very popular, for political reasons as well as for amusements (see John Dee).
In literature steganography played an important role. Many steganographs of that period have only been deciphered recently like some of the Shakespearean sonnets, which now seem to proof that the actor William Shakespeare was not the author of the famous poems and dramas, but that the latter' name was, and Francis Bacon, or even Francis Tudor, as some ciphers and other sources talk of him as Queen Elisabeth I.'s secret son.
for further details see:
One kind of steganogram is digital watermarking:
Watermarks protect digital images, videos, but also audio and multimedia products. They are made out of digital signals, put into other digital signals. They try to be invisible on first sight and should be nearly impossible to remove. The process of producing watermarks is to overlay some sort of identifying image over the original image (non-digital watermarks, like on money can be seen by holding the paper against light). Copying the image destroys the watermark, which cannot be copied. Any alteration of the original destroys the watermark, too.
Watermarking is one of the typical inventions of cryptography to assist the biggest content owners, but advertised as something necessary and helpful for everybody. Who in fact gets any advantage out of watermarking? The private user most of the time will not really need it except for small entities of pictures maybe.
But the big enterprises do. There is a tendency to watermark more and more information in the Internet, which until now was considered as free and as a cheap method to receive information. Watermarking could stop this democratic development.
for further information see:
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Supposedly his real name was Aeneas of Stymphalus. He was a Greek military scientist and cryptographer. He invented an optical system for communication similar to a telegraph: the
Electronic messages are transmitted and received by computers through a network. By E-Mail texts, images, sounds and videos can be sent to single users or simultaneously to a group of users. Now texts can be sent and read without having them printed.
E-Mail is one of the most popular and important services on the Internet.
During the Tian-an men massacre reports and photos transmitted by fax machines gave notice of what was happening only with a short delay. The Chinese government has learned his lesson well and "regulated" Internet access from the beginning. All Internet traffic to and out of China passes through a few
Users are expected not to "harm" China's national interests and therefore have to apply for permission of Internet access; Web pages have to be approved before being published on the Net. For the development of measures to monitor and control Chinese content providers, China's state police has joined forces with the MIT.
For further information on Internet censorship, see Human Rights Watch,