some essential definitions

some essential definitions in the field of cryptography are:
- cryptoanalysis
- cryptology
- ciphers

"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)

codes
plaintext
ciphertext
to encipher/encode
to decipher/decode

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:
http://www.optonline.com/comptons/ceo/01004A.html
http://www.ridex.co.uk/cryptology/#_Toc439908851

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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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Another Question of Security

Even with the best techniques it is impossible to invent a cryptographic system that is absolutely safe/unbreakable. To decipher a text means to go through many, sometimes nearly - but never really - endless attempts. For the computers of today it might take hundreds of years or even more to go through all possibilities of codes, but still, finally the code stays breakable. The much faster quantum computers will proof that one day.
Therefore the decision to elect a certain method of enciphering finally is a matter of trust.

For the average user of computers it is rather difficult to understand or even realize the dangers and/or the technological background of electronic transmission of data. For the majority thinking about one's own necessities for encryption first of all means to trust others, the specialists, to rely on the information they provide.
The websites explaining the problems behind (and also the articles and books concerning the topic) are written by experts of course as well, very often in their typical scientific language, merely understandable for laymen. The introductions and other superficial elements of those articles can be understood, whereas the real background appears as untouchable spheres of knowledge.

The fact that dangers are hard to see through and the need for security measures appears as something most people know from media reports, leads directly to the problem of an underdeveloped democracy in the field of cryptography. Obviously the connection between cryptography and democracy is rather invisible for many people. Those mentioned media reports often specialize in talking about the work computer hackers do (sometimes being presented as criminals, sometimes as heroes) and the danger to lose control over the money drawn away from one's bank account, if someone steals the credit card number or other important financial data. The term "security", surely connected to those issues, is a completely different one from the one that is connected to privacy.
It is especially the latter that touches the main elements of democracy.

for the question of security see:
http://www-db.stanford.edu/pub/gio/CS99I/security.html

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Local Area Network (LAN)

A Local Area Network is an office network, a network restricted to a building area.

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Polybius Checkerboard


 

1

2

3

4

5

1

A

B

C

D

E

2

F

G

H

I

K

3

L

M

N

O

P

4

Q

R

S

T

U

5

V

W

X

Y

Z



It is a system, where letters get converted into numeric characters.
The numbers were not written down and sent but signaled with torches.

for example:
A=1-1
B=1-2
C=1-3
W=5-2

for more information see:
http://www.ftech.net/~monark/crypto/crypt/polybius.htm

http://www.ftech.net/~monark/crypto/crypt/pol...
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Memex Animation by Ian Adelman and Paul Kahn


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William Gibson

American science fiction author. Most famous novel: Neuromancer.

For resources as writings and interviews available on the Internet see http://www.lib.loyno.edu/bibl/wgibson.htm

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America Online

Founded in 1985, America Online is the world's biggest Internet service provider serving almost every second user. Additionally, America Online operates CompuServe, the Netscape Netcenter and several AOL.com portals. As the owner of Netscape, Inc. America Online plays also an important role in the Web browser market. In January 2000 America Online merged with Time Warner, the worlds leading media conglomerate, in a US$ 243,3 billion deal, making America Online the senior partner with 55 percent in the new company.

http://www.aol.com

http://www.aol.com/
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Censorship of Online Content in China

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 gateways, a few entry-points, thus making censorship a relatively easy task. Screened out are web sites of organizations and media which express dissident viewpoints: Taiwan's Democratic Progress Party and Independence Party, The New York Times, CNN, and sites dealing with Tibetan independence and human rights issues.

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, World Report 1999.

http://www.dpp.org/
http://www.nytimes.com/
http://www.hrw.org/worldreport99/special/inte...
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