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

TEXTBLOCK 1/2 // URL: http://world-information.org/wio/infostructure/100437611776/100438659070
 
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

TEXTBLOCK 2/2 // URL: http://world-information.org/wio/infostructure/100437611776/100438658921
 
Local Area Network (LAN)

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

INDEXCARD, 1/2
 
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...
INDEXCARD, 2/2