Homepage
Crypto
Index
Glossary
Enigma
Hagelin
Fialka
Nema
AT&T
Datotek
Gretag
HELL
ITT
Motorola
Mils
OMI
Philips
Racal
Siemens
STK
Tadiran
Telsy
Teltron
Transvertex
TST
USA
USSR
UK
Yugoslavia
Voice
Hand
OTP
EMU
Mixers
Phones
FILL
Codebooks
Algorithms
Spy radio
Burst encoders
Intercept
Covert
Radio
PC
Telex
People
Agencies
Manufacturers
• • • Donate • • •
Kits
Shop
News
Events
Wanted
Contact
About
Links
   Logo (click for homepage)
Codebooks
A codebook is a very old and effective method for concealing the contents of a message. Initially, codebooks were not intended for the encryption of messages, but as a simple means to make their distribution more efficient and cost-effective when sending them over telegraph lines or via radio by means of morse code. In most cases, letters, frequently used words or even complete sentences were replaced by three, four or five-letter codes. This made it easier (and cheaper) to send a message over a long distance. The international Q-Codes are a good example of this.

During WWII, codebooks were often used to encrypt a message, sometimes in addition to other cryptographic methods, such as Enigma or hand ciphers. Cracking a codebook is a difficult but not impossible task for a code breaker. Once a codebook is captured or reconstructed, messages are no longer secret. For this reason, codebooks are often classed as Security by Obscurity.
 
Codebooks on this website
Code International Lugagne (1914) Internationales Signalbuch 1931 The News Boe Code (1937) - Commercial Traffic and Shipping Codes Funkverkehrsheft für die Küstenverteidigung (1943) German Navy bigram tables used during WWII for Enigma traffic

 
Key material
When using mechanical cipher machines, such as the German Enigma, it was common practice to supply the daily settings of the machine, such as the order of the wheels and the initial position, on a so-called key sheet. In most cases, a key sheet contained the settings for several days, or sometimes even a full month, in advance. Please note that such a key sheet is not a codebook.
 
Further information

The New Boe Code book

 
Any links shown in red are currently unavailable. If you like the information on this website, why not make a donation?
© Crypto Museum. Created: Friday 04 September 2015. Last changed: Saturday, 11 June 2016 - 08:20 CET.
Click for homepage