|For ease of use, this has been divided into sections as listed below, together with a brief description of their purpose and content. The [size] of each is given in kilobytes as guide to downloading times.|
Each requires the use of an Acrobat Reader to allow it to be viewed and printed out.
|Essential reading whether using just a part or the whole of this material. Includes a short vocabulary with some definitions, and a list of some well-known names in the history of cryptology. There is also list of further sources of information. |
|How an ordinary message can re-arranged, in an orderly manner, so as to make it very difficult to read.|
|Disguising a message so that it does not even look as though it contains any secrets.|
|Using a code allows messages to be hidden and shortened at the same time.|
|Simple Cipher Messages|
|Hiding the messages by substituting other letters for those of the original text|
|Using numbers and some simple arithmetic to hide a message|
|How more complex arithmetic processes bury the messages even deeper.|
|Mechanical enciphering with a (very!) simplified paper model of the Enigma machine.|
|The science (or is it an art?) of breaking cipher messages, allowing them to be read without knowing the keyword or its equivalent.|
|Accounts of some other methods for creating ciphers.|
|Public Key Ciphers|
|How one particular modern cipher system (RSA) works, and can be made widely available to all, whilst retaining its security.|
|While all sections contain their own support materials, this has a few more general items.|
|The Small Code Book|
|An abbreviated code book which can be printed out and assembled.|
For use with Coded Messages (above).
|Diagrams suitable for making ohp slides or even projected directly onto a suitable screen or whiteboard.|
|The Gold Bug
|The famous short story by Edgar Allen Poe about cipher breaking which was the first account to appear in a work of fiction.|
|The Dancing Men|
|The story of how Sherlock Holmes broke a symbol cipher.|
|The Enigma Machine|
|Picture of the most well-known ciphering machine|
|The SIGABA Machine|
|Picture of the US equivalent of the Enigma machine.|
The British TypEx machine was similar to this one.
|The Hagelin Machine|
|Picture of the Hagelin M209 machine.|
This was a portable (purely mechanical) enciphering machine.
|Available yes, but a password will be needed to read this file.|