|Dͻ
|D |5Brainware |D
|Dͼ

^C^1King of the Jumble
^Cby
^CJim Weiler

Secret Writing
--------------
  Cryptography, or "secret writing," is not a modern invention.  To add mystery 
to their religious texts, Egyptian scribes sometimes scribed their hieroglyphs 
in unfamiliar forms. A Greek general, Aeneas Tacticus, described enciphering 
techniques still used by German secret agents in World War II.  For thousands 
of years, codes and ciphers have guarded the secret communications of rulers, 
diplomats, soldiers, and spies. 

  Secret messages rarely remain secret. Inevitably, cryptanalysts "break" the 
codes or ciphers that hide battle plans or state secrets.  In war, a broken 
cipher can mean the difference between victory and defeat.  In his book, ^1The 
^1Codebreakers^0, David Kahn speculates that in World War II, the work of American
cryptanalysts shortened the war with Japan by at least a year. Today, cryptanal-
ysis sections are the heart of U.S. intelligence agencies. 

  Obscure government agents are not the only people who study cryptography. 
Thousands of ordinary citizens are fascinated by the cat and mouse game played 
between cryptographer and cryptanalyst. Amateur cryptologists enjoy the 
intellectual challenge of cracking cryptograms; others, like children who never 
quite gave up their magic decoder rings, enjoy sharing coded messages with 
their friends. 

  ^1King of the Jumble^0 is a powerful tool for amateur cryptologists. The user 
can create cryptograms and cipher alphabets.  The program's sophisticated 
routines can help break cryptograms. Best of all, ^1King of the Jumble^0 eliminates
much of the drudgery involved in breaking a secret message.

Definitions
-----------
  Before we talk about the program itself, let's look at some cryptanalysis 
terms.  First, the message that is to be put in secret form is called 
^1plaintext^0.  The cryptographer uses a ^1cipher^0 or a ^1code^0 to transform plaintext
into a secret message. 

  What's the difference between a code and a cipher?   While there is no sharp 
dividing line, think of a code as a group of numbers or letters standing for 
whole words or phrases.  Two codewords might look alike but have different 
meanings.  While the letters "PDSFDF" could stand for "Buy a year's subscription 
to ~3|9Big Blue Disk^0"; "PDSFDA" might mean "hijack one kilogram of weapons-grade
plutonium."  The receiver must usually have a ^1codebook^0 to decode a coded 
message. 

  On the other hand, ciphers substitute a letter or symbol for each letter in a 
plaintext message.  The substituted letters make up a ^1cipher alphabet^0. 
Julius Caesar reportedly used this alphabet: 

^C^1plaintext: abcdefghijklmnopqrstuvwxyz
^C^1cipher:    defghijklmnopqrstuvwxyxabc

Caesar's Cipher thus transforms "rome or bust" into "urph ru exvw." 

  Using the cipher alphabet, the sender ^1enciphers^0 the message.  Once transmit-
ted, the secret message is called a ^1cryptogram^0.  When the cryptogram reaches its
intended audience, the person ^1deciphers^0 it back into plaintext.  The party who
^1intercepts^0 the cryptogram, however, will attempt to ^1break^0 or ^1decrypt^0 the cipher,
using the process of ^1cryptanalysis. 

Methods
-------
  How does a cryptanalyst attack a cryptogram?  The first step is to make a 
frequency chart which shows how often each letter occurs in the secret message.
This chart is then compared with a table showing the average frequency of 
letters in standard English text. 

  Suppose that the letter "X" appeared most often in a cryptogram.  Since "E" 
appears most often in standard English text, the cryptanalyst would first 
substitute "E" for "X."  Subsequent substitutions are based on other often-used 
letters. 

  Relationships between letters also help the cryptanalyst make educated 
guesses.  ^1Digrams^0 like "TH," "HE," and "ER" occur frequently in English. 
Letters in the cryptogram which mimic often-used digrams can provide important 
clues. 

  Note that standard frequency counts are based on ^1average^0 occurrence. The 
frequency chart of a lengthy cryprogram will correspond more closely to the 
standard than will that of a brief cryptogram.  The larger the sample, the more 
accurate the frequency analysis is. 

  Breaking a cryptogram requires logical thinking, not to mention a little 
intuition.  (A whole lot of patience doesn't hurt either.)  But remember that 
^1King of the Jumble^0 can't think for you.  That said, let's look at the 
program itself. 

The Program
-----------
  ^1King of the Jumble^0 is a set of utility and application routines used to
encrypt and decode substitution algorithms, to create codes, and to translate 
codes back into ordinary text.  It runs from three sub-menus: the Filer, Editor,
and Analyzer module. ESCAPE returns to the next higher level. 

The Filer
---------
  The Filer sub-menu loads, saves, and prints plaintext messages, cipher 
alphabets, and cryptograms.  The option to quit the program is also here.

The Editor
----------
  Choose the Editor sub-menu to enter cryptograms and plaintext messages. 
"Solve Cryptogram" displays the cryptogram -- letter substitutions are shown 
beneath the enciphered message. 

  The Editor's "Encrypt Plaintext Message" uses the plaintext message as a 
guide to create the cipher alphabet. With a little ingenuity, a cryptogram can 
be made to look like a ordinary English sentence or a sentence in a foreign 
language.  Remember to make note of the substitutions, however; use the 
Analyzer sub-menu's "Create Cipher" option to make a cipher alphabet that can 
be saved to disk. 

  To move around the Solve Cryptogram screen, use the arrow keys.

The Analyzer
------------
  Choose the Analyzer sub-menu to analyze the cryptogram you are attacking -- 
or to create a cipher alphabet, encrypt a plaintext message, or decrypt a 
cryptogram. 

  The Analyzer provides automatic solutions.  This doesn't mean that it breaks 
it, however.  Instead, autosolve provides possible letter substitutions for 
each letter in the cryptogram. This option bases its solution on a standard 
frequency count: it will always say that the most frequent letter is "E," for 
example. 

  The automatic solution begins by substituting the most common letter (E) and 
ends with the least common (Z). There is often no need to substitute every 
letter in the cryptogram -- the five or ten most common letters are sometimes 
enough. Press ESCAPE to abort letter substitution.  (Remember: return to the 
Editor's "Solve Cryptogram" option to view the cryptogram.) 

  "Digram Substitution" is another analysis tool.  It goes through the 
cryptogram and optionally replaces letter pairs with some of the most common 
English digrams. 

  Please be patient.  Digram substitution is an extremely slow and complex 
operation using all available memory.

An Overview
-----------
  ^1King of the Jumble^0 is a complex program, so we have not documented all of 
its options and functions. For solving long cryptograms, a cipher may be 
created from a solved cryptogram by entering letters while moving between View 
Cyrptogram and Create a Cipher in the Analyzer.  Save the cipher in the Filer 
and use to decrypt the remaining message. Before exploring the program on your 
own, take a look at these basic step-by-step instructions: 

To Create a Cryptogram:

1. Choose the Editor's "Enter Plaintext Message" option and enter message.

2. Acquire a cipher by loading a cipher from disk (use Filer menu) or creating 
   a cipher with the Analyzer's "Random Encryption" or "Create Cipher" options.

3. Choose the Analyzer's "Encrypt Cipher" option.

4. Go to the Filer menu to save or print a cryptogram.

To Break a Cryptogram:

1. Choose the Editor's "Enter Cryptogram" option and enter an enciphered 
   message. 

2. Use the Analyzer's ratio analysis and/or autosolve and digram substitution 
   routines. 

3. Go to the Editor's "Solve Cryptogram" option to work on solution. 

4. Go to the Filer menu to save the cryptogram.

For More Information
--------------------
  To learn more about the history and techniques of cryptography and 
cryptanalysis, try these two books: 

James Raymond Wolfe, ^1SECRET WRITING, The Craft of the Cryptographer^0 (New 
York: McGraw Hill, 1970).  An entertaining and informative introduction to 
cryptology. 

David Kahn, ^1THE CODEBREAKERS, The Story of Secret Writing^0 (New York: 
Macmillan, 1967).  A comprehensive history of cryptography and cryptanalysis, 
with epecially good chapters on cryptanalysis in World War II. 


DISK FILES THIS PROGRAM USES:
^FJUMBLE.EXE
^FCRYPTO.HLP
^FSAMPLE.JMS
^FSAMPLE.JCY
^FSAMPLE.JCP
^FBRUN20.EXE
^FRETURN.EXE
