Mixed Multilateral Substitution Ciphers
The first cipher we looked at was the simple substitution cipher. The second in Bronze was a Dinome.
To earn a silver medal however you will need to crack a mixed Monoliteral-Biliteral. In this case the enciphering may lead to a letter being represented by either one or two characters. See the example below.
The same method with variations can lead to whole range of ciphers of increasing complexity, but for now we'll start with something simple.
Cracking Multiliteral Substitution Ciphers
The first step is to determine what the frequency count of the letters/digits or symbols used. Determine if any stand out as above average. Then look for repeats and determine is the spacing between them is either an odd number or an even number. In monoliteral ciphers repeated patterns may occur at any seperation say 24,35 positions. In a biliteral this will always be an even numnber. A mixed cipher will have both.
Furthermore the digits,characters or symbols used for rows will appear quite often and so these will probably be on the 2nd,3rd and subsequant row coordinates. Of course the first row is blank.
Once the rows are roughly known break the cipher text into monomes and dinomes based on the row coordinates. Each dinome will start with one of the common row coordinates and include the next character. If the following character is not one of these then it is most likely a monome. This process is repeated throughout the text, breking the ciphertext into monomes and dinomes.
Once this has been done the ciphertext is now in the form of a monoalphabetic cipher and the usual methods can be used for breaking it.
The Cipher for the "Cipher Silver" location is:
E E E T T S E E T H E E E S O N E E E E
E S A R O E A D E T T S E R R E E S E D
E I N O E T E D H T S O E T E D D E T T
S E R R T I E T D I R N H D T S T O E E
E S O E D R S O D E D R H T H E E N T S
H E I N E E T I E T E D T T S D E O R T
S E R R E E T S E R R N H D T S D H T H
O D E T T S R E D O E T E D E A O E I E
T R T S D E H
As usual beware of muggles running around.