Route Transposition
Description
One of the simplest transposition ciphers is the Route Transposition Cipher where the plaintext is written into a complete block in a given direction, or route, and extracted using a different route to produce the ciphertext.
In total there are 48 different routes possible to write into the square and 48 routes to read from it. These are:
Horizontal
Vertical
Diagonal, top right to bottom left
Diagonal, bottom left to top right
Clockwise
Clockwise, from the middle
Alternative Horizontal (Boustrophedon)
Alternative Vertical
Alternative Diagonal, top right to bottom left
Alternative Diagonal, bottom left to top right
Anticlockwise
Anticlockwise, from the middle
Each of these directions can start from any corner or go in any direction if starting from the middle.
A limitation of this cipher type is that the plaintext must fill a complete block.
Example
Encipher the George Washington quote "It is far better to be alone, than to be in bad company” using a key square width of 6.
Write this into a block of width 6 in rows starting at the top left produces the following rectangle:
I T I S F A
R B E T T E
R T O B E A
L O N E T H
A N T O B E
I N B A D C
O M P A N Y
Reading from the block in columns starting from the top left results in the following cipher:
Ciphertext: IRRLA IOTBT ONNMI EONTB PSTBE OAAFT ETBDN AEAHE CY
Solving
Solving method: Brute force search.
After selecting the Route Transposition cipher, the grid width in the range of 3 to 20 can be selected from the Setup drop down menu. Only widths producing a complete grid will appear in the menu. The default setting of 0 will result in all valid grid widths being tested.