Code of the Week!

view of the enigma machine

For your chance to win your very own signed copy of Simon Singh's Code Book try out your codebreaking skills with the "Code of the Week".

Solution for the "Code of the Week!" week starting 21st January 2008

Week 10 Route Cipher

Vegemite is the best spread

Code of the Week 10 (week starting 21st January 2008)

Route Cipher

In a route cipher, the plaintext is first written out in a grid of given dimensions, then read off in a pattern given in a key. For example, using the plaintext

One method of encryption is called transposition. For example, using a grid with 4 Columns and 7 rows, the plaintext 'I ate chocolate for breakfast' can be written down the columns from left to right as below:

I

C

O

F

A

O

R

A

T

L

B

S

E

A

R

T

C

T

E

J

H

E

A

X

O

F

K

Z

The last 3 letters J, X and Z are just random letters to fill in the space.

Using the key of a clockwise spiral beginning in the top left hand corner, the ciphertext would become:

ICOFASTJXZKFOHCETAORBREAETALO

You may find out more information about the Route Cipher at:

http://www.braingle.com/brainteasers/codes/route.php

Using the same key and grid dimensions as in the example above, decipher the following ciphertext to be in the running for this week's prize.

GOOD LUCK!

Ciphertext

VTEPREADJSHIMEGEEBESTTSIE