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 4th February 2008

Week 12 Digraph Cipher

Ge rm an en ig ma ci ph er ma ch In ex
German Engima Cipher Machine

Code of the Week 12 (week starting 4th February 2008)

Digraph Cipher

A digraph is a pair of letters used to represent a single letter. For example, 'NG' can be used to represent 'B'.

A digraph cipher encrypts by substituting each digraph in the message with a different digraph or symbol.

Example:

Plaintext: DIGRAPH CIPHER

The plaintext letters are split into pairs: DI GR AP HC IP HE RX

If there is an odd number of letters, the letter 'x' is used as a 'dummy' letter to complete the pair.

'DI' is encrypted by finding the intersection of the column headed by 'd' with the row headed by 'I' which gives 'QY'

'GR' is encrypted as 'TP' (column 'T', row 'P')

The ciphertext is: QY TP NR UE VR UC EJ

More information on the Digraph Cipher may be found at: http://www.simonsingh.net/The_Black_Chamber/digraphcipher.htm

digraph cypher
Follow this link for a larger version of the digraph key

Decipher the following ciphertext using the digraph key above. Good luck!

TC EU NT RT VA ZG PY CZ RP ZG PZ VT RJ