TOPIC:

I have two copies of British intelligence telegraph messages partly in code, possibly playfair cypher. Is there anyone who could decode them. Thanks Graham Bradbury
[email protected]

I would perhaps speak to Tony Comer at GCHQ Cheltenham, he is their historian/archivist.

Graham,

What is the encoded text?

Graham
There are a number of on-line sites where messages in the Playfair cipher may be decoded.
Regards
IL.

IL,

I was looking at one of those sites yesterday. I would be interested to see how the site works. Presumably it must generate very many combinations and then spell check the output to see which makes sense? If they are encoding places, units and abbreviations in the source message, I'm not sure how the program will know it has the correct cypher.

I would be interested to see how the site works with an ABW message.

A key to one of these cyphers would probably be a 5x5 grid containing 25 letters of the alphabet. Has anyone seen such a code anywhere?

David
The deciphering of the Playfair cipher is done with a key word. Once the key word is known, it apparently is a matter of letter substitution. The sent message is laid out in a grid. And that is the sum total of IL's limited "knowledge". In classic espionage, messages can be sent with the key being a word on a certain page of a certain book. Interestingly, there is a website which allows a Playfair cipher to be deciphered. It would be very interesting to see either or both of Graham's examples of telegraphic coded messages.
Best regards
IL.