The mysterious code found on the dead pigeon (Numbered -40TW194) in Britain recently appears to come from the modified SIGABA used by the British. Known as the M-134 in the U.S. Army or the CSP-888/889/2900 of the U.S. NAVY, this device was used to encrypt and decrypt messages during WWII. The British also used the TypeX to communicate and the Bombe.
Looking at the beginning code of the cryptic message and the last of the code, you’ll see the same letters AOAKN. This appears to be the internal or external indicators. The External indicators usually told the classification of a document and the internal codes were used to enter into the SIGABA to set up the machine prior to decrypting it. The remaining text was entered into the machine using a keypad and was decrypted onto tape.
The full message –
AOAKN HVPKD FNFJW YIDDC
RQXSR DJHFP GOVFN MIAPX
PABUZ WYYNP CMPNW(or U) HJRZH
NLXKG MEMKK ONOIB AKEEQ
WAOTA RBQRH DJOFM TPZEH
LKXGH RGGHT JRZCQ FNKTQ
KLDTS FQIRW AOAKN 27 1525/6
The SIGABA used internal and external indicators and it appears by the message found; only the beginning and end match. Was this the TypeX being used?
Typically the SIGABA uses the internal and external indicators and the keys are set by classification (link below to the use of the SIGABA).
Is there a TypeX emulator out there??
Or is this a WWI simplex (acronym based) code?