Enigma - Encoding method used
Action Note The settings we used.
Disconnect the 4.5V battery system.    
Removed the light cover Two knurled screws left and right on the top central panel  
Lift up the rear panel This exposes the wheels and the mechanical working parts of the machine.  
Bring the lever forward so that the reflector disengages from the wheels   B
Carefully removed the three wheels    
Remove wheels from the shaft.    
Select the three wheels for use   V  IV  I

Select each wheel in turn and set the ring setting" or to use the German term "Select each wheel in turn and set the Ringstellung".

  S (19)  C (3)  A (1)

Place the wheels on the shaft in the correct order and replace in the machine.

    
Close the lid    
Replace the light panel. Tighten the screws  
Expose the patch panel    
Remove all existing patch cables    
Re-plug the board with the new cable patches.

We used ten plugs. Ten were used since 1939..

 NT DY HL UF IS BG ZC EJ XK OR
Close up the front panel    
Connect the power supply    
Set the wheels to the first daily setting

Up to September 15 1938, a common setting, known as a daily Grundstellung was used for every message on a particular day. The Grundstellung changed each day. It was read from the monthly key sheet which all operators were issued with each month for their network. (top secret document) Hence there was no need to transmit this tri-gram in clear, the rx chap just looked it up..

AFTER  September 15th, every message had a different Grundstellung - selected at random by the cipher clerk. This was required to be part of the transmission, hence we need to send the group NUP, since the rx does not know it!

NUP
Enter the first tri-graph Type AYT, lamps QGQ light AYT  This gave us QGQ the message key

Set the wheels to the Message Key QGQ

Note:

QGQ is the all important message key that is set on the wheels to encipher or decipher. By

enciphering this key from Grundstellung NUP and getting AYT we can tx NUP AYT  - the rx can reverse this, and get QGQ - since he has the same plugs and wheels.

QGQ Message Key

NUP Message Grundstellung

AYT enciphered message key
Type in the message  

(This will be shown here at a later date)

3 July 2005
Copy the lights to give us 4 x 5 letter groups.   (This will be shown here at a later date)
Formulate the broadcast message    
Enter message into morse keyer. This was done to ensure that an identical morse message was sent on each transmission time.

CQ DE GB2HQ bt ENIGMA MESSAGE bt

1200 20 NUP AYT bt

etc (to be filled in 3 July 2005)
     

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