The same was done for the slow rotor after a full rotation from the medium rotor. When figuring out the ciphered letter, Enigma would have to go through each rotor in order to get the new coded letter. For example, if Q was pressed, it might become Y after going through the fast rotor, then become S after the medium rotor, and finally become N after the slow rotor. The process is still not done. From there, the current would pass through a device called the "reflector." This device took the current and sent it back through the rotors at a different contact point, like K. The process would repeat through the rotors, but in reverse order. So the letter K might become C which goes to X and last to U. At this point the letter U would light up on the lamp board3. .
For added security, a plugboard or Steckerboard was added. This device would switch letters. For instance, if T was pressed, the plugboard might switch T with G, which.
in turn would switch G with T. When all the coding was .
done, the cipher would be unbreakable. .
In order for the receiving end to encode the message, they would have to know how Enigma was set up before coding. To know this information, the sending party would have to do a special coding at the beginning of the message. The special coding was written as follows. The first section was unencrypted and contained the sender, recipient, date, and time. After the first section, the special code was placed. For this coding the sender would choose three letters, for instance RTY, and set the rotors to those letters. These letters were the "Starting Position." This was also sent en clair, and sent twice in case there was confusion in the transmission4. The operator then picked three more letters, let us say WTB, to start the special coding. Those letters were the "Message Key." The operator would type WTB twice, which would be encrypted, and might output JSO NWV.