Enigma K; made by Ciphering Machines - Company Heimsoeth & Rinke, Berlin - Wilmersdorf.
After wirebound and wireless transmission was introduced with the Swiss armed forces, it became more and more evident, that the content of the messages should be kept in secret and should only reach it's destination and not be intercepted by enemy forces. So the necessity of encryption arose.
As a first step codebooks were used, but these were used primarily in technical and service communication, the messages themselves were encrypted with the Reglette or cipher tables.
In 1938, the first ENIGMA cipher machines from German production were acquired to serve on the high power shortwave station G1,5K.
After the English and also the Germans had succeeded in cracking the ENIGMA code, not only the radio messages of the German Wehrmacht, but also the ones of Swiss army were no longer safe.
In 1938, the first badge of 14 units of the German cypher machine ENIGMA K (the commercially available model) were acquired to be used with the high power radio stations G1,5K. From February 1939 to July 1940 a total of 265 machines were acquired.
The ENIGMA is a rotor-type cipher machine with a lamp display: the key is set with four wheels set tot the correct start position.
The ENIGMA K comes with a relector wheel, which is not moved during operation and is only set in the start position, and three permutation wheels. The permutation wheels, numbered I to III, can be mounted in different arrangements, the mounting order is also defined in the message key.
When you press one of the 26 letter keys, one of the 26 letters will light up. Each time, a key is pressed the right-hand permutation wheel is advanced by one position, with one notch; the middle wheel is moved one position after a complete revolution of the right wheel. Like found on an odometer, after one complete revolution of the middle wheel, the left permuting wheel is advanced by one step.
The message to be encrypted is entered by the typewriter keyboard and the letters of the encrypted message is copied from the lamp field and written on a telegram form, which is forwarded to the radio operator for transmission.
In rotor ciphering machines, one letter is replaced with another letter one time. When the same letter key is pressed again, the same plaintext letter is encrypted by a different letter. Thus the code is far more difficult to crack, than the simple letter substitution code of school-level detective games in which one letter is always replaced by the same other letter.
An separate second lamp panel made „almost real-time encryption“ possible. The signalman working on the ciphering machine keyed in the message and the signalman operating the transmitter immediately transmitted the letter displayed on the second lamp panel in morse code.
Cipher machine, three permutation wheels, one reflector wheel.
No electron tubes used.
In 1918, the German engineer Arthur Scherbius applied for a patent for his first rotor cipher machine. In 1923, the Enigma A was already for sale at a trade fair in Bern. After Scherbius had died in 1929, his company was bought by Heimsoeth & Rinke in 1934. Thousands of Enigma machines were used in the German Wehrmacht.
In Switzerland, the Enigma K was purchased as a commercially available cipher machine to be used on the high power radio stations in 1938 and after purchase, the secret wiring of the wheels was changed with regard to its use in Switzerland.
A large part of the ENIGMA machines in possession of the army was transferred to war reserve in 1958 and was liquidated in 1975. Some of the machines were kept ready for use in an emergency radio network of the Air Force / anti-aircraft troops until 1989, then 25 machines were sold to the public.
Other machines were used in the so-called „Koreafunk“, the wireless communication link to the Swiss contingent of ceasefire observers at the inner Korean border.