4 May 1994 was a grey, rainy spring day. But the people hurrying to the barracks hardly noticed. Only three weeks before, the then Federal Military Department had sent out a short invitation to a sale of transmission material. Among the items disposed of, it said, would be Enigma machines. That caused a sensation – for at that time, these devices were already sought after far beyond the narrow circle of collectors and fetched a high price.

The machines came from World War II Swiss army stocks. The late military historian Rudolf J. Ritter describes in an article how Switzerland obtained these machines: ‘The first machines arrived in 1938 as an adjunct to 14 heavy wireless stations that Switzerland had ordered from Germany in 1937’. The Swiss were delighted with the machines and immediately ordered more. By July 1942, they had 265 Enigma K machines. The army’s material management department modified the devices, changing, among other things, the wiring of the wheels and the drive mechanism.

The Nema – a machine developed independently in Switzerland and put into operation in 1947. It had significantly more wheels than the Enigma. In addition, the wheel drive was irregular. The higher number of wheels meant that more power was needed to operate the machine.
Swiss National Museum

It is extraordinary that such delicate devices should have been purchased in neighbouring Germany, of all places. However, time was short and there were not too many options. The Swiss army had to wait at least two years for the last batch of 180 Enigmas. That was far too long – Switzerland had to look for a new supplier. After all the years of working with the Enigma cipher machine, the Swiss had made some progress in cryptography and they decided to build their own machine. The order went to the Uster firm of Zellweger, which had produced the first radio developed in Switzerland.

The new cipher machine was called ‘Nema’ – short for ‘neue Maschine’ (new machine) – and this Nema was nothing more than an enhanced Enigma: it had more wheels than the Enigma, and the motion of the wheels was more irregular and therefore more difficult to reconstruct. A direct result of this was that considerably more pressure was needed to operate the cipher machine. This is probably why it was nicknamed the ‘finger breaker’. The Nema was not ready until after the war and was put into operation in spring 1947. 540 of these cipher machines went to the army, and the then Political Department, today's Federal Department of Foreign Affairs, received 100. These machines were used until the 1970s.

The Bletchley Park Estate. It was one of the most secret facilities in England during World War II. More than 10,000 people, including many women, worked here and in numerous other buildings in the surrounding park.
Photo: Dominik Landwehr

Enigma – the best cipher machine of its time

The Enigma has achieved some fame in the course of history: at the time, it used state-of-the-art technology and was considered very safe. It was produced in different versions. Switzerland was sold a special, weaker model, the Enigma K. The letter K (for kommerziell) denotes a commercial series. The Nazis had confidence in their cipher machine and enciphered much of their data with a more sophisticated version of this machine. What the Germans did not know was that in England, since the outbreak of war, a whole army of over 10,000 specialists – many of them women – had been working on deciphering it: they were based in an estate around Bletchley Park, between Oxford and Cambridge. Among them was the brilliant mathematician Alan Turing, who managed to decipher the most difficult of all Enigma machines, the Naval Enigma. It had four wheels instead of three and was a tough nut even for the specialists in Bletchley Park.

The information from Bletchley Park was filed under the ‘Ultra’ label and redistributed, a measure intended to disguise its origin. The specialists of the US intelligence service were also in on the secret. Bletchley Park's operations were among the best-protected British operations of World War II and remained a secret long after the war. In 1974, when Captain Frederick W. Winterbotham published his book The Ultra Secret about this operation, it caused a sensation. The secret had been kept until that time.

Incidentally, the code of the Swiss Enigma was one of the quickest to crack: a detailed report on the decoding of Swiss radio messages can be found in a paper from as early as November 1940 written by the Polish radio observers who had fled to France when war broke out. The Polish listeners may have passed on their knowledge to the British specialists in Bletchley Park. German specialists were also able to crack the Swiss code with ease, as is shown by documents that ended up in Switzerland after the war. And of course, the Americans were also able to crack the Swiss Enigma. However, they soon stopped working on this because they found no relevant messages.

An undated typewritten document entitled ‘Swiss Random Letter Traffic’ in the United States National Archives in Washington describes the Enigma settings that the Swiss used. One sentence reads: ‘The Swiss have no spare wheels for the machine which thus has only six possible wheel orders’.

After the Second World War, the Swiss Enigma machines were used a second time in the context of Switzerland's Korean mission. Switzerland began monitoring the armistice line between North and South Korea on behalf of the United Nations in 1953. Swiss sources say that modified Swiss Enigmas were used in the early years. Why did the Swiss use the demonstrably unsafe machine at that period, rather than the far superior Nema they had developed themselves? There are two explanations: firstly, the messages to be transmitted were generally banal and of no great military value, and secondly, the firm wanted to protect and not expose its own modern cipher machine Nema.

The Enigma and its history still fascinate us today. A number of films have focused on the subject, and the thriller author Robert Harris wrote an exciting novel on it as early as 1995.

An Enigma in use during World War II. Under the gaze of General Heinz Guderian, a radio operator receives a message that is deciphered by a soldier at the Enigma. The enciphered message is entered letter by letter onto the keyboard; the deciphered letters light up in the area above it.
German Federal Archives, Image 101I-769-0229-10A / Erich Borchert

The first page of the British account of the cracking of the Swiss Enigma.
Photo: Dominik Landwehr

An intercepted Swiss dispatch and its decryption. The document was originally supplied by Bletchley Park. It comes from the National Archives (Washington DC).

The starting page of the computer simulation of a Wehrmacht Enigma developed by Geoff Sullivan, Frode Weierud and David Hamer. The cipher can be seen bottom right. The wiring of a wheel is shown in the top right-hand corner. There are numerous computer simulations of Enigma and other machines on the internet.
https://cryptocellar.org/simula/