Sweden and cryptology

Sweden has a long and proud history in cryptology. From the world’s oldest mechanical cipher machine to breaking German codes during the Second World War, the Swedish legacy in this field goes back further than most people realise.

Few people know that the world’s first mechanical cipher machine was Swedish. In 1786, Baron Fredrik Gripenstierna presented the invention to King Gustav III. The secret message was entered in plain text on one side, while the encrypted text appeared on the other, where it was written down by a secretary who never saw the content of the original message. The machine also had a mechanical lock that prevented unauthorised access to its cryptographic functions. The prototype was never produced in further copies and has since been lost, but the documents describing the invention are preserved in the Swedish National Archives. 

Cryptology during the Second World War 

During the Second World War, Sweden faced one of its most critical cryptological tests. The Germans used a machine called the Geheimschreiber, or G-schreiber, for encrypted communication between their occupied territories in Norway and Denmark. The messages were sent via the Swedish telephone network, which, without the Germans’ knowledge, gave Sweden access to the traffic. The machines used to read the encrypted traffic were colloquially known as “apps”, short for “apparatus” rather than the modern sense of the word. A small linguistic curiosity that says something about the spirit of the time. 

It was the mathematician Arne Beurling who succeeded in breaking the encryption and making the traffic readable for Swedish analysts. The work was carried out in great secrecy, and for a period Sweden was able to read German military communications in plain text. But the capability also created an ethical dilemma. When it became known what was about to happen, the question arose whether the information could be acted on, or whether doing so risked revealing that the encryption had been broken, and with it losing the entire capability. 

The solution was to create alternative explanations for how the information had been obtained, for example that aircraft had observed movements that justified the action. 

– It was a constant balancing act. If you acted too obviously on the information, you risked the other side realising their cipher had been broken and changing systems, says Jens Bohlin, CEO of Tutus. 

The intelligence work built up during this period laid the foundation for what is today the FRA, the Swedish National Defence Radio Establishment.

A trusted cryptographic nation within the EU 

One of the reasons behind Sweden’s strong position in cryptology is the long-standing collaboration between government, academia and industry. It is a model that has made it possible to combine leading theoretical expertise with practical application and government requirements. 

Today, Sweden is one of five EU countries that are part of AQUA, the Appropriately Qualified Authority, a body for second-party evaluation of cryptographic products within the EU. The other countries are Germany, France, the Netherlands and Italy. 

What this means in practice is concrete: for a cryptographic product to be approved for protecting EU classified information, it requires both national approval from a member state and an independent second-party evaluation by one of the AQUA countries. Sweden’s place in this group reflects the trust and expertise built up over many years. 

– It’s something of a feather in Sweden’s cap, says Jens. 

This is also reflected in the results. Several Swedish companies today have products approved for protecting EU classified information, which requires both high technical quality and established trust with the evaluating authorities. 

NATO and quantum-safe algorithms 

With Sweden’s accession to NATO, ambitions have been raised further. There is a clear intention for Sweden to be able to supply cryptographic solutions for use by other NATO countries as well. 

At the same time, Sweden continues to build expertise at the academic forefront. Academia and the defence sector are collaborating on research into quantum-safe cryptographic algorithms, a field concerned with preparing cryptosystems for a future in which quantum computers could threaten today’s encryption. It is a rapidly developing field, and Sweden is among the leaders. 

From the cipher machine presented to Gustav III in the 18th century to quantum-safe algorithms in the 21st, Sweden has consistently been at the forefront of cryptology. At a time when threats to digital communication are becoming increasingly advanced, cryptological capability matters more than ever. With one foot in the EU, one in NATO and a strong academic tradition, Sweden is well placed to continue playing a central role in protecting information, both nationally and internationally.