National Defence Radio Establishment (Sweden) - History

History

Signals Intelligence has existed in Sweden since 1905 when Swedish General Staff and Naval Staff respectively, had departments for signals intelligence and cryptanalysis. These departments succeeded, for instance, to decode the Russian Baltic Sea Fleet cipher. After World War I, this ability mostly ceased as politicians did not see its value and did not grant funding. The Swedish Navy still continued in a smaller scale and developed the competence further. One of the first major successes was in 1933 when the cipher of the Russian OGPU (predecessor to KGB) was solved.

In 1937, the Swedish Defence Staff was established and the Crypto Department, with its Crypto Detail IV, was responsible for cryptanalysis. In 1940, when Germany occupied Denmark and Norway, the German Wehrmacht requested to use the Swedish telephone network for its communication. This was accepted and Crypto Detail IV immediately started to intercept. The traffic was almost always encrypted by the German state-of-the-art cipher machine Geheimfernschreiber. This device was believed to produce indecipherable messages, with its 893,622,318,929,520,960 different crypto key settings. After two weeks of single hand work, the Swedish professor of mathematics Arne Beurling decoded the cipher of the G-schreiber with only use of pencil and paper. This achievement was described by David Kahn, in his book The Codebreakers: "Quite possibly the finest feat of cryptanalysis performed during the Second World war was Arne Beurling's solution of the secret of the G-schreiber." During World War II, some 296,000 German messages were intercepted and in 1942 the Swedish Government took the decision to establish Försvarets Radioanstalt.

The first stationary collection site was located in the middle of Stockholm, but in 1940 it was moved to a number of villas in the suburban island of Lidingö. More sites were established in Sweden and in 1943, FRA moved its headquarters to Lovön, some 15 km from Stockholm. In the 1960s, even the location of the FRA headquarters was still highly secret.