Last month, German divers scanning the Baltic seafloor for abandoned fishing nets happened upon a rare piece of history: a strange contraption with keys and a rotor, rusted and covered in algae but relatively intact.
“A colleague swam up and said: [T]here’s a net there with an old typewriter in it,” lead diver Florian Huber tells the DPA news agency.
Similar to a typewriter, the device was indeed used for sending messages—in this case, of a dangerous and clandestine variety. As Agence France-Presse reports, the group’s find is a rare Enigma cipher machine used by Nazi Germany to transmit encrypted military communications during World War II.
The divers found the machine off the coast of northeast Germany in the Bay of Gelting, which is part of the Baltic Sea. On assignment for the World Wildlife Foundation (WWF), the team had been using sonar technology to scan for “ghost nets,” or abandoned fishing nets that pollute the oceans and pose a deadly threat to fish, seabirds and other marine mammals, per a statement.
As Huber notes, the group’s sonar equipment often detects strange objects on the seabed.
“I’ve made many exciting and strange discoveries in the past 20 years,” he tells Reuters. “But I never dreamt that we would one day find one of the legendary Enigma machines.”
When users composed messages on Enigma machines, the devices’ rotors substituted new letters for each stroke in order to encrypt the message. Operators who received the encoded message would need an Enigma of their own, as well as the precise starting positions of the sender’s rotors, to decode the message, according to Stephanie Pappas of Live Science.
The machine discovered by the divers had three rotors, so it likely came from a German warship. U-boats—powerful submarines that wreaked havoc on Allied forces during the first and second world wars—usually carried more complex four-rotor Engima devices, historian Jann Witt of the German Naval Association tells the DPA.
In 1945, as the global conflict drew to a close, the German Navy purposefully sank a number of submarines in the Bay of Gelting to ensure they wouldn’t be handed over to the Allies, Huber explains in the statement. Someone might have thrown this machine overboard around that time to protect military secrets, Witt suggests.
Though Enigma machines did, for a time, allow German forces to secretly communicate troops’ positions and plans of attack with impunity, the Allies eventually cracked their code.
Per BBC News, the Polish Cipher Bureau, including mathematicians Marian Rejewski, Henryk Zygalski and Jerzy Różycki, reconstructed a mock-up of the Enigma machine and made a first attempt at breaking the code in the late 1930s.
The Polish codebreakers’ efforts paved the way for subsequent research ventures, including British mathematician Alan Turing’s Bletchley Park team, which eventually cracked the increasingly sophisticated Enigma encryption. This achievement marked a major intelligence win for the Allies, and some historians estimate that it may have shortened the war by several years. Now recognized as a founder of modern computer science, Turing and his achievements were memorialized in the 2014 film The Imitation Game.
Germany produced about 20,000 Enigma machines during the 1930s and ’40s, but only a handful of these have survived to the present day, making the devices a prized collector’s item. In 2017, a mathematician in Romania sold a well-preserved three-rotor Enigma machine for roughly $51,620. Four-rotor Enigmas, meanwhile, have sold for upward of $400,000 at major auction houses.
Ulf Ickerodt, director of the archaeological office in Germany’s Schleswig-Holstein region, tells the DPA that the newly discovered Enigma machine will undergo cleaning after spending seven decades underwater. The contraption will then go on display at the local archaeology museum. All told, he says, the restoration process will take “about a year.”