Divers scouring the depths of the Baltic Sea, the arm of the North Atlantic Ocean between the Scandinavian peninsula and the countries of mainland northern and central Europe, have discovered an ‘Enigma’ encryption machine that was used by Nazi Germany to encode secret messages during World War II.
The divers made the discovery while searching the seabed using a sonar device for abandoned fishing nets that can be harmful for sea life.
Rusty and covered with barnacle, the machine is now in the restoration workshop of the Museum of Archaeology in Gottorf Castle in Schleswig, Germany. What is this cipher machine, and what role did it play in the War? What is its value now?
Significance of Enigma
The Enigma machine was invented by the German engineer Arthur Scherbius towards the end of World War I. While several different Enigma models were produced, the German military models that had a plugboard are believed to have been the most complex.
During World War II, the military of Nazi Germany used the encryption machine to transmit messages in code. The machine allowed for billions of ways to encode a message, and the Allied militaries and intelligence services found it extremely challenging to break the code of intercepted messages.
How did the machines work?
The plugboard was similar to a telephone switchboard, with wires with two ends that could be plugged into a slot. Each letter from the plaintext would be substituted for another at regular intervals to create a ciphertext, which was decrypted by the receiver who was aware of the pairings.
Every time a letter was pressed, the movable parts of the machine would change position, so that the next time the same letter was pressed, it would be enciphered as something different.
Different parts of the machine could be set up in different ways to allow for different combinations and enciphered letters. With a plugboard, some of the army versions swapped letters twice over. 📣 Follow Express Explained on Telegram
Unless the exact settings of the machine were known, it was near impossible to decipher the messages.
How was the Enigma cipher ultimately cracked?
By 1932, Polish cryptanalysts were able to decode German ciphers that had been written with an earlier version of Enigma. The Poles shared the information with the French and British intelligence services before World War II. The Germans were subsequently able to produce more sophisticated machines, which made it difficult to crack the code.
The Poles also built electro-mechanical machines to search for solutions by simulating the workings of an Enigma machine. These calculated the numerous possibilities through different settings.
The findings of the Polish mathematicians helped the English mathematician Alan Turing to develop his ‘bombe’ machine that made the use of “cribs”, using assumed or known parts of the message as a starting point, to break Enigma-encrypted machines.
What value does an Enigma machine have today?
Towards the end of World War II, as defeat seemed imminent, the Nazis began to destroy their Enigma machines to prevent them from falling into the hands of the victorious Allied powers. Once the war ended, then British Prime Minister Winston Churchill ordered that the surviving Enigmas should also be destroyed.
Not more than a couple of hundred Enigmas exist today. Their value is historical, and they are cherished by collectors.
In December 2019 auction house Sotheby’s sold an Enigma M4 for a record price of $800,000. Another was sold this year by Christie’s for $440,000.
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