The 10 most expensive Enigma machines ever auctioned
The Nazis thought their Enigma encryption machines were uncrackable.
They thought wrong.
When Alan Turing (with considerable help from Polish experts) solved the Enigma code, he shortened WWII by two years.
Today, these rare relics of the second world war are prized collectibles. And values keep soaring.
M4 four-rotor Enigma machine - $463,000
The M4, with four rotors, was used by the German navy – especially on U-boats.
Admiral Doenitz, who later became president of Germany following Hitler's death, ordered the four-rotor variant in 1941. He feared the capture of U-570 in August 1941 had compromised the code of the three-rotor version. And he was right.
The record holder - note the rare presence of four rotors
Four rotor machines are the rarest of the Enigmas. An estimated 120 remain today – 70% were destroyed by U-boat commanders before surrendering.
This example, manufactured in 1943, is fully operational – adding to its value. It's thought to have come from a U-boat base rather than a U-boat itself.
It sold for $463,500 at Bonhams New York on December 7, 2016 - a new record.
There are 50 Enigma machines on display around the world. Just seven are M4s.
M4 four-rotor Enigma machine - $365,000
Another four-rotor example sold for $365,000 at Bonhams in 2015.
“The Enigma machine is an exceptional encryption device, one of the most sophisticated and complicated of its type," explains Bonhams' Tom Lamb.
Late-war three-rotor Enigma machine - $269,000
A rare example of a late WWII Enigma
The German army (Wehrmacht) used this rare late-war example of the three-rotor version.
It sold for $269,000 at Bonhams in 2015.
German electrical engineer Arthur Scherbius patented the machine in 1918. It used interchangeable rotors to scramble messages.
Three-rotor Enigma machine - $230,563
There are roughly 1,200 surviving three-rotor Enigmas.
One wartime example sold for $230,563 at Sotheby's in 2015.
Early three-rotor Enigma machine - $209,000
A rare early example from the 1930s sold for $209,000 at Bonhams.
It's one of the first machines used by the Germans and played a part in the country's development of its military – contravening the terms of the 1919 Treaty of Versailles.
The three-rotor machine is still in working condition.
Film-used three-rotor Enigma machine - $208,137
Enigma collectors prefer machines with their original boxes - but all are rare
A three-rotor machine from 1939, the year the second world war began, sold for $208,137 at Christie's in 2011 – a then world record.
Interest in the piece was heightened by the fact it was used in 2001 film Enigma, a semi-fictionalised account of Turing's team of codebreakers at Bletchley Park.
Three telephone bidders fought to own the item.
Rare K-Model Enigma machine - $190,030
A 1936 example, with the unusual serial number K240, sold for $190,030 in October 2016 at Christie's.
The K stands for the German word Kommerziell – designating them for commercial use. The German railway used many of the K machines, as did the Italian navy during WWII.
Three-rotor Enigma machine - $167,962
The attempt to break the Enigma code was not public knowledge until 1970.
This example sold for $167,962 in 2016.
1943 three-rotor Enigma machine - $135,394
A 1943 example sold for $135,394 at Sotheby's in July 2016.
1941 three-rotor Enigma machine - $135,099
A 1941 three-rotor example sold for $135,099 in 2012 at Bonhams – a then world record.
The machine's particular attraction? Its matching serial numbers. As Bonhams' Laurence Fisher explains.
"Many machines were picked up by the allies as souvenirs during the final stages of the second world war and as such, in later years, tended to be 'mixed and matched', where rotors, outer cases and head blocks were replaced with another machines' parts," he said.
"This one has all elements bearing the same serial number, making this totally complete and original throughout."
Images: Bonhams, Christie's and Sotheby's