An M4 Enigma from World War II has set a new world record price at a Christie’s auction in New York.

I remember a time, about 15 years ago, when an original WW2 Enigma cost about $25,000. As it seems, I made a big mistake when I didn’t buy one. Since then, Enigma prices have virtually exploded:

In June this year a new record was set – an M4 Enigma from World War II was sold at $547,500 at a Christie’s auction in New York (thanks to David Allen Wilson for posting this link in the Cryptograms & Classical Ciphers Facebook group).


According to Bletchley Park experts, a total of almost 30,000 Enigmas were built during WW2 and in the years before. Other sources mention much higher numbers (up to 150,000), but these seem to be wrong. About 1,000 Enigmas still exist.

There are at least 60 different Enigma types in existence. The M4 is also referred to as U-boat Enigma, as it was used exclusively for encrypting radio traffic between German submarines and the German naval radio stations.

1,600 copies of the M4 Enigma were built, about 120 are still known to exist. This makes the M4 a special, but not really a rare Enigma type. Nevertheless, the M4 currently seems to be the most expensive Enigma. This has probably two reasons: first, the M4 had four rotors instead of three; and second, it played an important role in WW2.

The Enigma M4 was developed in 1941 after German admiral Karl Doenitz rightly suspected that the previous three rotor machine was compromised by Allied codebreakers. In fact, the fourth rotor made the Enigma considerably more secure, which put the British codebreakers in Bletchley Park in serious trouble.

To my knowlege, the M4 is the only Enigma with four rotors. Except for a few very early experimental models, which featured up to eight rotors, all other Enigmas had three rotors. It is important to note that a few Enigma variants (e.g. the Commercial Enigma) had a movable reflector, which is not distinguishable from a fourth rotor, unless one opens the upper cover of the machine.


The high prices that are currently paid for Enigmas indicate that there is a considderable interest in this fascinating machine. More and more museums want to have a copy. Today, even well-made Enigma rebuilds sell at $40,000.

For me, the Enigma is the reason that I became interested in crypto history. When I heard my first cryptology lecture series at the University of Karlsruhe in 1996, I learned that there was an encryption machine named “Enigma” that had played a role in WW2. My first crypto history publication (in the Internet Magazin) was about the Enigma. I knew about the Enigma years before I learned about the Voynich manuscript, the Zodiac Killer and the Debosnys murders. I hope, others who find the Enigma interesting will get involved in crypto history in general, too.

Further reading: How the Enigma evolved from complex to simple

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Kommentare (1)

  1. #1 Rallinger
    12. Juli 2017

    >Bought for 100€ at a flea market, WWII Enigma machine sells for 45,000€<