Inner secrets
of Enigma
Unique images from inside an Enigma machine have revealed
new insights about its complex mode of functioning
Scientists working at the University
of Manchester have shone new
light on the Enigma machine
used by the German military in
World War Two, which was fi nally cracked
by Alan Turing and his team of code
breakers at Bletchley Park.
The breakthrough into how the mighty
Enigma machines operated was made
possible by X-ray Computed Tomography
(CT) technology, courtesy of the Henry
Royce Institute for Advanced Materials
at The University of Manchester. 3D
reconstruction of a 1941 model used
in German Army communications has
revealed the engineering of the machine,
including its encryption rotors and wiring.
Employing X-ray CT, key features inside
the Enigma’s metal casing were tracked
down and exposed, including the wiring
and structure of the rotors that encrypted
messages, which were then sent using
the machine.
The CT technology, part of the
Henry Royce Institute for Advanced
Materials, works by collecting a series
of X-ray radiographs, which are then
reconstructed into a virtual 3D replica.
Professor Philip Withers, chief scientist
at the Henry Royce Institute and Regius
Professor of Materials at the University
of Manchester, comments: “Normally,
Royce facilities are probing new materials
to solve engineering problems in industry,
but, when we were approached, we were
keen to help. Gaining a fi rst look inside
the Enigma machine required us to take
over 1,500 separate X-ray radiographs.
It is exciting and appropriate to be able
to unlock some of the secrets of such an
iconic machine here at Manchester.”
The 1941 German army Enigma
machine was loaned to the university
by Bletchley Park and its owner,
cryptography enthusiast David Cripps.
It is the latest Enigma machine to be
verifi ed and one of only 274 registered.
Made in Berlin in 1941, the machine is
believed to have been supplied to the
Austrian Federal Ministry of the Interior
in Vienna.
As Cripps explains: “One thing we’ve
been able to do is actually look inside the
rotors and see the individual wires and
pins which connect the 26 letters
on each of the three rotors, enabling
a message to be encrypted. This is the
fi rst time anyone has been able to look
X-RAY CT TECHNOLOGY
inside the Enigma
with this level of detail, using a
technique that does not damage the
machine.”
The Enigma was held in the highest
regard by those who sought to lay bare
its secret workings all those years ago.
However, the sheer brute force power of
today’s neural networks has changed the
rules of the game, with passwords now
capable of being cracked in a relatively
short period of time. This was soberly
illustrated by a recent demonstration
held at the Imperial War Museum where
a neural network managed to crack the
Enigma Code in around 12 minutes.
Using DigitalOcean’s cloud servers
and artifi cial intelligence software
from Enigma Pattern, a short German
message was decoded at the IWM.
The software had been trained to learn
German through Grimm’s Fairy Tales and
was tested on an Enigma machine that
had 15,354,393,600 password variants.
The University of Manchester has
published videos of the Enigma X-ray CT
reconstruction, including the following at:
https://bit.ly/2qSyDM3.
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