Seeing Through the Enigma with Computed Tomography

Recently several German media outlets published the information about seven ENIGMA cipher machines from the Second World War which were accidentally found by divers in the Baltic Sea. In a newly founded cooperation between the Archaeological Office of Schleswig-Holstein and Fraunhofer IMTE, the machines are analyzed, digitally archived and prepared for their later restoration by the use of computed tomography, and will eventually be exhibited at the Foundation Schleswig-Holstein State Museums Schloss Gottorf.

Fraunhofer IMTE recently invested in a YXLON FF35 CT system. According to the YXLON website their application laboratory was significantly involved in the project.

The ENIGMA was used in the Second World War to encrypt the Wehrmacht’s (Unified Armed Forces of Nazi Germany) communications. The fact that several specimens are now being examined in detail bridges the gap with computer science. Alan Turing and his team were one of the founding fathers of computer science and the leading head of the British ‘code breakers’ in Bletchley Park which were able to decipher the ENIGMA codes.

At the end of the Second World War, as defeat was imminent, these devices were immediately rendered unusable and the Navy simply threw them overboard. However, the state of preservation of the devices found in the Baltic Sea is still unclear, because over the decades the silt of the Baltic Sea has compacted filling every cavity in the device. Together with the salt water this provided a generally favorable environment for their preservation. The challenge now lies in their non-destructive restoration and exploration. Modern computer tomography can provide a three-dimensional representation of the ENIGMA interior, which enables archaeological restorers to navigate through the layers of silt.

“We took 4000 individual X-ray images of the Enigma from different directions and then algorithmically reconstructed them into a 3D image,” says director Thorsten Buzug – Director of Fraunhofer IMTE.