Enigma patents

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Enigma brand sign
Arthur Scherbius (1878–1929) received his first patent for the Enigma on February 23, 1918 (photo 1913).

As Enigma patents are the patents referred to in connection with the during the First World War invented rotor key machine Enigma are made in the period from 1918 to about 1930th After the first and at the same time fundamental invention disclosure by the German Arthur Scherbius  (picture) with the title "Encryption apparatus", for which the patent was granted under the number DE 416 219 from February 23, 1918, many more registrations from domestic and foreign inventors followed, their ideas more or less strongly in the different Enigma modelsflowed in. In addition to the German Empire, patents were also granted in the Netherlands, the United Kingdom, France, Switzerland and the United States. After the Enigma was used on a trial basis from 1926, initially by the Reichsmarine and two years later by the German army, it then disappeared from the civilian market. Due to their important military importance for encrypting the secret communications of the Reichswehr and later the Wehrmacht , no further open patent applications were made after 1930. However, it can be assumed that there are a number of secret patents with which the list of Enigma patents given below under web links could be completed.

DE 416 219 “Encryption apparatus” dated February 23, 1918

The Wehrmacht's Enigma I still contained three rotating rollers in 1945, as Scherbius had described in his first Enigma patent in 1918.

Even during the First World War, the inventor Arthur Scherbius describes in his fundamental patent several essential elements of a “cipher device”, which a quarter of a century later was to play such an important role as the “Enigma key machine” in World War II . His first patent claim describes movable "intermediate cable carriers" (also called "intermediate cable carriers"), characterized in that they can be "moved past" fixed contact points. As a special embodiment it is explained that the intermediate line carriers can have the “shape of a cylinder (roller)”. The embodiment of movable rotors provided with electrical contacts, proposed here in 1918, can be found practically unchanged in the Enigma machines that were used up to 1945 and in some cases were used up until the 1970s.

The second claim is about the fact that the further rotation of the rollers “takes place irregularly according to size, direction and chronological sequence”. As an exemplary embodiment, Scherbius proposes a transmission for this purpose , with the aid of which the individual rollers can be indexed differently. In the descriptive text of his patent, the inventor suggests: "In order to increase the number of keys , several intermediate cable carriers are expediently connected in series". He illustrates his idea with the help of three rotating rollers, as used by the Wehrmacht on their Enigma I in 1945. In addition, Arthur Scherbius even mentions ten reels in this fundamental patent and the 100 trillion keys resulting from them (even without exchanging the reels).

However, these two cryptographically strong design features (use of "many" rollers and irregular further rotation) never found their way into the actually implemented Enigma. These were content with three or at most four rollers and used regular roller increments without a gearbox. The founding president of the Federal Office for Information Security (BSI), the mathematician and cryptologist Otto Leiberich, commented on this cryptographic error and said that with four cylinders “and with a non-uniform drive, the Enigma would never have been deciphered” .

On the other hand, another cryptographically rather weak sub-claim was implemented, namely that “each rear link carrier always moves forward by one contact point when the present link carrier has made a full turn”.

In the penultimate subclaim, Scherbius provided a switch to switch between encryption and decryption. This solution remained with the first Enigma models (Enigma A and Enigma B) until the reverse roller (VHF) was invented in 1926 (see below), which made the switch unnecessary, and that, starting with the Enigma C , was the case with all later ones Models was used.

The last sub-claim already mentions the use of "incandescent lamps" for display and thus anticipates the embodiment used later. After the “writing Enigma cipher machine” (models A, B and H), which, like a typewriter, put the text on paper with the help of type levers, the more modern, significantly lighter and more compact “incandescent lamp machines ” (models C, D , G, K, M1, M2, M3, M4, T, Z and Enigma I) a lamp field to display the letters.

US 1,657,411 “Ciphering Machine” dated February 6, 1923

Drawing from patent US1657411 : Ciphering Machine. Registered on February 6, 1923 , inventor: Arthur Scherbius. ‌

DE 452 194 “Electrical device for encryption and decryption” of March 21, 1926

The reverse roller only has contacts on one side and is what causes the Enigma's main cryptographic weakness.

Willi Korn invented the reverse roller in 1926, thereby making the key process involutorial . This means that if a U is encoded into an X in a certain position of the rollers, then an X is encoded into a U in this position. He simplified the operation and construction of the machine, because you no longer have to differentiate between encryption and decryption. In addition, he hoped for an increase in safety, because the current now flows through the rollers twice. “This decline in the current through the cipher roller set causes further scrambling. As a result of this arrangement, it is possible to get by with relatively few encryption rollers and still maintain a high level of encryption security, ” Korn explains the advantages of his reversing roller in the patent specification. However, this was a fallacy with far-reaching consequences.

Web links

Overview

NV "Securitas" in Amsterdam

Securitas union in Berlin

Encryption machines Akt.-Ges. in Berlin

Patents abroad

Individual evidence

  1. ↑ Louis Kruh, Cipher Deavours: The Commercial Enigma - Beginnings of Machine Cryptography . Cryptologia, Vol. XXVI, No. 1, January 2002, p. 11. Accessed: April 29, 2015. PDF; 0.8 MB
  2. ↑ a b Patent Specification Encryption Apparatus DRP No. 416 219. Accessed: Feb. 3, 2014. PDF; 0.4 MB
  3. ↑ Cipher A. Deavours, Louis Kruh: Machine Cryptography and Cryptanalysis Modern . Artech House, 1985, p. 40. ISBN 0-890-06161-0
  4. ↑ Otto Leiberich: From the diplomatic code to the trapdoor function. Spectrum of Science , Dossier Cryptography, 4/2001, p. 15.
  5. ^ Patent specification Ciphering Machine US No. 1,657,411 . Accessed: Feb. 3, 2014. PDF; 1.3 MB
  6. ^ Patent specification Electrical device for ciphering and deciphering DRP No. 452 194. Accessed: Feb. 3, 2014. PDF; 0.5 MB