Enigma-H

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Enigma Model H (1929)

The Enigma-H (also: Enigma H or Enigma Model H ; military name: Enigma II ) is an early model of the Enigma rotor key machine .

history

In the long history of the different Enigma models , the Enigma-H, introduced in 1929, was the sixth model chronologically (see also: family tree of the Enigma under web links ). At the same time, it was the last of the "writing Enigma cipher machines" and is a direct successor of the two earliest Enigma machines, the Model A from 1923 and the Model B from 1924. The Enigma-H was used in the period from 1929 to 1931 in relative terms manufactured in a small number by the cipher machines AG and used by the Reichswehr of the Weimar Republic . It was called Enigma II (pronounced: "Enigma Two") by her, as was later also by the Wehrmacht . Due to its high weight (approx. 50 kg), its bulky dimensions (650 mm × 450 mm × 380 mm) and also because of its high price of 8,000  ℛℳ to 12,000 ℛℳ, it was rarely used and was soon replaced by the much more manageable, lighter one and the cheaper Enigma I (read: "Enigma Eins"), which established itself as the standard machine for military applications.

The keyboard of the Enigma-H has a double assignment of the individual keys, as well as a switch between "digits and characters" and "letters": 

Q   W   E   R   T   Z   U   I   O   P
  A   S   D   F   G   H   J   K   L   Y
X   C   V    Z&Z   W.T.   Bu    B   N   M

The Enigma-H has a cryptographic feature that sets it apart from all other Enigma models, including the later ones. This is the use of eight firmly arranged (not interchangeable) rollers next to each other and a key space of more than 200 billion that can be adjusted by the roller position alone . In comparison, the well-known 17,576 cylinder positions of the Enigma I look ridiculously little. In addition, the Enigma-H did not have a reverse roller , so it did not have its cryptographic weaknesses . If this basic design with eight (instead of just three) rollers had been transferred to the Enigma I and, as there, the position of the rollers had been made interchangeable, this would have 8 with eight rollers! = 40,320 roller positions (instead of just 60 of the Enigma I) and, in combination with the roller positions, result in a cryptographically effective key space of 8,419,907,243,704,320 (more than eight quadrillion or almost 53 bits). Compared to the only good one million (about 20 bit) cryptographically effective possibilities of the actually implemented Enigma I, a significantly more powerful machine would have been created, which, despite the many application and procedural errors on the German side and the gigantic effort on the British side, would probably not have can be broken . The inventor of the Enigma, Arthur Scherbius , had already specified ten reels and the resulting around 100 trillion keys (without reel exchange) in his fundamental patent dated February 23, 1918 , and no reversing roller, but a switch for setting encryption and decryption, as well as an irregular further movement of the rollers that can be adjusted via gear is proposed. The Enigma-H came very close to this claim, in which four of the eight reels (the inner four) are used as the actual encryption reels and with the help of the remaining four reels (the two on the left and right on the outside) are indexed irregularly.

In contrast to the Enigma I, of which tens of thousands were later made, and an estimated 200 still exist, relatively few of the Enigma-H were made and - as far as is known - only a single copy has survived. This has the serial number H-221 and is in the Military History Museum in Budapest .

literature

Web links

Individual evidence

  1. ↑ Louis Kruh, Cipher Deavours: The commercial Enigma - Beginnings of machine cryptography . (PDF; 0.8 MB) In: Cryptologia , Rose-Hulman Institute of Technology, Taylor & Francis, Philadelphia PA 26.2002,1 (January), p. 2. ISSN  0161-1194 accessed March 4, 2016.
  2. ↑ Patent specification Cipher apparatus DRP No. 416 219. (PDF; 0.4 MB) p. 1; accessed March 4, 2016.
  3. ^ Friedrich L. Bauer: Decrypted Secrets, Methods and Maxims of Cryptology . 4th edition. Springer, Berlin 2007, p. 123, ISBN 3-540-24502-2 .
  4. ↑ Craig P. Bauer: Secret History - The Story of Cryptology . CRC Press, Boca Raton 2013, ISBN 978-1-4665-6186-1 , p. 286.
  5. ↑ Louis Kruh, Cipher Deavours: The Commercial Enigma - Beginnings of Machine Cryptography . (PDF; 0.8 MB) In: Cryptologia , Vol. XXVI, No. 1, January 2002, p. 11; accessed March 4, 2016.