Click for homepage
← Crypto
Pin-wheel →
Rotor machines
Rotor-based cipher machines

Below is an overview of electromechanical cipher machines in which the alphabet is transposed multiple times, by means of electric current, 1 flowing through moving rotors or cipher wheels 2 with scrambled wiring, resulting in a poly-alphabet substitution cipher. The wheels are commonly moved on each key-press. This process is known as wheel stepping. After each step, the wiring behaves differently. Some machines exhibit regular stepping, whilst others have a more complex wheel stepping pattern – also known as irregular stepping – which makes them less predictable.

  1. Although most machines use electric current, other means are also possible, such as liquids and air.
  2. Rotors is a typical American expression. In UK-English, rotors are commonly known as wheels.

Electromechanical rotor machines on this website
Enigma cipher machines
SIGABA cipher machines
British wheel-based TYPEX cipher machines
Combined Cipher machine
Siemens T-52 Geheimschreiber
Lorenz SZ-40/42 cipher machine
Swiss NEMA (replacement for Enigma K)
Fialka M-125 cipher machines
KL-7 rotor-based cipher machine (USA)
Hagelin HX-63 rotor-based cipher machine
OMI-Nistri (Italia)
Online TTY cipher machine KW-9
British electromechanical cipher machine (hybrid between Hagelin M-209 and Enigma G)
BID/60 British electromechanical wheel-based cipher machine, similar to the US KL-7
B-21, Hagelin's first cipher machine
B-211, the successor to the B-21
Russian copy of the Hagelin B-221
M-130 (Koralle) meteorologic cipher machine
T-204 (Wolna) telegraphy encryptor
T-205 (Wecha) telegraphy encryptor
Telekrypto-Gerät 35, developed by Edgar Gretener (Gratag) and Boris Hagelin.
One of the first electro-mechanical cipher machines build by Gretener
Gretag KFF-58 with TC-58 cipher attachment
Cipher machine that uses air instead of electric current
Traditionally, the smaller mechanical cipher machines from Hagelin (Crypto AG) do not belong to this class of machines, despite the fact that they contain moving rotors. Instead, they are a class of their own, which is known as the pin-and-lug cipher machines, or pinwheel machines.

Invention of the rotor machine
The concept of the rotor-based cipher machine was invented independently by several people, more or less at the same time, in different parts of the world. Traditionally, the invention has been attributed to these four men: Edward Hebern (USA, 1917), Arvid Damm (Sweden, 1919), Hugo Koch (Netherlands, 1919) and Arthur Scherbius (Germany, 1918).

In 2003 however, it emerged that the rotor machine was actually invented in 1915 by two Dutch naval officers: Theo van Hengel and R.P.C. Spengler. In his article The Dutch Invention of the Rotor Machine, author Karl de Leeuw explains when the machine was developed and how the design might have ended up in the hands of Hugo Koch, who patented it in 1919 [2][3].

  1. Wikipedia, Rotor machine
    Retrieved January 2014.

  2. Karl de Leeuw, The Dutch invention of the Rotor Machine, 1915-1923
    Cryptologia, January 2003, Volume XXVII, Number 1, pp. 73-94. Author's copy.

  3. Dutch Patent NL10700
    7 October 1919. Transferred to Securitas on 5 May 1922. 1
Further information
Any links shown in red are currently unavailable. If you like the information on this website, why not make a donation?
© Crypto Museum. Created: Wednesday 21 February 2018. Last changed: Tuesday, 11 June 2024 - 15:58 CET.
Click for homepage