Diagram of cyclometer, from Marian Rejewski’s papers
The cyclometer was a cryptologic device designed by the Polish Cipher Bureau (BS-4) to help decrypt the German Enigma machine during the 1930s. It was used to catalogue the cycle structure of permutations produced by the Enigma machine at various settings. Such a catalogue could then be used to look up the Enigma setting given the cycle structure for that day. Cipher Bureau building in the Kabaty woods, south of Warsaw. ... Cipher Bureau building in the Kabaty woods, south of Warsaw. ... Marian Rejewski as second lieutenant (signals), Polish Army in Britain, in late 1943 or in 1944. ... Jerzy Różycki, about 1928. ... Henryk Zygalski, about 1930. ... Former civilian cryptanalyst with the General Staff Biuro Szyfrów (Cipher Bureau) German Section (BS4). ... In the history of cryptography, the Enigma was a portable cipher machine used to encrypt and decrypt secret messages. ... Bomba is one of Puerto Ricos most famous musical styles. ... The method of perforated sheets was a codebreaking technique used against the Enigma machine (see Cryptanalysis of the Enigma). ... Cryptography (from Greek kryptós, hidden, and gráphein, to write) is, traditionally, the study of means of converting information from its normal, comprehensible form into an incomprehensible format, rendering it unreadable without secret knowledge — the art of encryption. ... In the history of cryptography, the Enigma was a portable cipher machine used to encrypt and decrypt secret messages. ... In mathematics, especially in abstract algebra and related areas, a permutation is a bijection from a finite set X onto itself. ...
Zygalski sheets: invented in 1938 by Henryk Zygalski and called "perforated sheets" by the Poles, they constituted a device that made possible the reconstitution of the Enigma's entire cipher key.
Conventionally, a lowest-order cyclometer drum, having numerals 0-9 on its edge, is driven by gearing from a meter disk which, in turn, is driven at a speed proportional to the instantaneous power usage.
A common problem with cyclometer registers arises from the numeric ambiguity during the time that a numeric transition is occurring in one or more of drums, and a 0-9 transition in one of the superior drums.
A drum counterweight 36 is disposed within units cyclometer drum 34 at a position placing it at the lower, or six-o'clock position, when the 0 of units cyclometer drum 34 is in the angular position shown.
A cyclometer has a sensor mounted on the support and a trigger mounted on the cylinder such that when the cylinder rotates, the trigger passes near the sensor.
The improvement comprises a cyclometer having a sensor mounted on the support and a trigger mounted on the cylinder such that when the cylinder rotates, the trigger passes near the sensor.
The squirrel cage 11 is provided with a cyclometer 43 which counts the number of rotations of the cylinder 27 of the cage and displays the number on a display 51 of the cyclometer.
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