Henryk Zygalski

Henryk Zygalski

Image of a photograph of Henryk Zygalski, a mathematician and cryptologist, who was part of a Polish team making significant breakthroughs in understanding how Germany's Enigma machine worked.

Zygalski and his colleagues were also able to decode encrypted German-military messages until shortly before Germany invaded Poland, in early September of 1939, starting World War II.

It was Henryk who developed perforated “Zygalski Sheets,” around October of 1938, to aid the Poles’ attempts to decode German military messages sent via the Enigma machine. At the time, Germans were only using three rotors in their machines.

Marian Rejewski, Zygalski’s colleague, describes how the perforated sheets worked:

When the sheets [there were 26 for each of the six possible sequences for inserting the Enigma’s three rotors] were superposed and moved in the proper sequence and the proper manner with respect to each other, in accordance with a strictly defined program, the number of visible apertures gradually decreased.

And, if a sufficient quantity of data was available, there finally remained a single aperture, probably corresponding to the right case, that is, to the solution.

From the position of the aperture one could calculate the order of the rotors, the setting of their rings, and, by comparing the letters of the cipher keys with the letters in the machine, likewise permutation S; in other words, the entire cipher key. (See Marian Rejewski, "The Mathematical Solution of the Enigma Cipher," Appendix E to Wladyslaw Kozaczuk, Enigma, 1984, at page 289.)

Marian Rejewski included an image of a Zygalski sheet in his article "An Application of the Theory of Permutations in Breaking the Enigma Cipher" - published in Applicaciones Mathematicae. 16, No. 4,. Warsaw 1980.Warsaw - during 1980 (the year of his death):

Bletchley Park, now a museum, includes a demonstration of two perforated Zygalski sheets.


Media Credits

Image online, courtesy Wikimedia Commons.


In-text image of Bletchely Park Zygalski-sheet demonstration by Toby Oxborrow; license CC BY-SA 2.0




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"Henryk Zygalski" AwesomeStories.com. Oct 07, 2013. Feb 21, 2020.
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