Biuro Szyfrów

("Cipher Bureau")

Methods and technology

"ANX" · Enigma "doubles" · Grill Clock · Cyclometer · Card catalog Cryptologic bomb Zygalski sheets · Lacida

Locations

Saxon Palace · Kabaty Woods PC Bruno · Cadix

Personnel

Chief Gwido Langer Deputy Chief Chief of Radio Intelligence Chief of German Section Maksymilian Ciężki German Section cryptologists Marian Rejewski · Jerzy Różycki Henryk Zygalski · Antoni Palluth Wiktor Michałowski Chief of Russian Section Jan Graliński Russian Section cryptologist Piotr Smoleński Others Jan Kowalewski Stanisław Leśniewski Stefan Mazurkiewicz Franciszek Pokorny Wacław Sierpiński

v • d • e

The Enigma cipher machine

Enigma machine Enigma rotors Breaking Enigma Polish Cipher Bureau Doubles Grill Clock Cyclometer Card catalog Bomba Sheets Bletchley Park Banburismus Herivel tip Bombe Hut 6 Hut 8 PC Bruno Cadix Ultra

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The grill (Polish: ruszt), in cryptology, was a method used chiefly early on, before the advent of the cyclometer, by the mathematician-cryptologists of the Polish Cipher Bureau in decrypting German Enigma-machine ciphers.^[1]

[edit] Method

The grill method is described by Marian Rejewski as being "manual and tedious"^[1] and, like the later cryptologic bomb, as being "based... on the fact that the plug connections [in the Enigma's commutator, or "plugboard"] did not change all the letters." Unlike the bomb, however, "the grill method required unchanged pairs of letters [rather than] only unchanged letters."^[2]

The grill method found application as late as December 1938 in working out the wiring in two Enigma rotors newly introduced by the Germans. (This was made possible by the fact that a Sicherheitsdienst net, while it had introduced the new drums IV and V, continued using the old system for enciphering the individual message keys.)^[3]

[edit] Notes

[edit] References

• Władysław Kozaczuk, Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two, edited and translated by Christopher Kasparek, Frederick, MD, University Publications of America, 1984, ISBN 0-89093-547-5.
• Marian Rejewski, "Summary of Our Methods for Reconstructing ENIGMA and Reconstructing Daily Keys, and of German Efforts to Frustrate Those Methods," Appendix C to Władysław Kozaczuk, Enigma, 1984, pp. 241–45.
• Marian Rejewski, "How the Polish Mathematicians Broke Enigma," Appendix D to Władysław Kozaczuk, Enigma, 1984, pp. 246–71.
• Marian Rejewski, "The Mathematical Solution of the Enigma Cipher," Appendix E to Władysław Kozaczuk, Enigma, 1984, pp. 272–91.