View source for Lacida

{{Short description|Polish rotor cipher machine}}
{{For |the genus of moths |Lacida (moth){{!}}''Lacida'' (moth)}}
{{Infobox computer hardware
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| invent-name  = [[Poland]]'s [[Biuro Szyfrów|Cipher Bureau]]
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| introduced   = Before [[World War II]]
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| type         = [[rotor machine|Rotor cipher machine]]
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The '''Lacida''', also called '''LCD''',<ref name="Barczak2010">{{cite book|author=C. L. Barczak|title=A Indecifrável Enigma|url=https://books.google.com/books?id=9804BQAAQBAJ&pg=PA224|date=11 March 2010|publisher=Clube de Autores|pages=224–|id=PKEY:90161545}}</ref> was a Polish [[rotor machine|rotor cipher machine]].  It was designed and produced before [[World War II]] by Poland's [[Biuro Szyfrów|Cipher Bureau]] for prospective wartime use by Polish military higher commands. Lacida was also known as Crypto Machine during a TNMOC Virtual Talk.<ref>{{cite web |last1=McCarthy |first1=Jerry |title=Virtual Talk LACIDA - A Polish Cryptomachine |url=https://www.youtube.com/watch?v=vQ5jQ7VKPPQ |website=www.youtube.com |access-date=Dec 24, 2020}}</ref>

==History==
The machine's name derived from the [[surname]] initials of [[Gwido Langer|Gwido '''''La'''''nger]], [[Maksymilian Ciężki|Maksymilian '''''Ci'''''ężki]] and [[Ludomir Danilewicz|Ludomir '''''Da'''''nilewicz]] and / or his younger brother, [[Leonard Danilewicz|Leonard '''''Da'''''nilewicz]].<ref>[[Władysław Kozaczuk]], ''Enigma'' (1984), p. 134.</ref>  It was built in [[Warsaw]], to the Cipher Bureau's specifications, by the [[AVA Radio Company]].<ref>[[Władysław Kozaczuk]], ''Enigma'' (1984), p. 212.</ref>

In anticipation of war, before the September 1939 [[invasion of Poland (1939)|invasion of Poland]], two LCDs were sent to [[France]]. From spring 1941, an LCD was used by the Polish ''Team Z'' at the Polish-, Spanish- and French-manned [[Cadix]] radio-intelligence and decryption center at [[Uzès]], near France's Mediterranean coast.<ref>[[Władysław Kozaczuk]], ''Enigma'' (1984), p. 119.</ref>

Prior to the machine's production, it had never been subjected to rigorous decryption attempts. Now it was decided to remedy this oversight.  In early July 1941, Polish [[cryptologist]]s [[Marian Rejewski]] and [[Henryk Zygalski]] received LCD-enciphered messages that had earlier been transmitted to the staff of the Polish Commander-in-Chief, based in London.  Breaking the first message, given to the two cryptologists on July 3, took them only a couple of hours.  Further tests yielded similar results.<ref>[[Władysław Kozaczuk]], ''Enigma'' (1984), pp. 134–35.</ref>  Colonel [[Gwido Langer|Langer]] suspended the use of LCD at Cadix.

In 1974, Rejewski explained that the LCD had two serious flaws.  It lacked a [[commutator]] ("plugboard"), which was one of the strong points of the German military [[Enigma machine]].  The LCD's other weakness involved the [[Reflector (cipher machine)|reflector]] and wiring.  These shortcomings did not imply that the LCD, somewhat larger than the Enigma and more complicated (e.g., it had a switch for resetting to deciphering), was easy to solve.  Indeed, the likelihood of its being broken by the German ''E-Dienst'' was judged slight. Theoretically it did exist, however.<ref>[[Władysław Kozaczuk]], ''Enigma'' (1984), p. 135.</ref>

==See also==
{{Cipher Bureau}}
* ''[[Biuro Szyfrów]]'' (Cipher Bureau)

==References==
{{reflist}}

==Further reading==
*[[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}}.
* K. Gaj, "Polish Cipher Machine - Lacida," ''Cryptologia'', 16 (1), January 1992, pp.&nbsp;73&ndash;80.

{{Cryptography navbox | machines}}

[[Category:Rotor machines]]
[[Category:Cipher Bureau (Poland)]]
[[Category:Cryptographic hardware]]
[[Category:Polish inventions]]
[[Category:Science and technology in Poland]]