The Lacida, also called LCD, was a Polish rotor cipher machine. It was designed and produced before

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

by Poland's Cipher Bureau for prospective wartime use by Polish military higher commands. Lacida was also known as Crypto Machine during a TNMOC Virtual Talk.

History

The machine's name derived from the

surname In many societies, a surname, family name, or last name is the mostly hereditary portion of one's personal name that indicates one's family. It is typically combined with a given name to form the full name of a person, although several give ...

initials of Gwido ''La''nger, Maksymilian ''Ci''ężki and Ludomir ''Da''nilewicz and / or his younger brother, Leonard ''Da''nilewicz. It was built in

Warsaw Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...

, to the Cipher Bureau's specifications, by the

AVA Radio Company The AVA Radio Company (Polish: ''Wytwórnia Radiotechniczna AVA'') was a Polish electronics firm founded in 1929 in Warsaw, Poland. AVA designed and built radio equipment for the Polish General Staff's Cipher Bureau, which was responsible for ...

. In anticipation of war, before the September 1939

invasion of Poland The invasion of Poland, also known as the September Campaign, Polish Campaign, and Polish Defensive War of 1939 (1 September – 6 October 1939), was a joint attack on the Second Polish Republic, Republic of Poland by Nazi Germany, the Slovak R ...

, two LCDs were sent to

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. From spring 1941, an LCD was used by the Polish ''Team Z'' at the Polish-, Spanish- and French-manned

Cadix ''Cadix'' was a World War II clandestine intelligence center at Uzès, in southern France, from September 1940 to 9 November 1942. During this period southern France was under the control of Vichy France and not occupied by Nazi Germany. At ''C ...

radio-intelligence and decryption center at

Uzès Uzès (; ) is a commune in the Gard department in the Occitanie region of Southern France. Uzès lies about north-northeast of Nîmes, west of Avignon, and southeast of Alès. History Originally ''Ucetia'' or ''Eutica'' in Latin, Uzès wa ...

, near France's Mediterranean coast. 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 This is a list of cryptographers. Cryptography is the practice and study of techniques for secure communication in the presence of third parties called adversaries. Pre twentieth century * Al-Khalil ibn Ahmad al-Farahidi: wrote a (now lost) book ...

Marian Rejewski Marian Adam Rejewski (; 16 August 1905 – 13 February 1980) was a Polish people, Polish mathematician and Cryptography, cryptologist who in late 1932 reconstructed the sight-unseen German military Enigma machine, Enigma cipher machine, aided ...

and

Henryk Zygalski Henryk Zygalski (; 15 July 1908 – 30 August 1978) was a Polish mathematician and cryptologist who worked at breaking German Enigma-machine ciphers before and during World War II. Life Zygalski was born on 15 July 1908 in Posen, German Empi ...

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. Colonel Langer suspended the use of LCD at Cadix. In 1974, Rejewski explained that the LCD had two serious flaws. It lacked a

commutator In mathematics, the commutator gives an indication of the extent to which a certain binary operation fails to be commutative. There are different definitions used in group theory and ring theory. Group theory The commutator of two elements, ...

("plugboard"), which was one of the strong points of the German military

Enigma machine The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication. It was employed extensively by Nazi Germany during World War II, in all branches of the W ...

. The LCD's other weakness involved the

reflector Reflector may refer to: Science * Reflector, a device that causes reflection (for example, a mirror or a retroreflector) * Reflector (photography), used to control lighting contrast * Reflecting telescope * Reflector (antenna), the part of an ant ...

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.

Władysław Kozaczuk Władysław Kozaczuk (23 December 1923 – 26 September 2003) was a Polish Army colonel and a military and intelligence historian. Life Born in the village of Babiki near Sokółka, Kozaczuk joined the army in 1944, during World War II, at B ...

, ''Enigma'' (1984), p. 135.

History

See also

References

Further reading