CALENDAR UNTIL 1939
1918
Arthur Scherbius patents the Enigma encryption machine.
1926
Enigma is used in the German Navy.
1928
Enigma is used in German land troops.
1929
January
a cryptographic course starts at the University of Poznan, among its participants are Marian Rejewski, Jerzy Różycki and Henryk Zygalski.
1929
summer
after the cryptographic course ends, Jerzy Różycki and Henryk Zygalski start working in a branch of the Cipher Bureau in Poznan.
1930
summer
after returning from Göttingen in 1930, Marian Rejewski also starts working at the Cipher Bureau.
1932
September
the team of the Poznań branch of the Cipher Office is transferred to Warsaw.
1932
October
Maksymilian Ciężki entrusts the attack on the Enigma codes to Marian Rejewski.
1932
December
Marian Rejewski reconstructs the machine and breaks the first messages encrypted with Enigma.
1933
the AVA company builds a dozen copies of Enigma, the Enigma message decryption starts full steam.
1935
the Polish team builds a cyclometer – the first electromechanical device that supports decryption.
1938
autumn
Germany introduces several new changes in the way Enigma is used and adds two new rotors.
1938
November
Marian Rejewski responds to the new challenge by constructing a “bomb”. At the same time, Henryk Zygalski designs the sheet method.
1939
January
English-French-Polish cryptographic conference in Paris. Poles defined by a British participant as “fools and ignorant”.
1939
July
second trilateral conference in Warsaw; Poles reveal to the future Allies their success in attacking the Enigma codes and provide complete knowledge of the methods used.
1939
August
under the influence of news from Poland, the UK launches the recruitment process of mathematicians and an expansion of the cryptographic centre in Bletchley Park.
1939
September
war breaks out, evacuation of the Cipher Bureau through Romania to France.
CALENDAR FROM 1939 TO 1942
1939
October
as a result of political disputes, the team of cryptologists is subordinated to the French.
1939
autumn
the troubles of the British with the use of knowledge transferred by the Poles, the French refuse to send the Poles to help break the deadlock.
1940
January
Alan Turing brings to France the Zygalski sheets, made in the UK based on Polish instructions. On 15 January, Poles break the first Enigma message during the World War II.
1940
April
Polish and British teams effectively break Enigma codes during the Norwegian campaign.
1940
May
Germany changes the use of the Enigma before the attacks on Benelux and France – allied cryptologists temporarily blinded.
1940
June
evacuation of the Polish team to the south of France and further to North Africa. In the United Kingdom, John Herivel breaks the decryption crisis.
1940
August
On the eve of the Battle of Britain, Bletchley Park receives the first copy of the Turing bomb, a development of the Rejewski bomb.
1940
September
decryptions of messages of the communications network of the Luftwaffe support the British in the crucial phase of the Battle of Britain.
1940
October
the French decide to transfer the Polish cryptologists to an unoccupied part of France and to organise a semi-conspiratorial cryptographic centre near the town of Uzes.
1941
spring
The British begin breaking the codes of German troops fighting in North Africa.
1941
April
thanks to documents obtained on board of a German ship near the coastline of Norway, the British break the code of the Enigma Kriegsmarine for the first time.
1941
May
the British domination over the Kriegsmarine codes strengthened by the documents found onboard the captured U-110 submarine.
1942
January
Jerzy Różycki and two other members of the Polish team die in a sea catastrophe in the Mediterranean Sea.
1942
February
German submarine fleet launches a 4-rotor model of Enigma. The British lose the ability to break its codes; increasing losses of the Allies in the Battle of the Atlantic.
1942
November
in connection with the Allied invasion of North Africa, Germany occupies southern France. The Polish centre is abruptly liquidated and its staff awaits the possibility of evacuation from the occupied territory.
1942
December
the gain onboard of the submarine allows to break the deadlock in the decryption of the 4-rotor Enigma.
CALENDAR FROM 1943
1943
February and March
Members of the Polish team try to cross the green border with Spain. A part of the team succeeds, but the group's commander, Lieutenant Colonel Langer and his deputy, Major Ciężki, fall into German hands as a result of betrayal of the French
1943
summer
Marian Rejewski and Henryk Zygalski, after their imprisoning in Spain, through Portugal and Gibraltar, enter the United Kingdom. They are not allowed to work in the centre, whose beginning were their own successes in attacking the Enigma code – until the end of the war they attack less significant German codes, especially hand-made Waffen SS codes.
1943
summer
bombs designed in the United States enter into use, many times faster than the British. Thanks to their use, most of the Enigma codes, including the 4-rotor model, are broken quickly and efficiently.
1944
spring
Langer and Ciężki stay in the prison camp at Eisenberg castle in the present-day Czech Republic. Unexpectedly, a board of the German radio intelligent service appearsin, trying to determine the scale of the former Polish success in the struggle with Enigma. Polish officers mislead them, saving the Enigma's decryption for the Allies.
1944
summer
Germans begin to suspect the possibility of Enigma codes being broken and introduce new devices complicating its decryption, among others the “Uhr” and a variable-headlight (UKD). The experience and technical superiority of the Allies allow them to overcome new challenges; Enigma decryptions contribute to the success of landings in Normandy and the victories in battles in France.
1945
May
Langer and Ciężki barely avoid liberation from the camp by the Soviet Army. Liberated by Americans, they go to London, where they will have a cold reception.
1945
Right after the end of World War II, the decryption of the Enigma, one of the greatest mysteries of the war, is transforming itself into one of the greatest secrets of the Cold War. The mathematical grounds of the attack on the codes of rotor machines elaborated by the Polish, are up-to-date and must remain a mystery.
1946
demobilised Marian Rejewski returns to the country, where he has to lay to rest all his ambition to secure himself and his family. Henryk Zygalski stays in the UK, which does not recognise his Polish university diploma. To be able to teach mathematics in British schools, he must repeat his studies.
1956
in the United States one of the bombs of World War II performs its last course; it was so far used to break Enigma encrypted messages from the East German police.
1967
Marian Rejewski after his retirement writes memories from his pre-war work and deposits them in the Military Historical Institute. The single-sentence mention of Enigma breaking in the book of a Polish historian is accepted with extreme disbelief.
1968
a number of British historians include in their work allusions to breaking Enigma and the role of Poles in this achievement. Due to the secret, their publications go unnoticed.
1973
retired French General Bertrand publishes memoirs in which he reveals both the fact of breaking Enigma and the role of the Polish.
1974
and later
and later – British authors in response to Bertrand's book publish a series of works containing a distorted image of the history of Enigma code breaking.
1982
and later
the process of gradual disclosure of US and British archives for Enigma begins. Work presenting a balanced picture of its history begin to appear, beginning with Gordon Welchman's book The Hut Six Story.
