In the history of cryptography, the Biuro Szyfrów was the Cipher Bureau of Polish Military Intelligence. On 8 May 1919, a Cipher Section (Sekcja Szyfrów) of the Polish Army was formed by Lt. Józef Staślicki, and a few months later was renamed Biuro Szyfrów. It contributed substantially to the defeat of the Soviets by Piłsudski during the Polish-Soviet War of 1920, as Soviet military cryptography of the time was less than unbreakable. Later on, German communications became its primary focus; "BS4" was the section dealing with German ciphers, headed by Maksymilian Ciezki. The history of cryptography dates back thousands of years, and for the most part, it has been the history of classical cryptography; that is, methods of encryption which can be performed using pen and paper (or perhaps with simple mechanical aids). ... May 8 is the 128th day of the year in the Gregorian Calendar (129th in leap years). ... 1919 was a common year starting on Wednesday (see link for calendar). ... The Union of Soviet Socialist Republics (USSR) (Russian: (СССР)  listen; tr. ... Term of Office from November 14, 1918 until December 9, 1922 Profession Statesman and military commander Political Party none, see Sanacja for details First Lady Maria Piłsudska Date of Birth December 5, 1867 Place of Birth Zułów, in todays Lithuania Date of Death May 12, 1935 Place of Death... Polish-Bolshevik War Conflict Polish-Bolshevik War Date 1919– 1921 Place Central and Eastern Europe Result Polish victory The Polish-Soviet War was the war (February 1919 – March 1921) that determined the borders between the Russian Soviet Federated Socialist Republic and Second Polish Republic. ... 1920 is a leap year starting on Thursday (link will take you to calendar) Events January January 7 - Forces of Russian White admiral Kolchak surrender in Krasnoyarsk. ...

Ciezki hired three young Polish mathematicians early in the 1930s: Jerzy Różycki, Henryk Zygalski and Marian Rejewski. Rejewski made one of the biggest advances in cryptographic history by applying methods of pure mathematics in breaking the German Army's new cryptosystem, Enigma, in 1932. The staff of the Biuro also designed, and had built, the cyclometer device to assist in the Enigma work, and later on the bomba kryptologiczna to do the same. Events and trends Technology Jet engine invented First atom was split with a particle accelerator Golden Age of radio begins in U.S. Science Nuclear fission discovered by Otto Hahn, Lise Meitner and Fritz Strassmann Pluto, the ninth planet from the Sun, is discovered by Clyde Tombaugh British biologist Arthur... Henryk Zygalski (1906-1978) was a Polish mathematician and cryptographer who joined the Biuro Szyfrow in 1932. ... Marian Rejewski as second lieutenant (signals), Polish Army in Britain, in late 1943 or in 1944. ... Wehrmacht was the name of the armed forces of Germany from 1935 to 1945. ... A cryptosystem (or cryptographic system) is the package of all procedures, protocols, cryptographic algorithms and instructions used for encoding and decoding messages using cryptography. ... In the history of cryptography, the Enigma was a portable cipher machine used to encrypt and decrypt secret messages. ... 1932 is a leap year starting on a Friday. ... The bomba (plural bomby) was a special-purpose codebreaking machine designed by Polish cryptanalysts and used to crack the German Enigma machine prior to World War II. A bomba was designed to exploit an obscure but fatal weakness in the Enigma cipher. ...

As it became clear that Poland could not survive the Nazi attack, most of the staff of the Biuro were evacuated. Many made it to France and some of them worked on German communications with French Intelligence in Paris and later at PC Bruno. After PC Bruno was shut down many of the Polish staff, including Rejewski, were again evacuated this time to Britain. Polish Defensive War of 1939 Conflict World War II Date 1 September - 6 October 1939 Place Poland Result Decisive German and Soviet victory The Polish September Campaign or Defensive War of 1939 (Polish: Wojna obronna 1939 roku) was the conquest of Poland by the armies of Nazi Germany, the Soviet... PC Bruno was the code name for the intelligence station operated at a farmhouse in the west of France to which French cryptanalysts retired after Paris was captured by the Germans in 1940. ...

One of the Biuro's staff, Antoni Palluth, was part owner of a small machine/radio shop (Wytwórnia Radiotechniczna AVA) which did much of the fabrication of the cyclometers, the bombas, and other devices. Some of the workers at that machine shop were not evacuated for one reason or another as Poland was overrun in September 1939 and were captured by the Germans. Somehow they managed to avoid saying anything which might lead the Germans to suspect that the Biuro had broken the Enigma. 1939 was a common year starting on Sunday (link will take you to calendar). ...