page_title: Cipher Bureau (Poland)
section_title: Stalking Enigma
hierarchical_section_title: Cipher Bureau (Poland) / Stalking Enigma
caption_attribution_description: English: Enigma Machine at the Imperial War Museum, London.
context_page_description: The Cipher Bureau, in Polish: Biuro Szyfrów the study of ciphers and codes, for the purpose of "breaking" them).
  The precursor of the agency that would become the Cipher Bureau was created in May 1919, during the Polish-Soviet War (1919–21), and played a vital role in securing Poland's survival and victory in that war.
  In mid-1931, the Cipher Bureau was formed by the merger of pre-existing agencies. In December 1932, the Bureau began breaking Germany's Enigma ciphers. Over the next seven years, Polish cryptologists overcame the growing structural and operating complexities of the plugboard-equipped Enigma. The Bureau also broke Soviet cryptography.
  Five weeks before the outbreak of World War II, on 25 July 1939, in Warsaw, the Polish Cipher Bureau revealed its Enigma-decryption techniques and equipment to representatives of French and British military intelligence, which had been unable to make any headway against Enigma. This Polish intelligence-and-technology transfer would give the Allies an unprecedented advantage (Ultra) in their ultimately victorious prosecution of World War II.
context_section_description: In late 1927 or early 1928, there arrived at the Warsaw Customs Office from Germany a package that, according to the accompanying declaration, was supposed to contain radio equipment.  The German firm's representative strenuously demanded that the package be returned to Germany even before going through customs, as it had been shipped with other equipment by mistake.  His insistent demands alerted the customs officials, who notified the Polish General Staff's Cipher Bureau, which took a keen interest in new developments in radio technology.  And since it happened to be a Saturday afternoon, the Bureau's experts had ample time to look into the matter.  They carefully opened the box and found that it did not, in fact, contain radio equipment but a cipher machine.  They examined the machine minutely, then put it back into the box.
  The Bureau's leading Enigma cryptanalyst Marian Rejewski commented that the cipher machine may be surmised to have been a commercial-model Enigma, since at that time the military model had not yet been devised. "Hence this trivial episode was of no practical importance, though it does fix the date at which the Cipher Bureau's interest in the Enigma machine began" – manifested, initially, in the entirely legal acquisition of a single commercial-model Enigma.
  On 15 July 1928 the first German machine-enciphered messages were broadcast by German military radio stations.  Polish monitoring stations began intercepting them, and cryptologists in the Polish Cipher Bureau's German section were instructed to try to read them.  The effort was fruitless, however, and was eventually abandoned.  There remained very slight evidence of the effort, in the form of a few densely written-over sheets of paper and the commercial-model Enigma machine. On 15 January 1929 Major Gwido Langer, after a tour of duty as chief of staff of the 1st Legion Infantry Division, became chief of the Radio-Intelligence Office, and subsequently of the Cipher Bureau. The Bureau's deputy chief, and the chief of its German section (BS-4), was Captain Maksymilian Ciężki.
  In 1929, while the Cipher Bureau's predecessor agency was still headed by Major Franciszek Pokorny (a relative of the outstanding World War I Austro-Hungarian Army cryptologist, Captain Herman Pokorny), Ciężki, Franciszek Pokorny, and a civilian Bureau associate, Antoni Palluth, taught a secret cryptology course at Poznań University for selected mathematics students.  Over ten years later, during World War II while in France, one of the students, Marian Rejewski, would discover that the entire course had been taught from French General Marcel Givièrge's book, Cours de cryptographie (Course of Cryptography), published in 1925.
  In September 1932, Maksymilian Ciężki hired three young graduates of the Poznań course to be Bureau staff members: Marian Rejewski, Jerzy Różycki and Henryk Zygalski.
caption: The Enigma machine was an electro-mechanical rotor machine with a scrambler consisting of (from right to left) an entry drum, three rotors and a reflector. It was available commercially from the early 1920s and was modified for use by the German military who adopted it later in the decade.
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