Cipher Bureau (Poland)

The Cipher Bureau (Polish: Biuro Szyfrów, [ˈbʲurɔ ˈʂɨfruf] ^ⓘ) was the interwar Polish General Staff's Second Department's unit charged with SIGINT and both cryptography (the use of ciphers and codes) and cryptanalysis (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 (1919–1921), 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.

On 8 May 1919 Lt. Józef Serafin Stanslicki established a Polish Army "Cipher Section" (Sekcja Szyfrów), precursor to the "Cipher Bureau" (Biuro Szyfrów). The Cipher Section reported to the Polish General Staff and contributed substantially to Poland's defense by Józef Piłsudski's forces during the Polish-Soviet War of 1919–1921, thereby helping preserve Poland's independence, recently regained in the wake of World War I. The Cipher Section's purview included both ciphers and codes. In Polish the term "cipher" (szyfr) loosely refers to both these two principal categories of cryptography. (Compare the opposite practice in English, which loosely refers to both codes and ciphers as "codes".)

During the Polish–Soviet War (1919–1921), approximately a hundred Russian ciphers were broken by a sizable cadre of Polish cryptologists who included army Lieutenant Jan Kowalewski and three world-famous professors of mathematics – Stefan Mazurkiewicz, Wacław Sierpiński, and Stanisław Leśniewski. Russian army staffs were still following the same disastrously ill-disciplined signals-security procedures as had Tsarist army staffs during World War I, to the decisive advantage of their German enemy. As a result, during the Polish-Soviet War the Polish military were regularly kept informed by Russian signals stations about the movements of Russian armies and their intentions and operational orders.

The Soviet staffs, according to Polish Colonel Mieczysław Ścieżyński,

had not the slightest hesitation about sending any and all messages of an operational nature by means of radiotelegraphy; there were periods during the war when, for purposes of operational communications and for purposes of command by higher staffs, no other means of communication whatever were used, messages being transmitted either entirely "in clear" (plaintext) or encrypted by means of such an incredibly uncomplicated system that for our trained specialists reading the messages was child's play. The same held for the chitchat of personnel at radiotelegraphic stations, where discipline was disastrously lax.