Cipher Bureau (Poland)

• 1. Origins And Early Wars

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  On the 8th of May 1919, Lieutenant Józef Serafin Stanslicki established a Polish Army Cipher Section within the General Staff building in Warsaw. This unit operated during the Polish-Soviet War that raged from 1919 to 1921. The section decrypted approximately one hundred Russian ciphers for the defense of Poland. A cadre of cryptologists included army Lieutenant Jan Kowalewski and three mathematics professors: Stefan Mazurkiewicz, Wacław Sierpiński, and Stanisław Leśniewski. Soviet staffs followed disastrously ill-disciplined signals-security procedures similar to those used by Tsarist armies during World War I. These errors allowed Polish forces to intercept entire operational orders from commanders like Mikhail Tukhachevsky and Leon Trotsky. In August 1920 alone, cryptologists decrypted four hundred ten signals from various Soviet units. Marshal Józef Piłsudski read these messages personally to guide his counteroffensive. The intelligence revealed a large gap on the Red Army's left flank near the Battle of Warsaw. This discovery enabled Poland to drive a war-winning wedge into the enemy lines. The work continued at Warsaw's radio station WAR, one of two long-range transmitters available at the time.

• 2. Mathematical Breakthroughs

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  In late 1927 or early 1928, a package arrived at the Warsaw Customs Office containing a cipher machine instead of radio equipment. German representatives demanded its return immediately, alerting customs officials who notified the Cipher Bureau. Marian Rejewski examined the commercial-model Enigma machine and noted it lacked military features. On the 15th of July 1928, German military radio stations began broadcasting encrypted messages that Polish monitors intercepted. Initial efforts to read them failed until December 1932 when Rejewski applied group theory to break the system. He reconstructed the precise interconnections of the Enigma rotors and reflector using French documents provided by Captain Gustave Bertrand. These documents included daily keys for September and October 1932 obtained from Hans-Thilo Schmidt in Berlin. Rejewski developed a method exploiting weaknesses in German operating procedures called characteristics. The Bureau commissioned AVA Radio Company to build replicas of the Enigma machine based on his specifications. There were 105,456 possible indicators across six rotor orders. The Germans increased difficulty by changing rotor orders quarterly then monthly and finally daily in 1936. They also expanded plugboard connections from six leads to between five and eight. A new reflector introduced in November 1937 required compiling a fresh catalog of characteristics.

• 3. Technological Evolution

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  The Cipher Bureau developed specialized tools to counter evolving German encryption methods. In mid-1930s, Rejewski devised the Cyclometer to catalog cycle structures of Enigma permutations. Henryk Zygalski created a manual method using twenty-six perforated sheets known as Zygalski sheets. Marian Rejewski commissioned AVA company to produce cryptologic bombs that automated decryption processes. Both the sheet method and the bomb worked only for single scrambler rotor orders so six sets were produced. On the 15th of December 1938, Germany introduced two new rotors increasing possible orders from six to sixty. This change rendered existing equipment insufficient for large-scale decryption until January 1940. The system changed again on the 15th of September 1938 when operators chose their own indicator settings instead of pre-defining them. However, sending enciphered message keys twice remained an insecure procedure exploited quickly. By January 1939, Germans increased plugboard connections to between seven and ten. Despite these hurdles, statistics compiled by Colonel Stefan Mayer in January 1938 showed seventy-five percent of messages solved. Leśniak later noted results exceeded normal possibilities with nearly ninety-five percent of German order of battle established before war broke out.

• 4. The Pyry Meeting

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  On the 25th of July 1939, Cipher Bureau chiefs Lt. Col. Gwido Langer and Major Maksymilian Ciężki met French and British representatives at Kabaty Woods near Pyry. They revealed Poland's Enigma-decryption techniques and handed over reconstructed machines along with Zygalski sheets and cryptologic bombs. The meeting included mathematicians Marian Rejewski, Jerzy Różycki, and Henryk Zygalski alongside intelligence chief Col. Stefan Mayer. British Commander Alastair Denniston and cryptanalyst Dillwyn Knox attended the session. French Major Gustave Bertrand led his delegation. Knox asked about entry drum connections which Rejewski answered simply as alphabetical order. Gordon Welchman later stated Ultra would never have started without learning details from Poles five weeks before World War II began. Dwight D. Eisenhower called intelligence from Bletchley Park priceless to his command. Winston Churchill feared German submarine wolfpacks could strangle Britain but naval decryption relied on Polish-pioneered techniques. A week after the meeting, Dillwyn Knox sent a letter dated the 1st of August 1939 thanking the Poles in their own language. He enclosed paper batons symbolizing the cryptological race he hoped to win.

• 5. Exile And Continuation

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  During the German invasion of Poland starting the 1st of September 1939, key personnel evacuated southeast into Romania then crossed Yugoslavia and neutral Italy to reach France. On the 20th of October 1939, work resumed at PC Bruno outside Paris collaborating with Britain's Government Code and Cypher School. Alan Turing spent several days at PC Bruno conferring with Polish colleagues in January 1940. The team made the first break into wartime Enigma traffic on the 17th of January 1940 covering messages from the 28th of October 1939. Eighty-three percent of keys found were solved at Bletchley Park while seventeen percent came from PC Bruno. Following France's capitulation in June 1940, survivors moved to Algeria before resuming operations at Cadix near Uzès on the 1st of October 1940. Cadix decrypted thousands of Wehrmacht SS and Gestapo messages across Europe including Soviet communications. On the 9th of November 1942, Bertrand learned Allies landed in North Africa via BBC broadcast and evacuated Cadix two days later when Germans marched into southern France. Jerzy Różycki died in January 1942 sinking of French passenger ship SS Lamoricière in Mediterranean Sea. Marian Rejewski and Henryk Zygalski hiked over Pyrenees mountains where a guide robbed them at gunpoint before reaching Spanish border. They were arrested on the 30th of January 1943 but released after three months following Red Cross intervention on the 4th of May 1943.

• 6. Legacy And Secrecy

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  Polish military chiefs Langer and Ciężki captured by Germans trying to escape France into Spain on night of 10, the 11th of March 1943 along with Antoni Palluth Edward Fokczyński and Kazimierz Gaca. Palluth and Fokczyński perished as slave laborers while others became prisoners of war. None betrayed the secret despite dire circumstances according to Stefan Mayer. Before war, Palluth co-owned AVA which produced equipment for Cipher Bureau knowing many decryption technology details. In Warsaw under German occupation other workers interrogated by intelligence commissions kept silent about compromises. In 1967 Polish historian Władysław Kozaczuk published book Bitwa o tajemnice revealing Enigma broken by Poles before World War II started. His disclosure came seven years before F.W. Winterbotham's The Ultra Secret changed conventional views of war history. A 1979 Polish film titled The Enigma Secret offered fair though superficial account of bureau story. Twenty-two years later Hollywood film Enigma criticized for historical inaccuracies including omission of Poland's fundamental work. Marian Rejewski returned to family in devastated Poland in late 1946 living another thirty-three years until death February 1980. Henryk Zygalski remained in England until August 1978.