The Enigma Code Breach

In the autumn of 1930, a new branch of the Ciphers Office was opened in utmost secrecy in Poznan. Rejewski, as well as his colleagues were employed there. In 1932, the group was moved to Warsaw, to start working on the Enigma Cipher. Their first success was a German Navy 4-letter cipher break. Rejewski was considered a leading cryptologist within the group. He was looking forward the new way of breaking the sophisticated German code. Since the Polish intelligence got an Enigma machine, Rejewski could develop the scheme of encryption from the mathematical point of view. Unfortunately, that machine was a commercial product, and the German army used the more complicated Enigma with auxiliary connectors' plate at the front panel.

During 1931, Polish Intelligence co-operated with the French Deuxieme Bureau, which led a most important agent within the Reichswehr Cipher's Office. Rejewski got a description of the militarised Enigma, as well as old keys tables. This helped him to eliminate many unknown figures in the permutation-alike equation he had previously created. Finally, in December 1932, Rejewski reconstructed the Enigma's internal connections. In January, 1933, the two other cryptologist became also involved in Rejewski's work. In the same month, the first German messages were decrypted. Since then, the General Staff had access to the most secret data transmitted by the German Army, Navy, Air Force, as well as the Ministry of Foreign Affairs.

It is being estimated, that during the 6-year period of Polish reading of the Enigma messages (between January, 1933 and September, 1939), about 100.000 transmissions were deciphered. The most important concerned the remilitarization of the Rhine Province, Anschluss of Austria and seizure of the Sudetenland, the last could be dangerous to Poland's interests.

The fact that the Enigma cipher was cracked was kept in the utmost secrecy even within the Polish General Staff's II Directorate. The officers got the messages signed with a code-name "Wicher" (that was the Enigma code break) that were considered fully reliable, but the source was classified.

In 1934, the General Staff's Cipher Office established a new site for their German branch (BS-4) in the Kabaty Forest near Warsaw. Rejewski and his colleagues have been working there until the breakout of WW II on 1 September, 1939.

Although the French helped the Poles with the Enigma code break, the fact was in exclusive hands of Poles until July 1939.

3. The Methods Of Cipher Breach
In February 1933, the Polish Army's General Staff placed an order at the AVA Radio Workshops in Warsaw to build military Enigma doubles. During that time, the General Staff possessed only one Enigma that was of a commercial type, without front panel auxiliary connectors that made the cipher stronger. By mid-1934, about 15 "made in Poland" Enigma's have been delivered. By the end of August 1939, about 70 such units were produced.

On 15 September, 1938, just two weeks before the conference in Munich, the Germans changed drastically their methods of using the Enigma cipher. Since the new key scheme seemed to be more complicated, the Polish cryptologists invented the first mechanical pseudo-computers to help them in their work. In October 1938, Rejewski designed a machine named "bomba kryptologiczna" (a cryptologic bomb), which was soon produced at the AVA Workshops. Also a "cyclometer" machine helped to assess the pattern of the key.

Simultaneously, the new method of a double-key crack was invented, which consisted of using sheets of paper with 51 by 51 holes (each set consisted of 26 sheets). The method allowed finding convergent places for the entire set.

However, starting with December 1938, the Germans upgraded their Enigma machines with 2 extra ciphering rotors (altogether 5 rotors). Although the Polish cryptographers could still read the German messages, the mass decryption effort required using 60 instead of only six cryptologic bombs and 60 paper sheets sets. During mid-July, 1939, Chief-of-Staff Lt.-Gen. Waclaw Stachiewicz, authorised the Ciphers Office to share all their knowledge on Enigma with the allied intelligence services. The representatives of France and England got Polish-made clones of the Enigma encryption machine during the meeting in Warsaw between 24 and 26 July, 1939. On 16 August 1939, General Stewart Menzies was given a copy of Enigma at the Victoria Station in London. The British begun to read the Enigma messages in mid-August, 1939.

4. Beginning Of The W.W.II - Evacuation To France
On 1 September 1939, Nazi Germany invaded Poland. The Ciphers Office, as well as ELINT surveillance stations were evacuated to Romania. While the situation on the front deteriorated, and the Soviet Union invaded Poland on 17 September 1939, the Ciphers Office received an order to destroy all documentation and equipment. Rejewski, Zygalski and Rozycki got to France during the last days of September 1939.

In October 1939, a joint Polish-French radio intelligence centre in Gretz-Armainvillers near Paris was created. It was given a code name "Bruno." Furthermore, the "Bruno" centre had a Teletype link to Gov't Code and Ciphers School in England. There were also Spanish code breakers employed at "Bruno" to crack the Spanish and Italian ciphers.

On 10 June 1940, the "Bruno" unit got an order to evacuation. On 24 June 1940 the cryptologists were evacuated by three French Air Force aeroplanes to Algeria. In mid-July 1940, the unit started to work clandestinely in Algiers. The Poles were enrolled into the Polish Armed Forces Branch "300" of the II Directorate, General Staff.