aviation in World War 2

bomber tactics
the Blitz
bombing of Coventry
bombing in the Bristol area
Combined Bomber (CBO)
Bomber Command
the Dambusters
bombing of Hamburg
1000 bomber raids
bombing of Dresden
bombing of Nuremberg
the Schweinfurt raids
German Night Fighters
the Pathfinders
Soviet bombing raids
Pearl Harbour
the Doolittle raid
the B-17 and B-29
fire bombing raids on Japan
Atomic Bombing of Hiroshima


ENIGMA, code name for the cipher machine, developed from a design patented by a Dutchman, H. A. Koch, in 1919 from which ULTRA intelligence was derived. Dr Arthur Scherbius, a Berlin engineer, marketed it in 1923; by 1929 he had been bought out by the German Army and Navy, which used different versions of it. So, in turn, did the Luftwaffe, the HISS, the Abwehr, and the Reichsbahn (German state railways). The machine seemed to the Germans wholly unbreakable: even in its simplest form, for every letter it sent there were hundreds of millions of possible solutions. They forgot how few letters there are in the alphabet; they forgot that no letter could stand for itself; and they forgot that the machine had no number-keys, so that figures had to be spelled out. These gave their potential opponents toe-holds enough. The Poles were reading some ENIGMA traffic as early as 1932, the French in 1938, the British in 1940; with startling results.

Polish Pre-War Code Breakers In The Early Period (1930s)

The first trials in Poland to break the newly introduced cipher by the Wehrmacht and Kriegsmarine were in 1928. The messages that were encoded with a new cipher were being picked up by four Polish ELINT stations: in Warsaw, Starogard near Gdansk (or then Danzig), in Poznan and in Krzeslawice near Cracow. Unfortunately, the methods involved in breaking the cipher code were fruitless. It seemed that the new cipher was a strong cryptography and cannot be cracked in an easy way. Therefore, the Ciphers Office (BS) of the Polish Army's General Staff decided to ask mathematicians for help. In January 1929, the Dean of the Department of Mathematics, Professor Zdzislaw Krygowski from the University of Poznan, made a list of his best graduating students who could have started working at the Ciphers Office. Later these students graduated a course of cryptography prepared by the Office. The best were: Marian Rejewski, Jerzy Rozycki and Henryk Zygalski who could work both at the University and at the General Staff's Ciphers Office without any problems at that time.

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.

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.

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.

The main problem the cryptologists were facing was the exchange of the key system, which took place in the German Army on 1 July, 1939. The first decrypted message at the "Bruno" centre on 17 January 1940 was from 28 October 1939.

The most helpful messages to assess the routine of the German Army Signals Corps were those sent every day just before 2400 hours. There was important information on call signs, wavelengths, and hours of operation, etc.

There were also false messages to deceive the enemy ELINT/SIGINT efforts, sent by the Germans. However, the most characteristic messages were: situation reports sent in the morning, noon, afternoons, evenings; intelligence reports; orders; logistic reports and others. The unit's most important effort was the warning about the German preparation to attack France.

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.

The Polish cryptologists were however to come back soon to occupied France under a secret agreement between the Polish and Free French governments and continue their work in underground in the City of Fouzes near Nimes. In the beginning of October 1940, the new secret unit was formed in Fouzes and code-named "Cadix." The "Bruno" centre successor decrypted the following types of German messages:

- German military orders to the units in Europe and in Libya,
- SS and Police (Polizei) messages from Europe,
- Spy radio communications between the field agents in Europe or in Libya and Abwehr HQ in Stuttgart,
- Diplomatic communications and German Armistice Commission's
- Communications in Wiesbaden and their branches in France and in North Africa.

Unfortunately, on 9 January 1942, Jerzy Rozycki died when M/S "Lamoriciere" he was travelling by, sunk near Balearic Isles.

Because of German ELINT threat, the unit's members were evacuated on 6 November 1942. Rejewski and Zygalski managed to get to neutral Spain. Later, via Gibraltar, they were transferred to England, where they started working at the Polish Army Signals Corps in Boxmoor near London, in fact for the Polish Armed Forces Branch "300" of the II Directorate. They later cracked the German SS formations cipher.