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
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
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
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
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 military orders to the units in Europe and in
- 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
- 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