MEANWHILE, in 1929 a commercial model of the
Enigma machine had fallen into the hands of the
Poles while it was en route from Berlin to
Warsaw. After inspecting it the Poles realised
Enigma’s potential for military use.
When the German Army started using
the machine a few years later, the Poles were
able to determine the wiring of the rotors then
in use by the German Army and, with the help of
reconstructed models of the machine, were later
able to decrypt a large portion of German Army
traffic.
The picture on the right shows the
sculpture in the stable-yard commemorating the
part played by the Poles in the Enigma story.
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Polish mathematician Marian Rejewski
and co-workers Henryk Zigalski and Jerzy Rozycki
had managed to build up a table of relationships
involving chains of letters from studying these
message-keys,  but
was still faced with the problem of identifying
the correct day-setting. Finding the proper
chains from the 105456 possiblilities had been a
difficult task.
The Poles (particularly Rozycki and
Zygalski), developed a technique using perforated
sheets for each rotor showing which letters could
be chained. Users would stack the sheets and
determine where the three letters were clear all
the way through. But they were still faced with
the problem of identifying the correct day-key
with its several thousand possibilites. To help
with this, the Poles eventually designed a
machine called a bomba that resembled three pairs
of Enigma machines linked together. AVA Radio
Manufacturing Company (Wytwornia Radiotechniczna
AVA) - the same company that built the Polish
copies of the Enigma - went on to build a number
of the new machines
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In 1939 the German Army increased
the complexity of their Enigmas. Previously it
had used just three rotors and simply moved them
from slot to slot.,  With the
introduction of an additional two rotors each day
the army could now select three rotors from a
choice of five. Rajewski now had to work out the
wiring of the two new wheels and to build ten
times as many Bomby, each representing a
different rotor arrangement.
The following month the situation
worsened when the Germans increased the number of
plugboard cables from six to ten. The total
number of possible keys increased to
159,000,000,000,000,000,000. It was more than the
Polish system was capable of handling.
The diagram of the Enigma machine n
the right shows how the path from the keyboard to
the lamp board may convert the letter 'Q' into
the letter 'U'. The added dimension of the
plugboard is not shown.
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The Poles decided, in mid-1939, to
share their work, and in July they met with
French and British cryptographers (including
Denniston) in the Pyry Forest in Poland and
passed to them some of their home built 'Enigmas'
and information on the team’s breakthrough,
and on the other techniques they had developed.
One of the Enigma copies eventually arrived at
Bletchley Park.
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Most of the Polish cryptographers
left Poland during the invasion and many went to
France where they worked with French
cryptographers on German transmissions until the
fall of France. Some of the French and Polish
teams escaped to England but none were employed
at Bletchley Park.
Rozycki died as a result of an accident in 1942;
Zygalski died in England in
1978.........................
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