Cryptography Reference
In-Depth Information
4-rotor Enigma. If the story told in [Harris] is authentic, then thousands
paid with their lives for changing the weather report dictionary.
Meanwhile, decryption was practiced with massive input. Roughly 7000
people (other sources, including [KahnCode], mention 30 000) worked
against time at the famous Bletchley Park in Great Britain. The topic by
Harris [Harris] is thought to give an authentic narration of this story.
It hadn't always been like this. In the beginning, about 200 cryptanalysts
and employees at Bletchley Park had a hard time getting a response from
the conservative English admiralty. The first military disasters and the
personal commitment of Churchill changed the situation. Cryptanalysis
became 'respectable' at that time.
From 1940 onwards, Great Britain regularly listened in on German air
force messages, and from 1941 onwards, they listened in on the navy's,
too. To my knowledge, there are unconfirmed speculations connecting
this with the fateful air raid on Coventry. Rumors had it that a radiogram
was previously intercepted. Churchill was said to have not responded
in order to prevent betraying that they had already broken the Enigma.
If this was the case, then it must have been awful for Bletchley Park
employees originating from Coventry: they knew in advance what was
going to happen and couldn't even warn their relatives. Nothing was to
be done to prevent the Germans from learning that the Enigma had been
broken. If a few details of this story are incorrect, sufficient similarly
awful situations can also be found. After all, national intelligence orga-
nizations are supposed to do everything to the best of their abilities in
order not to disclose the state of their cryptanalysis. Let's memorize this
sentence; it will play an important role later on.
•
The young mathematician Gordon Welchman improved the principle of
the
bombs
decisively with the so-called
diagonal board
, which made the
bombs
dramatically faster; now they required only 11 minutes for one
pass. The first batch of these devices was taken into operation in 1940;
200 were operating by the end of the war. Welchman is seen as the
actual hero in the Enigma story. He is probably identical to the hero Tom
Jericho in the topic by Harris [Harris] mentioned earlier.
So this is roughly Enigma's story. If you are interested in more details,
I recommend reading the rather thrilling and historically sound topic by
Kahn [KahnEnig]. Moreover, you will find several texts on the Web site
to this topic.
