The Enigma Machine and War
In 1939, the Germans managed to make their Enigma machine more sophisticated and
tougher to crack. Instead of having three rotors, they increased the number to five. Time
was running out and the Poles realized that Germany was going to invade Poland, so they
decided to share their work: They made copies of the machine for the French and the British.
Solving Enigma
World War II was fought between two
groups of nations: the Allied powers (in
green), which also included the United
States and China, among others, and the Axis
powers (in red), which also included Japan.
United Kingdom
Germany
Holland
France
Italy
Russia
Hungary
The main problem with solving the Enigma machine
was in breaking the code. Even if you knew all the
details about how the machine worked, it didn’t mean
you could decrypt messages easily. If you didn’t know
the settings of the rotors and plugboard, there were
100,000,000,000,000,000,000,000 possibilities to check!
A decoding machine called the bombe was originally
invented in Poland. This machine automated the search
for the settings. But the bombe became less and less
useful because the Germans were making their Enigma
machines more complex.
After Poland asked Britain and France for help, the
British Government set up the Code and Cypher School at
Bletchley Park in England. To help solve the puzzle, they
formed a group of mathematicians, cryptographers, chess
players and people who liked crossword puzzles! The group
helped to intercept and decrypt German communications.
One of the people in the group was the brilliant Alan Turing.
Turing quickly got to work. First, he improved the
design of the bombe. The Turing–Welchman bombe
(developed by Turing and Gordon Welchman) was
electro-mechanical.
This meant that it
was faster than the Polish
mechanical bombes. Instead
of taking days to decrypt
messages, it took just a few
hours. Since the decrypted information was fresher, it was
more valuable. Second, Turing came up with a number
of statistical tests to reduce the number of settings the
bombes had to check. This made decryption more efficient.
Third, he helped to decipher complicated German naval
messages that had seemed impossible to decipher.
After this, in July 1942, Turing developed a code-
breaking technique he named “Turingery.” This technique
helped to crack the sophisticated Lorenz machine. Later in
the war, he developed a speech-scrambling device that he
named “Delilah.” This device could encrypt and decrypt
spoken messages.
So how did Turing save millions of lives? Well, without
his work, the war would have gone on for much longer and
so many more lives would have been lost. At the end of the
war, in 1945, Turing was awarded the Order of the British
Empire medal by King George VI of the United Kingdom.
A young Alan Turing
62 Topic 3
