It is often remarked that "Wits win you a war, rather than numbers." Time and again it has been proven throughout history.
There have been many such examples when, despite being on the defense for a long time, a sudden breakthrough with the help of sheer intelligence helps to turn the tables. This is precisely what happened during World War II when Allied forces cracked the Enigma code used by Germans in their radio communication. This not only helped lead to an Allied victory, but also proved how the pure intelligence of a small group of people can save millions of lives.
So what was this Enigma code, and what made it so powerful that breaking it caused the collapse of the German forces?
Enigma was patented by Arthur Scherbius in 1918, an inventor who thought of it as a ciphering device
for businesses that needed to communicate confidential documents.
The German military caught interest, and commercial production was stopped in 1923.
Possibly the greatest dedicated cipher machine in human history the Enigma machine is a typewriter-sized machine,
with keyboard included, that the Germans used to encrypt and decrypt messages during
World War II.
The Enigma was used solely to encipher and decipher messages.
An Enigma machine allows for billions and billions of ways to encode a message, making it incredibly difficult for other nations to crack
German codes during the war — for a time the code seemed unbreakable.
Enigma machines use a form of substitution encryption. A simple example of a substitution encryption scheme is a Caesar cipher.
But Enigma machines are much more powerful than a simple Caesar cipher.
Imagine that each time a letter was mapped to another, the entire encoding scheme changed. After each button press,
the rotors move and repressing that same button routes current along a different path to a different revealed letter.
This is what makes Enigma machines so robust!
The Enigma Machine is an electromechanical device, which works through mechanical parts as an electric current passes through it.
The machine consists of four main components: keyboard, plugboard, lampboard and rotors.
From the cipher operator's point of view, it consisted of first a keyboard of 26 letters in the pattern of the normal German typewriter, with no keys for numerals or punctuation
Behind this keyboard was a "lampboard" of 26 small circular windows, each bearing a letter in the same QWERTZU pattern,
which could light up, one at a time, from bulbs underneath.
It measured about 13.5" x 11" x 6", and weighed about 26 lbs.
Behind the lampboard is the scrambler unit, consisting of a fixed wheel at each end, and a central space for three rotating wheels.
There are three rotors; fast (right), middle and slow (left).
All of these rotors have a gauge that displays numbers from 1 to 26.
And since there were 17,576 possible paths a letter could take through the rotor,
that gives us 1,054,560 possibilities altogether.
Finally, the vertical front of the Enigmas used by the Armed Services contained a "plugboard" with 26 pairs of sockets,
again in the QWERTZU pattern.
These could be connected by twin-cable leads but some sockets, usually six, were left unconnected.
They were said to be "self-steckered." Stecker is a plug.
After the signal comes out as an output from the slow rotor (left rotor), it goes through the reflector. It takes a letter as an input and
reflects a different letter as an output.
There were a few flaws with the way operators would use the machine, mostly failing to follow procedures.
But in terms of flaws in the design of the machine, the main one had to do with the reflector.
The reflector makes the Enigma self-reciprocal.
That means that, given the same starting conditions, the machine can both encrypt and decrypt.
Every letter was encrypted as a letter that was different than itself.
Germans put the phrase ‘Heil Hitler’ at the end of every encrypted message.
Alan Turing and other researchers exploited a these weaknesses in the implementation of the Enigma code
and gained access to German codebooks, and this allowed them to design a machine called a
'Bombe machine', which helped to crack the most challenging versions of Enigma.
Some historians believe that the cracking of Enigma was the single most important victory by the Allied powers during WWII.
Using information that they decoded from the Germans, the Allies were able to prevent many attacks.
However, to avoid Nazi suspicion that they had insight to German communications, the Allies had to allow some attacks to be carried out despite the fact that they had the knowledge to stop them.