March 2016, RSA, San Francisco – After hours spending on the show floor at RSA conference and the talks about security, vulnerability, encryption and authentication I stopped at the Gemalto booth in the North Hall of Moscone Convention Center to listen the presentation. Scott Meltzer from Gemalto was talking about the history of famous encrypting machine Enigma. The company also presented the real 1946 original Enigma machine (NEMA) at the booth. That was a Swiss, 4-rotor model with a movable reflector, built for the Swiss Army in 1946. 1 of 300 machines that are known to still exist today.
Here is the story that was presented.
The most common information that we hear about the Enigma code is that it was super-secret throughout WWII, and it took one man to invent but over 10,000 men to defeat.
Well, none of it is true.
The Enigma was invented in 1918 by Arthur Scherbius in Germany. The inventor was highly interested to share his “rotating rotors” encryption machine with the military but the WWI was just about to end and army wasn’t interested. So, instead he put his invention for commercial use and started the company. The first prototype called Enigma A came to life in 1923. Enigma D, the first commercial version, was produced in 1927 and sold in multiple countries to encrypt financial information, diplomatic communiques, and military messages. By 1928, both German Army and Navy were using customized and upgraded versions of those machines. In fact, the British government had actually purchased several first generation Enigma machines back in 1926.
So, what is the Enigma machine and how it works.
It’s a huge polyalphabetic substitution cypher. Each message is encrypted with its own unique key. Keys are around 17,000 characters long. There are non-repeating substitutions and no easily discernable pattern. The sender would press a key on the keyboard. This would advance the first rotor one step and send an electric signal from the keyboard, through the plug-board. This would be the first substitution in the cypher. Each rotor then introduced an additional substitution as that signal went through it. Another substitution at the reflector and then back through the rotors in reverse and out through the plug-board, with additional substitutions at each step. And finally the signal was sent to the lamp array to show the encoding of that letter. The genius of this electro-mechanical system was that the encoding was reciprocal. If you typed a “W” on one Enigma, and it came out a “B,” typing that “B” on another Enigma would reproduce the “W,” but only if their initial settings were the same. And because a rotor would move every time a key was pressed, the circuit created by the next key pressed would be completely different than the previous circuit and would generate a completely different substitution.
The Enigma was the most powerful and unbreakable code machine. Until 1932.
Just before Nazis came to power, three Polish mathematicians: Marian Rejewski, Jerzy Rozycki and Henryk Zygalski, successfully broke the Enigma. Poles were able to decrypt 75% of the German army’s Enigma-encrypted radio transmissions between 1933 and 1938. But once the war began in 1939, the Nazis upgraded their machines. They distributed 2 additional rotors, and they changed their procedures to plug several security holes that the Poles were exploiting. This didn’t stop the Poles from breaking some of the Nazis’ daily codes, but each success took much longer, and breaking the entire system would have required way more manpower than they had. They also knew from some of their decrypted messages that Hitler had set his sights on Poland and was planning his move within the next 6 weeks. So, five weeks before Nazis invaded, the Poles gave French and British codebreakers all their information, including working models of the Nazi’s military Enigmas they had reverse-engineered, along with the Cyclometers, Bombas and Zygalski decrytping sheets they used to decode them.
And this is when the more familiar story of breaking the Enigma code begins.
The story of The Bletchley Park Team – Dilly Knox, John Jeffreys, Peter Twinn and Alan Turing, along with over 11,000 others started to deliver their Ultra decrypts. “It was thanks to Ultra that we won the war” – said Winston Churchill to King George VI. BBC claimed that this team shortened the war by at least 2 years. The story was recently portrayed in the movie “The Imitation Game” starring Benedict Cumberbatch and Keira Knightley.