Cryptography

The History and Mathematics of Codes and Code Breaking

Tag: World War II

Cryptography Based in Recreation

99% Invisible's "Vox Ex Machina" tells of the history of vocal synthesis. This episode of the podcast was very informative, following vocal synthesis from it's inception to its modern-day applications. As I learned during the episode, vocal synthesis played a key role in secure communications for the Allies during World War 2. I found this interesting because I would never have thought to use such a method to encrypt communications. When I think of vocoders, I think of Black Moth Super Rainbow, one of my favorite bands, not cryptography.

The podcast producer made the material presented interesting by including interviews with people who worked on SIGSALY and providing a simulated conversation between Wilson and Churchill. This gave me a better idea of what SIGSALY actually did.

The producer made technical aspects of the material accessible by providing concrete examples of everything mentioned in the podcast.

Based on this episode, I think I want to talk about something that is not originally based on cryptography but instead was later applied to the cryptographic field. In terms of format, I would like to include examples of what I am discussing, making the material easier to digest for the listener. I would also like to have multiple speakers covering different portions of the show, as that makes things easier to understand.

 

World War II Cryptography

In case they're helpful, here are my sketchnotes from our guest speaker, history professor Michael Bess, earlier in the week.

Not Quite Like the Movies

For as long as I can remember, there's always been one thing about action movies that has bothered me above all else: while the bad guys can do whatever they want, without worrying about who they hurt, the good guys have to catch up to the bad guys while also attempting to contain collateral damage. It seemed so unfair to me, but the good guys wouldn't be good if they hurt everyone in their wake (which is one of the reasons why the new Superman movie was so disappointing, but I digress).

In the case of German and Allied forces in World War II, we can assume, for argument's sake, that the Germans would be the "bad guys", and the Allied forces would be the "good guys." If the pattern which caused so much of my childhood angst was being followed, it should happen that fighting the good fight would be a hinderance for the Allies. However it had the exact opposite effect. The cause that the Allies were fighting for, and the conviction that they held to complete their cause, was a major factor in their success with cracking the Enigma machine.

Singh mentions himself that motivation is a driving force in cryptography: in periods of peace, cryptographic breakthroughs are so few and far between simply because there is no need for them. In the case of Allied efforts, there was much need to break the Enigma machine. Lives were being lost at an astonishingly fast rate, and without knowledge of German plans, there was little chance for the Allied troops to make any gains. Both the higher ups and the cryptanalysts themselves understood that the stakes were incredibly high, which proved to be an incredibly motivating factor.

The need for information proved to be a very beneficial asset not only motivationally but also resourcefully. Because the Enigma machine was so complex, it required not only a lot of manpower to solve, but also a lot of machinery. Though previously in history there was some hesitation to fund cryptographic efforts, the creation of Bletchley Park is proof that Allied officials saw the need for cryptanalysis as part of their war effort. It's hard to tell how much priority cryptography would have gotten had the situation not been as dire.

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Let's Go De-fense! *clap, clap, clap-clap-clap*

Certainly the Germans' overconfidence in the power of Enigma led to their loss in the battle of cryptography in World War II, and my classmates have brought up many other great reasons: how the Allies worked together, a few genius individuals working for the Allies, the American use of Navajo code talkers, human error on Germany's part, and Poland's (specifically Marian Rejewski) contributions to cracking Enigma. But stepping back from that, I think in the grand scheme of things it comes down to who was playing offense and who was playing defense. In general, Germany was on the offensive: the Blitzkrieg bombing of Britain, the invasions into France, and their U-boats in the Atlantic. This made the Allies often on defense, not entirely sure where and when Germany would attack next. Because of this, I think they found it more imperative to crack Enigma; if the Allies knew when the next bomb would fall, or where German troops were camped, or where the U-boats were headed, they wouldn't be caught by surprise and could be far better prepared to fight back. Therefore they were willing to hire thousands of codebreakers to work at places like Bletchley Park, and invest money in a seemingly crazy machine to break Enigma. Until Enigma was completely broken, Germany did have the upper hand, and they weren't as worried about deciphering Allied messages as long as they kept winning battles and advancing.

When the Allies (thanks to Alan Turing and his machine) were finally able to decipher any Enigma message everyday, British officers recognized the advantage they now had, one that would only be kept if Germany continued to think they were still on offense. So the Allies were very careful to not let Germany know of their success, and only here does Germany's overconfidence in Enigma come into play. Up until this point they had every right to be confident in the secrecy of many of their communications, and it showed as they swept across Europe. But England could never do a perfect job covering up what they knew, and Germany's overconfidence in Enigma led them to ignore that. In the football game of World War II, the Allies defense had intercepted the football and were running for the touchdown, while Germany's offense still thought they were advancing towards their field-goal range and their cryptographic defense was off taking a water break in the locker room.

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A Uniquely American Code

One of the foremost advantages the Allies had during the Second World War was the United States’ Navajo Code Talkers. Because Native American tribes developed language and culture separately from Europe and Asia, there was no basis for the German cryptographers to begin to decrypt their codes. An extra layer of encryption was that the Navajo code corresponded to words or letters in the English language, rather than their own meanings, which made decryption more than simply understanding the Navajo language (which the Germans and Japanese were unable to do, anyway).

Though German forces were overly confident in the Enigma cipher and its complexity and impermeability, it did not mean they were unable to gain ground with cracking the Allies’ ciphers. Codes and cipher machines such as Type X and SIGABA may have been more effective than Enigma because Allied cryptographers were more careful than German ones. However, there was always a risk that the German cryptanalysts had begun to crack the codes, and decrypting the messages sent by those machines were also very slow. Implementing the Navajo Code Talkers made it basically impossible for the Germans to crack the code, and also expedited the process of sending and deciphering messages that greatly contributed to the Allies’ victory.

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Enigmatic Ingenuity

     While there are many reasons for the Allied cryptanalysts’ hard-won victory over the German cryptographers, the human factor—and German underestimation of its impact—stands foremost in my mind. Enigma machines, radios, weapons—these are all well and good, as long as people know how to use them. Clearly, the Germans were overconfident in the security of Enigma, but this overconfidence goes hand in hand with underestimation of the potential impact of human ingenuity and error.
     For the Germans, the Enigma machine initially provided an entirely secure method of communication. However, as time went on, the Enigma operators grew sloppy. They began using repetitive words, formed habits that allowed the Bletchley Park to break the Enigma. While the Germans could have placed less confidence in the security of the Enigma machine, they also could have recognized the potential for human error. Blinded as they were by the shininess of the Enigma machine, the Germans somewhat forgot about the people who were operating the machines. Humans, as it is said, are creatures of habit, and the German Enigma operators were no exception.
    For the British, German underestimation of the human factor proved critical in their path to victory. The Germans' mistakes did not just provide Bletchley Park with sufficient data to get a grip on the encryption. The underestimation of human ingenuity on the British side also resulted in the successful cryptanalysis of the Enigma code. The Germans seemingly did not predict the formation of an organization like Bletchley Park, where the best and brightest in every field related to cryptography, and many entirely unrelated. The British pulled in crossword addicts, scientists, bridge players, world class mathematicians, and history buffs. This ingenious mixture of people all thrown into the high pressure situations of worldwide war, working together, came up with many brilliant solutions to the Enigma problem. The Germans appear to not have thought of this possibility, or of the potential ingenuity of the people pulled together, and their subsequent capitalization on the errors of German cryptologists. The situation can really be viewed as one German Enigma operator and a machine against a diverse team of the brightest in the world. In the end, the human factor on both sides--error on one, and ingenuity on the other--resulted in British victory.
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The Wisdom from the Best

In the World War Two, the Allied cryptanalysts successfully broke German  Code and helped Allies win the war. One of the important facts I thought was the efforts from the genius.

In Ultra, the Allies hired the best one in different fields. They invited people (most were mathematicians and cryptanalysts) with unique talent, such as the Champion of Chess, the experts in crossword puzzle, linguists and so on. One of the most famous people they hired was Alan Turin. For example, Bletchley Park once used the crossword puzzle on ‘The Daily Telegraph’ as the test and asked the applicants finished it in 12 minutes. Bletchley Park also offered brilliant tools. Colossus, the world's first programmable digital electronic computer was used to help break the German Code. So one of the reason that helped Allied cryptanalysts be victorious over German cryptographers is that the Allies hired the top people in different fields and made them work together to solve problems.

The achievement of this strategy was so outstanding that during the World War Two, it helped Allies broke many codes. This greatly helped Allies save a lot of time and people, avoid the attack from enemy and finally win the war.

Photo Credit: Bletchley Park House - Mansion by Elliott Brown via flickr

Photo Credit: Bletchley Park House - Mansion by Elliott Brown via flickr

 

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