The History and Mathematics of Codes and Code Breaking


The Progress of Necessity

In 99% Invisible’s episode Vox Ex Machina, the producer outlines the transformation of a piece of groundbreaking technology from recreational to military use in the midst of the Second World War. The “Voder” was introduced in 1939 to a crowd of dazzled people at the World Fair. A marvel of mechanical mimicking of the human vocal chords, inventor Homer Dudley had embarked on a quest that would shape the way humans will communicate up to this day.

I really enjoyed how the producer, Delaney Hall, pulls the audience in with the dramatic shift from a playful invention to a wartime necessity. Soon after Pearl Harbor, the United States Government commissioned specifically Homer Dudley to design a machine that would effectively encrypt radio waves for secure communication. Halls use of a dramatic need with a ticking clock adds an element of interest to the podcast. Furthermore, she expands on not just the one time use of the “vocoder”, but the way it transformed the history of communication.

The continued decrease in size brought on by the military’s improvements was a gradual process that aided Cold War negotiations. Consequently, these adaptations eventually reached the grasp of the public. With AT&T’s lawsuit against the military to release information, the capability of public communication skyrocketed. I enjoyed the fun twist Hall applied to the end of the podcast where she included links to its effects on electronic music of famous artists. Hall’s creativity and dramatics made this podcast extremely gripping and will be elements I incorporate into my own podcast.


Sounds in Cryptography and Podcasts

What I found most interesting about the “Vox Ex Machina” podcast was Homer Dudley’s choice to use a pair of vinyl phonograph records as the key both the encryption and decryption process. Prior to listening to this podcast, I had not considered noise could be used as an encryption method. What surprised me even more was the security of Dudley’s encryption method.The single use keys were extremely secure because the enemy cannot replicate a record with the same random noises. Furthermore, even if the enemy was able to lay their hands on the keys, it would be useless without the SIGSALY machine and without knowledge of the agreed time to conference. To add an additional layer of security, the SIGSALY could only function in a narrow temperature range so it needed to be maintained specifically by an entire division of engineers. Enemies who got their hands on the machines might lack the knowledge about how to maintain and use the machine, thus rendering it unusable.

The podcast producer added audio tracks to the podcast which helped to better tell the story. For example, in the beginning of the podcast, the narrator is talking about the debut of the Voder at the New York World’s Fair, so he plays a recording of the Voder in action. A second example of this is when the narrator explains that as the SIGSALY machine processes voices, the voices are slightly mutated but the message is still intelligible. He then inserts a recording of what a SIGSALY communication might sound like to illustrate his statement. The variation in sounds also keeps the listener interested because he or she is not listening to the same voice speak for 20 minutes.

The narrator states an entire division of engineers was necessary to maintain the machine because it was so technically demanding. To make the technical aspects of the material accessible, the producer omits the technical details of the machine’s processes that were nonessential to the listener’s understanding of the SIGSALY. This way the foundational ideas are not lost but the processes that might confuse the general audience are not included.

This podcast inspired me to consider researching some non-conventional applications cryptography for my podcast. I will also aim to include different voices or sounds as this podcast has done to keep my audience captivated.

From Voxcoder to SIGSALY

The Voxcoder was one of the most interesting things I have ever heard of. The origin of the machine, being just a voice changer/imitator, really made me wonder what the creator had in mind when he made the machine. Being able to replicate a human or animal voice opens up so many pathways such as deception, manipulation, and somewhat discretion. I was extremely surprised when the machine was able to replicate the cow noise almost perfectly. It is also kind of scary considering that a machine can produce convincing human and animal noises. All I could imagine was hearing a a series of growls while walking through the house. After the Voxcoder was evolved into the Sigsaly the organization and complexity of the system used for conferences was baffling. There were so many steps to a single conference that it was sometimes hard to keep up with what part of the process the podcast was explaining. I think its cool but also limited that the conferences functioned by mixing and masking human voices with random noise. Its an incredible feat but if the Germans were able to figure out what was happening and develop a method of decoding it, the Allies would be screwed. It would be a more incredible feat if the Allies were able to completely scramble and distort the messages without having to mask it behind random noise.

Creating an Intriguing Podcast

The most interesting thing I discovered about the episode was how much of an impact the work of Bell Labs has on our lives today. In listening to the description of the amazing machine from the World’s Fair in 1939, I immediately assumed that all of its technology was incredibly outdated. However, I was amazed to learn that the technology is very important to the use in our phones today. Furthermore, I was also amazed with how quickly Bell Labs created such a security machine under such a time crunch. With the safety of the entire world possibly at sake, they were able to create the SIGSALY machine which allowed safe communication across the ocean.

I was very impressed with the noises used in the background of the podcast that related to the topic at hand. For instance there were man clips of conversations between FDR and Churchill, and also instances where the Voder was demonstrated. This helped to not only give the listener a better idea of what happened, but also to make it a much more enjoying podcast rather than just hearing one person talk for the entire time. Even the background music provided a nice contrast to the voice of the speaker.

The producer made the technical aspects very understandable by not assuming that the listener knew about the topic at hand, and therefore thoroughly explaining each step of what happened. By doing this the audience was able to understand complex and confusing things, such as the Voder, without ever seeing an image of what is like. I was very impressed with the podcast because I looked up what a Voder looked like after the podcast and it was very similar to what I had pictured. This means that the producer did a good job in making the concepts very accessible.

After listening to this, I would like to do my podcast on something similar, an obscure machine or company that was incredibly important in coding/decoding messages. I think I would like to do my podcast on something that is more important to present times, but then again it can be overstated how important the products from Bell Labs are to our lives today, for instance by making our cell phone transmissions work.


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.


Powered by WordPress & Theme by Anders Norén