# Cryptography

#### The History and Mathematics of Codes and Code Breaking

Because the onset of the telegraph inserted a middleman in the communication of a sender and receiver, messages not meant for prying eyes understandably needed to be encrypted with a more secure cipher like the Vigenère cipher. Since the invention of the telegraph in the 19thcentury, several other inventions or innovations in the world of communication have simultaneously increased the global spread of information, while also creating significant implications for security and privacy.  For example, with the first primitive forms of the telephone, an operator was needed to connect the caller to their recipient. This operator could hypothetically listen to any call they wanted to, which created a feeling of insecurity in this form of communication that was quite similar to that of the telegram—that of distrust in a middleman (or woman, as switchboard operators at this time were often female). Similarly, with the invention of radio in the 20thcentury, any message sent over radio waves could be picked up freely, so messages necessarily needed to be encrypted if they contained sensitive material, especially in times of war, as information gathering agencies would often employ this tactic to collect knowledge on the plans or whereabouts of their enemies. Needless to say, every technological advancement brings with it uncertainty, and the risk of cession of privacy or security should be considered before any advancement in communication becomes widespread.

One of the podcast episodes I chose to listen to was “Numbers Stations” from 99% Invisible.  The episode is hosted by Roman Mars, who discusses mysterious shortwave radio frequencies used to broadcast endless strings of numbers, also known as numbers stations.  Something I found very interesting about this topic was the degree of mystery and obscurity behind these broadcasts.  It is assumed that the numbers represent coded messages, but nobody knows who is meant to receive them.  The most popular theory is that these shortwave frequencies are used by government agencies such as the CIA to communicate with spies around the world, but there’s no way to be certain.

The producer does an excellent job at keeping the podcast interesting and engaging through the use of various sound clips.  He sprinkles in recordings of numbers station broadcasts throughout the episode, allowing listeners to feel like they are directly tuning in to them.  Additionally, there is a lot of creepy background music which serves to reinforce the sense of mystery behind numbers stations and make the listener want to know more about them.  Finally, the content is explained in a way that is relatively easy to understand.  The producer avoids using heavy jargon in order to keep his audience as broad as possible.

After listening to this episode, I realized how important it is to have good background music and other appropriate sounds.  It adds a whole new dimension to the experience.  Depending on the topic I choose, I plan to implement strong auditory elements into my own podcast to hopefully make it more engaging.

In the “Number Stations” podcast, I enjoyed learning about the fact that actual secret messages that nobody knows the reason or meaning of is actually being constantly transmitted on certain radio frequencies and generally accessible to pretty much anyone who has a radio and a knack for tuning to every possible station. Their message itself is kept secret but the transmission of the encrypted one is totally open to the public. What’s more interesting is that this isn’t only used by one country–many countries such as Germany, Spain, Russia, and China are exploiting this means of communication. I’m guessing that as long as the coders are confident in the strength of their system, it doesn’t matter who hears it. But what does matter to them is an easy way of getting messages out and heard by the receiving end (radio is pretty common).

What bolstered this podcast’s grip on the audience came from the insertion of actual radio dialogues that show us what these “number stations” usually sound like in addition to quotes from relevant sources or experts, such as Bruce Schneier.

Though I was very captivated after about 10 minutes into the podcast, it initially felt a little awkward and unorganized, just because without reading anything else on the website, this podcast sort of starts out of nowhere and is confusing. We’re not entirely sure what their main point is until 3 minutes in. Thus, in this case, reading the text article beforehand is essential, which many people may not immediately realize (they might go straight to the podcast, sit back, and enjoy). Unlike papers that are organized with an introduction, body, and conclusion, the podcast seemed like it started with a point and decided to go wherever with it on a whim, like speaking on a stream of consciousness.

This gives me the idea to make sure that right from the start of my own podcast, I will introduce the main points covered so the audience has a very clear idea of what they’re about to listen to.

I did like how this podcast has supplemental information when you scroll down the page. More visual components such as graphs that show data or directly depict the situation in the order that they are discussed would be extremely helpful to people who are listening to the podcast simultaneously.

Episode 97 of 99% Invisible, Number Stations, is a podcast that discusses the mysterious shortwave radio transmissions that simply list random numbers. The topic of the podcast is really interesting. Imagine just tuning a radio and you suddenly hear random numbers being said. What would go through your head? To me, it feels like something out of the Twilight Zone. The podcast goes on to describe what the transmissions were and how almost everybody was sending them out. So little. I find it amazing to think that they were so easily accessible but virtually impossible to be of use to anyone except the intended recipient. Maybe to bigger organizations like the CIA, who themselves were setting up a few of these stations, there was something to be done with these. However, to your average day person, the transmissions were meaningless and just eerily there. The producer paired the podcast with some pictures and a written summary of what the podcast contained. This helped in understanding the podcast as you were able to follow along and know what was about to be discussed. He also made references when speaking that a listener could go the extra step and look up. The podcast does an excellent job of catching a listeners attention, as well as providing sources that allow a listener to go the extra step and research the topic themselves. I would like to format my podcast in a similar way to this informative and intriguing podcast on number stations.