Cryptography

The History and Mathematics of Codes and Code Breaking

Month: August 2019 Page 1 of 3

Can mining students' data work?

The central argument of Morris’s essay is: although mining students’ data can not perfectly predict the campus violence and may provide issues of getting student private information without permission, this method is still helpful to reduce the possibility of school violence event. I agree with it. By surveilling student’s data on the internet, the school can both protect the student himself and the campus. First, if the school uses the data mining method to get students’ searching frequency and their comments on the social media, the school can analyze the data and find out the reasons that are responsible for the wired behavior. After this, the school can send faculty to solve the metal problems and prevent the situation become more serious. What’s more, if the school solves the students’ metal issues, it will create a healthier environment for studying. With this improvement, it can create a loop that healthier environment will lead to less mental issues. Less mental issues can lead to less campus violence. Thus, mining students’ data creates more benefits compare to doing nothing. However, school should still keep the data private instead of telling the situation to the whole faculty to prevent the violence. The school should use proper methods to solve the students’ metal issues in order to build a safer campus life.

Blog Assignment #3

For your third blog assignment, write a post between 200 and 400 words in which you (briefly) summarize and react to a passage in Little Brother that caught your attention. You might address why it interests you, connections you see between the passage and other ideas we've discussed this semester, or your opinion on arguments made in the passage.

Please (1) give your post a descriptive title, (2) assign it to the "Student Posts" category, and (3) give it at least three useful tags. Your post is due by 9:00 a.m. on Monday, September 9th.

Problem Set #1

Here's your first problem set, in both Word and PDF formats. It's due on paper at the start of class on Wednesday, September 5th.

In case they're helpful, here are some Excel files I've used in class.

Nothing to Hide

Chapter one of Simon Singh’s The Code Book begins with two stories. The first one is about Mary Queen of Scots and the second one is about Demaratus, an exiled Greek who nevertheless worked to communicate secretly with his homeland. While both of their stories were told to establish a theme of secret writing, the two stories have very little else in common. 

Demaratus’s story is one of a brave and cunning man who, upon learning of a Persian plot against his homeland, found a way to conceal the existence of his message so it could reach its destination safely. His heroics allowed the Greeks to prepare a fleet to meet the advance of Xerxes’s fleet and defend themselves from an attack that would otherwise have caught them completely off guard. Demaratus’s successful use of steganography, the act of concealing the existence of a message, allowed him to save Greece from a major military defeat. 

The story of Mary Queen of Scots did not end as pleasantly for Mary as Demaratus’s did for the Greeks. Mary had concealed her message using cryptography rendering it unreadable to those who did not have the cipher, rather than by hiding its existence in the first place. The fate of her life hung, not on whether or not her message would be discovered, for it already had been, but rather on whether it could be deciphered. Her encrypted message was, unfortunately for her, in the hands of a man named Thomas Phelippes, one of the finest cryptanalysts of his day. He eventually succeeded in decrypting the message and laid bare a plot by Mary to assassinate Queen Elizabeth and take the English throne. She was relieved of her head shortly thereafter. 

There are several differences between these two stories. Obviously, one story sees the message successfully and discreetly transported to its intended audience, while the other one has the message discovered and decrypted. In addition, the British one is likely more factual, as it is based on historical data and physical records, rather than the legends and folklore that likely drive much of Heroditus’s account of Demaratus. Finally, the type of secret writing involved varies between the two. In the Ancient Greek story, Demaratus used steganography to conceal the existence of his message whereas Queen Mary of Scots relied on cryptography to keep the contents of her message a secret even once the message had been discovered.

The Perils of Hubris in Cryptography

On page 41 of Simon Singh’s The Code Book, Singh makes the interesting assertion that “a weak encryption can be worse than no encryption at all.” This seemingly paradoxical statement reveals how hubris can be the downfall of any great cryptographic scheme. Best exemplified in the case of Mary Queen of Scots, when two parties deem a cipher or code secure and therefore write their messages freely with no fear of discovery, this overconfidence can ultimately result in their downfall. Had Mary’s messages not been so explicitly linked to the assassination plot of Queen Elizabeth, and instead been deliberately vague, the evidence against her would have been weak enough to possibly save her life.

The beheading of Mary Queen of Scots should serve as a cautionary tale to any modern cryptographer to remember the possibility that your enemy has already cracked your code, or that another part of the world is already much advanced in the art of code breaking. A good cryptographist should take extra precautions when crafting their message to ensure that, if the encryption fails, the implications of their message, should it land in the wrong hands, are as limited as possible. No code should be deemed unbreakable by its creators, and stenography and subtlety of language are just as crucial in encryption as a strong cipher or nomenclature.

Blog Assignment #2

For your second blog assignment, read the 2011 essay "Mining Student Data Could Save Lives" by Michael Morris of California State University at Channel Islands and write a post between 200 and 400 words that responds to the following prompt.

What is the central argument Morris makes in his essay? Do you agree with it? Why or why not?

This is a chance to practice your summarizing skills and to construct a (brief) response to an author's thesis. Feel free to draw on personal experiences in your response, if that's relevant.

Please give your post a descriptive title, and use the "Student Posts" category for your post. Also, give your post at least three tags, where each tag is a word or very short phrase (no more than three words) that describe the post's content. You're encouraged to use tags already in the system if they apply to your post.

Your post is due by 9:00 a.m. on Monday, September 2nd. If you have any technical problems using WordPress, don't hesitate to ask.

Bookmark Assignment #1

For your first bookmarking assignment, you're invited to bookmark anything you like that's related to cryptography. Look for a news article or resource on cryptography that's interesting to you. Be sure that you're bookmarking a credible source. If you're not sure where to go with this, look for inspiration in Singh Chapter 1. Save your bookmark to our Diigo group, and give your bookmark at least two useful tags.

Your bookmark is due by 9:00 a.m. on Friday, August 30th. We'll take a little time in class to share your finds. If you have any questions about using Diigo, don't hesitate to ask.

The Theatricality of Cryptography

The first chapter of Singh's The Code Book is packed with historical examples of cryptography. The Greeks, Persians, Arabs, French, and English, to name a few, were just some of the infinite number of societies and civilizations of which cryptography was crucial to their development. However, most of the examples described did involve people in positions of power. Kings, queens, nobles, and military leaders of all types have had to use cryptography to defend or expand their nations; clearly, cryptography has been crucial to changing history.

Despite the importance of these examples, I do believe that there has been a need for cryptography since the dawn of written language. I can't imagine that cryptography was only used by well-resourced people; there has always been a need for encryption and secrecy, even if it's on the most rudimentary level. Perhaps these are the only examples that survived, or perhaps Singh chose to include them because of their dramatic nature - after all, he does need to entice the reader somehow. It would be foolish to say that cryptography requires exceptional resources.

Yes, the most theatrical and interesting stories usually include a plot, some characters, and a dramatic, dire consequence that will result if the code is decrypted. But we can't discount the more simple, day-to-day interactions that may have required people to encrypt their messages, like a potter who may have needed to protect his or her recipe for glaze, or a citizen who wanted to hide the contents of a letter from their government. I can't imagine that examples such as these, though less exciting, didn't exist before the stories of kings, queens, armies, and wars.

21st Century Cryptanalyst

In chapter one of The Code Book, Simon Signh writes, “Cryptanalysis could not be invented until a civilization had reached a sufficiently sophisticated level of scholarship in several disciplines, including mathematics, statistics, and linguistics." (p. 15) This is a valid point. However, the necessity of education to become a cryptanalyst during the period of deep reflection in 610 AD, has changed dramatically in the modern world.

600 AD was not, by any means, a time of accessible education. Ptolemy’s influence had just reached the world in 100 AD, and Brahmagupta, who developed rules for the mathematical applications of 0, was just becoming prominent. Some of our basic principles were still being discovered. Needless to say, not everyone could afford the luxuries of schooling, even in basic subjects. 

Today, we have much more than ever before. Public schooling is essentially available to all of the western world, and many more people have the ability to learn the disciplines required to be an amatur cryptanalyst without prestiguous schooling. The fact that we can now use the “on our own” approach to achieve what many long before us needed ages to accomplish, is not something that should be looked upon shamefully, but instead as an indication of how far society has come.

 

How All Things Advance and Progress

While it can be determined that the evolution of cryptography and cryptanalysis is a result of a high level of academic and scholarly progression, the ability to analyze codes and ciphers does not necessarily have to come from that level of scholarship. In fact, amateur cryptanalysts are fully capable of analyzing and deciphering codes without much experience or training. It is fully possible that any normal person is able to solve these simple codes through trial and error.

In order to explain why the development of frequency analysis was so complicated and challenging and why in contrast, solving these substitution ciphers are seemingly so easy and simple, I want to use a simple example, or in fact any invention that we use practically today. One of the earliest and most profound inventions in human history is the wheel. The wheel took about 300 years to develop, yet today it is one of the simplest mechanisms that all of humanity understands. Similarly, Thomas Edison's invention of the lightbulb took one thousand attempts to master, yet today it is manufactured at an insane rate along with thousands of other inventions that probably took weeks, months, and even years to develop. In just the same manner, the people that developed frequency analysis may have spent hours and days trying to come up with the essence of frequency analysis, yet those that practice today have it down with ease due to the length of time for which it has existed.

Throughout time since the creation of frequency analysis, the human race has advanced in knowledge and logic and has since made the profound the simple. For this reason, even the most basic and amateur cryptanalyst has the ability to effectively decipher a substitution cipher "on their own".

Page 1 of 3

Powered by WordPress & Theme by Anders Norén