Cryptography

The History and Mathematics of Codes and Code Breaking

Month: September 2014 Page 2 of 6

More than Privacy

Cory Doctorow’s Little Brother is a great read that makes the reader question whether privacy is worth giving up for security. In the third chapter, Marcus is detained and told to unlock his phone and decrypt the files for the government agents. He refuses to comply, citing his right to privacy, but the agents ignore him and tell him he has no other choice and “Honest people don’t have anything to hide”.

This phrase stood out to me and made me think about our discussion in class where the question of security versus privacy was proposed. The argument that we should not be worried about our privacy being invaded if we have nothing to hide is used as a basic argument in favor of security over privacy; however, this passage makes me question that argument. Most people have nothing to hide, but I do not think that this makes it acceptable to take away the right to privacy for everyone. I also think that if one right can be taken away from us, then there is nothing stopping the government from stripping the other rights we have as well. What is the point of basic human rights if they can be declared no longer basic at any time?

This passage discusses our right to privacy, but it also has made me think about the effects of the decisions we make regarding it. If we allow the government to take away one of our rights, then we pretty much give up our rights in general. How we react to the current privacy situations, such as the NSA scandal, will affect more than just privacy, it will determine the level of liberty of future generations.

Extreme Security Measures

The book Little Brother by Cory Doctorow brought up many ideas and concepts that I did not know or think about. The idea of privacy and security and these wide spread implications were well illustrated in his novel. The concept of too much security and safety measures is shown in depth in the novel. The elaborate and invasive security system of Marcus’s school is a prime example of too much. The stride detectors and recorders to identify students is just plain ridiculous. The simple fact that the school has already had some of their security system features, the face recognition cameras, ruled unconstitutional displays the level of invasiveness that the school is using. The school issued library books with trackers is another prime example of the school infringing upon the student’s rights.  These are extreme examples of the ways that security and safety measures infringe upon our rights as citizens. The idea of extreme security and safety measures is carried from the school environment at the beginning to the entire city of San Francisco. The use of data mining the Fast Trak and Fast Pass to see irregular patterns in the movements of people is a great example of extreme safety protocol. This data mining as shown in the book just ended up upsetting the citizens and inconveniencing them. The book does a very good job of giving examples of extreme security and safety measures and showing their down falls.

Watch Out for the Middleman

The section of the book that most caught my attention can be found at the beginning of Chapter 10. Marcus is in the early stages of setting up the Xnet and is beginning to realize that his heavily encrypted system is most likely already infiltrated by members of Homeland Security. He asks himself what the right course of action would be and makes clear his intentions of feeding the false information to both sides in what he calls a “man-in-the-middle attack”. The process of steaming open letters is described and Marcus uses the metaphor of being a fat spider in the middle of communication to cause as much havoc as possible.

I find the idea of “man-in-the-middle attack” very interesting and it is something we have discussed a few times in our cryptography course. A prime example of this attack can be found in Singh chapter one when Mary Queen of Scots is imprisoned but still sends out instructions to attack Queen Elizabeth with weak encoding methods. Cryptanalysts were able to intercept Mary Queen of Scots’s letters, thus allowing her to be incriminated and manipulated by Queen Elizabeth’s men. Marcus’s solution to the problem of a “man-in-the-middle attack” is crypto of course. He describes a confusing method of encryption involving a double key which creates a double enciphering. I, however, was more interested in Marcus’s form of attack rather than his double key form of defense.

Protection & Prosecution

The passage in Little Brother that drew my attention the most was at the beginning of the book when Marcus and Darryl are escaping school. The emphasis on the face detection and gait detection that was used around the halls of the school for “protection” was something I could relate to. My Senior year of high school my school got a grant for around $80,000 to put in security cameras around the entire school, inside and out. (There was a small amount of irony in the grant because the money could only be put toward the security system. By the end of the year the school could not even afford standard school supplies like paper. I actually got extra credit in several classes for bringing stacks of paper for teachers to print the final on.) The idea of the security system was to protect students from unwanted intruders, however, the cameras are more often referenced to incriminate students leaving class during the day to go home or go out to lunch. I went to a standard public school of about 1,000 students in a town where the crime rate is lower than that of surrounding towns, not really a breeding ground for criminals. It was an extreme annoyance to not be allowed to leave school during the day. Marcus and Darryl’s struggle with leaving school is one that I can relate to, I have experienced a similar circumstance.

There needs to be a line drawn and a distinction made between measures taken to protect the citizenry (students in this situation), as opposed to measures taken to prosecute it. Certain trade offs have to be made, freedoms may be infringed upon slightly for the ultimate good, I am not complaining or arguing with that. However, omniscient observation is different than active investigation. When the daily activities of a person are substantially changed by a “protective” measure, then the PATRIOT Act has gone too far. An Orwellian future is unlikely, but the extreme picture of life painted in Little Brother is one that needs to be recognized in order to avoid it.

99% Accurate Means 1% Wrong

One passage that caught my attention in Little Brother was the explanation of false positives and why they cause so many problems in systems like the terrorism detection in the book. For some things, a test that is 99% accurate works great. However, if the test is trying to detect something that is very uncommon in a very large group—such as people who are terrorists, which the book estimates as making up 1/20,000% of a city’s population—then that 1% of inaccuracy begins to cause a huge problem. In a city like San Francisco, with 20 million people, incorrectly identifying 1% of the population as terrorists means investigating two hundred thousand innocent citizens—in order to maybe catch ten terrorists. And, as such a system would likely be far less than 99% accurate, the problem would be far worse.

Things like this are important to take into consideration in today’s society, which is becoming ever more concerned with security and devising new ways to prevent terrorist attacks—even if it means invading people’s privacy. While programs such as the one in the book are not currently in place in America, if an attack like the one on the Bay bridge were to occur there would likely be support for implementing them. However, there comes a point at which, in the name of “defending freedom,” freedom is actually taken away, and that’s something we need to be very careful of.

A Nod to the Opposition

Little Brother, while it is an incredible novel, is also a brilliant argument. The construction of the novel reads like a well planned out, immensely entertaining argumentative essay. Cory Doctorow presents readers with a situation in which privacy is being subordinated, or rather completely ignored, for the “safety” of San Francisco. His argument is very obviously in support of privacy. He does not, however, ignore the other side of the issue. Like an author of a well-written essay would, Doctorow recognizes the stance of the opposition and explains that side through the character of Marcus’ father.

In the beginning of Chapter 9, Marcus’ father has been detained by police officers after having the identity on one of his tracked cards “jammed,” or switched with people who are nowhere near him. At first, he’s absolutely furious, which is great for Marcus, or at least he thinks it is, because his father is finally seeing how awful and invasive the security is. Instead, his father is relieved by the idea that the DHS is putting more officers out on the streets to catch the “saboteurs” who are creating the jump in suspicious activity. Several times throughout the novel, passages are dedicated to the reactions of Marcus’ parents: his dad defending the DHS’s need to protect the city by whatever means necessary, and his mom explaining to Marcus that his father is just scared. Doctorow doesn’t really say that Marcus’s father is a terrible person for acting the way or believing the things he does, he just works hard, through Marcus, to prove why it isn’t the best way to look at the situation.

I found this nod to the opposition highly encouraging in my reading of Little Brother, as I felt as though Doctorow was trying to avoid the kind of blind, all-consuming argument that leads to people discounting what one says. He wasn’t trying to say that privacy is more important than safety, or that the government shouldn’t protect it’s citizens; he was saying that privacy cannot be eclipsed by a need for safety, and that the government needs to protect citizens’ rights as well as citizens themselves. I’m not sure what I was expecting when I first started reading Little Brother, but the intellectual construction and content of the novel far surpassed anything I thought I would find.

Blog Assignment #4

Ghost WriterFor your fourth 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 8:00 a.m. on Monday, September 29th.

Problem Set #3

Here’s your third problem set, available in both Word and PDF formats: Problem Set 3 (Word), Problem Set 3 (PDF).  It’s due at the start of class on Friday, September 26th.

Social Bookmarking Assignment #3

Interesting PinFor your third bookmarking assignment, find and bookmark a resource on a topic connected to Singh Chapter 2. You’re welcome to find a resource providing more information on something discussed in Chapter 2, or a resource focused on some aspect of cryptography from the time period covered in Chapter 2.

Be sure to give your bookmark at least two useful tags. Also, let us know why you found the bookmark interesting.

Your bookmark is due by 8:00 a.m. on Wednesday, September 24th. If you have any questions about using Diigo, don’t hesitate to ask.

Image: “Interesting Pin,” by me, Flickr (CC)

The Vigenère Cipher

For some time before the development of the Vigenère cipher, “anybody sending an encrypted message had to accept that an expert enemy codebreaker might intercept and decipher their most precious secrets.” (Singh, p. 45) How is this environment different from the one that Mary Queen of Scots experienced, where one didn’t know how likely it was that one’s encrypted message was secure?

Before the tragic execution of Mary Queen of Scots, the majority of people believed that the monoalphabetic substitution cipher would be sufficient in enciphering secrets. This is the exact reason why Mary Queen of Scots and her conspirators were extremely blunt and honest. Once the cipher was deciphered, she was immediately incriminated. However, at the same time of her death, a new polyalphabetic substitution cipher was used, the Vigenère cipher began to be involved greatly. The Vigenère cipher changed the landscape of all ciphers because it used twenty-six different alphabets for enciphering instead of only one. This made the deciphering process much more arduous or even close to impossible for the interceptor.
Back in Mary Queen of Scots time, it was not known that a number of people had figured out how to easily solve a monoalphabetic substitution cipher. Therefore, people kept using it. Once the news broke about the Mary Queen of Scots and the interceptor, mathematicians knew that it was necessary to create a much more difficult cipher in order to make sure secrets could be safe. The interceptors had made the adjustment, and it was time for the mathematicians to make their move. The Vigenère cipher was groundbreaking in that it stumped decipherers for years and years. Perhaps, had the fiasco involving Mary Queen of Scots not occurred, the advancement of cryptography as a whole could have been delayed hundreds of years. After this incident, anybody who used the simple monoalphabetic substitution cipher knew that they were under great risk of having their secret deciphered; this led to the rapid increase of technology and intelligence in the realm of cryptography.

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