As promised, here's a solution to Question 4 on Problem Set 5. I know it was a tough one, so if you didn't get it, hopefully you can at least understand the solution when it's all laid out. You don't need to understand the proof of Theorem 4, also in that PDF, but I've included it for those interested.
- Turning the Tide of WW2 Cryptography
- Turing the Mathematics of Cryptonomicon
- The Beautiful Mind of Lawrence Waterhouse
- Ending Engima
- Colors of the Rainbow: Japanese Ciphers of WW2
- When You Can Go Too Far and Not Far Enough: Ordo and Keys
- Only as Strong as the Weakest Link
- Data Havens for Fun and Profit
Learning Modular Arithmetic in Three Pages or Less
Taking One for the Team: Detachment 2702’s Contribution to WW2
Lawrence Waterhouse: A Different View on Everything
The Psychology of Bobby Shaftoe
How Mathematicians Think
The Awesomeness of Bletchley Park
When Bits Become Bytes
(For the record, four of those suggestions are mine.)
Now for some Pecha Kucha resources. First, the Pecha Kucha organization, which coordinates Pecha Kucha nights all around the world, including Nashville. The organization has used their network in creative ways to aid in disaster recovery efforts, including the 2011 Japan earthquake.
Here's the sample Pecha Kucha presentation I shared, by the University of British Columbia's Tegan Adams:
For more examples, check out Pecha Kucha Atlanta's website, which features lots and lots.
Finally, if you forget how to pronounce Pecha Kucha, here's a Muppets-themed reminder.
Image: "pecha kucha night book," Brandon Shigeta, Flickr (CC)
Adobe first launched the San José Semaphore back in 2006. This piece of public art – created as a part of its long-term headquarter site development in San Jose, Calif. – comprises four 10-foot high digitally displayed disks that transmit a code as they continue to change their rotation. Starting at twilight last night, they relaunched a newly commissioned display with a new challenge to the public, including those in the cryptology community such as yourself, to be the first to decode the new transmission. The first person to successfully crack the code wins a one year Adobe Creative Cloud membership, bragging rights, and acknowledgment on the Adobe website (www.adobe.com). Get all of the details on the official contest page and check out the news here.
As promised, here's a photo of the debate map you constructed during class today. Click on the image to see a larger version; it should be large enough to read the contents of the Post-it notes. Recall that arguments in favor of security were written on the yellow-green notes, and arguments in favor of privacy on the red notes.
- "Lower Merion School District and Blake Robbins Reach a Settlement in Spycamgate" by Forbes privacy reporter Kashmir Hill, who is worth following on Twitter (@kashhill)
- "Is Aviation Security Mostly for Show?" by security expert Bruce Schneier, in which he discusses the notion of "security theater"
- Little Brother StreamGraph by data visualizer Jeff Clark
- Jacket and interior book design for Little Brother by Emerson College student Jeannie Harrell
And some resources from our class on unsolved mysteries last week...
- Here's the Wired Magazine article on Kryptos: "Mission Impossible: The Code Even the CIA Can't Crack," Steven Levy, April 2009. And here's the New York Times story on the clue James Sanborn provided a couple of years ago.
- I took a few photos of the James Sanborn sculpture Iacto when I visited the University of Iowa a few weeks ago.
- James Sanborn has another interesting cryptography sculpture call the Cyrillic Projector. Below you can see a video project one of my former students, Lacy Tite, created about this second sculpture.
- Was Lewis Carroll actually Jack the Ripper? Probably not.
- The Wikipedia entry on the Voynich Manuscript is a good introduction to its weirdness and the various attempts over the years to figure it out.
- Just for fun, the Internet Anagram Server.
- I mentioned Andrew Wiles' proof of Fermat's Last Theorem in class as an example of a mathematical problem that had gone unsolved for hundreds of years. Here's a nice interview with Wiles about his work from PBS NOVA Online.
As promised, some links about Charles Babbage and Ada Lovelace...
- Here's what the Computer History Museum (the one in Mountain View, California) has to say about the Difference Engines built by the Science Museum in London.
- And here's the full, four-minute video from Wired about the Difference Engine now on display at the Computer History Museum:
- Plan 28 is the effort to build Babbage's Analytical Engine. Donations are currently being accepted.
- All of Sydney Padua's Lovelace and Babbage comics are available online, and all feature extensive footnotes and references! And here's the comic the BBC commissioned from Padua that explains Lovelace's and Babbage's contributions to the field of computer science.
- Ada Lovelace Day celebrates women in science, engineering, math, and technology. You can learn more about Ada Lovelace Day and the woman herself and read the thousands of blog posts written for Ada Lovelace Day.
And here's my Prezi showing Babbage's technique for breaking the Vigenere cipher.
The math department's undergraduate seminar kicks off this week, with a talk by grad student Michael Hull on some of the mathematics seen in the television show Futurama. These talks are designed to be interesting and accessible to any student, regardless of major. The Futurama talk will be at 6pm on Tuesday, September 25th, in Stevenson Center 1206. Pizza and sodas will be provided. Here's the blurb:
You may be familiar with the show Futurama, but did you know that the show contains a plethora of math references hidden in the background? Many of these references require quite a bit of mathematical training to even notice. We will show some examples of this from the show and explain a bit of the mathematical background behind what is going on. Topics will include cryptography, number theory, computer science, group theory, and more!
Here are few resources on the subject of the Creative Commons:
- About the Creative Commons Licenses
- Why Cory Doctorow Releases His Books Under the Creative Commons
- Compfight, a tool for search for Creative Commons images on Flickr
And here's a diagram showing some of the implications for cryptography of the speed of communication enabled by the telegraph:
Let's say that A, a member of the Black Team, is sending an encrypted message to B, also on the Black Team, in another city. The White Team consists of C, who intercepts the ciphertext; D, who decrypts the ciphertext; and E, who is in the same city as B and will act on the decrypted message to disrupt whatever B is doing.
If communication travels at the speed of a horse and if D isn't located near C or E, then the White Team will take a while to get the decrypted message in the hands of E, who can act on it. If, however, communication is virtually instantaneous, then the only thing slowing the White Team down is the time it takes D to decrypt the message. This increases the need for the Black Team to use strong encryption.
However, if C is capable of decrypting the message and can communicate directly with E, then the speed of communication doesn't matter as much. The only thing slowing the White Team down in that case, regardless of the speed of communication, is the time it takes to decrypt the message. The time between B receiving the plaintext and E receiving the plaintext will be equal to the amount of time it takes C to decrypt the message. Strong encryption is still important, but not more important because of the faster communication.