Category Archives: Crypto

Perhaps my favorite final exam problem ever.

Check out problem 5 on the final exam I am giving today in my Cryptology topics class.

Cartoon-Final-1

Thanks, XKCD.

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PlayStations as distributed computing nodes

This is cool:

Stanford University’s Folding@Home project, which puts personal computers to work studying the complicated process of protein folding, could soon get a big boost from an unlikely direction. Starting this month, owners of Sony’s PlayStation 3 video-game console will be able to take part in the research project when they’re not busy playing games.

Researchers have recruited about 200,000 desktop machines to participate in the project, which has implications for medical science. But the officials are bullish about PlayStations, according to Scientific American, because the gaming devices actually perform some simulations faster than most computers.

Here’s the whole Scientific American story. And there’s lots more distributed computing projects where that came from, such as Project RC5 which our Mac mini at home crunches on all day and night.

[via Wired Campus Blog]

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Fall Break overview

Fall Break is upon us, as is fall itself with rainy, cool weather today. It’s a break, but a full one:

  • This is the first day in over six weeks that I have had substantive time to work on the dual-degree engineering program. The deadline for curriculum proposals is coming up shortly and the thing needs to get done. I think I’ll make it. Some tweaking needs to be done: since we offer Calculus III only once every two years, students who want to do engineering but who start the program in even-numbered years can’t take it until they are juniors, which puts them a year behind in the engineering program. I’ve got a workaround right now for that, but it’s not pretty. So I am lobbying my department and dean to have Calculus III offered every year, like a normal math department would do.
  • This semester has been kicking my rear since about day 3 and hasn’t stopped. I have 14 hours’ of teaching plus being on P&T, which is about the equivalent of another 2-hour course. As a result, about 3 weeks ago all the structures that I’d set up for doing GTD got totally overrun with "stuff". I’ve been going day-to-day with to-do lists and so forth, but I’m going to have to take some time over break and declare productivity bankruptcy, and start the whole GTD thing over again with a much, MUCH fatter "Someday/Maybe" file (which will consist of the stuff in my projects list that got crowded out by the constant grading/prepping cycle).
  • Yesterday I had another grading blitz and got lots done. But I still have four untended items for the geometry class to get done. When this will get done is anybody’s guess.
  • Mom and Dad are driving up today to stay until Saturday morning. They are bringing Doodlebug one of these, and I hope she likes it, because they seem pretty cool. On tap is a tour of the new house (almost finished!), dinner at our favorite Chinese place tonight, then probably hitting the Childrens’ Museum tomorrow and more sights in downtown. And since they’re staying at one of these, we’ve promised Doodlebug that swimming in the hotel pool is part of the deal.
  • I’m doing a workshop at the Indiana Council of Teachers of Mathematics meeting on Sunday in Indy on factoring, the division algorithm, and how they relate to cryptography. It’s nice because it’s virtually the same workshop that I gave to a similar group of high school teachers back in June. The sad thing is, with my GTD system fried, I actually had forgotten I was doing this until yesterday. Oops.

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Filed under Crypto, Education, Engineering, Family, GTD, Higher ed, Life in academia, Math, Teaching

New Mersenne prime “probably” found

The Great Internet Mersenne Prime Search (GIMPS) home page is reporting that the 44th Mersenne prime has "probably" been found — i.e., the number has been registered with the GIMPS server and is undergoing checking — as of September 4. Verification should be done in a week. The 43rd one (found in December 2005) was over 9 million digits long; no indication of how big this one is, if it’s indeed a prime.

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del.icio.us tuesday #7

This week’s look into my del.icio.us bookmarks brings us to…

Powers of Ten (the video)

I think I remember seeing this when I was a kid. It’s a fascinating visualization of the differences between different powers of ten. The video starts with a viewpoint one meter above a family at a picnic, then zooms out to 10 meters, then to 100, then to 1000, then… all the way to 1025 meters, and then back to 1 meter and down to 10-15. See for yourself here at YouTube. (Hmm… I tried to embed the video directly but it screwed up the site. Is there something special I have to do to make it appear?)

I only wish they did one like this using powers of 2, for use in my cryptology teaching materials. I have the hardest time convincing students that a 32-bit key is not just twice as secure as a 16-bit key, but 216 times more secure.

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Technology banning, antique style?

I’ve been bidding in some eBay auctions over the last couple of days, the first time I’d done so in several months. I thought I’d do a little searching, just for fun, for antique cryptographic devices like one of these. I came across an auction for a 1945 NEMA Model 45 Enigma machine with a price of, er, $8939.99. Too rich for my blood, but could be fun to look at anyway. But when I tried to view the item, I got this (click to enlarge):
enigma2.png

There’s another auction for a similar Enigma-like machine that gives me the same “somebody thinks you shouldn’t be viewing this” message.

So let me get this straight: I can’t view an auction of a 60-year old Swiss cipher machine, in the USA, because of legal restrictions? Are they the same legal restrictions that classified the posting of PGP to a web server as a violation of an arms control treaty? If so, maybe I should become an arms trafficker.

Or perhaps this is another provision of DOPA? Because, you know, those predators out there would certainly want to keep themselves secret, so we can’t allow anybody to keep anything secret.

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del.icio.us “Tuesday” #5

As promised, here’s this week’s installment of del.icio.us Tuesday (a day late), where I pull a link from my del.icio.us bookmarks and highlight it. And as expected, it’s crypto-related this week:

enigmaco.de

enigmaco.de (read it as two words: enigma | co.de) is a very cool flash-based simulator for a three-rotor Enigma machine like the ones used by the German armed forces in WWII. I’ve used electronic Enigma simulators before for teaching purposes, both online and in prepackaged software, but this one by far has the best functionality and look-and-feel. The look somehow reminds me of something off the cover of a Neal Stephenson novel, which maybe was the intention.

You can set the rotors and the plugboard settings and then type a message in to get the ciphertext. As you type, it displays how the signal is routed through the rotors and plugboard to give the ciphertext letter. It works very smoothly (unlike some Flash implementations) and has some nifty features, like the ability to actually use the Enigma to send encrypted emails. Here’s a screenshot:

 enigma.png

There’s something satisfyingly ironic about having an advanced computer simulation of a cipher machine which drove the efforts to develop the first digital programmable computer in the first place. Have fun.

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