Author: Andrew Appel
-
Monitoring all the electrical and hydraulic appliances in your house
Dan Wallach recently wrote about his smart electric meter, which keeps track of the second-by-second current draw of his whole house. But what he might like to know is, exactly what appliance is on at what time? How could you measure that? You might think that one would have to instrument each different circuit at…
-
Unpeeling the mystique of tamper-indicating seals
As computer scientists have studied the trustworthiness of different voting technologies over the past decade, we notice that “security seals” are often used by election officials. It’s natural to wonder whether they really provide any real security, or whether they are just for show. When Professor Avi Rubin volunteered as an election judge (Marylandese for…
-
NJ court permits release of post-trial briefs in voting case
In 2009 the Superior Court of New Jersey, Law Division, held a trial on the legality of using paperless direct-recording electronic (DRE) voting machines. Plaintiffs in the suit argued that because it’s so easy to replace the software in a DRE with fraudulent software that cheats in elections, DRE voting systems do not guarantee the…
-
Court permits release of unredacted report on AVC Advantage
In the summer of 2008 I led a team of computer scientists in examining the hardware and software of the Sequoia AVC Advantage voting machine. I did this as a pro-bono expert witness for the Plaintiffs in the New Jersey voting-machine lawsuit. We were subject to a Protective Order that, in essence, permitted publication of…
-
Did a denial-of-service attack cause the flash crash? Probably not.
Last June I wrote about an analysis from Nanex.com claiming that a kind of spam called “quote stuffing” on the NYSE network may have caused the “flash crash” of shares on the New York Stock Exchange, May 6, 2010. I wrote that this claim was “interesting if true, and interesting anyway”. It turns out that…
-
Did a denial-of-service attack cause the stock-market "flash crash?"
On May 6, 2010, the stock market experienced a “flash crash”; the Dow plunged 998 points (most of which was in just a few minutes) before (mostly) recovering. Nobody was quite sure what caused it. An interesting theory from Nanex.com, based on extensive analysis of the actual electronic stock-quote traffic in the markets that day…
-
No Warrant Necessary to Seize Your Laptop
The U.S. Customs may search your laptop and copy your hard drive when you cross the border, according to their policy. They may do this even if they have no particularized suspicion of wrongdoing on your part. They claim that the Fourth Amendment protection against warrantless search and seizure does not apply. The Customs justifies…
-
Intractability of Financial Derivatives
A new result by Princeton computer scientists and economists shows a striking application of computer science theory to the field of financial derivative design. The paper is Computational Complexity and Information Asymmetry in Financial Products by Sanjeev Arora, Boaz Barak, Markus Brunnermeier, and Rong Ge. Although computation has long been used in the financial industry…
-
Thoughtcrime Experiments
Cosmic rays can flip bits in memory cells or processor datapaths. Once upon a time, Sudhakar and I asked the question, “can an attacker exploit rare and random bit-flips to bypass a programming-language’s type protections and thereby break out of the Java sandbox?” A recently published science-fiction anthology Thoughtcrime Experiments contains a story, “Single-Bit Error”…
-
NJ Voting-machine Trial: Defense Witnesses
I’ve previously summarized my own testimony and other plaintiffs’ witnesses’ testimony in the New Jersey voting machines trial, Gusciora v. Corzine. The defendant is the State of New Jersey (Governor and Secretary of State). The defense case comprised the following witnesses: Defense witness James Clayton, the Ocean County voting machine warehouse supervisor, is a well-intentioned…