Entries Tagged "sensors"

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Snooping on Text by Listening to the Keyboard

Fascinating research out of Berkeley. Ed Felten has a good summary:

Li Zhuang, Feng Zhou, and Doug Tygar have an interesting new paper showing that if you have an audio recording of somebody typing on an ordinary computer keyboard for fifteen minutes or so, you can figure out everything they typed. The idea is that different keys tend to make slightly different sounds, and although you don’t know in advance which keys make which sounds, you can use machine learning to figure that out, assuming that the person is mostly typing English text. (Presumably it would work for other languages too.)

Read the rest.

The paper is on the Web. Here’s the abstract:

We examine the problem of keyboard acoustic emanations. We present a novel attack taking as input a 10-minute sound recording of a user typing English text using a keyboard, and then recovering up to 96% of typed characters. There is no need for a labeled training recording. Moreover the recognizer bootstrapped this way can even recognize random text such as passwords: In our experiments, 90% of 5-character random passwords using only letters can be generated in fewer than 20 attempts by an adversary; 80% of 10-character passwords can be generated in fewer than 75 attempts. Our attack uses the statistical constraints of the underlying content, English language, to reconstruct text from sound recordings without any labeled training data. The attack uses a combination of standard machine learning and speech recognition techniques, including cepstrum features, Hidden Markov Models, linear classification, and feedback-based incremental learning.

Posted on September 13, 2005 at 8:13 AMView Comments

Cameras in the New York City Subways

New York City is spending $212 million on surveillance technology: 1,000 video cameras and 3,000 motion sensors for the city’s subways, bridges, and tunnels.

Why? Why, given that cameras didn’t stop the London train bombings? Why, when there is no evidence that cameras are effectice at reducing either terrorism and crime, and every reason to believe that they are ineffective?

One reason is that it’s the “movie plot threat” of the moment. (You can hear the echos of the movie plots when you read the various quotes in the news stories.) The terrorists bombed a subway in London, so we need to defend our subways. The other reason is that New York City officials are erring on the side of caution. If nothing happens, then it was only money. But if something does happen, they won’t keep their jobs unless they can show they did everything possible. And technological solutions just make everyone feel better.

If I had $212 million to spend to defend against terrorism in the U.S., I would not spend it on cameras in the New York City subways. If I had $212 million to defend New York City against terrorism, I would not spend it on cameras in the subways. This is nothing more than security theater against a movie plot threat.

On the plus side, the money will also go for a new radio communications system for subway police, and will enable cell phone service in underground stations, but not tunnels.

Posted on August 24, 2005 at 1:10 PMView Comments

Ambient Radiation Sensors

Here’s a piece of interesting research out of Ohio State: it’s a passive sensor that could be cheaper, better, and less intrusive than technologies like backscatter X-rays:

“Unlike X-ray machines or radar instruments, the sensor doesn’t have to generate a signal to detect objects ­ it spots them based on how brightly they reflect the natural radiation that is all around us every day.”

“It’s basically just a really bad tunnel diode,” he explained. “I thought, heck, we can make a bad diode! We made lots of them back when we were figuring out how to make good ones.”

First millimeter-wave detection systems, and now this. There’s some interesting research in remote sensing going on, and there are sure to be some cool security applications.

Posted on August 24, 2005 at 8:17 AMView Comments

Technological Parenting

Salon has an interesting article about parents turning to technology to monitor their children, instead of to other people in their community.

“What is happening is that parents now assume the worst possible outcome, rather than seeing other adults as their allies,” says Frank Furedi, a professor of sociology at England’s University of Kent and the author of “Paranoid Parenting.” “You never hear stories about asking neighbors to care for kids or coming together as community. Instead we become insular, privatized communities, and look for
technological solutions to what are really social problems.” Indeed, while our parents’ generation was taught to “honor thy neighbor,” the mantra for today’s kids is “stranger danger,” and the message is clear—expect the worst of anyone unfamiliar—anywhere, and at any time.

This is security based on fear, not reason. And I think people who act this way make their families less safe.

EDITED TO ADD: Here’s a link to the book Paranoid Parenting.

Posted on August 3, 2005 at 8:38 AMView Comments

Eavesdropping on Bluetooth Automobiles

This is impressive:

This new toool is called The Car Whisperer and allows people equipped with a Linux Laptop and a directional antenna to inject audio to, and record audio from bypassing cars that have an unconnected Bluetooth handsfree unit running. Since many manufacturers use a standard passkey which often is the only authentication that is needed to connect.

This tool allows to interact with other drivers when traveling or maybe used in order to talk to that pushy Audi driver right behind you 😉 . It also allows to eavesdrop conversations in the inside of the car by accessing the microphone.

EDITED TO ADD: Another article.

Posted on August 2, 2005 at 1:41 PMView Comments

Backscatter X-Ray Technology

Backscatter X-ray technology is a method of using X rays to see inside objects. The science is complicated, but the upshot is that you can see people naked:

The application of this new x-ray technology to airport screening uses high energy x-rays that are more likely to scatter than penetrate materials as compared to lower-energy x-rays used in medical applications. Although this type of x-ray is said to be harmless it can move through other materials, such as clothing.

A passenger is scanned by rastering or moving a single high energy x-ray beam rapidly over their form. The signal strength of detected backscattered x-rays from a known position then allows a highly realistic image to be reconstructed. Since only Compton scattered x-rays are used, the registered image is mainly that of the surface of the object/person being imaged. In the case of airline passenger screening it is her nude form. The image resolution of the technology is high, so details of the human form of airline passengers present privacy challenges.

EPIC’s “Spotlight on Security” page is an excellent resource on this issue.

The TSA has recently announced a proposal to use these machines to screen airport passengers.

I’m not impressed with this security trade-off. Yes, backscatter X-ray machines might be able to detect things that conventional screening might miss. But I already think we’re spending too much effort screening airplane passengers at the expense of screening luggage and airport employees…to say nothing of the money we should be spending on non-airport security.

On the other side, these machines are expensive and the technology is incredibly intrusive. I don’t think that people should be subjected to strip searches before they board airplanes. And I believe that most people would be appalled by the prospect of security screeners seeing them naked.

I believe that there will be a groundswell of popular opposition to this idea. Aside from the usual list of pro-privacy and pro-liberty groups, I expect fundamentalist Christian groups to be appalled by this technology. I think we can get a bevy of supermodels to speak out against the invasiveness of the search.

News article

Posted on June 9, 2005 at 1:04 PMView Comments

Billions Wasted on Anti-Terrorism Security

Recently there have been a bunch of news articles about how lousy counterterrorism security is in the United States, how billions of dollars have been wasted on security since 9/11, and how much of what was purchased doesn’t work as advertised.

The first is from the May 8 New York Times (available at the website for pay, but there are copies here and here):

After spending more than $4.5 billion on screening devices to monitor the nation’s ports, borders, airports, mail and air, the federal government is moving to replace or alter much of the antiterrorism equipment, concluding that it is ineffective, unreliable or too expensive to operate.

Many of the monitoring tools—intended to detect guns, explosives, and nuclear and biological weapons—were bought during the blitz in security spending after the attacks of Sept. 11, 2001.

In its effort to create a virtual shield around America, the Department of Homeland Security now plans to spend billions of dollars more. Although some changes are being made because of technology that has emerged in the last couple of years, many of them are planned because devices currently in use have done little to improve the nation’s security, according to a review of agency documents and interviews with federal officials and outside experts.

From another part of the article:

Among the problems:

  • Radiation monitors at ports and borders that cannot differentiate between radiation emitted by a nuclear bomb and naturally occurring radiation from everyday material like cat litter or ceramic tile.
  • Air-monitoring equipment in major cities that is only marginally effective because not enough detectors were deployed and were sometimes not properly calibrated or installed. They also do not produce results for up to 36 hours—long after a biological attack would potentially infect thousands of people.
  • Passenger-screening equipment at airports that auditors have found is no more likely than before federal screeners took over to detect whether someone is trying to carry a weapon or a bomb aboard a plane.
  • Postal Service machines that test only a small percentage of mail and look for anthrax but no other biological agents.

The Washington Post had a series of articles. The first lists some more problems:

  • The contract to hire airport passenger screeners grew to $741 million from $104 million in less than a year. The screeners are failing to detect weapons at roughly the same rate as shortly after the attacks.
  • The contract for airport bomb-detection machines ballooned to at least $1.2 billion from $508 million over 18 months. The machines have been hampered by high false-alarm rates.
  • A contract for a computer network called US-VISIT to screen foreign visitors could cost taxpayers $10 billion. It relies on outdated technology that puts the project at risk.
  • Radiation-detection machines worth a total of a half-billion dollars deployed to screen trucks and cargo containers at ports and borders have trouble distinguishing between highly enriched uranium and common household products. The problem has prompted costly plans to replace the machines.

The second is about border security.

And more recently, a New York Times article on how lousy port security is.

There are a lot of morals here: the problems of believing companies that have something to sell you, the difficulty of making technological security solutions work, the problems with making major security changes quickly, the mismanagement that comes from any large bureaucracy like the DHS, and the wastefulness of defending potential terrorist targets instead of broadly trying to deal with terrorism.

Posted on June 3, 2005 at 8:17 AMView Comments

Battlefield RFID Listening Rocks

From the Financial Times:

The US military is developing miniature electronic sensors disguised as rocks that can be dropped from an aircraft and used to help detect the sound of approaching enemy combatants.

The devices, which would be no larger than a golf ball, could be ready for use in about 18 months. They use tiny silicon chips and radio frequency identification (RFID) technology that is so sensitive that it can detect the sound of a human footfall at 20ft to 30ft. The project is being carried out by scientists at North Dakota State University, which has licensed nano-technology processes from Alien Technology, a California-based commercial manufacturer of RFID tags for supermarkets.

This kind of thing has been discussed for a while. One of the best discussions is still Martin Libicki’s paper from the mid-1990s, “The Mesh and the Net: Speculations on Armed Conflict in a Time of Free Silicon.” (It’s available as a book, and online.)

Posted on June 2, 2005 at 8:14 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.