Entries Tagged "cameras"

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Spying on Computer Monitors Off Reflective Objects

Impressive research:

At Saarland University, researchers trained a $500 telescope on a teapot near a computer monitor 5 meters away. The images are tiny but amazingly clear, professor Michael Backes told IDG.

All it took was a $500 telescope trained on a reflective object in front of the monitor. For example, a teapot yielded readable images of 12 point Word documents from a distance of 5 meters (16 feet). From 10 meters, they were able to read 18 point fonts. With a $27,500 Dobson telescope, they could get the same quality of images at 30 meters.

Here’s the paper:

Abstract

We present a novel eavesdropping technique for spying at a distance on data that is displayed on an arbitrary computer screen, including the currently prevalent LCD monitors. Our technique exploits reflections of the screen’s optical emanations in various objects that one commonly finds in close proximity to the screen and uses those reflections to recover the original screen content. Such objects include eyeglasses, tea pots, spoons, plastic bottles, and even the eye of the user. We have demonstrated that this attack can be successfully mounted to spy on even small fonts using inexpensive, off-the-shelf equipment (less than 1500 dollars) from a distance of up to 10 meters. Relying on more expensive equipment allowed us to conduct this attack from over 30 meters away, demonstrating that similar attacks are feasible from the other side of the street or from a close-by building. We additionally establish theoretical limitations of the attack; these limitations may help to estimate the risk that this attack can be successfully mounted in a given environment.

Posted on May 20, 2008 at 10:44 AM • View Comments

London's Cameras Don't Reduce Crime

News here and here:

Massive investment in CCTV cameras to prevent crime in the UK has failed to have a significant impact, despite billions of pounds spent on the new technology, a senior police officer piloting a new database has warned. Only 3% of street robberies in London were solved using CCTV images, despite the fact that Britain has more security cameras than any other country in Europe.

[…]

Use of CCTV images for court evidence has so far been very poor, according to Detective Chief Inspector Mick Neville, the officer in charge of the Metropolitan police unit. “CCTV was originally seen as a preventative measure,” Neville told the Security Document World Conference in London. “Billions of pounds has been spent on kit, but no thought has gone into how the police are going to use the images and how they will be used in court. It’s been an utter fiasco: only 3% of crimes were solved by CCTV. There’s no fear of CCTV. Why don’t people fear it? [They think] the cameras are not working.”

This is, of course is absolutely no surprise.

Posted on May 7, 2008 at 6:53 AM • View Comments

The Ineffectiveness of Security Cameras

Data from San Francisco:

Researchers examined data from the San Francisco Police Department detailing the 59,706 crimes committed within 1,000 feet of the camera locations between Jan. 1, 2005, and Jan. 28, 2008.

These were the total number of crimes for which police had reports—regardless of whether the crimes were caught on video. The idea was to look at whether criminals stopped committing crimes at those locations because they knew cameras were there.

Using a complicated method, researchers were able to come up with an average daily crime rate at each location broken out by type of crime and distance from the cameras. They then compared it with the average daily crime rate from the period before the cameras were installed.

They looked at seven types of crime: larcenies, burglaries, motor vehicle theft, assault, robbery, homicide and forcible sex offenses.

The only positive deterrent effect was the reduction of larcenies within 100 feet of the cameras. No other crimes were affected—except for homicides, which had an interesting pattern.

Murders went down within 250 feet of the cameras, but the reduction was completely offset by an increase 250 to 500 feet away, suggesting people moved down the block before killing each other.

The final report is expected to analyze the figures in more depth and to include other crimes, including prostitution and drug offenses.

This quote is instructive:

Mayor Gavin Newsom called the report “conclusively inconclusive” on Thursday but said he still wants to install more cameras around the city because they make residents feel safer.

That’s right: the cameras aren’t about security, they’re about security theater. More comments on the general issue here.

Posted on April 7, 2008 at 1:33 PM • View Comments

The Liquid Bomb

We finally have some actual information about the “liquid bomb” that was planned by that London group arrested in 2006:

The court heard the bombers intended to use hydrogen peroxide and mix it with a product called Tang, used in soft drinks, to turn it into an explosive.

They intended to carry it on board disguised as 500ml bottles of Oasis or Lucozade by using food dye to recreate the drinks’ distinctive colour.

The detonator would have been disguised as AA 1.5 batteries. The contents of the batteries would have been removed and an electric element such as a lightbulb or wiring would have been inserted.

A disposable camera would have provided a power source.

Any chemists want to take a crack at this one?

Posted on April 3, 2008 at 5:11 PM • View Comments

Speeding Tickets and Agenda

If you ever need an example to demonstrate that security is a function of agenda, use this story about speed cameras. Cities that have installed speed cameras are discovering motorists are driving slower, which is decreasing revenues from fines. So they’re turning the cameras off.

Perhaps a better solution would be to raise the fines to the remaining speeders to make up for the lost revenue?

EDITED TO ADD (3/31): Too many people thought that above comment was serious. It’s not. The whole incident illustrates why fines should never be considered part of a revenue stream: it gives the police a whole new agenda.

Posted on March 28, 2008 at 1:42 PM •

Camera that Sees Under Clothes

Interesting:

A British company has developed a camera that can detect weapons, drugs or explosives hidden under people’s clothes from up to 25 meters away in what could be a breakthrough for the security industry.

The T5000 camera, created by a company called ThruVision, uses what it calls “passive imaging technology” to identify objects by the natural electromagnetic rays—known as Terahertz or T-rays—that they emit.

The high-powered camera can detect hidden objects from up to 80 feet away and is effective even when people are moving. It does not reveal physical body details and the screening is harmless, the company says.

If this is real, it seems much less invasive than backscatter X ray.

Posted on March 17, 2008 at 6:30 AM • View Comments

Privacy and Power

When I write and speak about privacy, I am regularly confronted with the mutual disclosure argument. Explained in books like David Brin’s The Transparent Society, the argument goes something like this: In a world of ubiquitous surveillance, you’ll know all about me, but I will also know all about you. The government will be watching us, but we’ll also be watching the government. This is different than before, but it’s not automatically worse. And because I know your secrets, you can’t use my secrets as a weapon against me.

This might not be everybody’s idea of utopia—and it certainly doesn’t address the inherent value of privacy—but this theory has a glossy appeal, and could easily be mistaken for a way out of the problem of technology’s continuing erosion of privacy. Except it doesn’t work, because it ignores the crucial dissimilarity of power.

You cannot evaluate the value of privacy and disclosure unless you account for the relative power levels of the discloser and the disclosee.

If I disclose information to you, your power with respect to me increases. One way to address this power imbalance is for you to similarly disclose information to me. We both have less privacy, but the balance of power is maintained. But this mechanism fails utterly if you and I have different power levels to begin with.

An example will make this clearer. You’re stopped by a police officer, who demands to see identification. Divulging your identity will give the officer enormous power over you: He or she can search police databases using the information on your ID; he or she can create a police record attached to your name; he or she can put you on this or that secret terrorist watch list. Asking to see the officer’s ID in return gives you no comparable power over him or her. The power imbalance is too great, and mutual disclosure does not make it OK.

You can think of your existing power as the exponent in an equation that determines the value, to you, of more information. The more power you have, the more additional power you derive from the new data.

Another example: When your doctor says “take off your clothes,” it makes no sense for you to say, “You first, doc.” The two of you are not engaging in an interaction of equals.

This is the principle that should guide decision-makers when they consider installing surveillance cameras or launching data-mining programs. It’s not enough to open the efforts to public scrutiny. All aspects of government work best when the relative power between the governors and the governed remains as small as possible—when liberty is high and control is low. Forced openness in government reduces the relative power differential between the two, and is generally good. Forced openness in laypeople increases the relative power, and is generally bad.

Seventeen-year-old Erik Crespo was arrested in 2005 in connection with a shooting in a New York City elevator. There’s no question that he committed the shooting; it was captured on surveillance-camera videotape. But he claimed that while being interrogated, Detective Christopher Perino tried to talk him out of getting a lawyer, and told him that he had to sign a confession before he could see a judge.

Perino denied, under oath, that he ever questioned Crespo. But Crespo had received an MP3 player as a Christmas gift, and surreptitiously recorded the questioning. The defense brought a transcript and CD into evidence. Shortly thereafter, the prosecution offered Crespo a better deal than originally proffered (seven years rather than 15). Crespo took the deal, and Perino was separately indicted on charges of perjury.

Without that recording, it was the detective’s word against Crespo’s. And who would believe a murder suspect over a New York City detective? That power imbalance was reduced only because Crespo was smart enough to press the “record” button on his MP3 player. Why aren’t all interrogations recorded? Why don’t defendants have the right to those recordings, just as they have the right to an attorney? Police routinely record traffic stops from their squad cars for their own protection; that video record shouldn’t stop once the suspect is no longer a threat.

Cameras make sense when trained on police, and in offices where lawmakers meet with lobbyists, and wherever government officials wield power over the people. Open-government laws, giving the public access to government records and meetings of governmental bodies, also make sense. These all foster liberty.

Ubiquitous surveillance programs that affect everyone without probable cause or warrant, like the National Security Agency’s warrantless eavesdropping programs or various proposals to monitor everything on the internet, foster control. And no one is safer in a political system of control.

This essay originally appeared on Wired.com.

Commentary by David Brin.

Posted on March 11, 2008 at 6:09 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.