Entries Tagged "cameras"
Page 20 of 22
Digital Cameras Have Unique Fingerprints
Fridrich’s technique is rooted in the discovery by her research group of this simple fact: Every original digital picture is overlaid by a weak noise-like pattern of pixel-to-pixel non-uniformity.
Although these patterns are invisible to the human eye, the unique reference pattern or “fingerprint” of any camera can be electronically extracted by analyzing a number of images taken by a single camera.
That means that as long as examiners have either the camera that took the image or multiple images they know were taken by the same camera, an algorithm developed by Fridrich and her co-inventors to extract and define the camera’s unique pattern of pixel-to-pixel non-uniformity can be used to provide important information about the origins and authenticity of a single image.
The limitation of the technique is that it requires either the camera or multiple images taken by the same camera, and isn’t informative if only a single image is available for analysis.
Like actual fingerprints, the digital “noise” in original images is stochastic in nature that is, it contains random variables which are inevitably created during the manufacturing process of the camera and its sensors. This virtually ensures that the noise imposed on the digital images from any particular camera will be consistent from one image to the next, even while it is distinctly different.
In preliminary tests, Fridrich’s lab analyzed 2,700 pictures taken by nine digital cameras and with 100 percent accuracy linked individual images with the camera that took them.
There’s one important aspect of this fingerprint that the article did not talk about: how easy is it to forge? Can someone analyze 100 images from a given camera, and then doctor a pre-existing picture so that it appeared to come from that camera?
My guess is that it can be done relatively easily.
80 Cameras for 2,400 People
This story is about the remote town of Dillingham, Alaska, which is probably the most watched town in the country. There are 80 surveillance cameras for the 2,400 people, which translates to one camera for every 30 people.
The cameras were bought, I assume, because the town couldn’t think of anything else to do with the $202,000 Homeland Security grant they received. (One of the problems of giving this money out based on political agenda, rather than by where the actual threats are.)
But they got the money, and they spent it. And now they have to justify the expense. Here’s the movie-plot threat the Dillingham Police Chief uses to explain why the expense was worthwhile:
“Russia is about 800 miles that way,” he says, arm extending right.
“Seattle is about 1,200 miles back that way.” He points behind him.
“So if I have the math right, we’re closer to Russia than we are to Seattle.”
Now imagine, he says: What if the bad guys, whoever they are, manage to obtain a nuclear device in Russia, where some weapons are believed to be poorly guarded. They put the device in a container and then hire organized criminals, “maybe Mafiosi,” to arrange a tramp steamer to pick it up. The steamer drops off the container at the Dillingham harbor, complete with forged paperwork to ship it to Seattle. The container is picked up by a barge.
“Ten days later,” the chief says, “the barge pulls into the Port of Seattle.”
Thompson pauses for effect.
“Phoooom,” he says, his hands blooming like a flower.
The first problem with the movie plot is that it’s just plain silly. But the second problem, which you might have to look back to notice, is that those 80 cameras will do nothing to stop his imagined attack.
We are all security consumers. We spend money, and we expect security in return. This expenditure was a waste of money, and as a U.S. taxpayer, I am pissed that I’m getting such a lousy deal.
The Future of Privacy
Over the past 20 years, there’s been a sea change in the battle for personal privacy.
The pervasiveness of computers has resulted in the almost constant surveillance of everyone, with profound implications for our society and our freedoms. Corporations and the police are both using this new trove of surveillance data. We as a society need to understand the technological trends and discuss their implications. If we ignore the problem and leave it to the “market,” we’ll all find that we have almost no privacy left.
Most people think of surveillance in terms of police procedure: Follow that car, watch that person, listen in on his phone conversations. This kind of surveillance still occurs. But today’s surveillance is more like the NSA’s model, recently turned against Americans: Eavesdrop on every phone call, listening for certain keywords. It’s still surveillance, but it’s wholesale surveillance.
Wholesale surveillance is a whole new world. It’s not “follow that car,” it’s “follow every car.” The National Security Agency can eavesdrop on every phone call, looking for patterns of communication or keywords that might indicate a conversation between terrorists. Many airports collect the license plates of every car in their parking lots, and can use that database to locate suspicious or abandoned cars. Several cities have stationary or car-mounted license-plate scanners that keep records of every car that passes, and save that data for later analysis.
More and more, we leave a trail of electronic footprints as we go through our daily lives. We used to walk into a bookstore, browse, and buy a book with cash. Now we visit Amazon, and all of our browsing and purchases are recorded. We used to throw a quarter in a toll booth; now EZ Pass records the date and time our car passed through the booth. Data about us are collected when we make a phone call, send an e-mail message, make a purchase with our credit card, or visit a website.
Much has been written about RFID chips and how they can be used to track people. People can also be tracked by their cell phones, their Bluetooth devices, and their WiFi-enabled computers. In some cities, video cameras capture our image hundreds of times a day.
The common thread here is computers. Computers are involved more and more in our transactions, and data are byproducts of these transactions. As computer memory becomes cheaper, more and more of these electronic footprints are being saved. And as processing becomes cheaper, more and more of it is being cross-indexed and correlated, and then used for secondary purposes.
Information about us has value. It has value to the police, but it also has value to corporations. The Justice Department wants details of Google searches, so they can look for patterns that might help find child pornographers. Google uses that same data so it can deliver context-sensitive advertising messages. The city of Baltimore uses aerial photography to surveil every house, looking for building permit violations. A national lawn-care company uses the same data to better market its services. The phone company keeps detailed call records for billing purposes; the police use them to catch bad guys.
In the dot-com bust, the customer database was often the only salable asset a company had. Companies like Experian and Acxiom are in the business of buying and reselling this sort of data, and their customers are both corporate and government.
Computers are getting smaller and cheaper every year, and these trends will continue. Here’s just one example of the digital footprints we leave:
It would take about 100 megabytes of storage to record everything the fastest typist input to his computer in a year. That’s a single flash memory chip today, and one could imagine computer manufacturers offering this as a reliability feature. Recording everything the average user does on the Internet requires more memory: 4 to 8 gigabytes a year. That’s a lot, but “record everything” is Gmail’s model, and it’s probably only a few years before ISPs offer this service.
The typical person uses 500 cell phone minutes a month; that translates to 5 gigabytes a year to save it all. My iPod can store 12 times that data. A “life recorder” you can wear on your lapel that constantly records is still a few generations off: 200 gigabytes/year for audio and 700 gigabytes/year for video. It’ll be sold as a security device, so that no one can attack you without being recorded. When that happens, will not wearing a life recorder be used as evidence that someone is up to no good, just as prosecutors today use the fact that someone left his cell phone at home as evidence that he didn’t want to be tracked?
In a sense, we’re living in a unique time in history. Identification checks are common, but they still require us to whip out our ID. Soon it’ll happen automatically, either through an RFID chip in our wallet or face-recognition from cameras. And those cameras, now visible, will shrink to the point where we won’t even see them.
We’re never going to stop the march of technology, but we can enact legislation to protect our privacy: comprehensive laws regulating what can be done with personal information about us, and more privacy protection from the police. Today, personal information about you is not yours; it’s owned by the collector. There are laws protecting specific pieces of personal data—videotape rental records, health care information—but nothing like the broad privacy protection laws you find in European countries. That’s really the only solution; leaving the market to sort this out will result in even more invasive wholesale surveillance.
Most of us are happy to give out personal information in exchange for specific services. What we object to is the surreptitious collection of personal information, and the secondary use of information once it’s collected: the buying and selling of our information behind our back.
In some ways, this tidal wave of data is the pollution problem of the information age. All information processes produce it. If we ignore the problem, it will stay around forever. And the only way to successfully deal with it is to pass laws regulating its generation, use and eventual disposal.
This essay was originally published in the Minneapolis Star-Tribune.
Police Cameras in Your Home
This is so nutty that I wasn’t even going to blog it. But too many of you are e-mailing the article to me.
Houston’s police chief on Wednesday proposed placing surveillance cameras in apartment complexes, downtown streets, shopping malls and even private homes to fight crime during a shortage of police officers.
“I know a lot of people are concerned about Big Brother, but my response to that is, if you are not doing anything wrong, why should you worry about it?” Chief Harold Hurtt told reporters Wednesday at a regular briefing.
One of the problems we have in the privacy community is that we don’t have a crisp answer to that question. Any suggestions?
Photographing Airports
Patrick Smith, a former pilot, writes about his experiences—involving the police—taking pictures in airports:
He makes sure to remind me, just as his colleague in New Hampshire
had done, that next time I’d benefit from advance permission, and that “we live in a different world now.” Not to put undue weight on the cheap prose of patriotic convenience, but few things are more repellant than that oft- repeated catchphrase. There’s something so pathetically submissive about it—a sound bite of such defeat and capitulation. It’s also untrue; indeed we find ourselves in an altered way of life, though not for the reasons our protectors would have us think. We weren’t forced into this by terrorists, we’ve chosen it. When it comes to flying, we tend to hold the events of Sept. 11 as the be-all and end-all of air crimes, conveniently purging our memories of several decades’ worth of bombings and hijackings. The threats and challenges faced by airports aren’t terribly different from what they’ve always been. What’s different, or “too bad,” to quote the New Hampshire deputy, is our paranoid, overzealous reaction to those threats, and our amped-up obeisance to authority.
Who Watches the Watchers?
One problem with cameras is that you can’t trust the watchers not to misuse them:
Two council CCTV camera operators have been jailed for spying on a naked woman in her own home.
Mark Summerton and Kevin Judge, from Sefton Council, Merseyside, trained a street camera into the woman’s flat.
[…]
The images from the camera, including the woman without her clothes on, were shown on a large plasma screen in the council’s CCTV control room in November 2004, Liverpool Crown Court heard.
Over several hours, she was filmed cuddling her boyfriend before undressing, using the toilet, having a bath and watching television dressed only in a towel.
Judge Gerald Clifton told the three men: “To dismiss what was happening as laddish behaviour, something that the 21st Century apparently condones, is absurd.
“You only have to read the impact statements of the lady to realise the harrowing effect that this had on her.
“Her life has almost been ruined, her self-confidence entirely destroyed by the thought that prying male eyes have entered her flat.”
Also, The Register reported on this.
Now Everyone Gets to Watch the Cameras
From The Times:
Residents of a trendy London neighbourhood are to become the first in Britain to receive “Asbo TV”—television beamed live to their homes from CCTV cameras on the surrounding streets.
As part of the £12m scheme funded by the Office of the Deputy Prime Minister, residents of Shoreditch in the East End will also be able to compare characters they see behaving suspiciously with an on-screen “rogues’ gallery” of local recipients of anti-social behaviour orders (Asbos).
Viewers will then be able to use an anonymous e-mail tip-off system to report to the police anyone they see breaching an Asbo or committing a crime.
Someone knows what the deal is here:
“The CCTV element is part curiosity, like a 21st-century version of Big Brother, and partly about security,” said Atul Hatwell, of the Shoreditch Digital Bridge project.
Certainly this kind of system can be abused, but my guess is that worrying about this is kind of silly:
Andrew Duff, a Conservative councillor, raised concerns about the system being adopted by burglars to check unoccupied properties. “It could be used by dishonest people as well,” he said.
My guess is that this sort of system will reduce the crime rate, as criminals move to neighborhoods without these sorts of systems. But once everyone has this sort of system, criminals will adapt and the crime rate will return to its original rate.
Meanwhile, everybody loses more privacy.
Taser Cam
Here’s an excellent use for cameras:
Now, to help better examine how Tasers are used, manufacturer Taser International Inc. has developed a Taser Cam, which company executives hope will illuminate why Tasers are needed—and add another layer of accountability for any officer who would abuse the weapon.
The Taser Cam is an audio and video recorder that attaches to the butt of the gun and starts taping when the weapon is turned on. It continues recording until the weapon is turned off. The Taser doesn’t have to be fired to use the camera.
It’s the same idea as having cameras record all police interrogations, or record all police-car stops. It helps protect the populace against police abuse, and helps protect the police of accusations of abuse.
This is where cameras do good: when they lessen a power imbalance. Imagine if they were continuously recording the actions of elected officials—when they were acting in their official capacity, that is.
Of course, cameras are only as useful as their data. If critical recordings are “lost,” then there’s no accountability. The system is pretty kludgy:
The Taser Cam records in black and white but is equipped with infrared technology to record images in very low light. The camera will have at least one hour of recording time, the company said, and the video can be downloaded to a computer over a USB cable.
How soon before the cameras simply upload their recordings, in real time, to some trusted vault somewhere?
EDITED TO ADD: CNN has a story.
Instantaneous Data Grabbing
I think this is a harbinger of the future:
A high roller walks into the casino, ever so mindful of the constant surveillance cameras. Wanting to avoid sales pitches and other unwanted attention, he pays cash at each table and anonymously moves around frequently to discourage people who are trying to track his movements.
After a few hours of losses, he goes to the cashier and asks for a cash advance off of his credit card. The card tells the casino his name, but not much else. As is required by card issuers, the cashier asks for some other identification, such as a driver’s license. That license offers the casino a ton of CRM identification goodies, but the cashier is only supposed to glance at the picture and the name to verify identity and hand the license—and its info treasure trove—back to the gambler.
Not any more, at least if a Minneapolis company called Cash Systems Inc. has anything to say about it. The firm was recently awarded a U.S. patent for a device that can grab all of the data of almost any U.S. driver’s license in seconds and instantly dump it into a casino’s CRM system.
On the one hand, the technology isn’t very interesting; it’s probably just a camera and some OCR software optimized for driver’s licenses. But what is interesting is that the technology is available as a mass-market product.
Where else do you routinely show your ID? Who else might want all that information for marketing purposes?
Sidebar photo of Bruce Schneier by Joe MacInnis.