Entries Tagged "forensics"

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The Beginnings of a U.S. Government DNA Database

From the Washington Post:

Suspects arrested or detained by federal authorities could be forced to provide samples of their DNA that would be recorded in a central database under a provision of a Senate bill to expand government collection of personal data.

The controversial measure was approved by the Senate Judiciary Committee last week and is supported by the White House, but has not gone to the floor for a vote. It goes beyond current law, which allows federal authorities to collect and record samples of DNA only from those convicted of crimes. The data are stored in an FBI-maintained national registry that law enforcement officials use to aid investigations, by comparing DNA from criminals with evidence found at crime scenes.

[…]

The provision, co-sponsored by Kyl and Sen. John Cornyn (R-Tex.), does not require the government to automatically remove the DNA data of people who are never convicted. Instead, those arrested or detained would have to petition to have their information removed from the database after their cases were resolved.

Posted on September 27, 2005 at 11:31 AM • View Comments

Criminals Learn Forensic Science

Criminals are adapting to advances in forensic science:

There is an increasing trend for criminals to use plastic gloves during break-ins and condoms during rapes to avoid leaving their DNA at the scene. Dostie describes a murder case in which the assailant tried to wash away his DNA using shampoo. Police in Manchester in the UK say that car thieves there have started to dump cigarette butts from bins in stolen cars before they abandon them. “Suddenly the police have 20 potential people in the car,” says Rutty.

The article also talks about forensic-science television shows changing the expectations of jurors.

“Jurors who watch CSI believe that those scenarios, where forensic scientists are always right, are what really happens,” says Peter Bull, a forensic sedimentologist at the University of Oxford. It means that in court, juries are not impressed with evidence presented in cautious scientific terms.

Detective sergeant Paul Dostie, of Mammoth Lakes Police Department, California, found the same thing when he conducted a straw poll of forensic investigators and prosecutors. “They all agree that jurors expect more because of CSI shows,” he says. And the “CSI effect” goes beyond juries, says Jim Fraser, director of the Centre for Forensic Science at the University of Strathclyde, UK. “Oversimplification of interpretations on CSI has led to false expectations, especially about the speed of delivery of forensic evidence,” he says.

Posted on September 9, 2005 at 7:16 AM • View Comments

Lance Armstrong Accused of Doping

Lance Armstrong has been accused of using a banned substance while racing the Tour de France. From a security perspective, this isn’t very interesting. Blood and urine tests are used to detect banned substances all the time. But what is interesting is that the urine sample was from 1999, and the test was done in 2005.

Back in 1999, there was no test for the drug EPO. Now there is. Someone took a old usine sample—who knew that they stored old urine samples?—and ran the new test.

This ability of a security mechanism to go back in time is interesting, and similar to police exhuming dead bodies for new forensic analysis, or a new cryptographic technique permitting decades-old encrypted messages to be read.

It also has some serious ramifications for athletes considering using banned substances. Not only do they have to evade any tests that exist today, but they have to at least think about how they could evade any tests that might be invented in the future. You could easily imagine athletes being stripped of their records, medals, and titles decades in the future after past transgressions are discovered.

On the other hand, athletes accused of using banned substances in the past have limited means by which to defend themselves. Perhaps they will start storing samples of their own blood and urine in escrow, year after year, so they’d have well-stored and untainted bodily fluids with which to refute charges of past transgressions.

Posted on September 7, 2005 at 6:32 AM •

Cryptographically-Secured Murder Confession

From the Associated Press:

Joseph Duncan III is a computer expert who bragged online, days before authorities believe he killed three people in Idaho, about a tell-all journal that would not be accessed for decades, authorities say.

Duncan, 42, a convicted sex offender, figured technology would catch up in 30 years, “and then the world will know who I really was, and what I really did, and what I really thought,” he wrote May 13.

Police seized Duncan’s computer equipment from his Fargo apartment last August, when they were looking for evidence in a Detroit Lakes, Minn., child molestation case.

At least one compact disc and a part of his hard drive were encrypted well enough that one of the region’s top computer forensic specialists could not access it, The Forum reported Monday.

This is the kind of story that the government likes to use to illustrate the dangers of encryption. How can we allow people to use strong encryption, they ask, if it means not being able to convict monsters like Duncan?

But how is this different than Duncan speaking the confession when no one was able to hear? Or writing it down and hiding it where no one could ever find it? Or not saying anything at all? If the police can’t convict him without this confession—which we only have his word for as existing—then maybe he’s innocent?

Technologies have good and bad uses. Encryption, telephones, cars: they’re all used by both honest citizens and by criminals. For almost all technologies, the good far outweighs the bad. Banning a technology because the bad guys use it, denying everyone else the beneficial uses of that technology, is almost always a bad security trade-off.

EDITED TO ADD: Looking at the details of the encryption, it’s certainly possible that the authorities will break the diary. It probably depends on how random a key Duncan chose, although possibly on whether or not there’s an implementation error in the cryptographic software. If I had more details, I could speculate further.

Posted on August 15, 2005 at 2:17 PM • View Comments

Fingerprinting Paper

This could make an enormous difference in security against forgeries:

The scientists built a laser scanner that sweeps across the surface of paper, cardboard, or plastic, recording all of the unique microscopic imperfections that are a natural part of manufacturing such materials.

This scan serves as a fingerprint which, the scientists said, has two surprising properties: The fingerprints are robust, surviving scorching, dousing in water, crumpling, and scribbling over with pens. And these fingerprints depend on structures that are so complex and so small—on the scale of between one tenth and one ten-thousandth the diameter of a human hair—that nobody on the planet will be able to copy one for the foreseeable future. Unlike other methods such as using holograms or special inks, the fingerprint is already there.

Scientific American has more details:

All nonreflective surfaces are rough on a microscopic level. James D. R. Buchanan and his colleagues at Imperial College London report today in the journal Nature on the potential for this characteristic to “provide strong, in-built, hidden security for a wide range of paper, plastic or cardboard objects.” Using a focused laser to scan a variety of objects, the team measured how the light scattered at four different angles. By calculating how far the light moved from a mean value, and transforming the fluctuations into ones and zeros, the researchers developed a unique fingerprint code for each object. The scanning of two pieces of paper from the same pack yielded two different identifiers, whereas the fingerprint for one sheet stayed the same even after three days of regular use. Furthermore, when the team put the paper through its paces—screwing it into a tight ball, submerging it in cold water, baking it at 180 degrees Celsius, among other abuses—its fingerprint remained easily recognizable.

The team calculates that the odds of two pieces of paper having indistinguishable fingerprints are less than 10-72. For smoother surfaces such as matte-finished plastic cards, the probability increases, but only to 10-20. “Our findings open the way to a new and much simpler approach to authentication and tracking,” co-author Russell Cowburn remarks. “This is a system so secure that not even the inventors would be able to crack it since there is no known manufacturing process for copying surface imperfections at the necessary level of precision.”

To ensure the security of currency, you could fingerprint every bill and store the fingerprints in a large database. Or you can digitally sign the fingerprint and print it on the bill itself. The fingerprint is large enough to use as an encryption key, which opens up a bunch of other security possibilities.

This idea isn’t new. I remember currency anti-counterfeiting research in which fiber-optic bits were added to the paper pulp, and a “fingerprint” was taken using a laser. It didn’t work then, but it was clever.

Posted on August 12, 2005 at 10:30 AM • View Comments

DNA Identification

Here’s an interesting application of DNA identification. Instead of searching for your DNA at the crime scene, they search for the crime-scene DNA on you.

The system, called Sentry, works by fitting a box containing a powder spray above a doorway which, once primed, goes into alert mode if the door is opened.

It then sprays the powder when there is movement in the doorway again.

The aim is to catch a burglar in the act as stolen items are being removed.

The intruder is covered in the bright red powder, which glows under ultraviolet (UV) light and can only be removed with heavy scrubbing.

However, the harmless synthetic DNA contained in the powder sinks into the skin and takes several days, depending on the person’s metabolism, to work its way out.

Posted on June 22, 2005 at 8:39 AM • View Comments

Remote Physical Device Fingerprinting

Here’s the abstract:

We introduce the area of remote physical device fingerprinting, or fingerprinting a physical device, as opposed to an operating system or class of devices, remotely, and without the fingerprinted device’s known cooperation. We accomplish this goal by exploiting small, microscopic deviations in device hardware: clock skews. Our techniques do not require any modification to the fingerprinted devices. Our techniques report consistent measurements when the measurer is thousands of miles, multiple hops, and tens of milliseconds away from the fingerprinted device, and when the fingerprinted device is connected to the Internet from different locations and via different access technologies. Further, one can apply our passive and semi-passive techniques when the fingerprinted device is behind a NAT or firewall, and also when the device’s system time is maintained via NTP or SNTP. One can use our techniques to obtain information about whether two devices on the Internet, possibly shifted in time or IP addresses, are actually the same physical device. Example applications include: computer forensics; tracking, with some probability, a physical device as it connects to the Internet from different public access points; counting the number of devices behind a NAT even when the devices use constant or random IP IDs; remotely probing a block of addresses to determine if the addresses correspond to virtual hosts, e.g., as part of a virtual honeynet; and unanonymizing anonymized network traces.

And an article. Really nice work.

Posted on March 7, 2005 at 3:02 PM • View Comments

Smart Water

No, really. It’s liquid with a unique identifier that is linked to a particular owner.

Forensic Coding combined with microdot technology.

SmartWater has been designed to protect household property and motor vehicles. Each bottle of SmartWater solution contains a unique forensic code, which is assigned to a household or vehicle.

An additional feature of SmartWater Instant is the inclusion tiny micro-dot particles which enable Police to quickly identify the true owner of the property.

The idea is for me to paint this stuff on my valuables as proof of ownership. I think a better idea would be for me to paint it on your valuables, and then call the police.

Posted on February 10, 2005 at 9:20 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.