Entries Tagged "fingerprints"

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Duress Codes for Fingerprint Access Control

Mike Specter has an interesting idea on how to make biometric access-control systems more secure: add a duress code. For example, you might configure your iPhone so that either thumb or forefinger unlocks the device, but your left middle finger disables the fingerprint mechanism (useful in the US where being compelled to divulge your password is a 5th Amendment violation but being forced to place your finger on the fingerprint reader is not) and the right middle finger permanently wipes the phone (useful in other countries where coercion techniques are much more severe).

Posted on January 26, 2017 at 2:03 PM • View Comments

Stealing Fingerprints

The news from the Office of Personnel Management hack keeps getting worse. In addition to the personal records of over 20 million US government employees, we’ve now learned that the hackers stole fingerprint files for 5.6 million of them.

This is fundamentally different from the data thefts we regularly read about in the news, and should give us pause before we entrust our biometric data to large networked databases.

There are three basic kinds of data that can be stolen. The first, and most common, is authentication credentials. These are passwords and other information that allows someone else access into our accounts and—usually—our money. An example would be the 56 million credit card numbers hackers stole from Home Depot in 2014, or the 21.5 million Social Security numbers hackers stole in the OPM breach. The motivation is typically financial. The hackers want to steal money from our bank accounts, process fraudulent credit card charges in our name, or open new lines of credit or apply for tax refunds.

It’s a huge illegal business, but we know how to deal with it when it happens. We detect these hacks as quickly as possible, and update our account credentials as soon as we detect an attack. (We also need to stop treating Social Security numbers as if they were secret.)

The second kind of data stolen is personal information. Examples would be the medical data stolen and exposed when Sony was hacked in 2014, or the very personal data from the infidelity website Ashley Madison stolen and published this year. In these instances, there is no real way to recover after a breach. Once the data is public, or in the hands of an adversary, it’s impossible to make it private again.

This is the main consequence of the OPM data breach. Whoever stole the data—we suspect it was the Chinese—got copies the security-clearance paperwork of all those government employees. This documentation includes the answers to some very personal and embarrassing questions, and now opens these employees up to blackmail and other types of coercion.

Fingerprints are another type of data entirely. They’re used to identify people at crime scenes, but increasingly they’re used as an authentication credential. If you have an iPhone, for example, you probably use your fingerprint to unlock your phone. This type of authentication is increasingly common, replacing a password—something you know—with a biometric: something you are. The problem with biometrics is that they can’t be replaced. So while it’s easy to update your password or get a new credit card number, you can’t get a new finger.

And now, for the rest of their lives, 5.6 million US government employees need to remember that someone, somewhere, has their fingerprints. And we really don’t know the future value of this data. If, in twenty years, we routinely use our fingerprints at ATM machines, that fingerprint database will become very profitable to criminals. If fingerprints start being used on our computers to authorize our access to files and data, that database will become very profitable to spies.

Of course, it’s not that simple. Fingerprint readers employ various technologies to prevent being fooled by fake fingers: detecting temperature, pores, a heartbeat, and so on. But this is an arms race between attackers and defenders, and there are many ways to fool fingerprint readers. When Apple introduced its iPhone fingerprint reader, hackers figured out how to fool it within days, and have continued to fool each new generation of phone readers equally quickly.

Not every use of biometrics requires the biometric data to be stored in a central server somewhere. Apple’s system, for example, only stores the data locally: on your phone. That way there’s no central repository to be hacked. And many systems don’t store the biometric data at all, only a mathematical function of the data that can be used for authentication but can’t be used to reconstruct the actual biometric. Unfortunately, OPM stored copies of actual fingerprints.

Ashley Madison has taught us all the dangers of entrusting our intimate secrets to a company’s computers and networks, because once that data is out there’s no getting it back. All biometric data, whether it be fingerprints, retinal scans, voiceprints, or something else, has that same property. We should be skeptical of any attempts to store this data en masse, whether by governments or by corporations. We need our biometrics for authentication, and we can’t afford to lose them to hackers.

This essay previously appeared on Motherboard.

Posted on October 2, 2015 at 6:35 AM • View Comments

Fingerprinting Computers By Making Them Draw Images

Here’s a new way to identify individual computers over the Internet. The page instructs the browser to draw an image. Because each computer draws the image slightly differently, this can be used to uniquely identify each computer. This is a big deal, because there’s no way to block this right now.

Article. Hacker News thread.

EDITED TO ADD (7/22): This technique was first described in 2012. And it seems that NoScript blocks this. Privacy Badger probably blocks it, too.

EDITED TO ADD (7/23): EFF has a good post on who is using this tracking system—the White House is—and how to defend against it.

And a good story on BoingBoing.

Posted on July 21, 2014 at 3:34 PM • View Comments

Tracking People from Smartphone Accelerometers

It’s been long known that individual analog devices have their own fingerprints. Decades ago, individual radio transmitters were identifiable and trackable. Now, researchers have found that accelerometers in smartphone are unique enough to be identifiable.

The researchers focused specifically on the accelerometer, a sensor that tracks three-dimensional movements of the phone ­ essential for countless applications, including pedometers, sleep monitoring, mobile gaming ­ but their findings suggest that other sensors could leave equally unique fingerprints.

“When you manufacture the hardware, the factory cannot produce the identical thing in millions,” Roy said. “So these imperfections create fingerprints.”

Of course, these fingerprints are only visible when accelerometer data signals are analyzed in detail. Most applications do not require this level of analysis, yet the data shared with all applications—your favorite game, your pedometer—bear the mark. Should someone want to perform this analysis, they could do so.

The researchers tested more than 100 devices over the course of nine months: 80 standalone accelerometer chips used in popular smartphones, 25 Android phones and two tablets.

The accelerometers in all permutations were selected from different manufacturers, to ensure that the fingerprints weren’t simply defects resulting from a particular production line.

With 96-percent accuracy, the researchers could discriminate one sensor from another.

Posted on April 30, 2014 at 1:05 PM • View Comments

Details of Apple's Fingerprint Recognition

This is interesting:

Touch ID takes a 88×88 500ppi scan of your finger and temporarily sends that data to a secure cache located near the RAM, after the data is vectorized and forwarded to the secure enclave located on the top left of the A7 near the M7 processor it is immediately discarded after processing. The fingerprint scanner uses subdermal ridge flows (inner layer of skin) to prevent loss of accuracy if you were to have micro cuts or debris on your finger.

With iOS 7.1.1 Apple now takes multiple scans of each position you place finger at setup instead of a single one and uses algorithms to predict potential errors that could arise in the future. Touch ID was supposed to gradually improve accuracy with every scan but the problem was if you didn’t scan well on setup it would ruin your experience until you re-setup your finger. iOS 7.1.1 not only removes that problem and increases accuracy but also greatly reduces the calculations your iPhone 5S had to make while unlocking the device which means you should get a much faster unlock time.

Posted on April 29, 2014 at 6:47 AM • View Comments

Fingerprinting Burner Phones

In one of the documents recently released by the NSA as a result of an EFF lawsuit, there’s discussion of a specific capability of a call records database to identify disposable “burner” phones.

Let’s consider, then, the very specific data this query tool was designed to return: The times and dates of the first and last call events, but apparently not the times and dates of calls between those endpoints. In other words, this tool is supporting analytic software that only cares when a phone went online, and when it stopped being used. It also gets the total number of calls, and the ratio of unique contacts to calls, but not the specific numbers contacted. Why, exactly, would this limited set of information be useful? And why, in particular, might you want to compare that information across a large number of phones there’s not yet any particular reason to suspect?

One possibility that jumps out at me—and perhaps anyone else who’s a fan of The Wire—is that this is the kind of information you would want if you were trying to identify disposable prepaid “burner” phones being used by a target who routinely cycles through cell phones as a countersurveillance tactic. The number of unique contacts and call/contact ratio would act as a kind of rough fingerprint—you’d assume a phone being used for dedicated clandestine purposes to be fairly consistent on that score—while the first/last call dates help build a timeline: You’re looking for a series of phones that are used for a standard amount of time, and then go dead just as the next phone goes online.

Consider this another illustration of the value of metadata.

Posted on October 14, 2013 at 6:37 AM • View Comments

Apple's iPhone Fingerprint Reader Successfully Hacked

Nice hack from the Chaos Computer Club:

The method follows the steps outlined in this how-to with materials that can be found in almost every household: First, the fingerprint of the enrolled user is photographed with 2400 dpi resolution. The resulting image is then cleaned up, inverted and laser printed with 1200 dpi onto transparent sheet with a thick toner setting. Finally, pink latex milk or white woodglue is smeared into the pattern created by the toner onto the transparent sheet. After it cures, the thin latex sheet is lifted from the sheet, breathed on to make it a tiny bit moist and then placed onto the sensor to unlock the phone. This process has been used with minor refinements and variations against the vast majority of fingerprint sensors on the market.

I’m not surprised. In my essay on Apple’s technology, I wrote: “I’m sure that someone with a good enough copy of your fingerprint and some rudimentary materials engineering capability—or maybe just a good enough printer—can authenticate his way into your iPhone.”

I don’t agree with CCC’s conclusion, though:

“We hope that this finally puts to rest the illusions people have about fingerprint biometrics. It is plain stupid to use something that you can´t change and that you leave everywhere every day as a security token”, said Frank Rieger, spokesperson of the CCC. “The public should no longer be fooled by the biometrics industry with false security claims. Biometrics is fundamentally a technology designed for oppression and control, not for securing everyday device access.”

Apple is trying to balance security with convenience. This is a cell phone, not a ICBM launcher or even a bank account withdrawal device. Apple is offering an option to replace a four-digit PIN—something that a lot of iPhone users don’t even bother with—with a fingerprint. Despite its drawbacks, I think it’s a good trade-off for a lot of people.

EDITED TO ADD (10/13): The print for the CCC hack was lifted from the iPhone.

Posted on September 24, 2013 at 9:20 AM • View Comments

iPhone Fingerprint Authentication

When Apple bought AuthenTec for its biometrics technology—reported as one of its most expensive purchases—there was a lot of speculation about how the company would incorporate biometrics in its product line. Many speculate that the new Apple iPhone to be announced tomorrow will come with a fingerprint authentication system, and there are several ways it could work, such as swiping your finger over a slit-sized reader to have the phone recognize you.

Apple would be smart to add biometric technology to the iPhone. Fingerprint authentication is a good balance between convenience and security for a mobile device.

Biometric systems are seductive, but the reality isn’t that simple. They have complicated security properties. For example, they are not keys. Your fingerprint isn’t a secret; you leave it everywhere you touch.

And fingerprint readers have a long history of vulnerabilities as well. Some are better than others. The simplest ones just check the ridges of a finger; some of those can be fooled with a good photocopy. Others check for pores as well. The better ones verify pulse, or finger temperature. Fooling them with rubber fingers is harder, but often possible. A Japanese researcher had good luck doing this over a decade ago with the gelatin mixture that’s used to make Gummi bears.

The best system I’ve ever seen was at the entry gates of a secure government facility. Maybe you could have fooled it with a fake finger, but a Marine guard with a big gun was making sure you didn’t get the opportunity to try. Disney World uses a similar system at its park gates—but without the Marine guards.

A biometric system that authenticates you and you alone is easier to design than a biometric system that is supposed to identify unknown people. That is, the question “Is this the finger belonging to the owner of this iPhone?” is a much easier question for the system to answer than “Whose finger is this?”

There are two ways an authentication system can fail. It can mistakenly allow an unauthorized person access, or it can mistakenly deny access to an authorized person. In any consumer system, the second failure is far worse than the first. Yes, it can be problematic if an iPhone fingerprint system occasionally allows someone else access to your phone. But it’s much worse if you can’t reliably access your own phone—you’d junk the system after a week.

If it’s true that Apple’s new iPhone will have biometric security, the designers have presumably erred on the side of ensuring that the user can always get in. Failures will be more common in cold weather, when your shriveled fingers just got out of the shower, and so on. But there will certainly still be the traditional PIN system to fall back on.

So…can biometric authentication be hacked?

Almost certainly. I’m sure that someone with a good enough copy of your fingerprint and some rudimentary materials engineering capability—or maybe just a good enough printer—can authenticate his way into your iPhone. But, honestly, if some bad guy has your iPhone and your fingerprint, you’ve probably got bigger problems to worry about.

The final problem with biometric systems is the database. If the system is centralized, there will be a large database of biometric information that’s vulnerable to hacking. A system by Apple will almost certainly be local—you authenticate yourself to the phone, not to any network—so there’s no requirement for a centralized fingerprint database.

Apple’s move is likely to bring fingerprint readers into the mainstream. But all applications are not equal. It’s fine if your fingers unlock your phone. It’s a different matter entirely if your fingerprint is used to authenticate your iCloud account. The centralized database required for that application would create an enormous security risk.

This essay previously appeared on Wired.com.

EDITED TO ADD: The new iPhone does have a fingerprint reader.

Posted on September 11, 2013 at 6:43 AM • View Comments

U.S./Canadian Dispute over Border Crossing Procedures

Interesting:

The main sticking point was Homeland’s unwillingness to accept Canada’s legal problem with having U.S. authorities take fingerprints of people who approach the border but decide not to cross.

Canadian law doesn’t permit fingerprinting unless someone volunteers or has been charged with a crime.

Canada’s assurances that it would co-operate in investigating any suspicious person who approaches the border weren’t enough, said one Capitol Hill source.

“The Attorney General’s office really just wants to grab as much biometric information as it can,” said the source.

Posted on May 6, 2007 at 12:35 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.