Entries Tagged "face recognition"

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Obfuscation as a Privacy Tool

This essay discusses the futility of opting out of surveillance, and suggests data obfuscation as an alternative.

We can apply obfuscation in our own lives by using practices and technologies that make use of it, including:

  • The secure browser Tor, which (among other anti-surveillance technologies) muddles our Internet activity with that of other Tor users, concealing our trail in that of many others.
  • The browser plugins TrackMeNot and AdNauseam, which explore obfuscation techniques by issuing many fake search requests and loading and clicking every ad, respectively.
  • The browser extension Go Rando, which randomly chooses your emotional “reactions” on Facebook, interfering with their emotional profiling and analysis.
  • Playful experiments like Adam Harvey’s “HyperFace” project, finding patterns on textiles that fool facial recognition systems ­ not by hiding your face, but by creating the illusion of many faces.

I am generally skeptical about obfuscation tools. I think of this basically as a signal-to-noise problem, and that adding random noise doesn’t do much to obfuscate the signal. But against broad systems of financially motivated corporate surveillance, it might be enough.

Posted on November 5, 2019 at 6:15 AM • View Comments

Public Voice Launches Petition for an International Moratorium on Using Facial Recognition for Mass Surveillance

Coming out of the Privacy Commissioners’ Conference in Albania, Public Voice is launching a petition for an international moratorium on using facial recognition software for mass surveillance.

You can sign on as an individual or an organization. I did. You should as well. No, I don’t think that countries will magically adopt this moratorium. But it’s important for us all to register our dissent.

Posted on October 22, 2019 at 10:12 AM • View Comments

Cardiac Biometric

MIT Technology Review is reporting about an infrared laser device that can identify people by their unique cardiac signature at a distance:

A new device, developed for the Pentagon after US Special Forces requested it, can identify people without seeing their face: instead it detects their unique cardiac signature with an infrared laser. While it works at 200 meters (219 yards), longer distances could be possible with a better laser. “I don’t want to say you could do it from space,” says Steward Remaly, of the Pentagon’s Combatting Terrorism Technical Support Office, “but longer ranges should be possible.”

Contact infrared sensors are often used to automatically record a patient’s pulse. They work by detecting the changes in reflection of infrared light caused by blood flow. By contrast, the new device, called Jetson, uses a technique known as laser vibrometry to detect the surface movement caused by the heartbeat. This works though typical clothing like a shirt and a jacket (though not thicker clothing such as a winter coat).

[…]

Remaly’s team then developed algorithms capable of extracting a cardiac signature from the laser signals. He claims that Jetson can achieve over 95% accuracy under good conditions, and this might be further improved. In practice, it’s likely that Jetson would be used alongside facial recognition or other identification methods.

Wenyao Xu of the State University of New York at Buffalo has also developed a remote cardiac sensor, although it works only up to 20 meters away and uses radar. He believes the cardiac approach is far more robust than facial recognition. “Compared with face, cardiac biometrics are more stable and can reach more than 98% accuracy,” he says.

I have my usual questions about false positives vs false negatives, how stable the biometric is over time, and whether it works better or worse against particular sub-populations. But interesting nonetheless.

Posted on July 8, 2019 at 12:38 PM • View Comments

Technology to Out Sex Workers

Two related stories:

PornHub is using machine learning algorithms to identify actors in different videos, so as to better index them. People are worried that it can really identify them, by linking their stage names to their real names.

Facebook somehow managed to link a sex worker’s clients under her fake name to her real profile.

Sometimes people have legitimate reasons for having two identities. That is becoming harder and harder.

Posted on October 13, 2017 at 6:57 AM • View Comments

Apple's FaceID

This is a good interview with Apple’s SVP of Software Engineering about FaceID.

Honestly, I don’t know what to think. I am confident that Apple is not collecting a photo database, but not optimistic that it can’t be hacked with fake faces. I dislike the fact that the police can point the phone at someone and have it automatically unlock. So this is important:

I also quizzed Federighi about the exact way you “quick disabled” Face ID in tricky scenarios—like being stopped by police, or being asked by a thief to hand over your device.

“On older phones the sequence was to click 5 times [on the power button], but on newer phones like iPhone 8 and iPhone X, if you grip the side buttons on either side and hold them a little while—we’ll take you to the power down [screen]. But that also has the effect of disabling Face ID,” says Federighi. “So, if you were in a case where the thief was asking to hand over your phone—you can just reach into your pocket, squeeze it, and it will disable Face ID. It will do the same thing on iPhone 8 to disable Touch ID.”

That squeeze can be of either volume button plus the power button. This, in my opinion, is an even better solution than the “5 clicks” because it’s less obtrusive. When you do this, it defaults back to your passcode.

More:

It’s worth noting a few additional details here:

  • If you haven’t used Face ID in 48 hours, or if you’ve just rebooted, it will ask for a passcode.
  • If there are 5 failed attempts to Face ID, it will default back to passcode. (Federighi has confirmed that this is what happened in the demo onstage when he was asked for a passcode—it tried to read the people setting the phones up on the podium.)
  • Developers do not have access to raw sensor data from the Face ID array. Instead, they’re given a depth map they can use for applications like the Snap face filters shown onstage. This can also be used in ARKit applications.
  • You’ll also get a passcode request if you haven’t unlocked the phone using a passcode or at all in 6.5 days and if Face ID hasn’t unlocked it in 4 hours.

Also be prepared for your phone to immediately lock every time your sleep/wake button is pressed or it goes to sleep on its own. This is just like Touch ID.

Federighi also noted on our call that Apple would be releasing a security white paper on Face ID closer to the release of the iPhone X. So if you’re a researcher or security wonk looking for more, he says it will have “extreme levels of detail” about the security of the system.

Here’s more about fooling it with fake faces:

Facial recognition has long been notoriously easy to defeat. In 2009, for instance, security researchers showed that they could fool face-based login systems for a variety of laptops with nothing more than a printed photo of the laptop’s owner held in front of its camera. In 2015, Popular Science writer Dan Moren beat an Alibaba facial recognition system just by using a video that included himself blinking.

Hacking FaceID, though, won’t be nearly that simple. The new iPhone uses an infrared system Apple calls TrueDepth to project a grid of 30,000 invisible light dots onto the user’s face. An infrared camera then captures the distortion of that grid as the user rotates his or her head to map the face’s 3-D shape­—a trick similar to the kind now used to capture actors’ faces to morph them into animated and digitally enhanced characters.

It’ll be harder, but I have no doubt that it will be done.

More speculation.

I am not planning on enabling it just yet.

Posted on September 19, 2017 at 6:44 AM • View Comments

Fooling Facial Recognition Systems

This is some interesting research. You can fool facial recognition systems by wearing glasses printed with elements of other people’s faces.

Mahmood Sharif, Sruti Bhagavatula, Lujo Bauer, and Michael K. Reiter, “Accessorize to a Crime: Real and Stealthy Attacks on State-of-the-Art Face Recognition“:

ABSTRACT: Machine learning is enabling a myriad innovations, including new algorithms for cancer diagnosis and self-driving cars. The broad use of machine learning makes it important to understand the extent to which machine-learning algorithms are subject to attack, particularly when used in applications where physical security or safety is at risk. In this paper, we focus on facial biometric systems, which are widely used in surveillance and access control. We define and investigate a novel class of attacks: attacks that are physically realizable and inconspicuous, and allow an attacker to evade recognition or impersonate another individual. We develop a systematic method to automatically generate such attacks, which are realized through printing a pair of eyeglass frames. When worn by the attacker whose image is supplied to a state-of-the-art face-recognition algorithm, the eyeglasses allow her to evade being recognized or to impersonate another individual. Our investigation focuses on white-box face-recognition systems, but we also demonstrate how similar techniques can be used in black-box scenarios, as well as to avoid face detection.

News articles.

Posted on November 11, 2016 at 7:31 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.