Top Websites Secretly Track Your Device Fingerprint

Browser fingerprint tracking can bypass cookie restrictions and ignores the Do Not Track header

2 min read
Top Websites Secretly Track Your Device Fingerprint

Websites that really want to track you without permission have a way. A new report shows a surprising number of top Internet websites using so-called "device fingerprints" to secretly track visitors—a method that avoids legal limits on the use of cookies and also ignores the Do Not Track HTTP header.

The new report suggests that such secret tracking of Web users is more widespread than previous studies had found, according to researchers from KU Leuven in Belgium and New York University (NYU). Researchers counted 95 of the top 10 000 websites using device fingerprinting targeted at the Flash browser plugin used to play animations, videos, and sound files. They also found 404 of the top 1 million websites used device fingerprinting targeted at the JavaScript programming language used in web applications. Such fingerprinting can identify users on mobile phones and other devices that may not use Flash.

Device fingerprinting collects the properties of PCs, smartphones, and tablets that people use to access the Internet in order to create a unique identification. The fingerprint properties—including screen size, versions of installed software, and even lists of installed fonts—allow websites to track users without relying on the more common Internet cookies to follow users' online activities.

The technique can even track users who had requested not to be tracked by enabling a Do Not Track HTTP header, researchers found. The Do Not Track project has attempted to create a universal standard for opting out of online tracking that goes beyond implementation by individual web browsers, but the Washington Post reports that recent Do Not Track discussions by a working group organized under the World Wide Web Consortium (W3C) appear close to collapse.

The rise of device fingerprinting, also known as browser fingerprinting, falls under the category of "supercookie" technologies that avoid the traditional restrictions on tracking cookies, according to Information Week. Even anonymous Web-browsing tools such as Tor have vulnerabilities that allowed device fingerprinting to track users according to font lists. (The upcoming 2.4 version of Tor has been updated to fix that vulnerability after the KU Leuven/NYU team passed along a warning.)

Luckily, anybody who wants to scrutinize their favorite websites for such digital fingerprinting technologies can soon do so with the FPDetective tool used by the researchers. The team plans to make the tool available for free at, and will present its findings at the 20th ACM Conference on Computer and Communications Security this November in Berlin.

Photo: iStockphoto

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Metamaterials Could Solve One of 6G’s Big Problems

There’s plenty of bandwidth available if we use reconfigurable intelligent surfaces

12 min read
An illustration depicting cellphone users at street level in a city, with wireless signals reaching them via reflecting surfaces.

Ground level in a typical urban canyon, shielded by tall buildings, will be inaccessible to some 6G frequencies. Deft placement of reconfigurable intelligent surfaces [yellow] will enable the signals to pervade these areas.

Chris Philpot

For all the tumultuous revolution in wireless technology over the past several decades, there have been a couple of constants. One is the overcrowding of radio bands, and the other is the move to escape that congestion by exploiting higher and higher frequencies. And today, as engineers roll out 5G and plan for 6G wireless, they find themselves at a crossroads: After years of designing superefficient transmitters and receivers, and of compensating for the signal losses at the end points of a radio channel, they’re beginning to realize that they are approaching the practical limits of transmitter and receiver efficiency. From now on, to get high performance as we go to higher frequencies, we will need to engineer the wireless channel itself. But how can we possibly engineer and control a wireless environment, which is determined by a host of factors, many of them random and therefore unpredictable?

Perhaps the most promising solution, right now, is to use reconfigurable intelligent surfaces. These are planar structures typically ranging in size from about 100 square centimeters to about 5 square meters or more, depending on the frequency and other factors. These surfaces use advanced substances called metamaterials to reflect and refract electromagnetic waves. Thin two-dimensional metamaterials, known as metasurfaces, can be designed to sense the local electromagnetic environment and tune the wave’s key properties, such as its amplitude, phase, and polarization, as the wave is reflected or refracted by the surface. So as the waves fall on such a surface, it can alter the incident waves’ direction so as to strengthen the channel. In fact, these metasurfaces can be programmed to make these changes dynamically, reconfiguring the signal in real time in response to changes in the wireless channel. Think of reconfigurable intelligent surfaces as the next evolution of the repeater concept.

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