Browser fingerprinting: digital fingerprints

Computer scientists at FAU investigate how easily browsers can be tracked

Websites can retrieve information on visitors’ browser characteristics without their knowledge or consent. Combinations of such characteristics are generally unique, making visitors identifiable over periods of weeks. This is evidenced by the current results of an ongoing online study conducted by the Chair of Computer Science 1 at FAU since February of this year. Another goal of this study is to investigate strategies against such tracking. The FAU researchers have presented their current results on the study’s website. Participants for further scientific data analysis are still being sought.

Over 1000 participants from 30 countries have registered since February. The FAU computer scientists have thus far studied more than 6400 different fingerprints. This number arises in part because fingerprints change and in part because participants are free to test all their browsers and devices. The results of the study so far are certainly clear: 96 percent of the digital fingerprints are unique based on the combination of browser characteristics.

Participants’ fingerprints identifiable on the Internet for an average of three weeks

The unique structure of the study allows the FAU researchers to observe for the first time how fingerprints change over time and which factors increase their identifiability.

It has been found that identifiability of digital fingerprints, based on the most stable fingerprint over time, lasted an average of 3.3 weeks per participant. On average male participants were identifiable for approximately 3 weeks, female participants for 4 weeks. Overall 75 percent of men and 80 percent of women were identifiable for at least one week. Of the participants, 27 percent of men and 33 percent of women remained identifiable for at least 4 weeks. In investigating participants’ most stable fingerprint over time according to the type of device used, an average period of identifiability of 3 weeks was found for desktop devices and 4 weeks for mobile devices.

The FAU researchers also observed that 98 percent of fingerprints from desktop devices and 86 percent from mobile devices are unique. This is partially due to the fact that individual browser settings are comparatively difficult to set up on smartphones and tablets in comparison to desktop computers and laptops.

Thus far the researchers have not found any evidence that IT skills, level of education or data privacy behaviour influences the duration of identifiability. The FAU computer scientists have presented the preliminary results of their study at https://browser-fingerprint.cs.fau.de/statistics.

Online study continues, more participants sought

In order to better find answers to questions about identifiability and contributing factors and to develop countermeasures, the Chair of Computer Science 1 at FAU is seeking more study participants. Interested persons can register with their e-mail address at the study’s website, https://browser-fingerprint.cs.fau.de. Participants can de-register at any time. Participants’ e-mail addresses will be deleted from the database and all data will be anonymised when their participation in the study ends.

As part of every fingerprint measurement, participants will receive an overview of their browser characteristics which can be retrieved by websites. They will also regularly receive an e-mail report containing information on how long their fingerprints remain identifiable and how their results compare to other participants’.

Further information:

Study website and registration

Zinaida Benenson
Phone: +49 9131 8569908
cs1-browser-fingerprint@fau.de