What Is Device Fingerprinting And How Does It Work?

Marketers and advertisers today are a lot like detectives – always on the trail of a hot lead or potential customer.

Ad Tech Processes

What Is Device Fingerprinting And How Does It Work?

September 21, 2016 by
Chief Executive Officer

Marketers and advertisers today are a lot like detectives – always on the trail of a hot lead or potential customer.


But their job isn’t getting any easier. With more and more devices being used, changing technology standards, not to mention ad blockers, it is harder than ever to track users and connect with them in a personal way.

multiple devices
Being able to connect with potential customers at the right time and on the right device is essential for modern marketers.

One solution is device fingerprinting – an innovative way for marketers and advertisers to keep on top of the many places that customers may interact with their brand.

What is device fingerprinting?

Much like the trail of evidence that detectives follow to amass to zero in on a suspect, fingerprinting for devices works by gathering bits of information to form a general identifier. It is used mainly for web tracking (i.e. in a web browser).

While many different users may own the same device, each one will be configured slightly differently – “personalized” according to the user’s individual preferences and requirements. Data about these configuration changes can be aggregated to create a recognizable “device fingerprint.”

Information used to create a device fingerprint can include:

  • Browser version
  • Operating system
  • Items installed (plugins/fonts etc.)
  • Location & time zone settings

Why use device fingerprinting?

As people become more and more connected and carry out more and more actions online, they are more and more inclined to use multiple devices to accomplish their tasks. And this makes it more and more difficult for brands to connect personally with their target audiences.

This problem is only augmented because normal means of online tracking are facing more and more problems. Cookies, which have been the mainstay of digital advertising for years, have become more and more untenable in today’s privacy-sensitive environment.

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  • First of all, cookies do not offer a reliable way to track mobile usage.

    Secondly, cookies can be easily deleted by the consumer – and more and more are doing so.

    And thirdly, cookies make ads and ad campaigns more easily recognizable to ad blockers, effectively killing any chance an advertiser may have of connecting with a potential customer. With ad blocker usage set to grow by double digits this year, this is a real concern for ROI-conscious advertisers.

    Device fingerprinting offers a backup method of tracking when cookies can’t get the job done.

    For example:

    A person is looking to book a holiday to Paris. In the course of browsing the internet, he/she clicks on a banner ad advertising an all-inclusive package from a travel agency. However, the person does not book a trip immediately. Instead, they close their web browser (and thus potentially delete the cookies connected with the paid advertising they interacted with) and go to bed.

    The next day, the person decides to check out the travel agency’s website again and this time simply types in the agency’s address in the web browser. After perusing the site a bit, they end up booking the all-inclusive package they had originally seen in the banner ad.

    Now, because the conversion was completed the second time and could not be attributed to the banner ad by means of a cookie, the travel agency is unable to accurately determine the ROI of that ad.

    But thanks to device fingerprinting, it is possible to ascertain that the customer who booked the travel package used the same web browser (with the same “fingerprint”) as the one where the ad was previously served.

    How does device fingerprinting work?

    Calculating a device fingerprint begins when a user visits a website. The device fingerprint tracker collects all relevant information (browser version/type, OS, etc.).

    The interaction triggers the collection of a range of data (such as that listed above) which forms a special “hash” that is assigned to that particular device.

    The fingerprint is usually calculated on the server side – making it impossible to block. When used in combination with cookies or other identifiers, the accuracy of the tracking and attribution is greatly improved.

    The downside is, however, that calculating the “hash” and storing all the data required to create can be computationally intensive. This requires rather a large amounts of storage since the device IDs are not distributed back to the browser (as is the case when cookies are served) but must be kept on the server side.

    There is also some controversy regarding the use of device fingerprinting in conjunction with cookies for the creating of a complete “supercookie” or “evercookie.”

    The importance of device fingerprinting

    As noted already, the digital landscape is becoming more and more complex. For marketers and advertisers this means scrambling to keep up with the burgeoning array of touch-points that are created as consumers become more and more mobile in their browsing behavior.

    As cookies face more and more resistance from those who are privacy inclined and as new technologies emerge, methods like device fingerprinting – with their reliance on static, unchangeable information will play a significant role in powering digital advertising.


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