Android offers its users the possibility of customizing the system to unsuspected extremes, especially when apps come into play that allow us to change the launcher, play with icon packs and with a thousand and one factors that can turn our mobile into something “unique”. Although precisely this characteristic can cause different calculations to assign a DNI to our mobile, unless we change any of these factors in order to vary the identifier.
This technique is known as “fingerprinting”, and just as our Android can be identified through the camera, there is a method (somewhat far-fetched) that can allow recognize our phone among millions based on our desktop background. Our wallpaper. And everything can be done through a simple API offered by Android itself and that can be used by other apps that we install on the system.
Your wallpaper can give you away, but not much
Although it could be treated as a problem for our privacy, the truth is that this system does not throw personal information about us unless we have put a photo of a family member, a friend or even ourselves as the wallpaper. We just talk about a system that allows you to establish a unique code to be able to recognize your mobile among many others. A pattern that we can change without problems, on the other hand.
It happens that in Android there is an API embedded in Android that offers certain information about our desktop background. Specifically, we are talking about the WallpaperManager class that came together with Android 2, but that changed with the arrival of Android 8.1. The “vulnerability” or risk of information exposure was remedied to some extent. And a method has been developed to obtain information about our desktop background.
Using the getWallpaperColors function on Android, it is possible to extract the three main colors from our wallpaper, but using different advanced algorithms it is possible to go much further. Thus, once this complex process has been carried out it is possible to create a unique 256-bit identifier for our mobile phone based on our desktop background. It is logical to think that this number is identical to that of another mobile that uses the same desktop background, and it is true. Hence, the identifier can be “critical” only when we use our own photographs, since theoretically only we have them.
Through a series of complex algorithms, it is possible to create a DNI from your wallpaper.
Thus, it is possible to create an app to install on our mobile that extracts this identifier based on our wallpaper. To what end? In a very extreme case, let’s imagine that we install Twitter with two active accounts, and with this identifier it would be possible to conclude that both accounts are present on the same phone. Or that we install an app with one user, delete it, and reinstall it with another. As long as we do not change the desktop background, the identifier would be the same.
This procedure created to extract the identifier of our wallpaper is still a curiosity, Well, for it to represent a real risk to our privacy, it would be necessary, for example, that it could be executed through a web. But it needs to be an app installed on our phone that can access the API, and therefore everything becomes much more complex. However, it is curious to know that there are these procedures that can generate a unique identifier based on our customization, and that it is “easy” to use our desktop background due to the API of the system itself. Our advice? If you are someone given to conspiracy theories, use generic wallpapers.
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