With the start of Covid-19 notifications on Android smartphones, the topic of why Bluetooth contact measurement also requires activated location functions came up again and again. The reason for this is simply the basis of these Bluetooth functions in Android, which were developed many years ago and of course had a different background at the time. Google explains this again in a blog post and announces changes with the next Android update. In addition, there are already numerous improvements.
Google is changing the way Bluetooth scans for ENS apps
In the new Android 11, it is no longer necessary to activate the location for exposure notifications, currently known as Covid-19 notifications. The system and apps, such as the Corona-Warn-App, cannot derive the location of Bluetooth scans either now or in the future. For all other types of Android apps, the previous specifications remain unchanged.
ENS: Exposure Notifications Service
In my opinion, Google’s announcement also means that the functions related to Bluetooth and location determination are anchored very deeply in the system, so they probably cannot be updated to older Android versions. So the innovations are only interesting for very few people who will be using Android 11 from autumn or in the months that follow.
Corona warning app never asked for location
In principle, apps such as the Corona-Warn-App do not have their own access to the user’s location if there is no authorization to do so. We explained many weeks ago that the German Corona warning app does not even ask for the location and does not request the corresponding authorization. Because the Covid-19 notifications need the activated location, there was confusion.
More fundamental improvements announced for the interface
- If exposure is detected, health authorities now have more flexibility in determining the risk associated with that exposure based on technical information from the API.
- Updated Bluetooth calibration values for hundreds of devices to improve detection of nearby devices.
- The API now supports interoperability between countries following feedback from governments that have launched Exposure Notification apps.
- To help health authorities build apps more efficiently, we’ve added app reliability improvements and developer debugging tools.
- We’ve improved clarity, transparency, and control for users. For example, exposure notifications settings on Android now include a simple toggle on and off at the top of the page. In addition, users will be prompted with a reminder periodically when ENS is enabled.
To be absolutely clear, ENS does not use device localization, and the guidelines for using ENS prohibit public health applications from requesting or collecting device localizations. Instead, ENS uses Bluetooth technology to detect when two devices are in close proximity without revealing the location of either device. Although Bluetooth scans don’t necessarily reveal location, in some cases it can be used to infer your device’s location. For example, if a shopping application scans for the Bluetooth signals from a stationary Bluetooth beacon located in a store, then the application could conclude that you went to that store.
For privacy reasons, in 2015 we designed the Android operating system to allow Bluetooth scans only when the device’s location setting is enabled. At the time, no one could have guessed that Bluetooth scanning could one day help control a global pandemic like COVID-19.