German Corona tracing app available without Google services
A handful of Free Software developers today achieved what official bodies have been missing for months: They have made available the German Corona Warn App for tracing Covid-19 risk contacts in a version that is completely free of dependencies on Google and available in F-Droid, the Free Software app store.
Already in April this year, the Free Software Foundation Europe (FSFE) formulated two fundamental requirements for so-called Corona apps. First, there must be no obligation to use them, and second, they must be available as Free Software. At first glance, the German Corona Warn App (CWA) published in June, meets these criteria, like many others in Europe by now. However, the exchange of device keys via Bluetooth, on the basis of which the risk is calculated, is handled by an underlying interface.
The problem is that this interface software, called Exposure Notifications API and significantly developed by Apple and Google, is largely proprietary. This means it cannot be freely used, investigated, distributed and improved. In Google’s Android operating system it is also necessary to install and use the Play Services. These Google services intervene deeply in the system and undermine the digital sovereignty of the users. By default, this prevents the use of many Corona apps for people who value privacy and software freedom on their Android devices.
Volunteers solve problems step by step
A first major improvement was provided by Free Software developer and FSFE supporter Marvin Wißfeld in September. He built the exposure notification functionality into microG, a Free Software implementation of the proprietary Google services. This allows at least people who own a Google-free Android phone and have microG installed to use various Corona apps.
A few days ago, Christian Grigis, Fynn Godau, Marcus Hoffmann and Marvin Wißfeld went one step further. They integrated the exposure notification component of microG directly into the German Corona Warn App. This so-called Drop-In-Replacement enables even people who have neither the Google services nor their Free Software alternative microG installed, to use the CWA. In addition, as of today they are making the app available on F-Droid, an app store with exclusively Free Software. This is therefore also advantageous for those users who have installed microG or Google services, but prefer to obtain their software via F-Droid for security and convenience reasons.
microG main developer and FSFE supporter Marvin Wißfeld adds:
"The previous solution of installing microG is often out of the question for various reasons. But the new app from F-Droid,can also be run without problems on all current smartphones from, for example, Huawei some of which have been delivered without Google services since mid-2019. The German government and the RKI may have lost thousands of users of the Corona Warn App in recent months, as only Google and Apple users were targeted."
It is now up to the responsible bodies, the German government, the Robert Koch Institute (RKI) and their contractors SAP and T-Systems, to incorporate the changes into the main development branch, and thus to pull together with the Free Software community. In addition, this method can in principle also be used for Corona apps in other countries.
Free Software once again in a pioneering role
We see a familiar pattern here: the Free Software community presents a problem and a possible solution, but is turned away until volunteers solve the problem themselves with unpaid work and without official support. In this case, the resources of the authorties and companies involved would have easily sufficed to make these significant improvements themselves, or at least to support them. It is laudable that the CWA was consistently developed and published as Free Software from the very beginning, but it lacked the necessary consistency to remove technically and meanwhile unnecessary dependencies on proprietary software.
The FSFE appeals to governments and administrations to publish developed software as Free Software, to break dependencies on Google’s and Apple’s app stores and instead make their apps installable from independent sources like F-Droid, and to renounce proprietary dependencies. As Wißfeld explains, the Corona Warn App already offers concrete additional advantages in the fight against the pandemic:
"The free implementation has the potential - in the spirit of Free Software - for improvements that Google's proprietary interface does not allow. For example, it would be possible to display the time of a high risk encounter. This could - if the user voluntarily provides the data - help public health authorities to identify hotspots or clusters, or be used for statistical purposes to increase the effectiveness of protective measures."
We would like to thank all persons involved who made the use of the Corona App in Germany possible without having to accept any loss of software freedom.
The article was first published on FSFE.