Germany has backed a smartphone app to track the spread of Covid-19 without centralised storage of users’ movements.
The app, following the lead of Switzerland and Austria, will use Bluetooth connectivity to swap encrypted codes between people whose phones spend more than 15 minutes together.
If one user becomes infected, alerts will go out to other users stored by the smartphone app in the previous 14 days.
“This app should be voluntary, meet data protection standards and guarantee a high level of IT security,” said Jens Spahn, the federal health minister.“The main epidemiological goal is to recognise and break chains of infection as soon as possible.”
Berlin’s decision marks a last-minute U-turn against centralised storage, and could tip the balance away from how phone data is used to help control the pandemic.
Until Sunday Germany backed centralised storage and processing of anonymised data on a server controlled by national authorities or health insurers.
But hundreds of German privacy campaigners, activists and academics signed an open letter in recent days, warning of “government or private sector surveillance that would catastrophically hamper trust in and acceptance of such an application by society-at-large”.
For such an app to be effective, it has to be installed by 60 per cent of smartphone users. A survey showed that only 47 per cent of Germans, wary of state surveillance after two dictatorships, would install an app using centralised data storage.
Berlin’s U-turn prompted a very rare phenomenon of praise from opposition politicians.
Anke Domscheit-Berg, digital spokeswoman for the Left Party, had attacked as “stillborn” any app using centralised data storage. She said the federal government “deserved respect” for heeding privacy concerns, predicting the shift would boost acceptance of the app and save lives.
Aside from heeding privacy concerns, Berlin’s change of heart postpones introduction of any new app. Programmers of the centralised app protocol completed work earlier this month while German health authorities say software for a decentralised approach will be available “soon”, without naming a date.
The German decision also creates divisions in Europe. France, the UK and Italy are the main EU backers of centralised data storage for coronavirus contact tracing.
Competing approaches could limit the usefulness of such apps when European governments begin to lift travel restrictions across the continent.
In its decision, Germany is following the approach taken by Switzerland and Austria. Switzerland plans to introduce on May 11th its own app, based on a standard created by researchers in Zurich and Lausanne, called Decentralised Privacy-Preserving Proximity Tracing (DP-3T).
In Austria more than 400,000 people have already downloaded a Red Cross “Stop Corona” app. It also uses a decentralised approach to data and is being upgraded to the Swiss standard.
As well as privacy concerns, Germany’s shift was influenced by practical concerns. Apple reportedly refused to unlock iPhone Bluetooth connectivity to allow centralised apps run in the background.
This would mean phones using the app would remain unlocked for it to work, draining phone batteries more quickly.