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Laurie Clarke


Germany switches to decentralised contact tracing app in privacy U-turn

Germany has swerved from a centralised to decentralised approach to its coronavirus contact-tracing app. Chancellery minister Helge Braun and health minister Jens Spahn announced in a joint statement on Sunday that Germany would adopt a “decentralised” approach to Covid-19 contact tracing, and ditch the centralised alternative the country had been working on.

“This app should be voluntary, meet data protection standards and guarantee a high level of IT security,” they said. “The main epidemiological goal is to recognise and break chains of infection as soon as possible.”

Reuters reported that this was primarily over Apple’s refusal to budge on adapting its settings to allow centralised apps to run in the foreground on iOS devices. As it stands, only decentralised contact-tracing apps – the likes of which Apple and Google are developing – will be able to run in the background without draining the phone’s battery.

By contrast, centralised apps will likely require the user to keep their phone unlocked at all times with the app running in the foreground – a nightmare for security and battery drainage. 

Up until the announcement, Germany was supporting the Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT) centralised approach. However, the tide has been turning against centralised apps on the continent.

A heated rivalry between PEPP-PT and another group pushing a decentralised contact-tracing protocol, DP-3T, has flared up over recent weeks, and last week, a group of 300 academics worldwide signed a letter arguing that centralisation would lead to an increase in the likelihood that data is used for mass surveillance purposes further down the line. A number of academic and research institutions have announced their withdrawal from the PEPP-PT project due to its lack of transparency. 

At present, Italy remains committed to rolling out a contact-tracing app based on PEPP-PT infrastructure. The French government also remains committed to a centralised protocol, named ROBERT, and has been putting pressure on Apple and Google to make the necessary changes to their operating systems to allow the app to run in the background.

The UK is also still seemingly committed to a centralised approach, despite saying that it’s “working with Apple and Google on their welcome support for tracing apps around the world” in an NHSX blog post published on Friday. Other European countries such as Switzerland, Austria and the Czech Republic have opted for decentralised digital contact-tracing models.  

Decentralised approaches have been criticised as being less epidemiologically useful, but projects such as DP-3T have refuted this, saying their approach was developed with the participation of epidemiologists and that crucial information about the spread of the virus can still be passed along to health authorities within decentralised frameworks.