In the few days since we wrote about contact tracing using Bluetooth, Apple and Google have announced their contact tracing technology and some of the press are already saying this is the way out of the crisis.
What Is It?
The Apple/Google contact tracing is a new variant of standard Bluetooth advertising using ephemeral (changing) encrypted identifiers that identify people. Users retain anonymity up to the point of notifying infection. Decryption is achieved using keys uploaded to a central server.
In practical terms it’s a new API, to be provided in May, by Apple and Google and used in public health authorities’ apps. In time, it will be in-built functionality in iOS and Android to provide a ‘more robust’ solution. However, we all know most Android OEMs don’t upgrade their forks of Android so the more robust Android solution will have limited rollout.
If implemented properly it has the potential to solve the technical issues we mentioned in our previous post. More specifically, there’s potential to solve the problems of background processing and ease the permissions limitations on iOS and Android when advertising Bluetooth and scanning (receiving) Bluetooth. The solution also has the potential to track contacts across countries.
The Behavioural Unknowns
It’s unknown how many people would install such an app, how many would notify infection and how people might act when notified they have been in contact with infected person. Governments will need to incentivise take up.
Moxie Marlinspike and LightBlueTouchPaper have commented on how the system might not be completely anonymous in that it could be combined with other metadata by Apple, Google or Governments. Governments and large tech companies have recently been repeatedly breaking their privacy promises. Also, the delay in testing for the virus means that by the time patients receive test results they might be too sick to operate their phones. The system might also be open to disruption by nefarious parties.
While we know reducing physical contact reduces transmission, we know relatively little about ways of transmission, asymptomatic carriers and immunity. Factors such as these could determine the success or failure of a contact tracing solution and whether this really is the way out of the crisis.