Apple and Google unveiled more details Friday about their contact finder technology to stop the spread of the coronavirus (via Reuters). It contains provisions to protect the confidentiality of users without reducing efficiency.
Progress in solving contact detection problems with coronaviruses
The exposure time – the time when two phones were close to each other – is now rounded to five-minute intervals. This prevents the collection of detailed time data as it would help to pair devices with people. In addition, user identification numbers are randomly generated. Metadata such as Bluetooth signal strength and phone model must be encrypted. The same goes for information about who a user has been close to.
Apple and Google will provide data on Bluetooth energy levels. This is to allay health researchers’ concerns about the limits of the system. This means that researchers will better understand the duration and proximity of two phones. In addition, companies will provide information about the number of days that have passed since a user’s last contact with an infected person.