What info do these apps need?
Out of privacy concerns, the apps would not need much personal information. Apple and Google said they don’t want to use GPS location data from the cellular network, though public health agencies might ask for that.
The apps are also voluntary, so people would need to choose to download the apps to participate, though the tech companies said they plan to add some of the functions in the phones’ basic operating systems.
How can Bluetooth track who’s nearby?
Bluetooth was standardized as a technology in the 1990s and named for a Viking king, Harald “Bluetooth” Gormsson. (The now-familiar logo is a combination of the king’s initials.)
When Bluetooth is turned on, your phone uses radio waves to figure out which other devices are nearby. In this case, it would blast out an opaque string of characters called an identifier beacon — and other nearby phones would make a time-stamped log of that identifier.
The beacon would change every few minutes to prevent