You can’t upload who you were close to because you only have a set of pieces of data that can’t be traced back to people without their key. Only if infected, you upload your key to the server which distributes it to the others who can then tell if they’ve been close to you.
> Only if infected, you upload your key to the server
You are more right than I was initially, thanks!
Actually, to be even more precise: only if infected, you upload the set of your own derived keys, and apparently only for the days you could have transmitted the virus to other people.
From the documentation:
"Upon a user testing positive, the Daily Tracing Keys for days where the user could have been affected
are derived on the device from the Tracing Key. We refer to that subset of keys as the Diagnosis Keys.
If a user remains healthy and never tests positive, these Daily Tracing Keys never leave the device."
