So you've probably all heard about the new #CovidApp from the Canadian federal government. I was surprised initially that they were doing it given some of the concerns people have had about the UK's approach and other countries. But I took a deeper look and its really quite a clever approach they've taken to give you some useful protection and maintain privacy.
The main idea of the app is to use Bluetooth connections to anonymously link with nearby phones with the app installed. Since Bluetooth is shortrange, if you are in Bluetooth range you may be in COVID range. It also looks at the signal to figure out if you are within 2m of another phone. If you are, then your phone swaps random codes, generated right then, like random numbers for the lottery. The numbers don't tell the other phones who you are, but your phone keeps track of the numbers it shared and received for two weeks.
Then, and this is the clever part, if someone tests positive, they can log on to the provincial gov't site and get another random one-time-code. This is like the two-factor authentication codes you get from gmail and other websites. You type that code into your app and this confirms officially to your phone's app that you tested positive. It then uploads all the codes it sent out for the past two weeks to the main server and notifies the people you got close to. Again, this really can all be anonymous, because the app doesn't know who you are, the codes don't identify you, and no one ever sees all the information. The app doesn't even use GPS, so it doesn't know where you are.
I've downloaded it, so has my family, I hope other people do too.
Download the Covid19 App here: https://www.canada.ca/en/public-health/services/diseases/coronavirus-disease-covid-19/covid-alert.html