Every day, COVID Alert checks a list of random codes from people who tell the app they've tested positive for the infection.
The federal government's exposure-notification app launched in Ontario Friday, after a almost month-long delay during which Ottawa unsuccessfully tried to get other provinces to sign on.
"If they test positive for the virus, users can choose to upload their random codes to a central server located in Canada".
The app uses strong measures to help protect the privacy and confidentiality of its users and any data it collects.
COVID Alert does not use Global Positioning System or track your location.
The COVID Alert app is available on the Apple Store and Google Play for free.
As the prime minister announced Ontario would have first access to the Canada-wide COVID notification app, B.C. health officials refused to say when the app would be activated for residents of the country's westernmost province.
"(I) t bears noting that an app, described worldwide as extremely privacy sensitive and the subject of reasoned concern for the future of democratic values, is defended by the Government of Canada as not subject to its privacy laws", the OPC's review report notes.
The Privacy Commissioner of Canada and his Ontario counterpart both support the application, they said in a joint statement July 31.
To stay safe as more of the province reopens, Ontarians should continue to follow public health guidelines including physical distancing with people not in their social circle, wearing a face covering if physical distancing is a challenge, washing hands thoroughly and frequently, and if anyone thinks they have COVID-19 or have been in contact with someone who has COVID-19, get tested. And if you have been in contact with anyone who tested positive, you will also be notified.
A step-by-step guide shows how COVID Alert works and what users can expect when it comes to finding out whether they were exposed to COVID-19. The app was designed by the Canadian Digital Service using open source code from Shopify.
When first announced in June, Trudeau said the app would be "completely voluntary".
Manual contact tracing won't be replaced by the app. "I will use it".
"This is again cause for modernizing our laws so that they effectively protect Canadian citizens", he said.
The app is now only live in Ontario, launching weeks after a test-run across the province was delayed.
The news release goes on to say that the app has undergone a "security assessment" by BlackBerry as well as the Canadian Centre for Cyber Security, saying that all "data provided to the app will be securely stored and protected". "They were totally aware that there's going to be some hesitancy with people using this app", said Dr. Isaac Bogoch on CTV News Channel.