Covid Alert App
The Covid Alert App is available in several provinces in Canada.With the recent explosion in cases, and the 50%+ community transmission, downloading the Covid Alert App is even more critical. This was a joint effort by several organizations who came together to make this happen, and went through several levels of iron clad privacy and security reviews.
Tobi Lutke and Craig Miller from Shopify explained how the ๐๐๐๐๐๐๐๐ ๐๐๐๐๐
๐๐๐๐๐๐๐ ๐๐๐ works to me in great detail, and I used that to write this easy to understand post explaining the app.
๐๐จ๐ญ๐ญ๐จ๐ฆ ๐ฅ๐ข๐ง๐ ๐จ๐ง ๐ญ๐ก๐ข๐ฌ ๐ข๐ฌ ๐ญ๐ก๐๐ญ ๐ญ๐ก๐๐ซ๐ ๐๐ซ๐ ๐ง๐จ ๐ฉ๐ซ๐ข๐ฏ๐๐๐ฒ ๐๐จ๐ง๐๐๐ซ๐ง๐ฌ, ๐ง๐จ ๐๐๐ญ๐ ๐๐จ๐ง๐๐๐ซ๐ง๐ฌ ๐๐ง๐ ๐๐๐ฌ๐จ๐ฅ๐ฎ๐ญ๐๐ฅ๐ฒ ๐ง๐จ ๐ซ๐๐๐ฌ๐จ๐ง ๐ฐ๐ก๐ฒ ๐ฒ๐จ๐ฎ ๐ฌ๐ก๐จ๐ฎ๐ฅ๐๐งโ๐ญ ๐๐จ๐ฐ๐ง๐ฅ๐จ๐๐ ๐๐ง๐ ๐ข๐ง๐ฌ๐ญ๐๐ฅ๐ฅ ๐ญ๐ก๐๐ฌ๐ ๐๐ฉ๐ฉ๐ฌ. ๐๐ ๐ฒ๐จ๐ฎ ๐ฐ๐๐ง๐ญ ๐ญ๐จ ๐ฅ๐๐๐ซ๐ง ๐ฆ๐จ๐ซ๐ ๐จ๐ง ๐ก๐จ๐ฐ ๐ญ๐ก๐๐ฒ ๐ฐ๐จ๐ซ๐ค, ๐๐จ๐ง๐ญ๐ข๐ง๐ฎ๐ ๐ซ๐๐๐๐ข๐ง๐ .
Importantly, these are not โcontact tracingโ apps. Exposure notification apps simply notify you if youโve been near someone who later tested positive for COVID-19. Contact tracing apps, however, let people log their location and share it with public health authorities. According to the rules Apple and Google have laid out, any exposure notification app that uses their technology cannot track locations.
๐๐จ๐ฐ ๐๐จ ๐ญ๐ก๐๐ฒ ๐ฐ๐จ๐ซ๐ค?
The app essentially sends out your random code (which changes every 5 minutes) to nearby phones and also listens for other phones transmitting their codes. It then stores that information. This is done using Bluetooth Low Energy (BLE) and occurs in the background after the app is installed. Teams have worked very hard to compress the data requirements, so it does not use your data or bandwidth and does not interfere with the normal activities on your phone.
๐๐ก๐๐ญ ๐ก๐๐ฉ๐ฉ๐๐ง๐ฌ ๐ง๐๐ฑ๐ญ?
If someone tests positive for Covid-19, they would then receive a key code that they can input into the app. ๐ฐ๐ ๐ถ๐๐๐๐๐๐, ๐๐๐ ๐๐๐ ๐๐๐ ๐๐๐๐ ๐๐๐ ๐๐๐๐ ๐๐๐ ๐๐๐๐๐ ๐๐๐๐ ๐๐๐๐ ๐๐๐๐๐๐๐ ๐๐๐๐๐๐.
Once you input this key into the app and confirm that you have received a positive diagnosis, your app will send all the codes it has been broadcasting to a centralized database.
All phones regularly check with this centralized database. When someone tests positive, the centralized database sends out all their random codes and if there is a code that matches, then your app alerts you that you may be exposed and it gives you recommendations on what to do next.
Essentially the app notifies the phones that have passed within close range in the 14 preceding days. An exposure is counted based on how strong the Bluetooth signals are. If you are closer than 2m/6ft for longer than 15 min, it was recorded as a potential exposure in the app.
๐๐ก๐๐ญ ๐๐๐จ๐ฎ๐ญ ๐ฉ๐ซ๐ข๐ฏ๐๐๐ฒ ๐๐จ๐ง๐๐๐ซ๐ง๐ฌ?
As mentioned above, the app uses Bluetooth Low Energy (BLE) to do this exposure notification. It doesnโt use GPS, so no contact or location or any other private information is stored. In addition, even when the Bluetooth signal is sent, anonymous random codes are transmitted – so nothing that contains any personal identifiers are used.
๐ช๐ต๐ฎ๐ ๐ฎ๐ฟ๐ฒ ๐๐ผ๐บ๐ฒ ๐ผ๐ณ ๐๐ต๐ฒ ๐ฐ๐ฎ๐๐ฒ๐ฎ๐๐?
The flip side of using BLE unfortunately is that it is a new technology that was only released a few years ago. Due to this, older phones using iOS older than 13.5 cannot support it.
The other caveat is that there could be some discrepancies with respect to crowded locations – say for instance two apartments that are close enough to allow signals to be transmitted and received. However, the likelihood of this is low given that the signals only register an exposure of distance is within 2m/6ft and for greater than 15 minutes.
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๐๐๐๐ ๐๐๐๐๐๐๐๐:
๐๐ก๐๐ฌ๐ ๐๐ฉ๐ฉ๐ฌ ๐๐ซ๐ ๐๐ง ๐ข๐ฆ๐ฉ๐จ๐ซ๐ญ๐๐ง๐ญ ๐ฌ๐ญ๐๐ฉ ๐ข๐ง ๐ญ๐ก๐ ๐ญ๐๐ฌ๐ญ๐ข๐ง๐ , ๐ญ๐ซ๐๐๐ข๐ง๐ , ๐ข๐ฌ๐จ๐ฅ๐๐ญ๐ข๐ง๐ ๐ข๐ง๐ข๐ญ๐ข๐๐ญ๐ข๐ฏ๐. ๐๐ก๐ ๐จ๐ง๐ฅ๐ฒ ๐ฐ๐๐ฒ ๐ฐ๐ ๐๐๐ง ๐๐๐๐ญ ๐ญ๐ก๐ข๐ฌ ๐ฏ๐ข๐ซ๐ฎ๐ฌ ๐ข๐ฌ ๐ญ๐ก๐ซ๐จ๐ฎ๐ ๐ก ๐ฌ๐๐ข๐๐ง๐๐, ๐ฌ๐จ ๐ฉ๐ฅ๐๐๐ฌ๐, ๐ ๐ฎ๐ซ๐ ๐ ๐๐ฏ๐๐ซ๐ฒ๐จ๐ง๐ ๐ญ๐จ ๐๐จ๐ฐ๐ง๐ฅ๐จ๐๐ ๐ญ๐ก๐๐ฆ ๐๐ฌ ๐ฌ๐จ๐จ๐ง ๐๐ฌ ๐ญ๐ก๐๐ฒ ๐๐ซ๐ ๐ฆ๐๐๐ ๐๐ฏ๐๐ข๐ฅ๐๐๐ฅ๐ ๐ข๐ง ๐ฒ๐จ๐ฎ๐ซ ๐๐ซ๐๐.
References:
Google and Apple Exposure Notification report:
Easy to understand language on how it works:
Info graphic:
Contact tracing vs Exposure notification:
Ontario Covid Alert app: