?????? ???? ?? ???? ?? ???? ????? ??? ?? ??????? ????????, ?? ???? ???????? ??? ?????????? ?? ?????? ??? ??? ???????’? ???????? ??? ??????? ????? ????. ?? ??? ???? ?? ????? ???? ?? ??? ???? ????, ???????? ???????.

Importantly, these are not ‘contact tracing’ apps. Exposure notification apps simply notify you if you’ve 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.

??? ?? ???? ?????

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.

???? ??????? ?????

If someone tests positive for Covid-19, they would then receive a key code that they can input into the app. ?? ???????, ??? ??? ??? ???? ??? ???? ??? ????? ???? ???? ??????? ??????.

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.

???? ????? ??????? ?????????

As mentioned above, the app uses Bluetooth Low Energy (BLE) to do this exposure notification. It doesn’t 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.

???? ??? ???? ?? ??? ????????

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.

????? ????????:

????? ???? ??? ?? ????????? ???? ?? ??? ???????, ???????, ????????? ??????????. ??? ???? ??? ?? ??? ???? ???? ????? ?? ??????? ???????, ?? ??????, ? ???? ???????? ?? ???????? ???? ?? ???? ?? ???? ??? ???? ????????? ?? ???? ????.