So... NHS Contact Tracing App

[elsiegee40]

what about android?

 

I don’t have android. Try going to your phone settings and looking there

[Seb1780]

OK, I think I now understand there are different notification types depending on whether the App has picked up on contact with a known +ve case or whether NHS has sent a message to me about contact. Given that both the messages I received were followed by the "don't worry" message I assume these were the former, thanks @Boredguy

 

Following on from this, does it mean that when you get the notification it is *at that time* that the contact is/has occurred? If so this is worrying because both mine have been around midnight, when my phone is on my bedside table and nowhere near anybody else (except Mrs Seb).

 

I've looked in the iOS settings, and found the exposure notifications section of the app. Thanks @aicrd and @elsiegee40. Now I need to know what this all means! I can see pairs of "Exposure Checks" results, approximately every 4 hours. Is this the regular checking of data with the central system? I can see that for all of the checks the "Matched Key Count" is zero, so I still don't understand why I'm getting notifications.

[aicrd]

I believe the exposure checks are keys your phone has exchanged with others and vice versa. I've got quite a few from 3 or 4am which I've attributed to people walking past my bedroom window at night, since the walls here aren't that thick and my bedside table is right next to the window.

[elsiegee40]

I believe the exposure checks are keys your phone has exchanged with others and vice versa. I've got quite a few from 3 or 4am which I've attributed to people walking past my bedroom window at night, since the walls here aren't that thick and my bedside table is right next to the window.

 

Mine seem to be in pairs at 4 hourly intervals. I’m pretty sure it’s the app checking in somewhere online.

 

I was on the second floor of a building last night. Husband’s phone was near, but that’s all.

Edited October 26, 2020 by elsiegee40

[aicrd]

Mine seem to be in pairs at 4 hourly intervals. I’m pretty sure it’s the app checking in somewhere online.

 

I was on the second floor of a building last night. Husband’s phone was near, but that’s all.

[ATTACH]59580[/ATTACH]

 

Ah yes that does make more sense. Looking at mine they also seem to be every 4 hours.

 

Apple do have some in depth documentation on how the exposure API works: https://developer.apple.com/documentation/exposurenotification/building_an_app_to_notify_users_of_covid-19_exposure

[E_G_R2]

Interesting, was on a train full of students going through Nottingham and Sheffield heading for Manchester (live dangerously is my motto) and nothing for that journey.

[elsiegee40]

Interesting, was on a train full of students going through Nottingham and Sheffield heading for Manchester (live dangerously is my motto) and nothing for that journey.

 

It’s not that kind of log. It’s just logging when the app checks in with test and trace central

 

One’s probably a send operation and the other a receive operation. The pair are done every 4 hours

Edited October 26, 2020 by elsiegee40

[TechMonkey]

what about android?

 

In Settings > Google

[mavhc]

I don't think it can tell if 2 positive matches are from the same person or not, as that would let you track someone using bluetooth, your random key changes every 15-20 mins.

 

The time you get the notification is after this series of events: your phone is near someone else's phone, exchanges keys. days later that person feels ill, gets a test. days later their test result comes back positive, they log that in the app. the app uploads all the keys it generated to the central server. every few hours your app downloads all the positive keys. it finds a match and gives you a notification. the nhs app runs the algorithm to decide if you were close enough for long enough to have a reasonable chance of being infected.