5 ms·

One issue I see is that when I query the central repository of infected IDs I expose to the central server the IDs I've been in contact with (unless I always do

One issue I see is that when I query the central repository of infected IDs I expose to the central server the IDs I've been in contact with (unless I always download all of them, but that doesn't seem feasible). It seems like this could be solved by providing a K-anonymous query interface like the one exposed by Have I Been Pwned. I wrote to the contact email address of Pepp-Py, which is a European initiative do develop a system that seems pretty much the same as this, suggesting this, but I got no answer (not that I was really expecting one).

joshuamorton 7y ago
Ah you mentioned the HIBP example, although for this search space you may be able to get by with just a download of all of them. If you stick to, say, state by state sharding, you get around 30 MB of hashes for the worst case (NYC). If you further reduce that by only providing new confirmed hashes since a timestamp, the client can track when they last downloaded the data and pull only the delta, you end up with a few MB a day, which compares quite well to say, a video call.
- lultimouomo 7y ago
  Geographical based sharding seems to break down once people travel though. Just a single visit to a hub airport might have gotten you in contact with people form all around the world (I assume that the objective of this initiative is to try and get us at least part way back to normal). Even if you don't travel, but other people are, you will be in contact with people who are registered as infected in a different region. Also I don't think NYC is at all the worst case in the world, there are a lot of megacities that dwarf it in size...
  - chispamed 7y ago
    You could still have geo sharding if the device also saved the location locally and shared the diagnosis for every zone it’s been in / downloaded the data for all zones. Ofc that would mean more data to process for travelers but it should still be way less than the data of the entire globe.
The_Double 7y ago
You have to download the entire database. The check is done inside the framework, recorded ids are not exposed to the frontend apps.

joshuamorton 7y ago

Ah you mentioned the HIBP example, although for this search space you may be able to get by with just a download of all of them. If you stick to, say, state by state sharding, you get around 30 MB of hashes for the worst case (NYC). If you further reduce that by only providing new confirmed hashes since a timestamp, the client can track when they last downloaded the data and pull only the delta, you end up with a few MB a day, which compares quite well to say, a video call.

lultimouomo 7y ago
Geographical based sharding seems to break down once people travel though. Just a single visit to a hub airport might have gotten you in contact with people form all around the world (I assume that the objective of this initiative is to try and get us at least part way back to normal). Even if you don't travel, but other people are, you will be in contact with people who are registered as infected in a different region. Also I don't think NYC is at all the worst case in the world, there are a lot of megacities that dwarf it in size...
- chispamed 7y ago
  You could still have geo sharding if the device also saved the location locally and shared the diagnosis for every zone it’s been in / downloaded the data for all zones. Ofc that would mean more data to process for travelers but it should still be way less than the data of the entire globe.

The_Double 7y ago

You have to download the entire database. The check is done inside the framework, recorded ids are not exposed to the frontend apps.