4 ms·

Went over the docs (Google and Apple's), but there are a few things that are not clear to me. This is my summary of how I interpreted it works: - A [Tracing K

Went over the docs (Google and Apple's), but there are a few things that are not clear to me. This is my summary of how I interpreted it works: - A [Tracing Key] is stored locally in every device. - A [Rolling Key] gets regenerated every day based on the [Tracing Key] - A [Proximity Identifier] gets regenerated every 15 minutes and broadcasted to other bluetooth devices. - The Contact Tracing Bluetooth Specification does not require the user’s location; any use of location is completely optional to the schema. - Other devices save the [Proximity Identifier] locally. - History is stored for a couple of weeks Some questions about how I interpreted the rest: - The device wakes up once a day and downloads the list of identifiers that have been known/reported to have COVID. It compares on device that you are on that list. Q: Wouldn't this list be insanely long? More so if it doesn't have any concept of location? - If you have COVID-19, you can report to the servers that you were found to have it. Your rolling identifiers gets uploaded to the "cloud server". Q: Which "cloud server"? Whose cloud server? Any clarifications are strongly welcomed :) - If diagnosed with COVID-19, users consent to sharing Diagnosis Keys with the server.

y7 7y ago
> Q: Wouldn't this list be insanely long? More so if it doesn't have any concept of location? I don't think such a list would be that long: 1. It's not unreasonable to have some approximate concept of location (e.g. "New York City and surroundings") 2. A contract tracing app is only useful when the number of new infections is low enough, such that all possible contacts can be tested. 3. For a tracing key 32 bytes would suffice. Even for 15,000 relevant infections you're only looking at 0.5 MB of data.
- donarb 7y ago
  The "location" data would be self size limiting since its based on the users who are using the app provided by a local public health agency, like a city or county.
- rburhum 7y ago
  Thanks for the answer. Now, I am not sure your tracing key gets updated as far as I understood. Isn't the individual 15-minute long identifiers that get updated? Also, not sure you can limit to surroundings just yet... people are still moving too much.
donarb 7y ago
> Q: Which "cloud server"? Whose cloud server? Apple/Google are providing the API to public health systems who would write an app that uses the API. So your city/county/state would distribute an app used by people who live there. The server would be owned by the entity that wrote the app.

y7 7y ago

> Q: Wouldn't this list be insanely long? More so if it doesn't have any concept of location? I don't think such a list would be that long: 1. It's not unreasonable to have some approximate concept of location (e.g. "New York City and surroundings") 2. A contract tracing app is only useful when the number of new infections is low enough, such that all possible contacts can be tested. 3. For a tracing key 32 bytes would suffice. Even for 15,000 relevant infections you're only looking at 0.5 MB of data.

donarb 7y ago
The "location" data would be self size limiting since its based on the users who are using the app provided by a local public health agency, like a city or county.
rburhum 7y ago
Thanks for the answer. Now, I am not sure your tracing key gets updated as far as I understood. Isn't the individual 15-minute long identifiers that get updated? Also, not sure you can limit to surroundings just yet... people are still moving too much.

donarb 7y ago

> Q: Which "cloud server"? Whose cloud server? Apple/Google are providing the API to public health systems who would write an app that uses the API. So your city/county/state would distribute an app used by people who live there. The server would be owned by the entity that wrote the app.