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by tinus_hn 2258 days ago
The proposed system requires download of 16 bytes per infected user per day. Unless this really gets out of hand that’s not in the megabytes range.
1 comments

Yes, this is where OP lost me.

> Published keys are 16 bytes, one for each day. If moderate numbers of smartphone users are infected in any given week, that's 100s of MBs for all phones to DL.

"Moderate" rate of infections is not millions of new cases per week worldwide. That would be such a catastrophe that contact tracing would be useless.

Currently there are 1.2 million active infections. Doesn’t this mean every smartphone in the world would need to download 17 MB per day?

If more cases would be tested in India or Africa or Sputh America a ten fold increase wouldn’t be unthinkable.

No, my understanding is you only would download two weeks worth of keys when a new infection is reported. There is an assumption in any method of contact tracing that once people test positive that they are isolating themselves. If they don't, there is no reason to do the tracing since the virus will simply spread exponentially.
The downloads are mediated by country specific apps. You don’t need numbers from the whole world.