Explain how having every person you're in contact with being tracked by governments and corporations can be done in a 'privacy preserving way'. The very concept of contact tracing is probably the greatest violation of privacy I've seen proposed yet.
The central authority just has a list of tokens from infected people. A corrupt central authority could also massively deploy token recorders across an area and then see when and where the infected people were seen, but governments already have that capability just from the cellular systems.
A simple method is to have phones directly exchange random numbers over bluetooth. If and only if someone tests positive, they publish their phone's recent random number transmissions. All phones download all published random numbers (just random numbers, no personal info) and see whether they've received any of them via bluetooth.
This way the phone knows whether it's been in contact with someone who tested positive, but nobody else knows. Since the user has a strong incentive to get a covid test at that point, that's fine.
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[1] https://github.com/RaphaelJ/covid-tracer/blob/master/README....