Apr 11, 2020

I recommend everybody to look at the whitepaper which discusses this type of protocol extensively: https://github.com/DP-3T/documents/blob/master/DP3T%20White%...

A lot of the arguments against this were rehashed the last few weeks over and over. As an passive participant to such discussions I can't express how tiring it is to see new people drop into these conversations without reading up on what already has been discussed beforehand.

Apr 10, 2020

> It means that contacts with infected persons can't be linked across days, and it means that I can't build an app that alerts me that someone who was previously infected just walked by.

Edit: This actually turns out to be correct, but your conclusion:

> It means that contacts with infected persons can't be linked across days, and it means that I can't build an app that alerts me that someone who was previously infected just walked by.

Is not possible, because every time secrets are made public, the secret key is reset.

[1] https://github.com/DP-3T/documents/blob/master/DP3T%20White%...

Apr 10, 2020

The spec pdf looks a lot like the DP-3T protocol. The DP-3T docs have more explanation and a good discussion of privacy aspects.

https://github.com/DP-3T/documents

paper: https://github.com/DP-3T/documents/blob/master/DP3T%20White%...

data protection aspects: https://github.com/DP-3T/documents/blob/master/DP3T%20-%20Da...

Here's an overview comparing that approach to some others (such as Singapore's tracetogether): https://github.com/vteague/contactTracing