[olliej]

Increasing the lifetime for what are currently "daily keys" reduces the precision of the contact reporting - e.g. your example of a week means that a positive user would need to report at least 3 weeks of keys, so someone can now do correlation over 3 weeks instead of X days.

There's no inclusion of location data as that has no value - the only thing that this protocol cares about was whether you were in the vicinity of someone who has tested positive for cover-19, and so suggest you get tested. Knowing where you are/were has no value for that purpose.

[rrrrrrrrrrrryan]

I think he was trying to say you could reduce the computation by narrowing the space-time radius, then searching for matches. Even a state-level restriction would be enough to substantially narrow down the possible matches without sacrificing anonymity.