First look at Apple/Google contact tracing framework

First look at Apple/Google contact tracing framework:

1) Once a day, your device derives a new key ("daily tracing key").

2) It uses that to derive a new "proximity ID" every time your device's bluetooth address changes (15min), which is broadcast to nearby BT sensors.

1/10

— Moxie Marlinspike (@moxie) April 10, 2020

from Hacker News https://twitter.com/moxie/status/1248707315626201088