Indeed, if I understand correct, the device locally stores a bunch of keys of people you've been in contact to, and there is no way of working backward from the

Indeed, if I understand correct, the device locally stores a bunch of keys of people you've been in contact to, and there is no way of working backward from the keys to who it was, and these keys also change daily. Then when someone marks themselves as infected for days A through Z, their keys for those days is sent to devices, where the devices check locally if they have the given person-day keys stored. Do I understand this correctly? It's almost all done locally, there's nothing about location, and almost nothing is send up until you mark yourself as infected, right? EDIT: This is the best high level explained I've found: https://blog.google/documents/57/Overview_of_COVID-19_Contact_Tracing_Using_BLE.pdf https://blog.google/documents/57/Overview_of_COVID-19_Contac...