That's a legitimate concern, but I think the German app is designed so that the government does not get the contact data. Here's how I understand the system:

That's a legitimate concern, but I think the German app is designed so that the government does not get the contact data. Here's how I understand the system: Your phone saves the ID numbers of the phones it's come into close contact with. The IDs are randomly generated, so they don't contain any information about the person carrying the phone. When someone tests positive for the virus, they can transmit their ID to a central server, which then broadcasts that ID to everyone with the app. The app checks that ID against its local list of contacts.