Here is how I think the app should have worked. Instead of requesting codes from a central government server to be distributed to people you come into contact

Here is how I think the app should have worked. Instead of requesting codes from a central government server to be distributed to people you come into contact with, your phone could have generated its own codes for distribution. Then when a COVID infection is found, the gov could simply publish a list of all codes collected by the infected person. Your phone could request this public list daily and you could choose to get a COVID test if your code is in the public list. The government would have no way to link any codes to a particular phone or person. A lot less data would need to collected, stored, and managed. This app is designed to allow the government to find and collect anybody they think needs testing. It can also be used to find and punish anybody breaking social distancing laws. (Updated for clarity)