In short, we don't collect data about who you are, where you go, or who you're near. With the app, your phone periodically sends out what we call Bluetooth chirps, essentially saying to nearby phones, “Hey, I'm here!” If another phone is nearby chirping, “Hey, I'm here too,” both phones will log the interaction and store it for 2-4 weeks right there inside your device. After 2-4 weeks, the interaction is permanently deleted.
If you are diagnosed with COVID-19, you can choose to share your test results in the app after being verified by local health officials. Once you do that, you input a positive verification code number into the app. Immediately, other devices that have recently heard your phone’s Bluetooth chirps will be notified of an exposure. The notification contains no personal information and no locations. If a hacker broke into the app, they would just find a bunch of random numbers.