How WellMet work?
WellMet is a social distance tracker. It allows the user to track the number of close contact from the smartphone Bluetooth sensor. By advertising and scanning device UUID(Universally unique identifier) using low energy wireless radio also known as the beacon, another user can collect and range the distance nearby devices by the signal strength. WellMet will collect other device’s UUID when only in close range at 2 meters and will alert the user when the device closer than 1 meter. The application will keep the record of the met device in the offline database on the user phone and show a number of close contact users within the last 7 days.
The privacy-first principle applied to WellMet design. Even the user device UUIDs have been advertised and everyone can collect it for tracking the user. The UUID is designed to collect without reveal user identity. It creates from the derivative of the unique user code one-way hashing with the date of advertising the UUID. The UUID will change daily to prevent tracking user location by other scanners over a day but still provide enough identity for the app to track numbers without counting a completely random beacon all the time.
The user code is a uniquely large number generate from a pseudo-random number generator. Because it cannot create the true random number in the computer, WellMet intentionally collects a phone number from the user to provide more uniqueness to the user code. The phone number can be any number the user likes. It does not use for any application beyond this.
WellMet using only the offline database on the user phone. Not even internet permission required to run the app. From this high level of data privacy, it cannot be useful to other services. Health care services like WHO, local government could use the data to track potential close contact infected users. The data exporting feature comes to help. Without the user manually export and send their data to the service, the data still safe in the user's hand. The services can create an online infected database for other users to look up their advertised beacon UUIDs re-create from their user code to see if they ever get close contact with the infected and determine their own situation. Because of using the one-way hashing technique, no user can be tracked down by anyone, not by even the government or WellMet creator.
WellMet is free and opensource software, the source code hosted on Github:
https://github.com/artiya4u/wellmet
Download it now at:
https://github.com/artiya4u/wellmet/releases/latest
