Contact Tracing

 With the COVID-19 pandemic,  public and public health agencies are seeking ways to better control contagion.

 In 2017 BBC ran an experiment where British citizens were offered a smart phone application (app) to track their movements and correlate such movements with crowds to mathematically simulate a virus outbreak. 

 With the COVID-19 outbreak Singapore's government offered a smart device app TraceTogether.  Singapore has closed its borders, but business remains open. The app uses Bluetooth tracking with the user's permission to inform subscribers of potential contacts with known infections. Problem they found, not enough subscribers to be that effective.

 Now Apple and Google are working a similar method but the capability is to be built into the smart device's operating system. Thus iOS, iPadOS, Android would gain the capability with the normal smart device updates. This allows the capability to be turned off when the crisis passes, better control, regulation, and integration with public health technical capabilities.

 Warning about having smart devices with Wi-Fi enabled while away from the home network. The device will "beacon" its home network name as well as recent network names the device has associated with. The normal behaviour is to silently associate with any of these Wi-Fi network names. Convenient for home networks so no user actions needed to leave home and come back within Wi-Fi range. Not so safe as anyone with a radio can see these Wi-Fi beacons, name their Wi-Fi network name to match the beacon name, and you device will silently associate with this rogue network.

 Bluetooth has a shorter range with the integrated radio. Bluetooth randomizes its MAC address. The proposed tracking effort would further hash and change a Rolling Proximity Identifier every 15-20 minutes. These are received and recorded by any other Bluetooth device within range. The sending device can recreate these Identifiers.
Your device changes and sends these identifiers. Your device receives and records those other devices seen by the Bluetooth radio with an automatic delete after a preset interval. 
 When someone is diagnosed the public health authority issues that person a certificate which is added to the infected person list. If your device has been within Bluetooth proximity you will be informed so as to take the appropriate actions.

 Recall the HIPPA regulations and similar regulations, practices, and procedures are suspended during a pandemic. COVID-19 is a notifiable disease, health officials must inform the public. A contact tracing system can predict where the supplies needed should be deployed.

 Time will tell if this effort helps with the spread of COVID-19 and any follow-on contagions. 

 Our current efforts have been abused. People citing infection to have their workplace sent home, and all manner of other malformed behaviours.

 Then the issue of a difference between radio/Bluetooth proximity and virus transmit proximity. Apartment floors and walls as an example. And the reverse - virus spread via mutual touched surfaces and no radio proximity.