Identify iOS device using iBeacon or CoreBluetooth in background

2
votes

I have an app that runs 2 modes:

  • Mode 1: Advertises the App UUID

  • Mode 2: Monitors and ranges for the App UUID

When the 2 devices are in proximity a notification is triggered. When in the foreground I'm able use the Major / Minor values to send the unique device ID (guessing Bluetooth MAC address) to device in mode 2 and call a webservice to identify 'who' the device belongs to.

This method does not seem to be possible in the background? I've read that the Bluetooth packet that's advertised by iOS device either strips the Bluetooth MAC address and major / minor values out when advertising, or the device running the app in the background receiving the notification chooses not to receive it?

My question is really this:

Is it possible to detect which device is advertising the Apps UUID even if the device monitoring has the app in the background using CoreBluetooth iBeacon or CoreLocation services?

1
iosiphonecore-bluetoothibeacon
The transmitting app must be in the foreground, if it is then the receiver can be in the background and the major/minor values used to distinguish 4+ billion unique devices (if systematically assigned) as already mentioned. - Chris Stratton

1 Answers

3
votes

Yes, you can do this using CoreLocation iBeacon APIs in mode 2 and CoreBluetooth APIs to advertise an iBeacon with device-specific major and minor identifiers in mode 1.

To clarify, you CANNOT use the Bluetooth Mac address as iOS spoofs this on the receiver side (both in the background and foreground), assigning a unique one per session that is not always consistent for the same transmitting device.

Using an iBeacon transmission you must know the iBeacon ProximityUUID in advance on the receiver, so the 16-bit major and 16-bit minor fields are all that you can use to uniquely identify a device. That gives you over a billion combinations so it should be sufficient.

You can monitor for the single iBeacon UUID in the background, then iOS will wake up your app for 5 secs, allowing you to use the iBeacon ranging APIs to read the major and minor identifiers. All of this works in the background for mode 2, except transmitting as an iBeacon which requires the foreground for mode 1.