If a BLE can't force a disconnect, how can we authenticate a connection?

Question

I believe I read that the peripheral side cannot terminate a connection?

terminate a connection CBPeripheralManager side

How then, can we authenticate a connection at the application level? We are making an iOS app connect to another iOS app, we only want them to connect to each other. After connection they exchange private-key-based challenge/response questions, and a failure should result in a refusal of the connection. This of course works fine on the central side, if it doesn't get the correct reply it closes the connection. But if the peripheral cant cancel the connection, then how do we prevent a different central from connecting, and staying connected to the peripheral?

Answer 1

When a central connects but does not authenticate correctly, do not respond to requests from it. Every CBATTRequest includes the requesting central, and updateValue(_for:onSubscribedCentrals:) lets you control which centrals you respond to.

If they're not authenticated. Don't talk to them. Or more correctly, send them .insufficientAuthentication to all their requests. If they are well behaved, they will disconnect. If they are badly behaved, there is nothing you can do about that (this is always true; even if you could disconnect them, they could still flood you with connection requests).

You cannot force them to disconnect, however. They may be communicating with another app, and you are not allowed to stop that. You can only refuse to talk to them yourself or send them errors.