I want to use the different levels of authentication for a central to connect to a peripheral.
I've seen in the EncryptedBatteryMonitor example you provide l38 and 39 the way to declare a characteristic of a service which require encryption to write on it:

I've also seen in the source code that it is possible to have other option for it.

There is also the enum BLE_GATT_PERM_ { (which I don't understand the usage)

So to go back to the example, I don't understand how the callback function for the pairing works.
There are functions declared between line 58 and 151 named callbacks, and key management.
I don't understand how to use them, and where to declare them.

In the function setEventHandler, the only handler available are the connect and disconnect.

When I try to use this example, every time I try to pair a device to the example running, I got an error, and no evidence of the callback function called, nothing prints on the Serial port.

Can you help me with this please ? To understand how to use the different callback pairing functions, and the different parameters available and the purpose of the different existing enum and all the things I wonder into this field.

Is there documentation about how to use this feature ?

Is there another existing library usable to use secure pairing between two elements ?

Additional context

Additional reports

• Impossible to use secure/encrypted pairing - arduino nano 33 BLE #295 (comment)