BLE connection with custom device with DTLS protocol

Hello

I have a custom BLE device with which I need to have a secure connection over DTLS protocol to the iOS app. The device has two Characteristics, one to read and one to write.

Could anyone give me some hints? ;)

My best idea is to use CoreBluetooth with L2CAP streem, and connect it somehow with Network.framework which has DTLS included. Is it a good trail? How to do that?

Cheers