Disable encryption on "Just Works" pairing on NRF52DK

Hey guys,

I'm working on a project and want to build up on the Nordic BLE UART example (mobile device app and node firmware). As far as I know the pairing between the node and, e.g., a mobile device works with the "just works" method in the stock examples and there is by default an unauthenticated key exchange for link encryption, right? In my use case the encryption isn't necessary, is there a way to skip this key exchange and thus the encryption? E.g. by changing some settings in the GAP or GATT initialisation?

Thanks in advance!