I recently tried to add security features (encryption, no MITM) to my application, and I am using nRF Sniffer to verify. nRF Master Control Panel gives me the request for the devices to pair and says that the devices are bonded. However, even though Sniffer/Wireshark says "Encrypted: Yes", it still gives me perfectly readable data. So, is nRF Sniffer just smart enough to decrypt messages as long as it's listening to that connection from the beginning?
Also, is it possible to view "junk" traffic? It would make me feel a bit better to be able to see decryption obviously not working, i.e. seeing unreadable packets.