There was recently a similar question on Slack.
BLE Mesh has a similar requirement to encrypt/decrypt contents of advertising packets.
From: users@... <users@...> On Behalf Of 1606140 via Lists.Zephyrproject.Org
Sent: 25 August 2019 13:53
Subject: [Zephyr-users] #bluetooth #nrf52832 #bt
Hi, all. I am encrypting the UUID of my beacon and wants to decrypt it at the scanner's end. But the problem is that the docs say only about encryption function bt_encrypt_be(). How
do I decrypt my UUID at the scanner's end?.