NwkSKey
NwkSKey, short for Network Session Key, is a 128-bit symmetric key used in LoRaWAN to secure network-layer communications. It is one of the session keys established after a device joins the network, the other being the AppSKey (Application Session Key). In over-the-air activation (OTAA), NwkSKey and AppSKey are derived from a device root key during the join procedure and are provisioned to both the device and the network server; in activation-by-personalization (ABP), the keys are pre-shared and installed on the device and the network server.
The primary role of the NwkSKey is to provide integrity protection and confidentiality at the LoRaWAN MAC
Security considerations include the sensitivity of NwkSKey to network integrity, since a compromise can allow tampering