I was going through the security specification of 5G network and stopped at a point where it was mentioned that UE shall support integrity protection of user data along with the integrity protection of RRC and NAS-Signalling. Section 5.1.3.1 also mentions that integrity protection of the user data between UE and gNB is optional to use.
I want to know that for which cases/scenarios, it would be needed to enable integrity protection for user data between UE and gNB ?
Enabling both integrity and ciphering for the user data would be an overhead, therefore I started thinking about scenarios/cases.