* Without a valid 5G NAS security context:
* Send REGISTRATION REQUEST with cleartext IEs only.
* After activating a security context via Security Mode Control:
wrap the entire REGISTRATION REQUEST (with both non-cleartext and cleartext)
in a NAS message container IE, include it in SECURITY MODE COMPLETE
* With a valid 5G NAS security context:
* If non-cleartext IEs are needed, wrap the entire message in a NAS message container IE and cipher it.
* If only cleartext IEs are needed, send the message directly without the NAS message container IE.