g- nificant bit part (8 bits) of destination layer-2 ID and is forwarded to physical layer as group destination ID. This identifies the target of the intended data in SCI and is used for filtering of packets at the physical layer. The second bit string is the MSB part (16 bits) of the destination layer-2 ID which is carried within the MAC header. This is used for fil- tering of packets at the MAC sublayer. In the case of V2X sidelink communication, desti- nation layer-2 ID is not split and is carried within the MAC header. No access stratum signaling is required for group formation and to configure source layer-2 ID, destination layer-2 ID and group destination ID in the UE. These identities are either provided by higher layer or derived from identities provided by higher layer. In case of groupcast and broadcast, the ProSe UE ID provided by higher layer is used directly as the source layer-2 ID and the ProSe layer-2 group ID provided by higher layer is used directly as the destination layer-2 ID in the MAC sublayer. In the case of one-to-one communica- tions, the ProSe UE ID provided by higher layer is used directly as the source layer-2 ID or the destination layer-2 ID in the MAC sublayer. In the case of V2X sidelink communica- tion, higher layer provides source layer-2 ID and destination layer-2 ID. 5G network security is still under development by 3GPP for device-to-network communica- tions. The C-V2X security was not updated with Rel-15. However, the enhancements devel- oped for network access and associated security aspects will apply to the network-enabled mode of communication. As for the direct mode of operation, the security design for the Rel-14 C-V2X is expected to remain unchanged, namely specifying the reuse of the application-level security already defined by IEEE for DSRC systems. In particular, LTE Rel-14 does not support vehicle identity privacy when it sends V2X traf- fic via the network. Architectural changes would be required to support user/vehicle ano- nymity from the operator. It is expect