# Advancing C-V2X for Level 5 Autonomous Driving from the Perspective of 3 GPP Standards
## 4 4G and NSA-Based 5G V2X Services
### System Support
#### 4.1.4 Security Aspects Support  
The 3 GPP support for 4G & 5G V2X services with regard to enhancements in either V2X architectures or V2X application layer confirms huge improvements for efficient and effective utilization of cellular technologies and vehicular communications as documented in various technical reports and specifications. Security is yet another important aspect and is required for secure vehicular communication between vehicles, pedestrians, networks, and other related entities. In this regard, the technical specification (_TS 33.185_) of _Rel-14-15-6-16_ started supporting security aspects by introducing requirements on the network entities, architectures, procedures, and solutions for supporting secure V2X and aV2X services. In what follows next, we provide an interesting and critical analysis of the security aspects of C-V2X features. The overall architectural enhancements (specified in (_TS 23.285 Rel-16_)) for vehicular communication services addressing safety and non-safety aspects in 4G & 5G V2X services are a base for introducing security aspects for V2X architectural interfaces. Hence, the research community should note important V2X security requirements for interfaces between network elements, interfaces between UE and V2X control function (V3), an interface between external provider and 3 GPP network (MB2), V2X application data, V2X entities secure environment, and privacy. These V2X security requirements will allow the researchers to explore and identify new security paradigms and aspects of V2X features in addition to the current available V2X security solutions. For instance, [PERSON] et al. [20] provides a protocol that combines short-size signatures and bilinear pairing cryptography to ensure authentication and privacy. Furthermore, the potential areas where security solutions have been proposed for V2X are: V2X communication between network elements, V2X communication between UE and V2X control function (V3), an interface between the V2X application server and 3 GPP network (MB2), and privacy in V2X services. The stated solutions include general descriptions and security procedures (in (_TS 33.185 Rel-16_)) along with other technical specifications that help in achieving the goals of security aspects in V2X services. The discussed technical specification for security aspects of V2X services encourages the researchers working with 3 GPP to introduce other technical specifications (_TS 33.836 Rel-16_ and _TS 33.536 Rel-16_), which specify security aspects for eV2X and aV2X services. The former specification document provides details on eV2X system architecture analysis, potential requirements, and solutions evaluations. The considered security aspects i.e., security and privacy for new interfaces in 5G eV2X system architecture, eV2X unicast over PC5, and eV2X group communication over PC5, and their complete descriptions are available in the former specification document. The latter specification document provides requirements to achieve the security for V2X services, procedures to fulfill the specified requirements, and details on 5 GS in order to facilitate vehicular communication for V2X services and V2X architecture (available in _TS 23.287_). In addition, it considers security aspects for cases other than those available in the document (_TS 33.185 Rel-16_) i.e., PC5 reference point security. The other important security cases are V2X over reference points i.e., Uu and NR-based PC5. These interfaces are well known in comparison to all other reference points due to their importance in vehicular communication for V2X services. It is also noteworthy, that these interfaces and other reference points are used in the V2X architectures as discussed in document (_TS 23.287_). The communication modes i.e., unicast and groupcast, over NR PC5 are considered the potential for security impacts in technical specification (_TS 33.836 Rel-16_) because the security for broadcast mode may receive several changes in the upcoming releases.