# EAIA: An Efficient and Anonymous Identity-Authentication Scheme in 5G-V2V
## 2 Related Work
If successful, RSBS generates and sends local group signature private key pairs for V2V communication within the same area. The protocol in [16] aimed to perform key updates among vehicles without RSU coverage, using secure channels established with existing public group keys. The requesting party proves its identity using an asymmetric key-based challenge-response mechanism to the key-providing party. It is worth noting that the latest research shows that drones can be used as deployment protocol facilities to replace RSUs to achieve a wider dynamic communication authentication range. Unlike traditional broadcasting methods, drones can quickly align antenna beams by sensing the spatial position of the receiver [17]. However, due to the limited communication resources of drones and the difficulty of infrastructure construction in many complex tracking areas (such as forests), they cannot provide real-time tracking decisions [18]. While these methods can be effective in certain scenarios, they depend on comprehensive infrastructure deployment and maintenance, which is not feasible in infrastructure-free or weak infrastructure environments. Secondly, although research on inter-vehicle mutual authentication without infrastructure is limited, some studies propose solutions addressing the authentication issue through various techniques. The solution in [19] proposed a blockchain-based protocol for V2I authentication, V2I handover authentication, and V2V broadcast authentication without relying on traffic infrastructure (e.g., RSU) or trusted authority (TA). Vehicles can broadcast accident reports to other vehicles without RSUs, but pre-broadcast authentication still relies on V2I, not purely V2V authentication. The authors in [20] proposed an identity-based cryptography (IBC) scheme for V2V identity authentication and key agreement. C-V2X devices use their vehicle identification (VID) as their public key. The key management center (KMC) generates private keys for C-V2X devices based on their VID. C-V2X devices transmit secret data encrypted with the recipient's public key and verify each other using an identity-based cryptographic challenge-response protocol, negotiating working keys for encrypted communication. The protocol in [21] proposed a new 5G-V2X architecture leveraging network slicing (NS) to ensure different V2X service characteristics and analyzed security requirements based on V2X service types. When vehicles request subscribed services, NSSF determines whether to allow the request, mapping allowed and configured S-NSSAI, and isolating mapped slices. VCF, responsible for V2X service authorization and revocation, transmits V2V service credentials without revealing sensitive vehicle information. Vehicles with V2V service credentials and proximity discover each other, negotiating shared keys for secure communication via 5G millimeter-wave direct V2V links or operating PC5 interfaces. The authors in [22] proposed an authentication mechanism executable in infrastructure-free VANET environments based on LiDAR information for vehicle authentication, called LiDAR. LiDAR authenticates vehicles using available hardware based on shared surrounding information, establishing secure V2V symmetric keys after verifying common object types, distances, and angles. Most existing methods remain unsuitable for environments lacking RSUs. Moreover, due to their innovative nature, these schemes often do not conform to traditional vehicular network frameworks, resulting in practical application limitations. However, some studies demonstrate feasibility and reference value even without RSUs, leveraging conventional vehicular network frameworks. The authors in [23] proposed a multiregion authentication and privacy protection protocol (MAPP) based on bilinear pairing cryptography and short digital signatures. The protocol supports message and identity authentication within single and multiple regions, enhancing the security and availability of 5G-V2X networks.