The security issues in Vehicle Ad Hoc Networks (VANETs) are prevalent within Intelligent Transportation Systems (ITS). To ensure the security of vehicle-to-infrastructure (V2I) communication, extensive research on V2I authentication has been conducted in recent years. However, these protocols often overlook the limitations of communication range, leading to failures in V2I communication. Consequently, addressing the challenge of secure V2I communication in areas not covered by distributed roadside units (RSUs) remains a significant task. To address these issues, the current study proposes an Anonymous Certificate-less Hybrid Mutual Authentication Protocol (ACHMAP) based on Vehicle-to-Vehicle-to-Infrastructure (V2V2I) communication. In the proposed protocol, a secure multi-hop link is established through vehicle-to-vehicle (V2V) mutual one-time token authentication. Subsequently, the out-of-coverage vehicle and relevant RSUs complete V2I mutual authentication using signcryption messages transmitted by vehicle nodes. In the security analysis, it is demonstrated that the entire V2V2I stage can resist various security attacks, such as replay attacks, impersonation attacks, and threats to user anonymity, while preserving confidentiality and integrity. We simulated the proposed protocol using Network Simulator 3 (NS-3) to confirm that the authentication mechanism has lower overhead and minimal authentication delay in V2V2I communication.

中文翻译：

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用于车辆到基础设施通信的混合相互身份验证，无需路边单元的覆盖


车辆自组网 （VANET） 中的安全问题在智能交通系统 （ITS） 中普遍存在。为了确保车辆到基础设施 （V2I） 通信的安全性，近年来对 V2I 身份验证进行了广泛的研究。但是，这些协议往往忽视了通信范围的限制，导致 V2I 通信失败。因此，在分布式路边单元 （RSU） 未覆盖的区域应对安全 V2I 通信的挑战仍然是一项重要任务。为了解决这些问题，目前的研究提出了一种基于车对车到基础设施 （V2V2I） 通信的匿名无证书混合相互身份验证协议 （ACHMAP）。在拟议的协议中，通过车对车 （V2V） 相互一次性令牌身份验证建立安全的多跳链路。随后，覆盖外车辆和相关 RSU 使用车辆节点传输的签名加密消息完成 V2I 双向身份验证。在安全分析中，证明了整个 V2V2I 阶段在保持机密性和完整性的同时，可以抵御各种安全攻击，如重放攻击、冒充攻击和对用户匿名的威胁。我们使用 Network Simulator 3 （NS-3） 模拟了拟议的协议，以确认身份验证机制在 V2V2I 通信中具有较低的开销和最小的身份验证延迟。