Vehicular Ad-hoc Network (VANET) is vital for supporting intelligent transport systems, such as traffic data sharing and cooperative processing in the modern city. However, data security and privacy are the critical factors restricting the development. To address these challenges, several certificateless conditional privacy-preserving authentication (CPPA) schemes with anonymity and traceability have been proposed. These schemes avoid complicated certificate management in the PKI framework and key escrow in the ID-based protocol. However, there still exist drawbacks such as computational complexity, high communication cost or security vulnerability. Recently, Ali et al. proposed an efficient certificateless CPPA (CLCPPA) scheme for VANETs, but we have found that this scheme fails to resist a signature forgery attack. To achieve a trade-off between security and efficiency, we first demonstrate the insecurity of Ali et al.’s protocol and then introduce a security-enhanced solution. To show the feasibility and utility of our proposal, we perform a security analysis in the security model. Moreover, we evaluate the performance via comparing it with other existing schemes. From the comparison results, we can find that our scheme is more efficient than prior state-of-art solutions, in terms of signing (improving 66.75%), the verification (improving 33.19%) and bandwidth requirement (reducing 14.75%). Therefore, our proposal is more suitable to be applied in VANETs.

中文翻译：

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VANET 的高效无证书条件隐私保护认证

车载自组织网络 (VANET) 对于支持智能交通系统至关重要，例如现代城市中的交通数据共享和协同处理。然而，数据安全和隐私是制约发展的关键因素。为了应对这些挑战，已经提出了几种具有匿名性和可追溯性的无证书条件隐私保护认证（CPPA）方案。这些方案避免了 PKI 框架中复杂的证书管理和基于 ID 协议中的密钥托管。但是，仍然存在计算复杂、通信成本高或安全漏洞等缺点。最近，阿里等人。为 VANETs 提出了一种有效的无证书 CPPA (CLCPPA) 方案，但我们发现该方案无法抵抗签名伪造攻击。为了在安全性和效率之间取得平衡，我们首先展示了 Ali等人的协议的不安全性，然后介绍了一种安全性增强的解决方案。为了展示我们提议的可行性和实用性，我们在安全模型中进行了安全分析。此外，我们通过将其与其他现有方案进行比较来评估性能。从比较结果可以看出，我们的方案在签名（提高 66.75%）、验证（提高 33.19%）和带宽需求（降低 14.75%）方面比之前的 state-of-art 解决方案更有效。因此，我们的建议更适合应用于 VANET。