Nowadays, as an essential technique for intelligent transportation, vehicular ad hoc networks (VANETs) has significantly improved people’s travel experience, providing richer, and smarter services for vehicles while ensuring driver safety. However, considering that VANETs are complex, some security challenges still remain, including but not restricted to privacy preserving of vehicles, authentication of messages, limited resources in computational power, and network bandwidth. To address these issues, many privacy-preserving identity authentication schemes for VANETs have been proposed recently. However, these schemes still suffer some limitations. First, their computational overheads are heavy due to the complex calculations. Second, some schemes are vulnerable to various security weaknesses, unable to resist normal attacks. Third, in some schemes, the same pseudonym keeps unchanged and it is linked to the corresponding private key of user. The consequence is that if the user wants to change its pseudonym, the corresponding private key must be changed. In order to further solve the above problems, we propose a novel privacy-preserving identity authentication protocol based on the certificateless aggregate signature scheme, allowing the user to generate a fuzzy identity to hide her real identity, and the private key can be kept unchanged even if the corresponding pseudonym is updated. Furthermore, to achieve efficiency in computation, bilinear mapping is avoided in our proposed scheme. We prove that our protocol satisfies unforgeability in the random oracle based on a classic complexity assumption. Finally, the security and efficiency analyses demonstrate that our construction enjoys more security features and better performance compared with the existing schemes.

中文翻译：

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一种高效的 VANET 动态匿名身份认证方案

如今，车载自组织网络（VANETs）作为智能交通的一项重要技术，极大地改善了人们的出行体验，在保障驾驶安全的同时为车辆提供了更丰富、更智能的服务。然而，考虑到 VANET 的复杂性，仍然存在一些安全挑战，包括但不限于车辆的隐私保护、消息的身份验证、有限的计算能力资源和网络带宽。为了解决这些问题，最近提出了许多用于 VANET 的隐私保护身份认证方案。然而，这些方案仍然存在一些局限性。首先，由于计算复杂，它们的计算开销很大。二是部分方案存在各种安全漏洞，无法抵抗正常攻击。第三，在某些方案中，相同的假名保持不变，并链接到相应的用户私钥。结果是，如果用户想要更改其假名，则必须更改相应的私钥。为了进一步解决上述问题，我们提出了一种新的基于无证书聚合签名方案的隐私保护身份认证协议，允许用户生成一个模糊身份来隐藏自己的真实身份，私钥甚至可以保持不变如果相应的假名已更新。此外，为了提高计算效率，我们提出的方案避免了双线性映射。我们证明我们的协议满足基于经典复杂性假设的随机预言机的不可伪造性。最后，