Vehicular Public Key Infrastructure (VPKI) plays a vital role in ensuring secure and privacy-preserving communication in vehicular ad hoc networks (VANETs). However, current VPKI architectures face significant challenges in terms of scalability, resilience, and privacy preservation. This paper proposes a novel threshold-based VPKI architecture to overcome these limitations. Leveraging a Schnorr threshold signature scheme based on elliptic curve cryptography, the proposed architecture eliminates the reliance on individual certificate authorities (CAs) and distributes trust among multiple CAs in a threshold certificate signing approach. This enhances resilience and mitigates the single point-of-failure vulnerability. The architecture also addresses sybil-based misbehaviors through a time-restrictive pseudonym design that eliminates multiple simultaneous use of pseudonyms. Furthermore, the scheme reduces the size and latency of Certificate Revocation List (CRL) distribution by clustering multiple CAs in a threshold setting and adopting a region-specific CRL. The paper presents detailed analysis of the security, privacy and performance benefits of the proposed architecture. Results from the performance evaluation shows the improved resiliency, reduced handover rates, and better scalability potential of the proposed threshold-based VPKI architecture compared to existing techniques. The proposed threshold-based VPKI holds great promise in ensuring secure and privacy-preserving communication in VANETs, paving the way for safer and more efficient vehicular networks.

翻译：车载公钥基础设施（Vehicular Public Key Infrastructure, VPKI）在确保车载自组织网络（VANETs）安全且隐私保护的通信中扮演着关键角色。然而，当前VPKI架构在可扩展性、弹性和隐私保护方面面临重大挑战。本文提出一种新颖的基于门限的VPKI架构以克服这些局限。该架构利用基于椭圆曲线密码学的Schnorr门限签名方案，通过门限证书签名方法，消除了对单一证书权威机构（CA）的依赖，并将信任分布于多个CA之间，从而增强了弹性并缓解了单点故障脆弱性。该架构还通过一种时间受限的假名设计来应对基于女巫（Sybil）的异常行为，该设计消除了假名的多实例同时使用。此外，该方案通过在门限设置中聚类多个CA并采用区域特定的证书撤销列表（CRL），降低了CRL分发的规模和延迟。本文对所提架构的安全性、隐私性和性能优势进行了详细分析。性能评估结果表明，与现有技术相比，所提出的基于门限的VPKI架构具有更高的弹性、更低的手续切换率以及更优的可扩展潜力。所提出的门限式VPKI在确保VANETs中安全且隐私保护的通信方面具有巨大前景，为更安全、更高效的车载网络铺平了道路。