Securing V2X Communications for the Future - Can PKI Systems offer the answer?

Over recent years, emphasis in secure V2X communications research has converged on the use of Vehicular Public Key Infrastructures (VPKIs) for credential management and privacy-friendly authentication services. However, despite the security and privacy guarantees offered by such solutions, there are still a number of challenges to be conquered. By reflecting on state-of-the-art PKI-based architectures, in this paper, we identify their limitations focusing on scalability, interoperability, pseudonym reusage policies and revocation mechanisms. We argue that in their current form such mechanisms cannot capture the strict security, privacy, and trust requirements of all involved stakeholders. Motivated by these weaknesses, we then proceed on proposing the use of trusted computing technologies as an enabler for more decentralized approaches where trust is shifted from the back-end infrastructure to the edge. We debate on the advantages offered and underline the specifis of such a novel approach based on the use of advanced cryptographic primitives, using Direct Anonymous Attestation (DAA) as a concrete example. Our goal is to enhance run-time security, privacy and trustworthiness of edge devices with a scalable and decentralized solution eliminating the need for federated infrastructure trust. Based on our findings, we posit open issues and challenges, and discuss possible ways to address them.