Blackchain: Scalability for Resource-Constrained Accountable Vehicle-to-X Communication

TL;DR

Blackchain introduces a scalable, blockchain-based system for accountable vehicle-to-X communication that decentralizes revocation authority, enhances transparency, and improves security in resource-constrained environments.

Contribution

The paper presents a novel hierarchical consensus mechanism for scalable, decentralized revocation in V2X communication using blockchain technology.

Findings

Provides a distributed event data recorder (EDR) with compressed global state

Enables collaborative revocation without centralized trust

Demonstrates scalability through hierarchical consensus

Abstract

In this paper, we propose a new Blockchain-based message and revocation accountability system called Blackchain. Combining a distributed ledger with existing mechanisms for security in V2X communication systems, we design a distributed event data recorder (EDR) that satisfies traditional accountability requirements by providing a compressed global state. Unlike previous approaches, our distributed ledger solution provides an accountable revocation mechanism without requiring trust in a single misbehavior authority, instead allowing a collaborative and transparent decision making process through Blackchain. This makes Blackchain an attractive alternative to existing solutions for revocation in a Security Credential Management System (SCMS), which suffer from the traditional disadvantages of PKIs, notably including centralized trust. Our proposal becomes scalable through the use of hierarchical consensus: individual vehicles dynamically create clusters, which then provide their consensus decisions as input for road-side units (RSUs), which in turn publish their results to misbehavior authorities. This authority, which is traditionally a single entity in the SCMS, responsible for the integrity of the entire V2X network, is now a set of authorities that transparently perform a revocation, whose result is then published in a global Blackchain state. This state can be used to prevent the issuance of certificates to previously malicious users, and also prevents the authority from misbehaving through the transparency implied by a global system state.