Zero-Knowledge Proof of Traffic: A Deterministic and Privacy-Preserving Cross Verification Mechanism for Cooperative Perception Data (2312.07948v1)

Abstract: Cooperative perception is crucial for connected automated vehicles in intelligent transportation systems (ITSs); however, ensuring the authenticity of perception data remains a challenge as the vehicles cannot verify events that they do not witness independently. Various studies have been conducted on establishing the authenticity of data, such as trust-based statistical methods and plausibility-based methods. However, these methods are limited as they require prior knowledge such as previous sender behaviors or predefined rules to evaluate the authenticity. To overcome this limitation, this study proposes a novel approach called zero-knowledge Proof of Traffic (zk-PoT), which involves generating cryptographic proofs to the traffic observations. Multiple independent proofs regarding the same vehicle can be deterministically cross-verified by any receivers without relying on ground truth, probabilistic, or plausibility evaluations. Additionally, no private information is compromised during the entire procedure. A full on-board unit software stack that reflects the behavior of zk-PoT is implemented within a specifically designed simulator called Flowsim. A comprehensive experimental analysis is then conducted using synthesized city-scale simulations, which demonstrates that zk-PoT's cross-verification ratio ranges between 80 % to 96 %, and 80 % of the verification is achieved in 2 s, with a protocol overhead of approximately 25 %. Furthermore, the analyses of various attacks indicate that most of the attacks could be prevented, and some, such as collusion attacks, can be mitigated. The proposed approach can be incorporated into existing works, including the European Telecommunications Standards Institute (ETSI) and the International Organization for Standardization (ISO) ITS standards, without disrupting the backward compatibility.

• The paper proposes a deterministic zero-knowledge proof mechanism that validates traffic observations without revealing vehicle identities or locations.
• It employs cryptographic cross-verification, achieving an 80% verification rate within 2 seconds in a city-scale simulation using Flowsim.
• The study demonstrates that zk-PoT effectively overcomes traditional ITS validation limitations, enhancing both security and privacy in cooperative perception.

Introduction to Cooperative Perception

Connected automated vehicles (CAVs) in Intelligent Transportation Systems (ITSs) rely on the sharing of perception data to enhance safety and efficiency on the road. However, a persistent challenge has been authenticating these data to ensure they are reliable and not falsified by ill-intentioned vehicles. This blog post discusses an innovative solution to this problem—the zero-knowledge Proof of Traffic (zk-PoT)—which focuses on validating traffic observation data while preserving the privacy of the involved vehicles.

The zk-PoT Mechanism

The mechanism behind zk-PoT lies in cryptographic proofs. Rather than utilizing traditional methods that depend on past behavior or set rules, zk-PoT allows vehicles to generate cryptographic proofs of the traffic events they observe. Multiple vehicles can independently corroborate the same observation by cross-verifying their proofs without revealing any private information, such as the vehicle's identity or location. This technique ensures that the verification process is both privacy-preserving and deterministic.

A comprehensive simulator, Flowsim, was used to test and evaluate the performance of zk-PoT in a synthesized city-scale environment. The results exhibited a high cross-verification rate, with 80% of the data being verified within just 2 seconds, all with a relatively low protocol overhead.

Overcoming Limitations of Previous Approaches

The paper highlights that traditional data validation methods in ITS may fall short as they lack the capability to deterministically validate data. zk-PoT overcomes this by not relying on statistical evaluations or predefined rules. It provides a robust solution that integrates seamlessly with existing ITS standards set by organizations such as the European Telecommunications Standards Institute (ETSI) and the International Organization for Standardization (ISO).

Implications and Future Directions

With the proposed zk-PoT approach, the ITS domain stands to benefit from an enhanced security framework that is more resistant to various attacks and does not compromise on the privacy of CAVs. Attack analyses suggest that many common attacks can be prevented or have their impact mitigated when using zk-PoT. Moreover, the protocol is flexible enough to be used in conjunction with current trust management methods, possibly serving as a method to establish initial trustworthiness.

zk-PoT's adaptability extends beyond just vehicles with V2X communication capabilities, indicating a broader relevance for a variety of ITS applications. Future studies could further refine the approach to incentivize data sharing, address potential Sybil attacks, and ensure the protocol's aptitude in mixed traffic conditions that include non-V2X vehicles.

Overall, the zero-knowledge Proof of Traffic sets a new standard for data validation in ITS, paving the way for safer and more reliable cooperative perception among connected vehicles.