Improving Unlinkability in C-ITS: A Methodology For Optimal Obfuscation

Yevhen Zolotavkin, Yurii Baryshev, Vitalii Lukichov, Jannik Mähn, Stefan Köpsell

2023

Abstract

In this paper, we develop a new methodology to provide high assurance about privacy in Cooperative Intelligent Transport Systems (C-ITS). Our focus lies on vehicle-to-everything (V2X) communications enabled by Cooperative Awareness Basic Service. Our research motivation is developed based on the analysis of unlinkability provision methods indicating a lack of such methods. To address this, we propose a Hidden Markov Model (HMM) to express unlinkability for the situation where two vehicles are communicating with a Roadside Unit (RSU) using Cooperative Awareness Messages (CAMs). Our HMM has labeled states specifying distinct origins of the CAMs observable by a passive attacker. We then establish that high assurance about the degree of uncertainty (e.g., entropy) about labeled states can be obtained for the attacker under the assumption that he knows actual positions of the vehicles (e.g., hidden states in HMM). We further demonstrate how unlinkability can be increased in C-ITS: we propose a joint probability distribution that both drivers must use to obfuscate their actual data jointly. This obfuscated data is then encapsulated in their CAMs. Finally, our findings are incorporated into an obfuscation algorithm whose complexity is linear in the number of discrete time steps in the HMM.

Paper Citation

in Harvard Style

Zolotavkin Y., Baryshev Y., Lukichov V., Mähn J. and Köpsell S. (2023). Improving Unlinkability in C-ITS: A Methodology For Optimal Obfuscation. In Proceedings of the 9th International Conference on Information Systems Security and Privacy - Volume 1: ICISSP, ISBN 978-989-758-624-8, pages 677-685. DOI: 10.5220/0011786900003405

in Bibtex Style

@conference{icissp23,
author={Yevhen Zolotavkin and Yurii Baryshev and Vitalii Lukichov and Jannik Mähn and Stefan Köpsell},
title={Improving Unlinkability in C-ITS: A Methodology For Optimal Obfuscation},
booktitle={Proceedings of the 9th International Conference on Information Systems Security and Privacy - Volume 1: ICISSP,},
year={2023},
pages={677-685},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0011786900003405},
isbn={978-989-758-624-8},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 9th International Conference on Information Systems Security and Privacy - Volume 1: ICISSP,
TI - Improving Unlinkability in C-ITS: A Methodology For Optimal Obfuscation
SN - 978-989-758-624-8
AU - Zolotavkin Y.
AU - Baryshev Y.
AU - Lukichov V.
AU - Mähn J.
AU - Köpsell S.
PY - 2023
SP - 677
EP - 685
DO - 10.5220/0011786900003405