{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,17]],"date-time":"2026-02-17T12:18:45Z","timestamp":1771330725494,"version":"3.50.1"},"reference-count":56,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,4,9]],"date-time":"2025-04-09T00:00:00Z","timestamp":1744156800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Future Internet"],"abstract":"<jats:p>The mix-zone method is effective in preserving real-time vehicle identity and location privacy in Vehicular Ad Hoc Networks (VANETs). However, it has limitations in low-vehicle-density scenarios, where adversaries can still identify the real trajectories of the victim vehicle. To address this issue, researchers often generate numerous fake beacons to deceive attackers, but this increases transmission overhead significantly. Therefore, we propose the Communication-Efficient Pseudonym-Changing Scheme within the Restricted Online Knowledge Scheme (CPCROK) to protect vehicle privacy without causing significant communication overhead in low-density VANETs by generating highly authentic fake beacons to form a single fabricated trajectory. Specifically, the CPCROK consists of three main modules: firstly, a special Kalman filter module that provides real-time, coarse-grained vehicle trajectory estimates to reduce the need for real-time vehicle state information; secondly, a Recurrent Neural Network (RNN) module that enhances predictions within the mix zone by incorporating offline data engineering and considering online vehicle steering angles; and finally, a trajectory generation module that collaborates with the first two to generate highly convincing fake trajectories outside the mix zone. The experimental results confirm that CPCROK effectively reduces the attack success rate by over 90%, outperforming the plain mix-zone scheme and beating other fake beacon schemes by more than 60%. Additionally, CPCROK effectively minimizes transmission overhead by 67%, all while ensuring a high level of protection.<\/jats:p>","DOI":"10.3390\/fi17040165","type":"journal-article","created":{"date-parts":[[2025,4,9]],"date-time":"2025-04-09T07:49:02Z","timestamp":1744184942000},"page":"165","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["CPCROK: A Communication-Efficient and Privacy-Preserving Scheme for Low-Density Vehicular Ad Hoc Networks"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-5255-7187","authenticated-orcid":false,"given":"Junchao","family":"Wang","sequence":"first","affiliation":[{"name":"Cybersecurity and Computing Systems Research Lab, Department of Computer Science, University of Hertfordshire, Hatfield AL10 9AB, UK"}]},{"given":"Honglin","family":"Li","sequence":"additional","affiliation":[{"name":"School of Computer Science, University of St Andrews, St Andrews KY16 9AJ, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0839-1769","authenticated-orcid":false,"given":"Yan","family":"Sun","sequence":"additional","affiliation":[{"name":"School of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4NS, UK"}]},{"given":"Chris","family":"Phillips","sequence":"additional","affiliation":[{"name":"School of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4NS, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8819-5831","authenticated-orcid":false,"given":"Alexios","family":"Mylonas","sequence":"additional","affiliation":[{"name":"Cybersecurity and Computing Systems Research Lab, Department of Computer Science, University of Hertfordshire, Hatfield AL10 9AB, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7793-6128","authenticated-orcid":false,"given":"Dimitris","family":"Gritzalis","sequence":"additional","affiliation":[{"name":"Department of Informatics, Athens University of Economics & Business, 10434 Athens, Greece"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,9]]},"reference":[{"key":"ref_1","unstructured":"Kumar, A., and Bansal, M. (2017, January 21\u201323). A review on VANET security attacks and their countermeasure. Proceedings of the 2017 4th International Conference on Signal Processing, Computing and Control (ISPCC), Solan, India."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"121526","DOI":"10.1109\/ACCESS.2020.3007115","article-title":"Comparison of IEEE 802.11 p and LTE-V2X: An evaluation with periodic and aperiodic messages of constant and variable size","volume":"8","author":"Gozalvez","year":"2020","journal-title":"IEEE Access"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Shahid, M.A., Jaekel, A., Ezeife, C., Al-Ajmi, Q., and Saini, I. (2018, January 19\u201320). Review of potential security attacks in VANET. Proceedings of the 2018 Majan International Conference (MIC), Muscat, Oman.","DOI":"10.1109\/MINTC.2018.8363152"},{"key":"ref_4","first-page":"1","article-title":"Cellular V2X as the essential enabler of superior global connected transportation services","volume":"1","author":"Papathanassiou","year":"2017","journal-title":"IEEE 5G Tech Focus"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6389","DOI":"10.1109\/TITS.2023.3252082","article-title":"Secure and efficient authenticated key management scheme for UAV-assisted infrastructure-less IoVs","volume":"24","author":"Tan","year":"2023","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/CC.2018.8424578","article-title":"Cooperative vehicular content distribution in edge computing assisted 5G-VANET","volume":"15","author":"Luo","year":"2018","journal-title":"China Commun."},{"key":"ref_7","first-page":"1","article-title":"A survey on VANET technologies","volume":"121","author":"Tanuja","year":"2015","journal-title":"Int. J. Comput. Appl."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5713","DOI":"10.1109\/TVT.2020.2979232","article-title":"Empirical models for the realistic generation of cooperative awareness messages in vehicular networks","volume":"69","author":"Sepulcre","year":"2020","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e452","DOI":"10.1002\/spy2.452","article-title":"A blockchain-based trusted vehicle service recommendation scheme in intelligent transport systems","volume":"8","author":"Chen","year":"2025","journal-title":"Secur. Priv."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Chen, C.M., Hao, Y., Kumari, S., and Amoon, M. (IEEE Trans. Intell. Transp. Syst., 2025). An Intelligent Blockchain-Enabled Authentication Protocol for Transportation Cyber-Physical Systems, IEEE Trans. Intell. Transp. Syst., early access.","DOI":"10.1109\/TITS.2025.3539565"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2423915","DOI":"10.1155\/2019\/2423915","article-title":"A comprehensive survey on VANET security services in traffic management system","volume":"2019","author":"Sheikh","year":"2019","journal-title":"Wirel. Commun. Mob. Comput."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Kaur, R., Singh, T.P., and Khajuria, V. (2018, January 11\u201312). Security Issues in Vehicular Ad-Hoc Network (VANET). Proceedings of the 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI), Tirunelveli, India.","DOI":"10.1109\/ICOEI.2018.8553852"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1109\/MSP.2017.6","article-title":"Driving habits data: Location privacy implications and solutions","volume":"15","author":"Bellatti","year":"2017","journal-title":"IEEE Secur. Priv."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1109\/MITS.2019.2898973","article-title":"Security and privacy issues in intelligent transportation systems: Classification and challenges","volume":"13","author":"Hahn","year":"2019","journal-title":"IEEE Intell. Transp. Syst. Mag."},{"key":"ref_15","first-page":"100247","article-title":"Secure authentication and privacy-preserving techniques in Vehicular Ad-hoc NETworks (VANETs)","volume":"25","author":"Manivannan","year":"2020","journal-title":"Veh. Commun."},{"key":"ref_16","unstructured":"European Telecommunication Standard Institute (ETSI) (2021). ETSI TS 102 941 Version 2.1.1\u2014Intelligent Transport Systems (ITS); Security; Trust and Privacy Management, ETSI."},{"key":"ref_17","unstructured":"European Telecommunications Standards Institute (ETSI) (2012). ETSI TS 102 867 v1.1\u2014Intelligent Transport Systems (ITS), Security, Stage 3 Mapping for IEEE 1609.2, ETSI."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Wiedersheim, B., Ma, Z., Kargl, F., and Papadimitratos, P. (2010, January 3\u20135). Privacy in inter-vehicular networks: Why simple pseudonym change is not enough. Proceedings of the 2010 Seventh International Conference on Wireless On-Demand Network Systems and Services (WONS), Kranjska Gora, Slovenia.","DOI":"10.1109\/WONS.2010.5437115"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1109\/COMST.2017.2771522","article-title":"A survey on pseudonym changing strategies for vehicular ad-hoc networks","volume":"20","author":"Boualouache","year":"2017","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_20","unstructured":"Butty\u00e1n, L., Holczer, T., and Vajda, I. (2007, January 2\u20133). On the effectiveness of changing pseudonyms to provide location privacy in VANETs. Proceedings of the European Workshop on Security in Ad-Hoc and Sensor Networks, Cambridge, UK."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1109\/MPRV.2003.1186725","article-title":"Location privacy in pervasive computing","volume":"2","author":"Beresford","year":"2003","journal-title":"IEEE Pervasive Comput."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"16842","DOI":"10.1109\/ACCESS.2018.2800907","article-title":"Independent mix zone for location privacy in vehicular networks","volume":"6","author":"Guo","year":"2018","journal-title":"IEEE Access"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/j.comcom.2022.07.012","article-title":"BioMixD: A bio-inspired and traffic-aware mix zone placement strategy for location privacy on the internet of drones","volume":"195","author":"Svaigen","year":"2022","journal-title":"Comput. Commun."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Wang, J., Sun, Y., and Phillips, C. (2023, January 20\u201323). Fake Beacon: A Pseudonym Changing Scheme for Low Vehicle Density in VANETs. Proceedings of the 2023 IEEE 97th Vehicular Technology Conference (VTC2023-Spring), Florence, Italy.","DOI":"10.1109\/VTC2023-Spring57618.2023.10199627"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Wang, J., Sun, Y., and Phillips, C. (2023, January 19\u201321). Enhanced Pseudonym Changing in VANETs: How Privacy is Impacted Using factitious Beacons. Proceedings of the 2023 Wireless Telecommunications Symposium (WTS), Boston, MA, USA.","DOI":"10.1109\/WTS202356685.2023.10131712"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Vaas, C., Khodaei, M., Papadimitratos, P., and Martinovic, I. (2018, January 5\u20137). Nowhere to hide? Mix-Zones for Private Pseudonym Change using Chaff Vehicles. Proceedings of the 2018 IEEE Vehicular Networking Conference (VNC), Taipei, Taiwan.","DOI":"10.1109\/VNC.2018.8628449"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"7985","DOI":"10.1109\/JIOT.2020.3043640","article-title":"Cooperative location privacy in vehicular networks: Why simple mix zones are not enough","volume":"8","author":"Khodaei","year":"2020","journal-title":"IEEE Internet Things J."},{"key":"ref_28","unstructured":"Weinfeld, A. (2010, January 7\u201311). Methods to reduce DSRC channel congestion and improve V2V communication reliability. Proceedings of the 17th ITS World CongressITS JapanITS AmericaERTICO, Tokyo, Japan."},{"key":"ref_29","first-page":"49","article-title":"The impact of transmission overheads on IEEE 802.11 throughput: Analysis and simulation","volume":"2","author":"Sarkar","year":"2011","journal-title":"J. Sel. Areas Telecommun. (JSAT)"},{"key":"ref_30","unstructured":"Freudiger, J., Raya, M., F\u00e9legyh\u00e1zi, M., Papadimitratos, P., and Hubaux, J.P. (2007, January 14). Mix-zones for location privacy in vehicular networks. Proceedings of the ACM Workshop on Wireless Networking for Intelligent Transportation Systems (WiN-ITS), Number CONF, Vancouver, BC, Canada."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1569","DOI":"10.1109\/JSAC.2007.071007","article-title":"AMOEBA: Robust location privacy scheme for VANET","volume":"25","author":"Sampigethaya","year":"2007","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Emara, K., Woerndl, W., and Schlichter, J. (2015, January 22\u201326). CAPS: Context-aware privacy scheme for VANET safety applications. Proceedings of the 8th ACM Conference on Security & Privacy in Wireless and Mobile Networks, New York, NY, USA.","DOI":"10.1145\/2766498.2766500"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Lefevre, S., Petit, J., Bajcsy, R., Laugier, C., and Kargl, F. (2013, January 16\u201318). Impact of v2x privacy strategies on intersection collision avoidance systems. Proceedings of the 2013 IEEE Vehicular Networking Conference, Boston, MA, USA.","DOI":"10.1109\/VNC.2013.6737592"},{"key":"ref_34","unstructured":"Humbert, M., Manshaei, M.H., Freudiger, J., and Hubaux, J.P. (2009, January 9\u201313). On the optimal placement of mix zones: A game-theoretic approach. Proceedings of the 16th ACM Conference on Computer and Communications Security P. Citeseer, Chicago IL, USA."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1108","DOI":"10.1007\/s12083-014-0269-z","article-title":"Mix-zones optimal deployment for protecting location privacy in VANET","volume":"8","author":"Sun","year":"2015","journal-title":"Peer- Netw. Appl."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Palanisamy, B., and Liu, L. (2011, January 11\u201316). Mobimix: Protecting location privacy with mix-zones over road networks. Proceedings of the 2011 IEEE 27th International Conference on Data Engineering, Hannover, Germany.","DOI":"10.1109\/ICDE.2011.5767898"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1109\/TVT.2011.2162864","article-title":"Pseudonym changing at social spots: An effective strategy for location privacy in vanets","volume":"61","author":"Lu","year":"2011","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"3209","DOI":"10.1109\/TITS.2019.2924856","article-title":"PRIVANET: An Efficient Pseudonym Changing and Management Framework for Vehicular Ad-Hoc Networks","volume":"21","author":"Boualouache","year":"2019","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Khodaei, M., and Papadimitratos, P. (2018, January 5\u20137). Poster: Mix-Zones everywhere: A dynamic cooperative location privacy protection scheme. Proceedings of the 2018 IEEE Vehicular Networking Conference (VNC), Taipei, Taiwan.","DOI":"10.1109\/VNC.2018.8628340"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1007\/s11036-009-0167-4","article-title":"Wireless location privacy protection in vehicular ad-hoc networks","volume":"15","author":"Song","year":"2010","journal-title":"Mob. Netw. Appl."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"548","DOI":"10.1007\/s12083-017-0557-5","article-title":"A trigger-based pseudonym exchange scheme for location privacy preserving in VANETs","volume":"11","author":"Wang","year":"2018","journal-title":"Peer- Netw. Appl."},{"key":"ref_42","first-page":"100499","article-title":"Impacts of location-privacy preserving schemes on vehicular applications","volume":"36","author":"Mdee","year":"2022","journal-title":"Veh. Commun."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Al-Marshoud, M.S., Al-Bayatti, A.H., and Kiraz, M.S. (2021). Improved Chaff-Based CMIX for Solving Location Privacy Issues in VANETs. Electronics, 10.","DOI":"10.3390\/electronics10111302"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Zhang, S., Li, M., Liang, W., Sandor, V.K.A., and Li, X. (2022). A Survey of Dummy-Based Location Privacy Protection Techniques for Location-Based Services. Sensors, 22.","DOI":"10.3390\/s22166141"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"109686","DOI":"10.1016\/j.petrol.2021.109686","article-title":"Well performance prediction based on Long Short-Term Memory (LSTM) neural network","volume":"208","author":"Huang","year":"2022","journal-title":"J. Pet. Sci. Eng."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"9492","DOI":"10.1109\/TITS.2021.3125744","article-title":"A secure dynamic mix zone pseudonym changing scheme based on traffic context prediction","volume":"23","author":"Li","year":"2021","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"14740","DOI":"10.1109\/TITS.2024.3400312","article-title":"A Hybrid Reinforcement Learning-Based Method for Generating Privacy-Preserving Trajectories in Low-Density Traffic Environments","volume":"25","author":"Zhang","year":"2024","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1109\/TAC.1979.1102177","article-title":"An algorithm for tracking multiple targets","volume":"24","author":"Reid","year":"1979","journal-title":"IEEE Trans. Autom. Control"},{"key":"ref_49","unstructured":"Haykin, S. (1998). Neural Networks: A Comprehensive Foundation, Prentice Hall PTR."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1109\/72.279188","article-title":"Recurrent neural networks and robust time series prediction","volume":"5","author":"Connor","year":"1994","journal-title":"IEEE Trans. Neural Netw."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1109\/TITS.2020.3012034","article-title":"Deep learning-based vehicle behavior prediction for autonomous driving applications: A review","volume":"23","author":"Mozaffari","year":"2020","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1759","DOI":"10.1109\/LRA.2018.2805314","article-title":"A recurrent neural network solution for predicting driver intention at unsignalized intersections","volume":"3","author":"Zyner","year":"2018","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_53","unstructured":"Goodfellow, I., Bengio, Y., and Courville, A. (2016). Deep Learning, MIT Press."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"1584","DOI":"10.1109\/TITS.2019.2913166","article-title":"Naturalistic driver intention and path prediction using recurrent neural networks","volume":"21","author":"Zyner","year":"2019","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"100296","DOI":"10.1016\/j.bdr.2021.100296","article-title":"NGCU: A new RNN model for time-series data prediction","volume":"27","author":"Wang","year":"2022","journal-title":"Big Data Res."},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Emara, K. (2016, January 8\u201310). Poster: Prext: Privacy extension for veins vanet simulator. Proceedings of the 2016 IEEE Vehicular Networking Conference (VNC), Columbus, OH, USA.","DOI":"10.1109\/VNC.2016.7835979"}],"container-title":["Future Internet"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1999-5903\/17\/4\/165\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:13:17Z","timestamp":1760029997000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1999-5903\/17\/4\/165"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,9]]},"references-count":56,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2025,4]]}},"alternative-id":["fi17040165"],"URL":"https:\/\/doi.org\/10.3390\/fi17040165","relation":{},"ISSN":["1999-5903"],"issn-type":[{"value":"1999-5903","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,9]]}}}