Blockchain Papers

Ali Samanipour, Omid Bushehrian

No abstract is available for this record.

Μαρία Νίκη Ζωγράφου

Motion prediction –forecasting the future trajectories of surrounding vehicles, pedestrians and cyclists is a safety-critical component of the autonomous-driving pipeline that must run in real time on embedded hardware. State-of-the-art predictors, however, are trained on compute clusters and are too large to run on a single consumer GPU, placing both ends of the contemporary pipeline out of reach for an individual researcher. This thesis asks how small a competitive trajectory predictor can be made before its accuracy degrades, and whether the lost accuracy can be recovered through knowledge distillation without enlarging the model or worsening the calibration a downstream planner depends on. The study uses HiVT, a transformer-based Laplace-mixture predictor that is small enough to be both trained and run on a single GPU, evaluated on the Argoverse 1 benchmark. The accuracy–capacity trade-off is first characterised by sweeping the embedding width (128, 64, 32, 16) and locating the point at which a from-scratch student falls measurably below the teacher. The mode-permutation problem is then identified: because HiVT trains its mixture modes with a winner-takes-all loss, the mode slots of two independently trained models do not correspond, so any distillation term that aligns modes by index supervises the student with self-contradictory targets. To resolve this, a permutation-invariant mixture negative-log-likelihood objective is derived that treats the teacher’s modes as an order-free set of soft targets and supports unequal mode counts, with a proof of invariance. Experiments show that a mean-target variant of this objective recovers roughly 84% of the HiVT 32→ HiVT-64 capacity gap (−9.2% minFDE over a matched non-distilled baseline) at zero added inference cost, but degrades full-distribution calibration (mixture NLL +41%, calibration error 5×) by discarding the teacher’s predictive variance. A distribution-matching objective that also distils the teacher’s per-mode scales removes this penalty entirely, leaving the student better calibrated than both the non distilled baseline and the teacher while retaining the full geometric gain. The benefit grows as the student shrinks: at width 16 (55× smaller than the teacher) distribution-matching distillation improves minFDE by −22.7%—roughly 2.5× the width-32 gain—recovering ∼81% of the width-16→width-32 gap, with calibration improving rather than degrading. Distillation thus buys close to a full size-class of accuracy for free, and most where capacity is scarcest. A final efficiency analysis quantifies the deployment frontier: parameter and memory savings are fixed and unconditional (15× at width 32, 55× at width 16), whereas the single-scene latency speed-up is far sublinear and batch-dependent (on CPU ∼3× online, rising to ∼5.5× under modest batching), locating the compression benefit primarily in memory footprint. Overall, the answer to how small a competitive HiVT can be made is encouraging: with a permutation-invariant, calibration-preserving distillation loss, a 55×-smaller student reaches roughly the accuracy of an un-distilled model nearly four times its size at no calibration cost.

Nabeeha Zahid, Shahzaib Tahir, Fahad Algarni, Hasan Tahir · 6 authors

The Internet of Vehicles (IoV) is changing the contemporary mobility, as it allows real-time communication between vehicles, infrastructure, and cloud services. Nevertheless, such growing connectivity brings on serious privacy, regulatory, and trust issues especially because sensitive behavioral and location information is exposed. The current IoV-security systems tend to be based on identity-based checks, or centralized trust authorities, which can lead to infringement of user privacy and cause surveillance and profiling threats. The paper is inspired by privacy-preserving architectures in the Metaverse to suggest a decentralized trust system of IoV systems on the basis of zero-knowledge proofs, namely zk-SNARKs. The suggested solution allows vehicles to cryptographically verify that they meet regulatory or operational regulations- i.e. valid insurance, safety test, or emissions- without revealing personal identifiers or raw information. The framework enables building scalable, low-latency and audible trusts and following data minimization principles through combining zk-SNARK verification and Layer 2 blockchain solutions.

Giwoong Kim, Youjeong Son, Shiho Kim

As autonomous driving technology advances towards Level 4 and 5, virtual simulation has become an indispensable tool for safety validation. However, a critical ''trust gap'' exists between developers and regulators; submitting raw simulation logs poses risks of data tampering (integrity issues) and intellectual property leakage (privacy issues). To address this, we propose ZK-V, a universal, privacy-preserving verification framework designed to interface with various autonomous driving simulators. By leveraging Zero-Knowledge Proofs and blockchain technology, ZK-V allows a Prover to cryptographically demonstrate that a simulation run adhered to specific safety constraints such as collision avoidance and speed limits without revealing the underlying telemetry data. This paper outlines the simulation-agnostic system architecture and constraint logic, offering a scalable solution for decentralized, trust-free certification in the Web 4.0 mobility era.

Maha Bouaziz, Houda Jmila, Skander Mhadhbi, Darine Rammal · 12 authors

Abstract The integration of connected vehicles into 5G networks introduces stringent requirements in terms of latency, reliability, security, and adaptability that are not fully addressed by existing 5G architectures. In particular, Vehicle-to-Network (V2N) services must operate under high mobility, dynamic traffic conditions, and multi-tenant environments, while remaining resilient to security threats and operational anomalies. In this paper, we propose a 5G-based architecture for connected vehicles that addresses these challenges by combining deterministic communication, secure resource coordination, and runtime monitoring mechanisms. To enhance communication predictability beyond best-effort transport, the architecture integrates Time-Sensitive Networking (TSN) within the 5G transport network. Secure and transparent coordination across multiple stakeholders is supported through Distributed Ledger Technology (DLT), mitigating risks associated with centralized control. The architecture further incorporates heterogeneous data collection to enable adaptive resource management, as well as Runtime Verification and an AI-based anomaly detection system to monitor system behavior and network traffic in real time. By jointly addressing determinism, security, and adaptability within a unified 5G architecture, this work contributes a comprehensive foundation for reliable and secure connected vehicle services.

Zilin Huang, Zhengyang Wan, Zihao Sheng, Boyue Wang · 6 authors

Vision-language-model (VLM)-guided reinforcement learning (RL) has recently attracted significant attention for it, replacing brittle hand-crafted rewards with semantically grounded signals; however, deploying such simulation-trained policies on real vehicles remains a fundamental challenge, because they rely on simulator-native observations and simulator-coupled action semantics with no counterpart on physical hardware. We identify a general principle: the simulation-to-reality gap decomposes into two largely orthogonal axes, a sensing-and-dynamics domain gap and a task-and-geometry gap, the former closable without real-world policy training by re-projecting real perception and control onto the policy's training manifold. We formalize this as a transfer guarantee that bounds the deployment gap by three independently controllable error terms, and instantiate it as Sim2Real-AD, which combines a Geometric Observation Bridge, a Physics-Aware Action Mapping, a Two-Phase Progressive Training curriculum, and a Real-time Deployment Pipeline. As a proof of concept, a CARLA-trained VLM-guided RL policy is transferred zero-shot to a full-scale battery-electric Ford E-Transit van in Madison, WI, USA, and drives across car-following, obstacle-avoidance, and stop-sign scenarios using no real-world training data. To our knowledge, this is among the first zero-shot closed-loop deployments of a CARLA-trained VLM-guided RL policy on a full-scale real vehicle, and the decomposition offers a principled, broadly applicable route for moving simulation-trained, foundation-model-guided policies into the physical world, supporting energy-efficient intelligent driving on electrified transportation platforms. The demo video, code, and model checkpoint are available at: https://zilin-huang.github.io/Sim2Real-AD-website/.

Munawar Hasan, Apostol Vassilev, Edward Griffor, Thoshitha Gamage

The application of zero-knowledge proofs (ZKPs) in autonomous systems is an emerging area of research, motivated by the growing need for regulatory compliance, transparent auditing, and trustworthy operation in decentralized environments. zk-SNARK is a powerful cryptographic tool that allows a party (the prover) to prove to another party (the verifier) that a statement about its own internal state is true, without revealing sensitive or proprietary data about that state. This paper proposes Hermes Seal: a zk-SNARK-based ZKP framework for enabling privacy-preserving, verifiable communication in vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) networks. The framework allows autonomous systems to generate cryptographic proofs of perception and decision-related computations without revealing proprietary models, sensor data, or internal system states, thereby supporting interoperability across heterogeneous autonomous systems. We present two real-world case studies implemented and empirically evaluated within our framework, demonstrating a step toward verifiable autonomous system information exchanges. The first demonstrates real-time proof generation and verification, achieving 8 ms proof generation and 1 ms verification on a GPU, while the second evaluates the performance of an autonomous vehicle perception stack, enabling proof of computation without exposing proprietary or confidential data. Furthermore, the framework can be integrated into AV perception stacks to facilitate verifiable interoperability and privacy-preserving cooperative perception. The demonstration code for this project is open source, available on Github.

Arata Nakajima, Hideaki Miyaji, Hiroshi Yamamoto

The smart cities that collaborate with AI-driven autonomous robots are attracting attention for supporting various social activities in the real world. In facilities that provide such services, various systems managing the facility and robots may coexist in the common area. By enabling the systems to interoperate and share information about the status of the facility and robots, it becomes possible to realize a variety of services that support safety and security within the facility. However, while the operators of the facility want to monitor the detailed conditions of the robots, the operators of the robots are cautious about providing the information about the status of robots such as the moving trajectory and various sensor data. To resolve this dilemma, we propose a new system that enables estimation of the operational conditions of the robots by verifying the positions and trajectories at landmarks in the facility without disclosing their internal information. In the proposed system, we focus on the observation of environmental information that accurately reflects the real-world situation for estimating the proximity between the robot and each landmark. As the environmental information, both systems on robots and a facility measure CSI (Channel State Information) and acoustic information. In addition, by utilizing zero-knowledge proof (ZKP) technology, the system for the facility confirms the reliability of the process for estimating the proximity of the robots to the landmark without exchanging detailed internal information. Through the proof-of-concept experiment, applying the proposed system achieved high-accuracy proximity detection with both methods (CSI and acoustic information) yielding precision and recall rates exceeding 0.90.

Ezekiel Ologunde

Modern vehicles are distributed embedded computing platforms whose expanding network connectivity-CAN bus, Bluetooth, cellular telematics, and over-the-air (OTA) update channels-exposes them to the same class of adversarial attacks studied in cloud and enterprise environments. Machine learning (ML)-based intrusion detection systems (IDS) have emerged as the primary defensive response, yet these models are themselves vulnerable to adversarial perturbation: a well-crafted malicious CAN frame can evade an ML-based IDS in the same way that an adversarial image patch fools a computer-vision classifier. This paper traces the threat landscape from foundational automotive attack-surface studies through contemporary adversarial ML research, examines how resource-constrained embedded platforms limit defensive options, and proposes a defense architecture that combines behavioral anomaly detection with zero-knowledge proof (ZKP) attestation for invehicle control units. We argue that ZKP-based component attestation-previously dismissed as computationally impractical for embedded systems-is now feasible given recent advances in succinct non-interactive arguments of knowledge (SNARKs), and that combining it with adversarially trained ML-IDS models yields defensein-depth that addresses both network-layer and hardware-layer attack vectors.

Mohcine Baalla, Driss Bouzidi

In the need for high-security mechanisms, Trust Management Systems (TMSs) are implemented in vehicular networks such as Vehicular Ad Hoc Networks (VANETs) and the Internet of Vehicles (IoV) to ensure reliable interactions between vehicles. These systems nowadays are a key factor in building up security by evaluating and managing trust relationships among network participants. However, TMSs are inherently very vulnerable to Trust Manipulation Attacks (TMA), where we find malicious nodes attempting to deceive trust models by exploiting their evaluation mechanisms. One critical variant of this attack involves malicious nodes creating multiple fake identities, known as the Sybil attack, to falsely reinforce their trustworthiness. This deception will totally mislead legitimate vehicles, manipulate the decision-making processes, and at the end compromise the overall security and reliability of the network. To address this challenge, we propose a Zero-Knowledge Proof (ZKP)-based trust authentication scheme that ensures each vehicle can prove its legitimacy without exposing sensitive information. Our approach can and will prevent attackers from fabricating multiple identities to manipulate trust values. By integrating cryptographic authentication with trust management, our method significantly strengthens security and ensures that only legitimate vehicles can participate in trust-based evaluations. Through simulations, we demonstrate the effectiveness of our proposed solution in reducing the risk of Sybil-based. The results indicate that our approach not only enhances security but also maintains efficient trust computation, making it a viable solution for real-world vehicular networks.

Xingyu Chen, Weihua Zhang, Haijian Bai, Feng Zhu · 6 authors

No abstract is available for this record.

Xingxing Chen, Xiaohong Zhang, Shaojiang Zhong, Shuling Liu

Vehicular Ad Hoc Networks (VANETs) are now a pivotal component of Intelligent Transportation Systems. However, ensuring secure vehicle identity authentication and protecting user privacy remain two challenging issues in VANETs. Addressing these challenges, this paper seamlessly integrates blockchain technology with the InterPlanetary File System to realize a fully decentralized storage solution for identity verification information. Simultaneously, it employs zk-SNARK and elliptic curve cryptography to allow vehicle users to anonymously complete identity verification. Additionally, the lightweight identity authentication proof obtained after successful verification maintains credibility while reducing the computational and communication costs for both roadside units and vehicles. The security and performance analysis of the system show that the proposed scheme has significant advantages in both communication and computation compared with similar research, while also offering superior security and a broader range of functional attributes compared to existing competitive approaches.

SUN Kangkang, LI Jianhua, CHEN Xiuzhen, GUO Minyi

With the advancement of edge intelligence technology and the acceleration of urbanization, intelligent transportation systems (ITS) have experienced rapid development. Vehicle-road-cloud (VRC) collaboration was enabled through the coordinated sharing of vehicle-to-vehicle (V2V), vehicle-to-road (V2R), and vehicle-to-cloud (V2C) data in the Internet of vehicles, thereby constructing a more efficient cooperative intelligent transportation system (C-ITS). However, numerous security threats in VRC collaboration were found to severely impede the development of cooperative autonomous driving. The development status of VRC collaboration was first summarized, and the history of autonomous driving and the VRC-based autonomous driving environment were elaborated. Subsequently, attacks and security defense technologies in VRC collaboration were systematically categorized into two types: classical information security mechanisms and defense technologies, which were detailed from five aspects—information availability, integrity, confidentiality, authenticity, and non-repudiation; and machine learning-based security threats and defense technologies, which were analyzed from both centralized and distributed perspectives. Finally, future development directions and research priorities of VRC collaborative security technologies were forecasted, primarily covering federated learning, blockchain technology, secure multi-party computation, zero-knowledge proof, and differential privacy technology.

Yonas Teweldemedhin Gebrezgiher, Sekione Reward Jeremiah, Xianjun Deng, Jong Hyuk Park

Vehicle-to-everything (V2X) communication is a fundamental technology in the development of intelligent transportation systems, encompassing vehicle-to-vehicle (V2V), infrastructure (V2I), and pedestrian (V2P) communications. This technology enables connected and autonomous vehicles (CAVs) to interact with their surroundings, significantly enhancing road safety, traffic efficiency, and driving comfort. However, as V2X communication becomes more widespread, it becomes a prime target for adversarial and persistent cyberattacks, posing significant threats to the security and privacy of CAVs. These challenges are compounded by the dynamic nature of vehicular networks and the stringent requirements for real-time data processing and decision-making. Much research is on using novel technologies such as machine learning, blockchain, and cryptography to secure V2X communications. Our survey highlights the security challenges faced by V2X communications and assesses current ML and blockchain-based solutions, revealing significant gaps and opportunities for improvement. Specifically, our survey focuses on studies integrating ML, blockchain, and multi-access edge computing (MEC) for low latency, robust, and dynamic security in V2X networks. Based on our findings, we outline a conceptual framework that synergizes ML, blockchain, and MEC to address some of the identified security challenges. This integrated framework demonstrates the potential for real-time anomaly detection, decentralized data sharing, and enhanced system scalability. The survey concludes by identifying future research directions and outlining the remaining challenges for securing V2X communications in the face of evolving threats.

Nattawat Songsom, Jakapan Suaboot, Warodom Werapun

Merkle proof-based airdrops are a widely used mechanism in decentralized finance (DeFi) for distributing tokens securely and efficiently to eligible recipients. By leveraging Merkle trees, these airdrops minimize storage requirements and reduce transaction costs while ensuring the integrity of recipient lists. Unfortunately, their importance also attracts sophisticated attacks. Secondary preimage attacks, in particular, pose a major risk to the security of token distribution, potentially enabling adversaries to exploit vulnerabilities and drain tokens from airdrop contracts. This paper introduces FSA: a F ramework for analyzing S econdary preimage A ttacks on Merkle proof-based airdrops, designed to systematically address such vulnerabilities. The framework operates through four core contributions: (1) a validated quantitative damage assessment model using proof-of-concept experiments, (2) an analysis of attack repetition patterns in binary Merkle trees and Merkle Mountain Ranges, (3) identification of key factors influencing attack success, including token balances, hash values, and variable sizes, and (4) evaluation of mitigation strategies such as using non-64-byte leaf values, asymmetric hashing, and proof length validation. Through extensive analysis using the FSA, our experimental results demonstrate the framework's effectiveness in uncovering vulnerability patterns and developing targeted countermeasures.

Mohammed-Javed Padinhakara

The emerging paradigm of modern vehicles as sophisticated mobile data centers generates unprecedented volumes of telemetry, sensor, and interaction data that require novel management approaches. The architectural framework addresses dual requirements of edge processing for latency-sensitive applications and cloud infrastructure for deeper analytics and model development. Vehicle-to-everything communication protocols integrate with software-defined networks and distributed ledger technologies to ensure secure, efficient data exchange across the ecosystem. Technical challenges including bandwidth constraints, data redundancy, and privacy regulations are primary motivators for solutions based on federated learning, optimized compression algorithms, and context-aware processing. Resilient vehicular data management necessitates a multi-layered approach balancing computational requirements across the edge-cloud continuum while maintaining robust security postures. These foundations enable scaling next-generation intelligent transportation systems were vehicles function as key nodes in broader smart city infrastructures.

Reem Almaziad, Heba Kurdi

Vehicular Ad Hoc Networks (VANETs) are essential to intelligent transportation systems (ITS), enabling secure, real-time communication among vehicles and infrastructure. However, their decentralized and dynamic nature makes them vulnerable to threats such as Sybil attacks, message forgery, replay attacks, and Denial-of-Service (DoS). This paper presents VANETGuard, a lightweight scalable trust management system that enhances security and scalability in 5G-enabled smart vehicular networks. The proposed system integrates entropy-based anomaly detection, Bayesian inference for adaptive trust scoring, and a lightweight distributed ledger for decentralized, tamper-resistant trust storage. Large-scale simulations under realistic traffic and attack conditions demonstrate that VANETGuard achieves 99.97% detection accuracy, significantly reduces false positives, and maintains low latency and computational overhead while supporting over 300 vehicles. These results highlight VANETGuard’s potential to enable secure, efficient, and scalable trust mechanisms in next-generation ITS and urban mobility systems.

Zahraa Sh. Alzaidi, Ali A. Yassin, Zaid Ameen Abduljabbar, Vincent Omollo Nyangaresi

Authentication of vehicles and users, integrity of exchanged messages, and privacy preservation are essential features in VANETs. VANETs are used to collect information on road conditions, vehicle location and speed, and traffic congestion data. The open exchange of information within VANETs poses serious security threats. Furthermore, existing schemes have higher communication and computational costs, making them incompatible with resource-constrained VANET applications. This study proposes a multifactor authentication and privacy-preserving security scheme for VANETs based on blockchain and fog computing to meet all these requirements. The proposed scheme uses fingerprints and Quick Response (QR) codes as a multifactor to authenticate vehicle users and fog-cloud computing techniques to reduce the computational burden on RSUs and improve service quality and resilience. Additionally, the scheme synchronizes a consistent ledger across all RSUs using blockchain technology to store and distribute vehicle authentication statuses. Through a thorough comparison with relevant current protocols, the scheme shows a much-reduced computing expense and communication burden in situations with high vehicle density within a timeframe of 6.3846 ms and 544 bytes for communication costs. In addition, the proposed scheme demonstrates a successful balance between efficacy and complexity, protecting confidentiality, anonymous authentication, and ensuring integrity and conditional tracking. Formal and informal security analysis showed that the proposed scheme is more reliable, practical, and secure against many hostile attacks, such as modification attacks, 51% attacks, Sybil attacks, and MITM attacks.

Reem Almaziad, Heba Kurdi

This study introduces a secure and scalable hybrid trust management system for Vehicular Ad Hoc Networks (VANETs), designed to detect and mitigate diverse malicious activities, including Sybil attacks, Denial of Service (DoS), and data forgery. Integrating entropy-based anomaly detection, Bayesian reputation updating, and the IOTA Tangle as a distributed ledger, the system ensures robust, real-time trust evaluation in dynamic vehicular environments. Rigorous testing against adversarial scenarios demonstrated high detection accuracy, low latency, and resilience under varied attack conditions. Key contributions include enhanced scalability through edge computing, secure reputation storage using Distributed Ledger Technology (DLT), and real-time anomaly detection.

Jiaming Lai, Xiaohong Zhang, Shilin Liu, Shaojiang Zhong · 5 authors

Vehicular Ad hoc Network (VANET) is considered one of the feasible solutions to improve the efficiency and safety of modern transportation systems, and it provides new opportunities for creating a safe and efficient traffic environment. In recent years, this technology has attracted extensive attention from the academic community. However, VANET is an open network with frequent information interaction, and users are vulnerable to security and privacy threats. The existing schemes mainly consider the identity authentication of vehicles in vehicle enterprises (VEs). Due to concerns about the leakage of core data, VEs lack the motivation to establish a cross-vehicle enterprise identity authentication framework. Based on the above analysis, we propose a cross-vehicle enterprise authentication architecture by designing a two-stage certificate generation mechanism where certificate authority (CA) and VEs cooperate to generate identity credentials for vehicles. To address the concerns of VEs, we establish distributed trust and enable information sharing across VEs by introducing a consortium blockchain composed of car companies, CA, and pseudonym certificate authority (PCA). Considering the need for vehicles to access road traffic information, we use a public blockchain to store public information, and the practical byzantine fault tolerant (PBFT) algorithm is used to reach consensus. Instead of using computationally complex bilinear pairing and mapping-to-point hashing operations, the proposed scheme uses an elliptic curve cryptosystem (ECC), considering the limited hardware resources of the vehicle and RSU. In addition, our scheme integrates edge computing to solve complex computing tasks that cannot be performed locally and further reduces system latency. Security analysis and performance analysis show that our scheme has better performance than existing schemes in terms of security, computational overhead, and communication overhead.

Akarsh Singh, Shounak Sural, Tirthankar Sengupta, Shamik Sural

Autonomous vehicles (AVs) are gaining in popularity over the years as a viable cab service apps as well as for personal use. However, incidents of crashes involving AVs continue to occur, adversely affecting their prospects for widespread acceptance by both end users and regulatory authorities. While such cases are routinely investigated, in the absence of a human to testify on what caused the crash, one has to rely solely on available data. It is therefore imperative that the data logged by AVs is accessible to the concerned parties in a trustworthy manner. In this paper, we present AVChain—a novel framework for using a permissioned blockchain like HyperLedger Fabric (HLF) to record and share AV data comprised of sensors, actuators, maps, planning algorithms and machine learning models so that the data stays immutable even in the face of cross blaming among involved parties. Since the data volume is extremely large, we appropriately compress and down sample the same before storing in a distributed file system, namely, IPFS (Inter-Planetary File System). The hashes of such IPFS data called Content Ids (CIDs) are committed to the HLF network for making them tamper proof. The HLF ledger can later be queried to obtain the CIDs, which are then further used to retrieve and un-compress the original data from IPFS. Effectiveness and usability of AVChain is demonstrated by generating AV data from CARLA, which is a widely used open source AV simulator. For sharing AV data across organizations like sensor and actuator suppliers, map service providers, machine learning model developers and law enforcement authorities, the Weaver tool has been used to make multiple HLF networks interoperate. We have also developed a web application to demonstrate the working of AVChain. Results of an extensive set of experiments establish the efficacy of our approach.

Javad Shahparian, Seyed Hossein Erfani, Azadeh Zamanifar

No abstract is available for this record.

Hanh Tran Thi, Nghi Nguyen Van, Minh Nguyen Hieu, Hien Pham Thi · 6 authors

No abstract is available for this record.

Meng Li, Mingwei Zhang, Liehuang Zhu, Zijian Zhang · 6 authors

Smart Parking Services (SPSs) enable cruising drivers to find the nearest parking lot with available spots, reducing the traveling time, gas, and traffic congestion. However, drivers risk the exposure of sensitive location data during parking query to an untrusted Smart Parking Service Provider (SPSP). Our motivation arises from a repetitive query to an updated database, i.e., how a driver can be repetitively paired with a previously-matched-but-forgotten lot. Meanwhile, we aim to achieve repetitive query in an oblivious and unlinkable manner. In this work, we present Mnemosyne2 : decentralized and privacy-preserving smart parking with secure repetition and full verifiability. Specifically, we design repetitive, oblivious, and unlinkable Secure k Nearest Neighbor (SkNN) with basic verifiability (correctness and completeness) for encrypted-andupdated databases. We build a local Ethereum blockchain to perform driver-lot matching via smart contracts. To adapt to the lot count update, we resort to the immutable blockchain for advanced verifiability (truthfulness). Last, we utilize decentralized blacklistable anonymous credentials to guarantee identity privacy. Finally, we formally define and prove privacy and security. We conduct extensive experiments over a real-world dataset and compare Mnemosyne2 with existing work. The results show that a query only needs 8 seconds (175 ms) on average for service waiting (verification) among 500 drivers.