Blockchain-based secured event-information sharing protocol in internet of vehicles for smart cities

Abstract

An intelligent transportation system is an advanced application that aims to provide traffic congestion information, road accidents, emergency information to other vehicles, etc. In the traditional transportation systems, the road-side unit (RSU) acts as a central authority and plays an important role to maintain everything in the networks. To solve single point of failure, as well as to achieve data immutability, blockchain-based decentralized vehicular ad-hoc networks is very essential and important. In order to share critical information among all the road-side units, we design a blockchain-based decentralized vehicular ad-hoc network that supports data immutability property. We have also designed an authentication protocol for the vehicle’s user and a consensus mechanism to validate transactions. Besides, a smart contract mechanism has also been proposed. Informal security analysis confirms anonymity property with other security requirements. We have also calculated and discussed communication, computation, and storage overhead of the proposed scheme.

Introduction

In recent decades, smart and autonomous vehicles are increasing rapidly. The origin of modern technology such as sensors, internet of things (IoT) enabled smart devices provide a ground to these vehicles in smart cities, and the foundation of the intelligent transportation system (ITS) [1]. ITS aims to improve the efficiency of the transportation system and guarantee the safety and security of both drivers and pedestrians. The working functionality of smart and autonomous vehicles purely depends on the driver speed, communication among smart devices, and with other intelligent vehicles (IVs). In the vehicular ad-hoc networks (VANET), the IVs are equipped with the communication modules and sensors through which IVs collect the required information, and broadcast it to other IVs and roadside units (RSUs). The goal of internet-of-vehicles (IoV) is to broadcast the life-threatening event messages such as driver speed status, accident reports, environmental hazards reports, and traffic jam messages, etc. to the neighboring vehicles and RSUs in less time with high accuracy. The presence of malicious vehicles or attackers in the VANET system hurdles the above-stated process. The attacker may broadcast the false event messages to mislead the other vehicles, and as a result, the true event message cannot be disseminated properly to other vehicles and RSUs [2]. Hence, the authenticity of messages in VANET is crucial.

The emergence of IoV plays an essential role in saving the life of drivers by disseminating critical messages. According to the current scenario, three types of communication exist in the VANET system. The first type considers only vehicles, commonly known as vehicle-to-vehicle communication (denoted as V2V) [3]. V2V communication is achieved by using the on-board units (OBUs). The second type of communication exists between the vehicles and RSUs, known as vehicle-to-infrastructure (denoted as V2I). The RSUs are having more computing and storage power than vehicles. The third type of communication exists between vehicles and pedestrians or cyclists, known as vehicle-to-everything (denoted by V2X). Here, everything represents pedestrian, cyclist, etc. In principle, the VANET system does not follow any fixed topology or architecture. All the vehicles are equipped with the sensor unit (or node) through which vehicles collect data and transmit to the other vehicles and RSUs.

To participate in the data-sharing process in the VANET system, the critical event messages need to be transmitted correctly to IVs and RSUs. The event messages are broadly classified into three major categories: the first category includes normal notification messages. These messages such as driving status are broadcasted in the network at a regular interval of time. The second category includes safety notification messages. These messages i.e., accident messages and environmental hazards messages are broadcasted when critical events occur on the road. The last one is exposure messages. These messages are broadcasted when an attacker enters the network, and it tries to communicate with other entities of the network [4].

In the traditional VANET system, messages are transmitted to IVs and RSUs over the non-secure channels, and there is a high probability that it may be tempered or intercepted by the attacker. The event messages are collected by the RSUs, and they store the data in the cloud server platform, which forms a centralized database. This centralized approach in the traditional VANET system leads to security issues such as centralized malicious attacks. Therefore, the data-leakage problem may occur if it is attacked or tempered by the adversary. Since the number of IVs is increasing day-by-day, the maintenance cost for a centralized cloud database is also increasing, which is time-consuming. In high-density vehicles area, RSUs are overloaded with their computational resources, and on the other side, in the low-density area, RSUs may be idle with its computational resources [5]. Wireless communication in the VANET system may include illegal vehicles that broadcast falsified event messages to other IVs and RSUs in the data-sharing process and disrupts the normal transmission. The falsified information may cause a serious traffic accident. To address these challenges, it is necessary to design the decentralized storage system, and the blockchain mechanism is capable of solving these challenges.

To provide the privacy and trust, the following cryptographic primitives must be satisfied by the VANET system [2].

• Authentication: All the active entities such as vehicles must be verified before accessing the services from the VANET system.

• Non-repudiation: The active entities which are participating in the data-sharing process, cannot be denied the operation on the data.

• Integrity: The event messages which are sent by the active entity of the VANET system are not modified by other participating entities or by any malicious entity.

• Privacy: The identity of the vehicles is kept private while transmitting the critical event messages to other vehicles and RSUs.

• Availability: The active entities send the critical event details to other entities at any time, in spite of false events or bad conditions. Additionally, they are capable to deal with the attacks, and still provide their services.

• Confidentiality: The active entities use the cryptographic primitives (for e.g. encryption schemes, hash functions, etc.) for the secret data transmission to other participating entities.

• Traceability: This is the ability to trace the real identity of the vehicle when vehicle sends the false critical event detail to other vehicles and RSUs.

• Efficiency and robustness: The active vehicles can use small computations and overheads to transfer the event details to other vehicles and RSUs. But, critical event messages must be delivered to the vehicles and RSUs in real-time so that analysis of those messages can be done, and action can be taken accordingly.

Major motivations to use blockchain in the VANET system are listed below.

• Blockchain-based VANET system provides more security and trust in the existing VANET system without including any trusted-third party (or central authority).

• It provides a safe and reliable decentralized data storage system. As a result, the single-point failure problem does not exist.

• It provides conditional anonymity to preserve the identity of the vehicles when vehicles share the critical event details with other vehicles and RSUs.

• It provides chronologically ordered and immutable blocks.

• It provides validation and verification of critical event messages by more number of vehicles which are based on the consensus mechanism.

• It provides transparency in the VANET system as all active entities have the same replica of blockchain.

The main contributions of the paper include following,

• A framework for the VANET system with blockchain technology that provides the reliability of the critical messages is proposed in this paper.

• In order to provide the reliability of the message, a vehicle authentication protocol is designed by the cloud server and then the consensus algorithm is used for the assurance.

• We have designed a smart contract algorithm among the vehicles of the proposed system.

• Security analysis demonstrates that the protocol is free from related attacks and achieves all the required aspects like integrity, authentication, etc.

The rest of the paper is organized as follows: Section 2 gives a brief overview of blockchain including blockchain salient feature, different types of blockchain, the structure of a block, smart contract mechanism, consensus algorithm, and blockchain applications in different domains. Section 3 describes the related work based on the blockchain mechanism in the VANET system. Section 4 explains the proposed scheme. This section covers the three phases of the proposed scheme with a smart contracts mechanism among the vehicles. Section 5 describes the security analysis of the proposed protocol. Section 6 Shows the performance evaluation of our proposed protocol. And finally, Section 7 provides the conclusion of the paper with future research.