Smart contracts for secure vehicular sharing­access systems using blockchain technologies

Abstract: Ongoing research suggests decentralized solutions based on blockchain for vehicle sharing scenario, to solve the fairness and privacy violation issues in centralized platforms. Users can transfer funds and execute decentralized applications, called smart contracts, in these blockchain­based platforms. Among them, several smart contract schemes are designed for the booking and payment functionality, e.g. dPACE [21] and Sc2Share [50]. Renters and vehicle owners can directly interact with these deployed smart contracts and finish booking, driving and payment, combined with existing vehicle access protocols like HERMES [66]. However, current smart contracts for booking and payment only consider to be executed on the root chain, called Layer­1. In this way, the execution waiting times are too long and transaction fees incurred by the blockchain are too high. Such problems in vehicle sharing can be mitigated by executing smart contracts on Layer­ 2 of blockchain, which is an efficient off­chain technology whose purpose is to scale blockchain transaction capacity while retaining the decentralization benefits of the blockchain. This thesis aims to build a smart contract for booking and payment in vehicle sharing scenario, and use different Layer­2 technologies to test it. First, we design an improved smart contract based the Sc2Share’s structure. The improved points are: 1. Store previous renters’ information, including deposit amount and other booking details, to support sustainable usage in each vehicle. 2. Optimize dispute settlement, to handle malicious behaviors in rental process. 3. Add more events emission for better monitoring the state of vehicle. Then, we pick four representative Layer­2 schemes in latest Layer­2 technologies to compare fee costs. Our smart contract is tested on the representative schemes and a comparison between them is sorted out. We follow the whole steps in booking and payment to measure the performance and fee cost between different Layer­2 schemes. Besides, we also execute the smart contract on Layer­1 as a comparison. The result shows that the contract is executed at different costs in different Layer­2 technologies, but the costs are significantly lower and executions confirmation are faster than Layer­1. This implies that our smart contract with Layer­2 technologies can mitigate the problems mentioned before.