A Source Authentication Scheme for Road Condition Monitoring Using Consortium Blockchain

Road condition monitoring supports vehicles in acquiring real-time traffic information in vehicular ad-hoc networks (VANETs). However, malicious attackers may impersonate other vehicles to propagate forged traffic/road information. Therefore, authentication schemes based on the blockchain were proposed to check the legitimacy of vehicles. At first glance, these proposals can effectively accomplish the authentication process using smart contracts. However, these schemes have poor scalability. Specifically, with the certificate update and the number of revoked certificates growing, the blockchain state database storage continues to increase, which consumes additional computation and storage resources and affects the execution efficiency of smart contracts. In this paper, we address the aforementioned issues by proposing a consortium blockchain-based source authentication scheme for road condition monitoring (ACRoM). In ACRoM, the traffic report is uploaded to the regional trusted authority (RTA) together with one transaction constructed based on the unspent transaction output (UTXO) model. The transaction is utilized to accomplish the source authentication process, which is achieved by verifying the legality of each input contained in the transaction. Moreover, based on the UTXO model, we propose a transaction update mechanism to keep the database storage curve at dynamic stability rather than unlimited growth, which guarantees the scalability of ACRoM. The simulations show that the retrieval time remains at about 0.28 ms while the storage cost is stable at about 29.46 M for the blockchain state database. Besides, benefiting from the efficient batch-verification mechanism, the computation cost of source authentication is about 0.362 ms on average, which outperforms the existing state-of-art schemes.