Temporal Blockchains for Intelligent Transportation Management and Autonomous Vehicle Support in the Internet of Vehicles

Introduction

Present and future intelligent transportation and autonomous vehicles applications are using Internet of Vehicles (IoV) (Yang et al., 2014), Flying Ad-Hoc Networks (FANETs) (Bekmezci et al., 2013) and Vehicular Ad-Hoc Networks (VANETs) (Zeadally et al., 2012) as communication infrastructures. In this context, the Blockchain technology has been proposed for durable and trustworthy bookkeeping of the exchanged data (Guo et al., 2018; Diallo et al., 2020; Fu et al., 2020; Gupta et al., 2020; Li et al., 2020a; Narbayeva et al., 2020; Rehman et al., 2020; Javaid et al., 2021; Uddin et al., 2021; Chondrogiannis et al., 2022; Six et al., 2022). A blockchain (Nofer et al., 2017; Dinh et al., 2018; Zheng et al., 2018; Li et al., 2020b) is a public distributed ledger that stores committed transactions in an ordered list, or a chain, of blocks. Such a ledger is maintained by multiple distributed nodes (computers), which are linked in a peer-to-peer network (i.e., without a server node that has full control and central authority) and possibly do not trust each other, through a consensus mechanism (i.e., an agreement among these nodes on the truth of data stored in the blockchain) and cryptography (essentially hash algorithms and digital signatures). Notice that the ledger is replicated over all nodes. A transaction is a sequence of operations applied on some state respecting the ACID properties as in classical database systems. It cannot be modified once it is recorded in a block of the blockchain. A block is made up of a block header and a block body: the former contains, among others, the parent block hash that points to the previous block and a timestamp; the latter essentially contains transactions.

From a database point of view, a blockchain (Dinh et al., 2018; Mohan, 2018; Vo et al., 2018; Xu et al., 2019) can be considered as a distributed and replicated temporal database (Grandi, 2015; Jensen & Snodgrass, 2018a) that stores a large list of blocks: each timestamped block is replicated over all nodes of the network. More precisely, since block timestamps cannot be updated and the whole blockchain is an append-only data structure, a blockchain can be viewed as a transaction-time (Jensen & Snodgrass, 2018b) database, that is a database where each version of a time-varying datum (like the salary of an employee or the price of a product) is stamped with the time when such a version has been inserted in the database.

Among the strengths of blockchain, we find immutability, data integrity, transparency, distribution, absence of central/intermediary entity, and provision of trust in trustless environments. These advantages have lead to a wide use of blockchain technology in several fields, like data science (Liu et al., 2020), supply chains (Behnke & Janssen, 2020), business (Frizzo-Barker et al., 2020), economics (Kher et al., 2020), medicine (Zhang & Boulos, 2020), Internet of Things (IoT) (Pavithran et al., 2020), smart contracts (Singh et al., 2020), e-voting (Khan et al., 2020), finance (Chang et al., 2020), reputation systems (Sharples & Domingue, 2016), and security services (Li et al., 2020b), although it was initially developed to manage cryptocurrencies as Bitcoin (Nakamoto, 2008) and its successors.