ABSTRACT
The popularity of blockchain is on the rise as the technology is touted to become an enabler of many existing and futuristic applications. These applications range from cryptocurrency-based financial applications to secure supply chain management, privacy-protected medical data handling, secure yet transparent e-voting, decentralized Internet of Things (IoT), and fault-tolerant Unmanned Aerial Vehicles (UAVs) towards future 6G communication networks. There are numerous inherent features of blockchain that drive these applications, such as transparency, decentralization, non-repudiation, immutability, pseudonymity, provenance, and lower operational costs. Moreover, the smart contracts further enhance the capabilities of blockchain. Thus, this chapter aims to provide an in-depth understanding of blockchain and smart contracts. In particular, the chapter begins by introducing blockchain as one of the most popular types of Distributed Ledger Technology (DLT). Subsequently, the block structure, transaction process flow, salient features, and the different types of blockchain are presented. Next, the concept of smart contract is discussed along with its salient features and the different blockchain platforms that support smart contracts. Furthermore, the chapter introduces various growing applications of blockchain. Finally, the security aspects of blockchain and smart contracts are briefly discussed since it is an evolving technology.
