Blockchain is a distributed technology that guarantees secure and transparent data exchange without relying on a Trusted Third Party (TTP). Thanks to peer-to-peer networks and consensus mechanisms, it enables users to share reliable information directly. Smart contracts, which are self-executing programs, extend blockchain’s capabilities by automating agreements. First used in cryptocurrencies such as Bitcoin, blockchain is now being applied in a variety of areas to support decentralized and unforgeable systems. This chapter introduces the fundamentals of blockchain and smart contracts and explores their uses beyond cryptocurrencies.