Abstract
Blockchain is a framework that saves data records in adjacent blocks that are linked together using cryptography. It is in the form of a distributed database that maintains a continuously growing list of data records that are validated by the nodes participating in the chain. BC presents a decentralized solution, which does not require a third-party organization in the middle for achieving the intra-blocks trust. The information about every transaction ever completed in a blockchain is shared and always available to all nodes. This attribute makes the system more transparent than centralized transactions. The goal of blockchain technology is to provide anonymity, security, privacy, and Transparency to all its users. This chapter aims to provide the state-of-the-art information on the use of blockchain technology for securing IoT environments. The advantages and Limitations of blockchain technology for IoT architectures are analyzed. Conceptual blockchain-based IoT architectures for seven different cases are also presented. These being: Supply chain management and Manufacturing, Smart cities, Smart home, Healthcare IoT systems, identity management and access control systems, Electricity market systems, and Insurance systems. The most relevant future challenges for the application of blockchain to IoT challenges environments are also discussed.