Blockchains

This handbook is a selection of foundational aspects, security analysis and applications of  blockchains that consists of four parts. The first part  fundamentals,  introduces the concept of blockchain with adequate motivation and examples. This includes the basic building blocks such as distributed computing and systems, cryptography and security aspects, incentive mechanisms and game theoretic concepts. A brief history of the tools are discussed as well. Consensus algorithms form the basic backbone of blockchain protocols are presented in details. Various cryptographic tools like hash functions, digital signatures and commitment schemes are also introduced. Advanced cryptographic techniques such as  zero knowledge protocols, secret sharing, verifiable random functions that are used for privacy-preserving and secure design are discussed as well. Throughout the first part, not only are the are the tools introduced, but also why they are required and how these tools can be used in blockchain design and implementation. Special reference is drawn to applications.The second part of this handbook consists of popular blockchain designs and platforms.  The authors discuss the architecture of Bitcoin, Ethereum, Hyperledger, Monero, Tendermint and Algorand, and the authors plan to include recent research on various versions and flavours of the design. For example, they discuss both Proof of Stake and Proof of Work versions of Ethereum.The final part of this handbook discusses various security and privacy issues of Blockchain. It discusses the vulnerability and limitations of proof of work and proof of stake blockchains, and hybrid blockchains.  The last part of this handbook also presents applications of blockchain. A list of research challenges and directions of future work are included in this handbook. This resourceful reference targets students and researchers, who are starting to explore blockchain. Professionals working in blockchain security and applications will also find this handbook to be a valuable reference.