This book is your comprehensive guide to understanding Blockchain and Blockchain consensus algorithms. It covers distributed systems, distributed consensus, and relevant system models. And you'll explore how classical and modern consensus algorithms work. The book also covers quantum consensus and explains the role that quantum computing plays in distributed systems.

Consensus protocols allow participants in distributed systems to agree on a common value, despite faults. It's a fundamentally important construct in distributed systems. As a result of rigorous and ground-breaking research over the last four decades, many consensus mechanisms have been developed and are used in the industry today. However, with the advent of Blockchain technology, a renewed interest has arisen in this area, resulting in more research and innovation.

The first Blockchain, Bitcoin, was invented in 2008 and introduced a novel consensus protocol called Nakamoto consensus, a solution to the Byzantine General's problem formulated almost 30 years ago. Since the introduction of Bitcoin, the interest in Blockchain and consensus protocols has risen exponentially. As a result, researchers from academia and industry have proposed many new consensus mechanisms. While fundamental goals and some techniques remain the same as established classical protocols, these modern protocols introduce innovative methods to achieve consensus in Blockchain. Some classical algorithms have been modified to make them suitable for Blockchain and some new protocols have been developed.

This book is a detailed account of classical distributed consensus and Blockchain consensus algorithms. It explains why and how cryptocurrencies and Blockchain remain secure and decentralized without depending on a trusted third party. In addition, you'll learn how Blockchain can endure, even with hundreds or thousands of participants, out of which some might be malicious. The book introduces quantum consensus, which deals with the problem of reaching agreement in quantum networks and how to enhance classical results.

What You Will Learn

Understand distributed systems, distributed consensus, and relevant system models and protocols
Understand Blockchain and Blockchain consensus algorithms
Know how classical and modern consensus algorithms work
Know the inner workings of Paxos, RAFT, PBFT, HotStuff, proof of work, proof of stake, GRANDPA, Casper, proof of history, and other consensus protocols
Understand quantum Byzantine agreement and quantum consensus

Auteur

Imran Bashir has an MSc degree in information security from Royal Holloway, University of London, and a background in software development, solution architecture, infrastructure management, information security, and IT service management. His current focus is on the latest technologies such as Blockchain, IoT, and quantum computing. He is a member of the Institute of Electrical and Electronics Engineers (IEEE) and the British Computer Society (BCS). His book on Blockchain technology, Mastering Blockchain, is a widely accepted standard text on the subject. He has worked in various senior technical roles for different organizations around the world. Currently, he is living and working in London, UK.

Contenu

Chapter 1: Introduction Chapter Goal: to introduce distributed computing concepts, models and relevant concepts

No of pages - 30

Introduction 1.1. What is distributed computing 1.1.1.Characteristics (collection, coherent, same task, consists of nodes etc) 1.2. Distributed algorithms 1.3. Elements of distributed computing 1.4. computational (system) model 1.5. Space / time diagram 1.6. Time, clocks and order 1.7. Broadcast ordering 1.8. types 1.8.1.1.Message passing 1.8.1.2.Shared memory 1.9. Synchrony / timing 1.10. Adversary model 1.11. Faults 1.11.1.Process / program faults 1.11.2.Processor / machine 1.11.3.Communication / link faults 1.11.4.Storage faults 1.11.5.Types (omission, byzantine . . . etc.) 1.11.6.Correct processes 1.11.7.Fault tolerance 1.12. Abstractions 1.12.1.What and why abstractions? 1.12.2.to understand / build distributed computing - helps to state and reason about distributed computing 1.12.3.System model 1.12.4.Processes and links 1.12.5.Communication and networks 1.12.5.1.Latency and bandwidth 1.12.6.Agreement 1.12.7.Cryptography abstractions 1.13. Role of cryptography in distributed systems and consensus 1.14. CAP theorem 1.15. Summary Chapter 2: Cryptography Chapter Goal: to understand cryptography and build ground for use of cryptography in consensus

No of pages - 30

Cryptography 2.1.1.What is cryptography 2.1.2.CIA triad 2.1.3.Symmetric cryptography 2.1.4.Asymmetric cryptography 2.1.5.Hash functions 2.1.6.MACs 2.1.7.Digital signatures 2.1.8.Privacy 2.1.9.Zero knowledge 2.1.10.Summary Chapter 3: Distributed consensus Chapter Goal: to introduced the subject of consensus, why its important, history, how it developed, what are the requirements and relevant results and abstractions.

No of pages - 30

Distributed consensus 3.1. What is distributed consensus 3.1.1.Agreement abstraction 3.2. Goal of distributed consensus 3.2.1.Safety 3.2.2.liveness 3.2.3.Other properties and goals 3.3. Consensus system model 3.4. History 3.5. Types 3.6. Building blocks 3.7. Other abstractions 3.8. Two generals problem - network model 3.9. Byzantine generals problem - node behaviour model 3.10. Byzantine agreement 3.11. Replication 3.12. Primary - backup model 3.13. State machine replication 3.14. Fundamental results, lower bounds / upper bounds 3.15. FLP impossibility 3.16. How to circumvent FLP impossibility 3.16.1.Synchrony models , assumptions, eventual, partial synchrony etc. 3.16.2.Other methods 3.17. Cryptography in distributed consensus 3.17.1.Privacy in consensus algorithms 3.18. Where are we now 3.19. Summary Chapter 4: Blockchain Chapter Goal: to introduce blockchain, its structure, use cases and technical underpinnings.

No of pages - 20

Blockchain 4.1. What is blockchain 4.2. Background 4.2.1.The first blockchain 4.2.2.Bitcoin 4.2.3.Smart contracts 4.3. Blockchain is a distributed system 4.4. Basic structure 4.5. Benefits 4.6. Types 4.7. Available platforms 4.7.1.Ethereum 4.8. Use cases 4.9. Summary Chapter 5: blockchain consensus Chapter Goal: introduce blockchain consensus, relationship with classical consensus, need of consensus in blockchain, how generally it works and Bitcoin protocol.

No of pages - 20

Blockchain consensus 5.1. Relationship with distributed systems 5.2. Why consensus is needed 5.3. First appearance - with Bitcoin to circumvent double spending and Sybil attack 5.4. A confusion - a consensus mechanism, consensus facilitation mechanism or a Sybil attack defence mechanism 5.5. First blockchain consensus - in Bitcoin - PoW 5.6. Summary Chapter 6: early protocols Chapter Goal: to introduce what distributed consensus protocols were developed earlier , some fundamental relevant results and how these protocols work. This will develop intuition and basis for more advanced topics in the next chapter.

No of pages - 20

Early protocols 6.1. Byzantine agreement 6.2. Ben-Or 6.3. DLS 6.4. View stamped replication 6.5. Summary Chapter 7: Classical consensus algorithms Chapter Goal: introduced classical consensus protocols , inluding Paxos, RAFt, PBFT and understand how they work in detail

No of pages - 30

Classical protocols / algorithms This chapter covers classical protocols in detail, their design, how they work and where they are implemented. How and if they can be used in blockchain 7.1. Paxos 7.2. RAFT 7.3. PBFT 7.4. How to adapt these classical protocols for blockchain. 7.5. Summary Chapter 8: blockchain age protocols Chapter Goal: introduction to modern blockchain protocols and how they work.

No of pages - 40