Blockchain By Example

521 Pages·2019·16.823 MB·English

by  Bellaj Badr

Blockchain By Example
A developer's guide to creating decentralized applications
using Bitcoin, Ethereum, and Hyperledger
Bellaj Badr
Richard Horrocks
Xun (Brian) Wu
BIRMINGHAM - MUMBAI
Blockchain By Example
Copyright © 2018 Packt Publishing
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First published: November 2018
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ISBN 978-1-78847-568-6
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Foreword
From the time Badr Bellaj first told me about his intention to write a book about blockchain,
I was highly supportive of his endeavor. I even managed to suggest topics that I, as a
veteran developer, still needed to understand. A year later, after reading this book, my
expectations have been surpassed and I could not be happier. Therefore, it's my pleasure to
provide this foreword and to recommend Bellaj's book, Blockchain by Example.
It is generally agreed that blockchain is a disruptive technology that has shaken the IT
scene. Consequently, it has increasingly drawn the interest of a lot of developers. However,
according to my experience, it's hard for newcomers to find a helpful guide that explains
blockchain in the easiest possible terms, and teaches with concrete examples how to use
major blockchain solutions to build projects.
This book is intended to change this situation and acts as an introduction to blockchain
technology from a developer viewpoint. It's an undertaking of great potential value, and
Bellaj and his coauthors have done it justice.
In fact, this book will help you, step by step, to build realistic projects from scratch using
different concepts and technologies, namely Bitcoin, Ethereum, Quorum, and Hyperledger.
You'll find, among other topics, how a developer can create a Bitcoin-like coin, run an ICO,
and implement privacy-preserving solution in business.
This book isn't just for absolute beginners. It's also a good book for introducing experienced
programmers to blockchain technologies or even bringing up to speed developers already
familiar with these technologies. It helps if you know a bit about blockchain when you step
in, but if you don't, hang on and you should pick up the basic ideas as you go along.
Bellaj is an educator, and a darn good one. He wants us to acquire practical skills instead
understanding only the superficial concepts! He knows that if you and I are ready to learn,
we have to practice: we have to do the work. In his chapters, he will continually challenge
you to propose new features for the presented project. We are well advised to try to
implement what he suggests and to create pull requests.
I have enjoyed the book and found it valuable. I think you will, too. Enjoy!
Sam Hauer
Cofounder of NSApps
Contributors
About the authors
Bellaj Badr is an experienced security and software engineer who loves blockchain with a
passion. Currently, he is the CTO at Mchain, a blockchain start-up that develops blockchain
solutions for companies.
Alongside his role as CTO, he acts as technical consultant, offering strategic and technical
consulting to many companies worldwide. Aside from this, he is involved in many
blockchain projects involving the establishment of new blockchain business-oriented
protocols. Badr is a frequent speaker at developer conferences and is father to two angels.
I would like to thank my family for their support and my awesome children, Arwa and
Youssef, for letting me finish this book.
Richard Horrocks is a freelance Ethereum and full-stack developer based in the UK, and
holds a BA and MSc in natural sciences from the University of Cambridge. He worked for
many years as a technical lead for Cisco Systems, where he worked on the operating
systems of carrier-grade routing hardware, before leaving the world of IT to work as an
English teacher.
The advent of cryptocurrency piqued his interest sufficiently to lead him back to IT, and,
since 2015, he has been working with Ethereum and other cryptocurrencies. His specialist
interests are cryptoeconomics and incentive layers, with a particular focus on mechanism
design and token engineering.
When not in front of a computer, he enjoys yoga and falling off motorbikes.
Xun (Brian) Wu is the founder and CEO of SmartChart. He has 16+ years of extensive,
hands-on, design and development experience with blockchain, big data, cloud, UI, and
system infrastructure. He has coauthored a number of books, including Seven NoSQL
Databases in a Week, Hyperledger Cookbook, and Blockchain Quick Start Guide. He has been a
technical reviewer on more than 50 technical books for Packt. He serves as a board
adviser for several blockchain start-ups and owns several patents on blockchain. Brian also
holds an NJIT computer science masters degree. He lives in New Jersey with his two
beautiful daughters, Bridget and Charlotte.
I would like to thank my parents, wife, and children for their patience and support
throughout this endeavor.
About the reviewers
Karthikeyan Sukumaran has been involved in blockchain research and development for
the past three years and has over a decade of industry experience in connection with mobile
and web platforms. He has been a CEO for his own blockchain start-up, where he
architected multiple blockchain projects for various consulting, automobile, supply chain,
logistics, and financial companies. He is also a renowned speaker within the Indian
blockchain community. Currently, Karthikeyan is an associate director (DLT
Labs—Blockchain R&D) for The Depository Trust and Clearing Corporation (DTCC),
India.
Aafaf Ouaddah is a veteran security engineer, currently pursuing a PhD involving
blockchain. She has wide-ranging experience in distributed systems. Currently, she is
a lead researcher investigating security and privacy in distributed systems, blockchain, IoT
and fog computing. She has presented more than 10 research papers at various conferences
and workshops and has published in reputed international journals with IEEE, Springer,
and Elsevier.
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Table of Contents
Preface 1
Chapter 1: Say Hello to Blockchain 6
The emergence of blockchain and cryptocurrency 7
From virtual currencies to cryptocurrency 7
The invention of bitcoin 8
What is blockchain? 10
Blocks 11
Transactions 11
Smart contracts 11
Interact with the blockchain 12
Getting started 12
Running a bitcoin client for the first time 13
Synchronizing the blockchain 14
Running Bitcoin Core 15
Running Electrum 18
Method 1 – Building a raw transaction using Bitcoin Core 19
Funding our address 19
Unspent transaction output 20
Creating the transaction 21
Transaction structure 23
Signing the transaction 24
Sending the transaction 27
Retrieving your message online from the blockchain 27
Using the local blockchain 28
Method 2 – build a raw bitcoin transaction in JavaScript 30
Preparation 30
Let's code 31
Types of blockchains 34
Classification of blockchains 34
Summary 36
Chapter 2: Building a Bitcoin Payment System 37
What is Bitcoin? 38
Why choose Bitcoin as a platform? 38
Getting started with Bitcoin 39
Setting up a Regtest environment 39
First commands 40
Transactions in bitcoin 41
Mining 42
Bitcoin scripting 42
Building a P2PKH script using JavaScript 45
Building a custom script 46