If you are reading this line, I want to congratulate you because you have already overcome the most difficult hurdle in the pursuit of the understanding blockchain, and specifically, Ethereum smart contracts. This hurdle is the overwhelming hype surrounding this promising yet premature technology and trying to know what is really going on under the hood.
I am a software developer, and through my book, which you are viewing in your electronic device or physically holding in your hand, we will together embark on a fascinating journey through this enigmatic and revolutionary technology.
The chapters in this book have been arranged in an incremental fashion. We start with a gentle introduction to blockchain using the familiar bitcoin, and quickly dive into the world of Ethereum and the major players in its ecosystem.
Then we proceed to do some hands-on coding of a typical "Hello World" smart contract. We then take on the subject of decentralized autonomous organizations, decentralized applications, and smart contract optimization. We also analyze two famous multi-million-dollar hacks that recently occurred in the Ethereum community, along with the preventive measures employed to avoid them in future.
We then move on to the intricacies of the solidity programming language and web3.js library.
The final chapters mainly deal with the development of standardized tokens, the concept of initial coin offering, potential enterprise use cases of smart contracts, designing a decentralized micro-blogging platform, and surfing the dark web marketplace.
We conclude the book by providing primers on advanced topics with promising future prospects such as graph-based DLTs and quantum secured blockchains.
At the onset, I want to have a clear understanding between us. Even though I am the author of this book and it is my sole responsibility to present the facts as accurately as possible in this book, in no possible way do I consider myself as the sole authority on this subject.
As my reader, I want you to realize that I am just another overenthusiastic fellow learner who will try to assist you with your pursuit of knowledge by introducing the optimal amount of information required to kick-start your journey. And I will make you aware of the hurdles and pitfalls I faced along the way so that you can learn from my mistakes.
Enough said. Let's start our journey to blockchain and get our hands dirty with Ethereum Smart Contract Development.
Happy reading!
This book is dedicated to novice programmers, solution architects, and blockchain enthusiasts who want to build powerful, robust, and optimized smart contracts using solidity from scratch and in combination with other open source JavaScript libraries. If you want to build your own extensive, decentralized applications that can smartly execute on a blockchain, then this book is what you need! An open and inquisitive mind is a necessary and sufficient prerequisite. Some preliminary knowledge of data structures, object-oriented programming, networking concepts, and cryptography is a plus and will help the reader to understand the concepts presented in this book.
Chapter 1, Blockchain Basics, will serve as a warm-up session about blockchain before we deep dive into Ethereum and smart contract development. To really appreciate blockchain, we must understand the two founding pillars on which blockchain as a technology is firmly grounded: distributed systems and cryptography. Once we have covered these two core concepts, we try to understand a blockchain from two different perspectives: as a software developer and as a trader of financial instruments. Then we probe into the internal logical architecture of a block in the blockchain, focusing the bitcoin block structure, and get a gentle introduction to the mining and forking process. We conclude the chapter by discussing how blockchain has evolved in recent years and clearly marking out its current position in the technological hype cycle.
Chapter 2, Grokking Ethereum, will help us to understand the meaning of decentralization and whether Ethereum is truly decentralized. We will also cover its core technological stack and get familiarized with various jargon, such as Mist, EVM, Swarm, Whisper, Ether, and Gas. We will briefly discuss the notion of a Turing-complete language. We'll then revisit forking, mining, and block architecture from the perspective of Ethereum. We'll end this chapter by getting a notion of Ethereum wallets and client interfaces, which will serve as a firm base for smart contract development.
Chapter 3, The Hello World of Ethereum Smart Contract, provides a hands-on guide to developing our first smart contract. As an unspoken tradition of a software developer, we start with a "Hello World" program. Then we try some basic arithmetic increment and decrement operations using a contract. We then learn how to code a loop inside a smart contract and how to raise an issue in GitHub. We end this chapter by creating our own private blockchain right from the genesis block, attach it with Geth, and use the Mist browser to deploy one of the smart contracts we studied in this chapter, after mining some ethers.
Chapter 4, A Noob's Guide to DApps and DAOs, develops our understanding towards decentralized applications from a developer's perspective. We introduce the high-level steps to develop a decentralized application. Then we explore a unique marketplace called ethercast, which serves as an aggregator of several DApps. We then move on to design a decentralized autonomous organization. We conclude this chapter with a retrospection of the infamous DAO hack, which led to the ETH/ETC split, from a purely technical perspective.
Chapter 5, Deep-Diving into Smart Contracts, digs deeper into smart contract designs. We start by understanding the textbook definition of a smart contract. Then we move on to understand different smart contract models and the role of code in a smart contract. We go through the basic anatomy of a smart contract and see how a smart contract works. Then we shift our focus to advanced topics such as smart contract optimization, auditing, and ERC20 compliance. We conclude the chapter with a hands-on drill of building a voting DApp.
Chapter 6, Solidity in Depth, is all about the Turing complete solidity language on the Ethereum blockchain. We will start by probing into the design decision of why we really need a new language like solidity. The next sections will cover the nuances of the solidity language and the basic syntax used in it. Specifically, we'll cover contract-oriented features, functions and events, inheritance, libraries, expressions, control structures, units, and variables. Then we'll look at the optimizer and debugging options. We will conclude this chapter by analyzing the code flaw that led to the recent parity wallet hack in the Ethereum blockchain, which stole around $30 million worth of ethers.
Chapter 7, Primer on Web3.js, introduces a special application programming interface library written in JavaScript. This interface connects our web browser with the Ethereum blockchain node. We will begin this chapter by understanding the difference between Geth, Web3.js, and Mist. Then we will learn how to import this API library and get connected with Geth. We will then explore the API structure inside the web3.js library. We'll conclude the chapter by studying the design of an ownership contract.
Chapter 8, Developing Cryptocurrency from Scratch, provides a hands-on tutorial to develop an ERC20 standardized token using the Truffle framework. We then dive in to the concepts of initial coin offering (ICO) and how to identify genuine ICOs among fake and Ponzi schemes. The chapter concludes by discussing various token conversion process and pair-trading concepts.
Chapter 9, Enterprise Use Cases, provides some exciting and promising use cases of Ethereum smart contracts. We also discuss the design of a decentralized micro-blogging platform using solidity.
Chapter 10, BaaS and the Dark Web Market, introduce us to the blockchain framework of Microsoft and IBM. We conclude this chapter by discussing the difference between the Conventional Web and the Dark Web (.onion website and TOR) and how to safely browse the Dark Web to find use cases of cryptocurrencies.
Chapter 11, Advanced Topics and the Road Ahead, deals with exciting topics such as graph-based DLTS with a focus on Tangle, quantum secured blockchain, Ethereum improvement protocols, consortium blockchains, distributed autonomous societies, and common design patterns for solidity.
- Inform the reader of the things that they need to know before they start, and spell out what knowledge you are assuming
- Some preliminary knowledge of data structures, object-oriented programming, networking concepts, and cryptography is a plus but not mandatory
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There are a number of text conventions used throughout this book.
CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Open your Google Chrome browser and type remix solidity in Google, as shown in Figure 3.1."
A block of code is set as follows:
{"jsonrpc":"2.0","method":"eth_coinbase","params":[],"id": 67}Any command-line input or output is written as follows:
$ geth --datadir=./chaindata/ init genesis.jsonBold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Click on the Create button as highlighted in Figure 3.7. Voila! You just created your smart contract."
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