Introduction

Unless you have been living on Mars in the last few months, you have surely witnessed the meteoric rise and (hopefully) temporary fall of cryptocurrencies. You have also definitely heard and read about blockchain, perhaps even about decentralized applications.But do you know how they actually work?

Although cryptocurrencies are currently in a relative low within their continuous boom and burst cycle, the underlying technology is here to stay. Decentralized applications, also known as Dapps, are applications that take advantage of the decentralization of peer-to-peer networks with the immutability and untamperability of the blockchain data structure. In simple terms, you can think of a Dapp as an application whose logic runs concurrently on thousands of servers, each owned by a different party, and whose data is stored on the blockchain. Independent execution and crossvalidation on many servers guarantees integrity of the processing; the blockchain data structure guarantees integrity of its data.

This architecture makes Dapps inherently trustless, which means as a user you do not need to trust anyone or any institution to be confident your data will get processed and stored correctly and as intended. This is guaranteed by the technology.

The potential offered by this innovation is already being harvested to build provenance and supply-chain management systems that allow different companies and institutions to interact in a trustless fashion throughout the production process of finished goods such as diamond or medicines, therefore minimizing or eliminating completely the risk of counterfeiting.

Building Ethereum Dapps will teach you how to build decentralized applications on the Ethereum blockchain. Not only can you finally understand what happens under the bonnet of a blockchain and of a Dapp, but you will be able to write smart contracts in no time, following the best practice, and deploy them onto the Ethereum network.

In this eBook you will find two sample chapters. Chapter 1 is a general introduction to decentralized application and blockchain technology. Chapter 3 is more hands-on: you will have the opportunity to play with Go Ethereum, also known as geth, the most popular Ethereum client. I will show you how to launch simple commands, which will allow you to get network and blockchain information and manage accounts. At the end of each chapter, we will also start building SimpleCoin, a simple demo cryptocurrency.

I hope you find these chapters interesting and continue your Ethereum learning journey in the full book!