Book Image

Advanced Blockchain Development

By : Imran Bashir, Narayan Prusty
Book Image

Advanced Blockchain Development

By: Imran Bashir, Narayan Prusty

Overview of this book

Blockchain technology is a distributed ledger with applications in industries such as finance, government, and media. This Learning Path is your guide to building blockchain networks using Ethereum, JavaScript, and Solidity. You will get started by understanding the technical foundations of blockchain technology, including distributed systems, cryptography and how this digital ledger keeps data secure. Further into the chapters, you’ll gain insights into developing applications using Ethereum and Hyperledger. As you build on your knowledge of Ether security, mining, smart contracts, and Solidity, you’ll learn how to create robust and secure applications that run exactly as programmed without being affected by fraud, censorship, or third-party interference. Toward the concluding chapters, you’ll explore how blockchain solutions can be implemented in applications such as IoT apps, in addition to its use in currencies. This Learning Path also highlights how you can increase blockchain scalability, and discusses the future scope of this fascinating and powerful technology. By the end of this Learning Path, you'll be equipped with the skills you need to tackle pain points encountered in the blockchain life cycle and confidently design and deploy decentralized applications.
Table of Contents (25 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
15
Blockchain - Outside of Currencies
16
Scalability and Other Challenges
Index

Introduction to Oraclize


Oraclize is a service that aims to enable smart contracts to access data from other blockchains and the World Wide Web. This service is currently live on bitcoin and Ethereum's testnet and mainnet. What makes Oraclize so special is that you don't need to trust it because it provides proof of authenticity of all data it provides to smart contracts.

In this chapter, our aim is to learn how Ethereum smart contracts can use the Oraclize service to fetch data from the World Wide Web.

How does it work?

Let's look at the process by which an Ethereum smart contract can fetch data from other blockchains and the World Wide Web using Oraclize.

To fetch data that exists outside of the Ethereum blockchain, an Ethereum smart contract needs to send a query to Oraclize, mentioning the data source (representing where to fetch the data from) and the input for the data source (representing what to fetch).

Sending a query to Oraclize Oraclize means sending a contract call (that is, an internal...