Book Image

Blockchain Developer's Guide

By : Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty
Book Image

Blockchain Developer's Guide

By: Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty

Overview of this book

Blockchain applications provide a single-shared ledger to eliminate trust issues involving multiple stakeholders. It is the main technical innovation of Bitcoin, where it serves as the public ledger for Bitcoin transactions. Blockchain Developer's Guide takes you through the electrifying world of blockchain technology. It begins with the basic design of a blockchain and elaborates concepts, such as Initial Coin Offerings (ICOs), tokens, smart contracts, and other related terminologies. You will then explore the components of Ethereum, such as Ether tokens, transactions, and smart contracts that you need to build simple DApps. Blockchain Developer's Guide also explains why you must specifically use Solidity for Ethereum-based projects and lets you explore different blockchains with easy-to-follow examples. You will learn a wide range of concepts - beginning with cryptography in cryptocurrencies and including ether security, mining, and smart contracts. You will learn how to use web sockets and various API services for Ethereum. By the end of this Learning Path, you will be able to build efficient decentralized applications. This Learning Path includes content from the following Packt products: • Blockchain Quick Reference by Brenn Hill, Samanyu Chopra, Paul Valencourt • Building Blockchain Projects by Narayan Prusty
Table of Contents (37 chapters)
Title Page
About Packt

51% attacks

All blockchains can suffer from consensus attacks, often referred to as 51% attacks because of the original consensus attack possible in Bitcoin. Every blockchain relies on the majority of its users or stakeholders being good actors, or at least not coordinating against the rest of the network. If the majority (or even a large minority) of the powerful network actors in a blockchain system coordinate against the rest, they will be able to launch double-spend attacks and extract large amounts of value from the network against its will.

While once theoretical, there have recently been a number of successful 51% attacks against different blockchains, such as Verge (find the link in the references). In systems that are more centralized, such as proof-of-stake systems where there may be a small number of extremely large stakeholders, it is entirely possible that similar coordination's could occur with something as simple as a few phone calls if concerned stakeholders have sufficient...