Book Image

Building Blockchain Projects

By : Narayan Prusty
Book Image

Building Blockchain Projects

By: Narayan Prusty

Overview of this book

Blockchain is a decentralized ledger that maintains a continuously growing list of data records that are secured from tampering and revision. Every user is allowed to connect to the network, send new transactions to it, verify transactions, and create new blocks, making it permission-less. This book will teach you what blockchain is, how it maintains data integrity, and how to create real-world blockchain projects using Ethereum. With interesting real-world projects, you will learn how to write smart contracts which run exactly as programmed without any chance of fraud, censorship, or third-party interference, and build end-to-e applications for blockchain. You will learn about concepts such as cryptography in cryptocurrencies, ether security, mining, smart contracts, solidity, and more. You will also learn about web sockets, various API services for Ethereum, and much more. The blockchain is the main technical innovation of bitcoin, where it serves as the public ledger for bitcoin transactions.
Table of Contents (16 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Gas


Gas is a unit of measurement for computational steps. Every transaction is required to include a gas limit and a fee that it is willing to pay per gas (that is, pay per computation); miners have the choice of including the transaction and collecting the fee. If the gas used by the transaction is less than or equal to the gas limit, the transaction processes. If the total gas exceeds the gas limit, then all changes are reverted, except that the transaction is still valid and the fee (that is, the product of the maximum gas that can be used and gas price) can still be collected by the miner.

The miners decide the gas price (that is, price per computation). If a transaction has a lower gas price than the gas price decided by a miner, the miner will refuse to mine the transaction. The gas price is an amount in a wei unit. So, a miner can refuse to include a transaction in a block if the gas price is lower than what it needs.

Note

Each operation in EVM is assigned a number of how much gas it...