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

Globally available variables


There are special variables and functions that always exist globally. They are discussed in the upcoming sections.

Block and transaction properties

The block and transaction properties are as follows:

  • block.blockhash(uint blockNumber) returns (bytes32): The hash of the given block only works for the 256 most recent blocks.
  • block.coinbase (address): The current block miner's address.
  • block.difficulty (uint): The current block difficulty.
  • block.gaslimit (uint): The current block gas limit. It defines the maximum amount of gas that all transactions in the whole block combined are allowed to consume. Its purpose is to keep the block propagation and processing time low, thereby allowing a sufficiently decentralized network. Miners have the right to set the gas limit for the current block to be within ~0.0975% (1/1,024) of the gas limit of the last block, so the resulting gas limit should be the median of miners' preferences.
  • block.number (uint): The current block number...