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

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Blockchain Developer's Guide
Brenn Hill | Samanyu Chopra | Paul Valencourt | Narayan Prusty
Dec, 2018 | 9 hours 24 minutes
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Table of Contents (37 chapters)
Title Page
Title Page
Copyright
Copyright
About Packt
About Packt
Contributors
Contributors
Preface
Preface
Free Chapter
1
Blockchain 101
Blockchain 101
Processing a financial transaction
Ledger
Concept of a trustless system
Introducing blockchain
Summary
2
Components and Structure of Blockchain
Components and Structure of Blockchain
Blocks
The chain between blocks
Hashing and signatures
Digital signatures
Example block data
Blockchain miners
Blockchain validators
Smart contracts
Blockchain speed
Summary
3
Decentralization Versus Distributed Systems
Decentralization Versus Distributed Systems
Distributed systems
Consensus and coordination
Backups
Summary
4
Cryptography and Mechanics Behind Blockchain
Cryptography and Mechanics Behind Blockchain
Principles of security
Historical perspective – classical cryptography
Types of cryptography
Summary
5
Bitcoin
Bitcoin
The history of Bitcoin
Why Bitcoin is volatile
Keys and addresses
Transactions
Blocks
Bitcoin network
Wallets
Summary
6
Altcoins
Altcoins
Introducing Altcoins
Alternative currency
Acquiring cryptocurrency 
Summary
7
Achieving Consensus
Achieving Consensus
Practical Byzantine fault tolerance algorithm 
Proof of Work
Proof of Stake
Proof of Authority
Proof of Elapsed time
Summary
References
8
Advanced Blockchain Concepts
Advanced Blockchain Concepts
Blockchain and banks
Summary
9
Cryptocurrency Wallets
Cryptocurrency Wallets
Introduction to cryptocurrency wallets
Summary
10
Alternate Blockchains
Alternate Blockchains
Various uses of blockchain
Ripple
Stellar 
Tendermint
Monax
Summary
11
Hyperledger and Enterprise Blockchains
Hyperledger and Enterprise Blockchains
History of Hyperledger
Hyperledger projects
Tools in Hyperledger
Summary
12
Ethereum 101
Ethereum 101
Introducing Ethereum
Components of Ethereum
Ether
Summary
13
Solidity 101
Solidity 101
Basics of Solidity
Programming in Solidity
Summary
14
Smart Contracts
Smart Contracts
Why smart contracts?
Smart contract approaches
Limitations of smart contracts
Summary
15
Ethereum Accounts and Ether Tokens
Ethereum Accounts and Ether Tokens
Introducing Ethereum accounts
Ethereum block validation
Disadvantages of Ethereum-based tokens
Summary
16
Decentralized Applications
Decentralized Applications
What makes an application decentralized
Major decentralized blockchain applications
Summary
17
Mining
Mining
Cryptocurrency mining
Algorithms 
Mining hardware
Miner types
Mining pools
Mining software
Summary
18
ICO 101
ICO 101
The current state of the ICO market
Typical aspects of an ICO campaign
Issues with ICOs and blockchain projects
19
Creating Your Own Currency
Creating Your Own Currency
Understanding types of cryptocurrency
Creating one's own cryptocurrency
Summary
20
Scalability and Other Challenges
Scalability and Other Challenges
Scalability and decentralization
Blockchains in business
Usability
51% attacks
Network forks
Catastrophic bugs
Lack of interoperability
Low availability of blockchain skills
Privacy
Energy consumption
Summary
References
21
Future of Blockchain
Future of Blockchain
Ongoing fragmentation and specialization
Legal and regulatory evolution
Technological stabilization
Intersecting with AI and IoT
Summary
22
Understanding Decentralized Applications
Understanding Decentralized Applications
Decentralized autonomous organization
User identity in DApps
User accounts in DApps
Accessing the centralized apps
Internal currency in DApps
What are permissioned DApps?
Popular DApps
Summary
23
Understanding How Ethereum Works
Understanding How Ethereum Works
Transactions
Timestamp
Nonce
Block time
Forking
Genesis block
Peer discovery
Whisper and Swarm
Ethereum Wallet
Serenity
Summary
24
Writing Smart Contracts
Writing Smart Contracts
Solidity source files
The structure of a smart contract
Data location
What are the different data types?
Control structures
Creating contracts using the new operator
Exceptions
External function calls
Features of contracts
Libraries
Returning multiple values
Importing other Solidity source files
Globally available variables
Ether units
Proof of existence, integrity, and ownership contract
Compiling and deploying contracts
Summary
25
Getting Started with web3.js
Getting Started with web3.js
Introduction to web3.js
Building a client for an ownership contract
Summary
26
Building a Wallet Service
Building a Wallet Service
hooked-web3-provider and ethereumjs-tx libraries
Introduction to LightWallet
Building a wallet service
Summary
27
Building a Smart Contract Deployment Platform
Building a Smart Contract Deployment Platform
Calculating a transaction's nonce
Introducing solcjs
Building a contract deployment platform
Summary
28
Building a Betting App
Building a Betting App
Introduction to Oraclize
Working with strings
Building the betting contract
Building a client for the betting contract
Summary
29
Building Enterprise Level Smart Contracts
Building Enterprise Level Smart Contracts
Exploring ethereumjs-testrpc
What are event topics?
Getting started with truffle-contract
Introduction to truffle
Summary
30
Building a Consortium Blockchain
Building a Consortium Blockchain
What is a consortium blockchain?
What is Proof-of-Authority consensus?
Introduction to parity
Summary
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Index
Index

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...
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