Decentralized Applications

118 Pages·2016·11.67 MB·English

by  Siraj Raval

Decentralized
Applications
HARNESSING BITCOIN'S BLOCKCHAIN TECHNOLOGY
Siraj Raval

Decentralized Applications
Harnessing Bitcoin’s Blockchain Technology
Siraj Raval
BBeeiijjiinngg BBoossttoonn FFaarrnnhhaamm SSeebbaassttooppooll TTookkyyoo
Decentralized Applications
by Siraj Raval
Copyright © 2016 Siraj Raval. All rights reserved.
Printed in the United States of America.
Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472.
O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are
also available for most titles (http://safaribooksonline.com). For more information, contact our corporate/
institutional sales department: 800-998-9938 or [email protected].
Editor: Tim McGovern Indexer: Judy McConville
Production Editor: Colleen Lobner Interior Designer: David Futato
Copyeditor: Octal Publishing, Inc. Cover Designer: Randy Comer
Proofreader: James Fraleigh Illustrator: Rebecca Demarest
August 2016: First Edition
Revision History for the First Edition
2016-07-13: First Release
See http://oreilly.com/catalog/errata.csp?isbn=9781491924549 for release details.
The O’Reilly logo is a registered trademark of O’Reilly Media, Inc. Decentralized Applications, the cover
image of a silver roughy, and related trade dress are trademarks of O’Reilly Media, Inc.
While the publisher and the author have used good faith efforts to ensure that the information and
instructions contained in this work are accurate, the publisher and the author disclaim all responsibility
for errors or omissions, including without limitation responsibility for damages resulting from the use of
or reliance on this work. Use of the information and instructions contained in this work is at your own
risk. If any code samples or other technology this work contains or describes is subject to open source
licenses or the intellectual property rights of others, it is your responsibility to ensure that your use
thereof complies with such licenses and/or rights.
978-1-491-92454-9
[LSI]
Thank you, Jade. Your truth set me free.

Table of Contents
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
1. What Is a Decentralized Application?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Preliminaries: What Is Bitcoin? 1
What Is a Decentralized Application? 3
Feature 1: Open Source 4
Feature 2: Internal Currency 6
Feature 3: Decentralized Consensus 6
Feature 4: No Central Point of Failure 7
The History of Decentralized Applications 8
PopcornTime 9
OpenBazaar 9
FireChat 9
Lighthouse 10
Gems 10
Enabling Technologies 11
Defining the Terms 11
Getting Started 14
2. A Flourishing Dapp Ecosystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Decentralized Data 15
Option 1: Storing Data Directly in the Bitcoin Blockchain 16
Option 2: Storing Data in a Distributed Hash Table 17
Decentralized Wealth 21
Decentralized Identity 26
Decentralized Computing 29
Decentralized Bandwidth 31
Decentralized Markets for Decentralized Assets 33
v
Practical Decentralization 36
3. Building Your First Dapp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Go 39
Centralized Architecture 40
Decentralized Architecture: Introduction to IPFS 41
What Are We Building? 43
Setup 43
Routing 48
Data Storage and Retrieval 49
Passing and Displaying Data to the Frontend 52
Dapp Economics 54
Remaining Problems 58
Private Networks 58
Human-Readable Names 59
Showing Only Peers on Mikro, Not IPFS in General 59
Tamper-Free Payments 59
4. OpenBazaar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Why Make OpenBazaar? 61
What Is OpenBazaar? 62
How Does OpenBazaar Work? 63
Merchant 63
Buyer 64
Notary 65
How to Install OpenBazaar 66
Possible Errors 66
Identity 70
Reputation 71
What Could OpenBazaar Have Done Better? 74
5. Lighthouse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Functionality 78
SPV Wallets 84
Identity 84
6. La’Zooz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
What Is La’Zooz? 87
Distribution Protocol 88
DAO Structure 89
UX 91
Architecture 92
vi | Table of Contents
Contracts 95
Improvements 96
Conclusion 97
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Table of Contents | vii