Bits To Bitcoin: How Our Digital Stuff Works

369 Pages·2018·7.037 MB·English

by  Mark Stuart Day

Bits to Bitcoin

Bits to Bitcoin
How Our Digital Stuff Works
Mark Stuart Day
with illustrations by C. A. Jennings
The MIT Press
Cambridge, Massachusetts
London, England
© 2018 Mark Stuart Day
All rights reserved. No part of this book may be reproduced in any form by any
electronic or mechanical means (including photocopying, recording, or information
storage and retrieval) without permission in writing from the publisher.
This book was set in Stone Serif by Westchester Publishing Services. Printed and bound
in the United States of America.
Excerpt from The Wizard of Oz granted courtesy of Warner Bros. Entertainment Inc.
Library of Congress Cataloging-in-Publication Data
Names: Day, Mark Stuart, author. | Jennings, C. A., illustrator.
Title: Bits to bitcoin : how our digital stuff works / Mark Stuart Day ; illustrated by
C.A. Jennings.
Description: Cambridge, MA : MIT Press, [2018] | Includes index.
Identifiers: LCCN 2017046504 | ISBN 9780262037938 (pbk. : alk. paper)
Subjects: LCSH: Computer science--Popular works.
Classification: LCC QA76 .D3333327 2018 | DDC 004--dc23 LC record available at
https://lccn.loc.gov/2017046504
10 9 8 7 6 5 4 3 2 1
OZ: Pay no attention to that man behind the curtain! The great Oz has spoken!
Dorothy (pulling back curtain): Who are you?
Man: Oh… I… I am the great and powerful… Wizard of Oz.
Dorothy: You are? I don’t believe you.
Man: Well, I’m afraid it’s true. There’s no other wizard except me.
—From The Wizard of Oz (1939)

Contents
Preface ix
Acknowledgments xiii
1 Introduction 1
I Single Process
2 Steps 5
3 Processes 17
4 Names 31
5 Recursion 41
6 Limits: Imperfect Programs 49
7 Limits: Perfect Programs 65
II Interacting Processes
8 Coordination 81
9 State, Change, and Equality 89
10 Controlled Access 101
11 Interrupts 111
12 Virtualization 123
13 Separation 135
14 Packets 151
15 Browsing 155
viii Contents
III Unstoppable Processes
16 Failure 177
17 Software Failure 199
18 Reliable Networks 207
19 Inside the Cloud 217
20 Browsing Revisited 241
IV Defending Processes
21 Attackers 253
22 Thompson’s Hack 263
23 Secrets 273
24 Secure Channel, Key Distribution, and Certificates 289
25 Bitcoin Goals 307
26 Bitcoin Mechanisms 315
27 Looking Back 335
Index of Metaphors and Examples 337
Subject Index 341
Preface
As a high school student in the late 1970s, I wrote an article for the school
newspaper explaining what a personal computer could do. Among its other
virtues, it could store recipes. That wasn’t wrong—it just doesn’t seem like
the first thing you’d choose to say about a modern computer.
Back in those days, it was easy to perceive that something important
was happening, but we couldn’t quite see all the way to today’s capabilities.
Since we now have an abundance of devices and services using computers
and communications, there is no longer any need to argue for the value of
computers. Indeed, the challenge now is getting people to disconnect from
their mobile phones, tablets, music players, and laptops long enough to dis-
cuss the merits of something else.
Alongside the evolution of computers from bizarre novelty to ubiquitous
necessity, there’s been a substantial amount of discovery and invention. In
roughly the same way that it was once useful to explain what computers
were, I think it’s now useful to explain something about the larger context
of computer systems and infrastructure.
In everyday life, plumbing is tremendously important but little noticed
until it goes wrong—and likewise computational infrastructure. You most
likely don’t care much about the pipes in your house unless one of them
springs a leak or otherwise fails, in which case you develop a strong need for
someone to fix it immediately (and are willing to pay them well to do so).
Being a “computational plumber” is likewise a good but generally unglam-
orous life. I have had the good fortune to examine a cross-section of the
world’s major organizations, where I have seen some of the good, bad, and
ugly of what they do with their infrastructure.
It is strange to observe that it is easier for a nonspecialist to learn what
physicists know about special relativity than to learn what computer scientists