Index
Please note that index links point to page beginnings from the print edition. Locations are approximate in e-readers, and you may need to page down one or more times after clicking a link to get to the indexed material.
A
ABI (application binary interface)
deploying sample betting application, 267–268, 272–274, 284–290
fast-track application tutorial, 136–137, 141
public functions listed on, 93–94
sample betting application, 240, 242, 244, 247–248
access, smart property and, 42–44
accessor functions, Solidity, 137
accounts, Ethereum, 105–110
addBetToTable helper function, 283
addBidToTable helper function, 282
addGameToTable helper function, 275
ADP (Automatic Data Processing), 7
AlphaPoint Distributed Ledger Platform, private blockchain, 176–177
Amdahl’s law, 230
American Revolution, Byzantine Generals Problem, 10–11
ANJ (Aragon Network Jurisdiction), DAO, 97–99
architecture
INFURA, 120–122
Web 3.0 technology stack, 72–73
Whisper layered, 71
Arizona Electronic Transactions Act (AETA), 86–88
ARPANET, 1970s, 55–56
Asor, Ohad, 68–69
asset management settlement use case, 38–39
asset ownership, Openchain, 214
automated testing, smart contracts, 171
Automatic Data Processing (ADP), 7
AWS (Amazon Web Services), deploying application to, 290
B
b-money (Wei Dai), 15
BaaS (Blockchain-as-a-Service), cloud platform, 13
Base58 encoded hash, IPFS objects as, 61
Berners-Lee, Tim, 57–58
best practices. See Ethereum application best practices
bets. See sample betting application; sample betting application deployment
BFT-SMaRt consensus protocol, Symbiont Assembly private blockchain, 215
BGL (block gas limit), 156–157, 235, 240, 242
BGP (Byzantine Generals Problem), 8–11
bids. See sample betting application; sample betting application deployment
Bitcoin (BTC)
blocksize and SegWit, 18–19
blocksize governance challenges, 218–220
bugs in core code, 221–222
Byzantine fault tolerance and, 10
designing, 11–13
incapable of hosting dapps, 233–234
as legal tender, 76–79
and merkle root, 19–20
and merkle trees, 21–22
mining, 17–18
overview of, 16
scripting, 22
and secure hashing, 20–21
state transition, 16–17
Bitcoin Cash, 220
Bitfury, 28
Bitland initiative, 82
BitLicense, Ripple, 22
Bitmessage, 70
BitTorrent Sync, 70
block gas limit (BGL), 156–157, 235, 240, 242
blockchain
business use cases. See business use cases
Byzantine Generals Problem vs., 9
categories of, 174–175
challenges. See challenges, blockchain; technical challenges
blockchain (cont.)
changing legal landscape, 76–79
defined, 1
fast tracking smart contract. See Ethereum, fast track application tutorial
legal ramifications of records, 81–82
mining in Ethereum, 107–108
model for IPFS, 62–63
obviating most evidentiary issues, 75
privacy laws and, 79–81
private. See private blockchain; private blockchain technology
sample application. See sample betting application
technologies, 147
technology use cases. See technology use cases
Blockchain Alliance, 30
Blockchain-as-a-Service (BaaS), cloud platform, 13
blockchain, introduction
Bitcoin. See Bitcoin (BTC)
in cloud computing, 32
collaborative implementations, 24–26
DAOs, 31–32
decentralized file storage, 30–31
Ethereum, 23–24
in financial technology space, 27
in gambling and betting, 32
and identity, 28–29
implementations, 15
as information technology, 6–8
Namecoin, 22
overview of, 1–6
and practice of law, 29–30
in real estate, 28
Ripple, 22–23
Satoshi Nakamoto breakthrough, 11–13
in sharing economy, 27–28
trust, Byzantine Generals Problem, 8–11
types of, 13–15
Blockchain Revolution (Tapscott), 29
blocks
Bitcoin fields for, 17–18
contract debugging and interaction, 244
Ethereum, 115
properties for Solidity, 132
public blockchain transaction flow, 1–2
blocksize, and Bitcoin, 18–19, 218–220
browser, running Ethereum dapps in, 138–139
BTC. See Bitcoin (BTC)
bugs, smart contract, 221–228
business use cases
currency and tokens, 33–35
digital tokens, 36–37
financial services. See financial services use cases
IoT protocol projects, 52–53
smart contracts, 46–52
C
Cakeshop, Quorum networks, 214
callable oracles, 153–154
callback, sample contract deployment, 243
cancelOpenBids private helper function, 252–253
categories, blockchain, 174–175
Cello, Hyperledger, 195
central intermediaries, removing in Web 3.0, 57
centralization bias, 108–109
centralization, Ethereum and, 110
centralized applications, dapps (decentralized applications) vs., 104
CFTC (Commodity Futures Trading Commission), 77
Chain Core, private blockchain, 177
challenges, blockchain
governance, 218–221
overview of, 217–218
technical. See technical challenges
Chaumian blinding cryptography, 15
cloud computing
blockchain and, 32
Ethereum Virtual Machine as, 147
rise of, 55
Swarm storage system, 64
trust issues with U.S., 56
Code and Other Laws of Cyberspace (Lessig), 76
code execution, EVM, 117–118, 147
“Code is law,” and blockchain, 76
coding limitations, smart contract legal issues, 87
Codius platform, Ripple, 171
collaborative implementations, blockchain, 24–26
collateral, using smart property as, 45–46
commodity, Bitcoin in U.S. deemed as, 77
communication
decentralized, 69–72
Ethereum using Whisper for, 120
compilers, Remix/browser Solidity, 140
components
Ethereum transaction, 110–111
smart contract, 83–84
Composer, Hyperledger, 195–196
concurrency, distributed computation systems, 66
confidential group communication, 69–72
consensus
Bitcoin mining, 17–18
Bitcoin state transition, 16–17
consortium blockchain and, 173
private blockchain and, 173, 175
solving trust problem, 48
consortium blockchain, 14, 174
constructor arguments, Solidity, 136–137
content addressing, IPFS nodes, 60
contract accounts, Ethereum, 105
contract addresses, handling persistent, 160–162
contract function, 138
contract-related functions, Solidity, 136
control and flow statements, Solidity, 127–128
control, smart property and, 42, 45–46
core code, bugs in Bitcoin, 221–222
CPA (cost per action/cost per acquisition), smart contract design, 88–96
CPC (cost per click), smart contract design, 88–96
createGame() function, 249–250, 268
cross-shard communication, technical challenges, 229
cryptocurrencies
blockchain as underpinning of Bitcoin, 13
definition of, 33–34
explosion of, 34
as legal tender, 76–79
role in replacing real cash, 34–35
and tokens, 33–35
top ten, 35
why blockchain works for, 33
cryptography
blockchain information technology, 6
blockchain using, 4–5
NSA deliberately weakening for spying, 56
Quorum use of, 214
Solidity and, 134–135
currency
Bitcoin advantages over fiat, 12
business use cases, 33–35
current state, Ethereum accounts in, 105
cycle time, smart contracts for faster, 40
D
DAO (decentralized autonomous organization)
blockchain in, 31–32
compliance with federal services regulation, 100
data as property and, 100
defined, 96
digital tokens, 104
and due diligence, 101
Ethereum fork and, 220
examples of, 96
and exiting contracts, 100
and intellectual property, 99–100
and jurisdiction, 97–99
legal issues, 96–97
liability, 99
overview of, 123–124
who/what is responsible and, 100
DAO hack, 220–224
dapp (decentralized application)
blockchain technology for, 148
create blockchain betting. See sample betting application
digital tokens for, 104
profile of Ethereum, 122–123
running in browser, 138–140
smart contracts implemented as, 104, 164
Swarm, 63
understanding, 233–234
Whisper use cases, 71
data
Know Your Customer use case, 37–38
layout of blockchain, 3–5
seeding in contract deployment, 266–271
data breaches
data structures, 92–93, 245–247
data types/related functions, Solidity, 128–131
Date type, 138
DBM (decentralized business model), digital currency startups, 36
DCO (derivatives clearing organization) license, 77
debugging, smart contracts, 164–165
decentralized applications, using Ethereum, 122–123
decentralized autonomous organization. See DAO (decentralized autonomous organization)
decentralized communications, 69–72
decentralized digital currency. See also Bitcoin (BTC), 15
decentralized file storage, 30–31, 148
decentralized logic, smart contracts, 148
decentralized messaging, Whisper for, 148
decentralized name registration database, Namecoin, 22
“A Declaration of the Independence of Cyberspace” (Barlow), 55
Delaware, blockchain legislation, 81, 86
delegatecall, 169–170
denial-of-service. See DoS (denial-of-service) attacks
deployment
Monax tutorial, 202–212
sample application. See sample betting application deployment
derivatives clearing organization (DCO) license, 77
development environment, set up for blockchain betting dapp, 235
DGCL (Delaware General Corporation Law), 81
DHT (distributed hash table)
Telehash, 70
digital currency startups, 36
digital fingerprint. See hashing (digital fingerprint)
digital tokens. See tokens
digitized passports, privacy protection, 79
directed acyclic graph (Merkle DAG), IPFS, 60–61, 177
directory structure
IPFS, 62
Truffle, 146
distributed computation, 2, 6–7, 66
distributed hash table. See DHT (distributed hash table)
distributed storage systems
InterPlanetary File System (IPFS), 59–62
overview of, 59
Storj, 64–65
Swarm, 62–64
DLT (distributed ledger technology)
blockchain details, 48–49
Corda as, 25–26
Hyperledger Fabric as, 24–25
legal ramifications of blockchain records, 81–82
potential of, 6
Ripple as advanced, 22–23
solving trust problem using, 48
Domus Tower, private blockchain, 177–178
DoS (denial-of-service) attacks
Bitcoin blocksize debate and, 218
blockchain technical challenges, 222–223
in Ethereum transactions, 111
IoT projects vulnerable to, 52
smart contract challenges, 171
Swarm resistance to, 64
VPN vulnerability to, 69
doSomething function, proxy contracts, 161–162
dry run using private nets, smart contracts, 167–169
due diligence, DAO and, 101
dynamically sized array types, layout of storage, 137–138
E
e-discovery software, litigation discovery, 75
ECPA (Electronic Communications Privacy Act of 1986), 55
electricity, sharing economy for, 28
Elements project, private blockchain technology, 178
encryption
Bitmessage, 70
Storj files, 65–66
enforceability, smart contract legal challenges, 86
Enigma cloud platform, 31
ENS (Ethereum Name Service) contract, bugs, 224–227
enterprise applications, smart contracts in, 164
EOAs (externally owned accounts), Ethereum, 105
EOS Project, 171
ERC20 token standard, Ethereum, 36
ether (ETH)
the cryptocurrency, 105–107
deploying to mainnet by obtaining, 266
as Ethereum tokens, 104
network fuel (gas) in Ethereum transactions, 111
Ethereum
blockchain development. See Truffle
blockchain support for Turing complete, 234
denial-of-service attacks on, 222–223
digital tokens, 36
Golem using transactions of, 67–68
governance challenges, 220–221
for smart contracts, 23–24
Swarm deep integration with, 62–64
Whisper as part of, 70–72, 120, 148
Ethereum application best practices
autopsy of wallet bug, 169–170
blockchain development. See Ethereum blockchain development
debugging smart contract, 164–165
future and, 171–172
smart contract design, 154–162
smart contract interaction, 164
smart contract life cycle/migration, 163–164
smart contract validation, 165–169
Ethereum blockchain development
best practices, 146–147
blockchain technologies, 147
calling contracts from contracts, 149–150
handling events, 151–154
setting up environment for Truffle, 145–146
Solidity basics continued, 148–149
Ethereum Classic (ETC), 220
Ethereum, fast track application tutorial
developing simple smart contract, 140–143
overview of, 125
running dapps in browser, 138–140
Solidity basics, 126–127
Solidity block/transaction properties, 132
Solidity control/flow statements, 127–128
Solidity data types, 128–131
Solidity functions/parameters, 134–137
Solidity order of operation, 133
Solidity storage layout, 137–138
Solidity visibility specifiers, 131
Ethereum Foundation, 103
Ethereum Name Service (ENS) contract, bugs, 224–227
Ethereum technology
accounts, 105–110
Bitcoin vs., 103–104
block, 115
code execution, 117–118
decentralized applications, 122–123
decentralized autonomous organizations, 123–124
ether the cryptocurrency, 105–106
infrastructure, storage and communication, 120
INFURA, 120–122
mining, 107–110
network fuel (gas), 111
obtaining ether, 106–107
scalability, 119–120
state transition function, 116–117
transactions, 110–111
Turing complete, 118–119
Ethereum Wallet, 139
events
debugging smart contracts using, 165
defining smart contract, 93
handling EVM, 151–154
sample betting application, 248
TransferOwnership, 149–150
evidence
blockchain data as, 75–76, 87–88
blockchain ledgers/systems as, 81
digital signatures as, 87–88
EVM (Ethereum Virtual Machine)
calling contracts from contracts, 149–150
denial-of-service attacks on, 222–223
halting contracts, 162
handling events, 151–154
Hyperledger Burrow as, 24–25
other blockchain technologies, 148
Solidity basics for, 148–149
understanding, 147
evolution, smart contract, 83–84
Explorer, Hyperleger, 196–197
external functions, Solidity, 131
externally owned accounts (EOAs), Ethereum, 105
F
Fabric, Hyperledger, 24–25, 180–194
Factom/Epigraph, 28
fast track application tutorial. See Ethereum, fast track application tutorial
fat clients, 56
fault tolerance
distributed computation systems, 66
Federal E-Sign Act, 87–88
Federal Rules of Criminal Procedure, Rule 41, 80
fees
mining in Ethereum using protection of, 109
smart contracts reducing, 41
fiat currencies, Bitcoin vs., 12
fields
Ethereum account, 105
Ethereum block, 115
Ethereum message, 114–115
Ethereum transaction, 110–111
IPFS objects, 60–61
fields, Bitcoin block, 17–18
file storage
blockchain decentralized, 30
Ethereum using Swarm for, 120
Filecoin, Swarm vs., 64
final state, Ethereum, 105
financial crisis of 2008, emergence of Bitcoin, 12
financial services
blockchain implementation trends, 7
blockchain technology in, 27
DAO compliance with regulations, 100
private blockchains in, 173
financial services use cases
asset management settlement, 38–39
global payments, 41–42
insurance claims processing, 38–40
Know Your Customer, 37–38
smart property, 42–43
trade finance, 40–41
transferring ownership of smart property, 43–44
using smart property as collateral, 45–46
flow statements, Solidity, 127–128
fog computing, 67
for statement, Solidity, 128
forking Bitcoin, 220
front-end user interface, deploying sample application, 271–280
functional tests, smart contract validation, 165
functions
creating game, sample betting application, 249–250
debugging smart contract, 164
defining smart contract, 92–95
handling events, 152
sample betting application, 250–259
Solidity parameters and, 134–137
Solidity visibility specifiers, 131
G
gambling, on blockchain, 32, 234–235
game. See sample betting application; sample betting application deployment
GameCreated event, 274–275
game_id, 251
GameScored event, 274–275
Garzick, Jeff, 221
gas
concept in EVM, 149–150
contract deployment, 242
Ethereum transactions, 111–114
single contract design, 156
testing smart contract, 167
gasPrice
concept in EVM, 149–150
contract debugging/interaction, 245
contract deployment, 242–243
Ethereum transactions, 111–114
Gaza Strip, blockchain land registry system, 82
GDPR (General Data Protection Regulation), EU, 79–80
getActiveGames function, 273
getGameById helper function, 251–252, 254
getGames function, 274–275, 280
Geth (Go Ethereum) command line client
application development environment, 235
deployment to mainnet, 266
DoS attacks on Ethereum and, 223
dry run using private nets, 167–169
getOpenBids contract function, 281–282
getTransactionReceipt(tx), 138, 245
GHOST (Greedy Heaviest Observed SubTree) protocol, 108–109
Git, Truffle development environment set up, 145
GitHub site, 126
global payments use case, financial services, 41–42
GNT (Golem Network Tokens), 68
Golem supercomputer, 67–68
Google Maps, immigration case, 81
governance
blockchain challenges, 218–221
DAO and jurisdiction, 97–99
law firms weak in information, 76
as risk of smart contracts, 85
use cases. See legal and governance use cases
Greek debt crisis, 12
H
Haiti, blockchain land registry system, 82
halting contracts, best practices, 162–163
halting problem, Ethereum Turing completeness and, 117–118
Hashcash puzzles, 15
hashing (digital fingerprint)
Bitcoin and Merkle tree, 19–20
Bitcoin and secure, 20–21
IPFS, 60–61
Health Insurance Portability and Accountability Act of 1996 (HIPAA/HITECH), and blockchain, 79
Hearn, Mike, 218–219
Hero of Alexandria, vending machine, 82–83
HIPAA/HITECH (Health Insurance Portability and Accountability Act of 1996), and blockchain, 79
HitPath. See smart contract design example
HydraChain, private blockchain technology, 179
Hyperledger frameworks
blockchain collaborative implementation, 24–25
blockchain support for Turing complete, 234
Hyperledger Burrow, 24–25
Hyperledger Cello, 195
Hyperledger Composer, 195–196
Hyperledger Explorer, 196–197
Hyperledger Fabric, 24–25, 180
Hyperledger Fabric tutorial, 180–194
Hyperledger Sawtooth, 24–25, 195
overview of, 179–180
private blockchain technology, 179
reference architecture, 25
I
ICO (initial coin offering), 36, 156–157
identity
blockchain and, 28–29
Know Your Customer use case, 37–38
transferring smart property ownership, 43–44
if-then-else statement, Solidity, 127
illegal monetary transactions, and Bitcoin, 78, 79
implementations, blockchain
Bitcoin. See Bitcoin (BTC)
collaborative, 24–26
Ethereum, 23–24
Namecoin, 22
Ripple, 22–23
trends, 7–8
incentive system, Swarm, 64
index.html, 271–276
information technology, blockchain, 7–8
infrastructure, Ethereum, 120
inherited functions, Solidity, 131
init helper function, wallet bug, 170
initial coin offering (ICO), 36, 156–157
initialization, Monax tutorial, 198
initWallet, wallet bug, 169–170
input element, Bitcoin transactions, 19
insurance claims processing use case, 38–40
Interbit, private blockchain technology, 197
interface
front-end user, 271–276
smart contract design, 154
intermediate layer(s), overcoming scalability, 228
internal functions, Solidity, 131
Internet, Web 1.0 and Web 2.0, 56–57
interoperability, smart contract challenges, 85
IoT (Internet of Things), 24–25, 52–53
IOTA project, future of smart contracts, 171
IP (intellectual property), DAO and, 99–100
IPFS (InterPlanetary File System)
blockchain decentralized file storage, 30
as distributed storage system, 59–62
IPNS, IPFS naming system, 60
IRS, 77–78
J
Jaguar supercomputer, 67
JUMP instruction, Ethereum Turing completeness, 118
JUMPI instruction, Ethereum Turing completeness, 118
jurisdiction
DAO and, 97–99
smart contract legal challenges, 86–87
K
kill function
contract debugging and interaction, 244
creating killable contract, 238–239
killable contract, code, 238–239
Kraken supercomputer, 67
KYC (Know Your Customer)
banking regulations require banks to, 28–29
financial services use case, 37–38
L
land registry system, blockchain, 82
large files, IPFS, 62
law
blockchain and practice of, 29–30
blockchain development challenges, 217
Electronic Communications Privacy Act of 1986, 55
lawyers, blockchain changing operations of, 74–76
layout, storage, 137–138
La`Zooz, 27–28
ledger of transactions
blockchain as distributed, 2
blockchain information technology, 6–8
public banking systems vs. Bitcoin, 12
legal and governance use cases
beginning of autonomous law. See smart contracts
blockchain and privacy laws, 79–81
blockchain changing legal landscape, 76
blockchain development challenges, 217
cryptocurrencies as legal tender, 76–79
DAOs, 96–101
overview of, 75–76
ramifications of blockchain records, 81–82
legal challenges
DAO, 96
smart contracts, 85–87
liability
smart contracts and, 87
libraries, sample contract deployment, 241
life cycle
blockchain development, 7
smart contract migration, 163–164
smart contract validation, 165
Lightning Network (for Bitcoin), 228
link fields, IPFS objects, 60–61
linked contracts, 156–157, 160
locktimes, contract deployment, 267, 268
log function, proxy contracts, 160–161
logs
events, sample betting application, 248
retrieving bets from blockchain, 282–283
lotteries, on blockchain, 234–235
M
mainnet, deploying to, 266, 290
majority voting, conensus in Quorum, 214
mapping, layout of storage, 137–138
memory, EVM code execution, 117
Merkle DAG (directed acyclic graph), 60–61, 177
Merkle tree
Bitcoin and, 19–20
for long-term sustainability, 21–22
Patricia tree combined with, 108
messages, 111–114
MetaMask
betting application user interface, 272–273, 276
deploying sample betting application to AWS, 290
developing contract, 139–140
development environment, sample betting dapp, 235
installing, 139
placing bets in betting application, 284–287
using browser for decentralized web via, 138
migration, smart contract life cycle, 163–164
mining
Bitcoin, 17–18
pools, attacks against Bitcoin, 78
as validation/verification/committing process, 34
MLATs (Mutual Legal Assistance Treaties), 79–80
modules, smart contract design best practices, 154
Monax, private blockchain technology, 197–213
monetary policy, Bitcoin, 77
money laundering, 78–79
money transfers, Ripple for, 23
money, using blockchain for, 5
MongoDB, bugs in Bitcoin core code, 222
MultiChain, private blockchain technology, 213
Mutual Legal Assistance Treaties (MLATs), 79–80
N
Nakamoto, Satoshi, 11–13, 16, 218
name registration database, Namecoin as decentralized, 22
Namecoin, 22
National Security Agency (NSA), wiretaps on user data, 55–56
Nebulae supercomputer, 67
negotiation rights, smart property, 42–43
Netflix, 40 percent of all Internet traffic, 55
Nethereum package monitoring, EVM events, 151–152
network fuel (gas), Ethereum transactions, 111–114
network-of-blockchain solutions, scalability challenges, 228–229
nodes
Bitcoin and Merkle tree, 19–20
IPFS, 59–60
scalability of Ethereum platform, 119–120
syncing Ethereum, sample betting dapp, 235–236
nonce (random number)
Ethereum transactions, 111
transferring ownership for smart property, 43–44
normal accounts, Ethereum, 105
normal life cycle flow tests, smart contract validation, 165
notHalted modifier, halting contracts, 162
NSA (National Security Agency), wiretaps on user data, 55–56
O
ObjectTech, 79–81
Onename, 28
The Onion Router (TOR), 70, 80–81
open source revolution, blockchain vs., 7–8
Openchain, private blockchain technology, 214
OpenZeppelin module, smart contract design, 154
operations
blockchain has only two, 1
order of Solidity, 132–133
oracles (data providers), 38, 153–154
output element, Bitcoin transactions, 19
overflow attacks, smart contract validation, 166
ownership
DAO legal issues, 96
legal ramifications of blockchain records, 81–82
smart property and, 42–46
Solidity best practices for Ethereum, 148–149
P
p2p (peer-to-peer) technology
Bitcoin/Ethereum and, 56
defined, 4
emergence of Bitcoin, 12
lodging sites, 28
public blockchain as, 4
swarm, IPFS content addressing, 60
pages, front-end user interface, 271
parameters, game, 250
Parity, 167–170
parseBids helper function, 269–270, 281–282
passwords
contract debugging/interaction, 244
no central authority managing in blockchain, 4
sample contract deployment, 242–243
seeding data in contract deployment, 269
payable functions, sample betting application, 249
payments infrastructure, Stellar, 215
payouts, betting sample application, 259–260
PC (personal-computer) revolution, 55
performance, smart contracts and, 85
persistence, Swarm for, 120
persistent contract addresses, best practices, 160–162
Place Bet button, 283–284
Pneumatika (Hero of Alexandria), vending machine, 83
POE (“proof of existence”), and blockchain, 29
Poloniex, Ethereum DAO fork and, 220
portability, 197
PoS (proof-of-stake) mining algorithm, 16, 120, 221
post-genesis block, ether (ETH) issuance model, 106–107
PoW (proof-of-work)
emergence of Bitcoin, 12
Ethereum scalability and, 120
HydraChain and, 179
overview of, 16
PPSS (private peer sampling service), Whisper, 72
privacy
driving blockchain design, 217
future of smart contracts for absolute, 171
Interbit private blockchain technology, 197
laws, and blockchain, 79–81
private blockchain advantages, 175
private blockchain
creating/configuring for development, 237–238
private blockchain technology
AlphaPoint Distributed Ledger Platform, 176–177
Chain Core, 177
Corda, 177
Domus Tower, 177–178
Elements Core, 178
HydraChain, 179
Hyperledger, 179
Hyperledger Fabric tutorial, 180–194
Hyperledger frameworks, 179–180
Hyperledger Iroha, 194
Hyperledger Sawtooth, 195
Hyperledger tools, 195–197
Interbit, 197
Monax, 197–198
Monax tutorial, 198–213
MultiChain, 213
Openchain, 214
Quorum, 214
Stellar, 215
Symbiont Assembly, 215
private functions, Solidity, 131
private key, cryptography, 4–5
private peer sampling service (PPSS), Whisper, 72
promises, 272–274
“proof of existence” (POE), and blockchain, 29
proof-of-stake (PoS) mining algorithm, 16, 120, 221
proof-of-work. See POW (proof-of-work)
properties, Solidity block/transaction, 132
property
DAO data as, 100
virtual currencies taxed as, 77
Provenance, 29
proxy contracts, 160–162
public blockchain
comparing blockchains, 14–15
defined, 174
overview of, 13
scalability challenge of, 228
transaction flow, 1–2
what is different about, 3–4
public functions, 131, 248–250
public key cryptography, 60, 70
Q
Qm, all hashes begin with, 61
Quorum, private blockchain technology, 214
R
random sampling, blockchain security, 231–232
read permission, private blockchain use cases, 175
reading, sample betting application, 261–263, 266
real cash, cryptocurrencies replacing, 34–35
real estate, blockchain and, 28
recording transactions, and scalability, 228
records, legal ramifications of blockchain, 81–82
reentrancy exploit, 166–167
registration, Monax tutorial, 198
regulations
challenges of blockchain development, 217
DAO compliance with financial services, 100
reinjection vulnerability, DAO hack, 223
Republic of Georgia, blockchain land registry, 82
resource sharing, distributed computation systems, 66
responsibility, liability of DAOs, 100
“right to be forgotten” laws, European privacy laws, 79
risk
DAO liability for, 99
legal contract, 5–6
smart contract, 85
Ropsten test network, 130
S
S3 console, deploying sample application to AWS, 290
sample betting application
bidding, 250–259
compiling contract, 240
contract debugging/interaction, 243–246
creating/configuring private development chain, 237–238
creating game, 249–250
creating killable contract, 238–239
defining data structures, 246–247
deploying contract, 240–243
deployment. See sample betting application deployment
development environment set up, 236
enumerables, 247
events, 248
lotteries/betting/gambling, 234–235
reading bids, 261–263
reading games, 261
scoring games and payouts, 259–260
storage variables, 247–248
syncing Ethereum Node, 236–237
understanding dapp, 233–234
withdrawing, 260–261
sample betting application deployment
bet page markup, 277–280
deploying full contract, 265–266
deploying to AWS, 290
deploying to mainnet, 266
displaying bets, 282–283
displaying game information, 280
displaying open bids, 281–282
front-end user interface, 271–276
placing bids/bets, 283–287
scoring games, 287–288
seeding data, 266–271
withdrawing money, 288–289
Sawtooth, Hyperledger, 24–25, 195
scalability
Bitcoin/Merkle tree and, 21–22
blockchain challenges, 228–229
distributed computation systems and, 66
Ethereum challenges, 119–120, 221
Interbit private blockchain technology and, 197
SegWit improving Bitcoin, 19
scalability (cont.)
smart contract challenges, 85, 171
schema, Bitcoin blockchain, 17–18
scoring games, 259–260, 279–280, 287–288
SCP (Stellar Consensus Protocol), 215
scripting
Bitcoin, 22
contract debugging/interaction, 243–245
seeding data in contract deployment, 266–271
SDLC (software development life cycle), and separate ledgers, 173
SEC (Securities and Exchange Commission), sale of DAO tokens, 96–97
second-layer solutions, scalability, 228
secure hash algorithm (SHA), 19–21
secure hashing, and Bitcoin, 20–21
Securities and Exchange Commission (SEC), and DAO tokens, 96–97
Securities and Exchange Commission (SEC) v. W. J. Howey Co (1946), 36–37
security
blockchain design driven by, 217
bugs in core code, 221–222
cryptography for, 4–5
DAO and jurisdiction, 97–99
denial-of-service attacks and, 222–223
distributed computation systems, 66
issues on VPN gateways, 69–70
smart contract, 84, 155–156, 223–228
Storj advantages, 65–66
via random sampling, 231–232
seeding data, contract deployment, 266–271
SegWit (Segregated Witness), 18–19, 178
self-sovereign identity, digitized passports, 79
selfdestruct function, killable contracts, 239
server monitor, as oracle, 153–154
service-level liability, DAO, 99
setGameResult function, 287–288
SHA (secure hash algorithm), 19–21
ShapeShift.io, 29
sharding
blockchain challenges, 229–231
Ethereum challenges to allow, 221
storing encrypted Storj files, 65–66
sharing economy, blockchain in, 27–28
simplified payment verification (SPV) nodes, Ethereum scalability, 120
single contract design
difficulting of managing, 156
linked contracts vs., 156–157
small files, IPFS, 61–62
smart contract design, best practices
halting contracts, 162–163
handling persistent contract addresses, 160–162
linked contracts, 156–157
modules and interfaces, 154
security and roles, 155–156
single contract design, 156
user-specific contracts, 158–160
smart contract design example
defining data structures, 92–93
events, 93
functions, 93–95
overview of, 88–89
in practice, 95–96
using blockchain for advertiser payment application, 89–92
smart contract mediator (SCM), 29
smart contracts
blockchain and practice of law, 29–30
blockchain details, 48–49
blockchain for decentralized logic, 148
DAO and. See DAO (decentralized autonomous organization)
defined, 6
deploying to test chain. See sample betting application deployment
deployment, 141–142
developing simple, 140–141
development steps for writing. See sample betting application
example of, 50–52
fast-tracking to Ethereum blockchain. See Ethereum, fast track application tutorial
insurance claim processing use case, 39–40
monitoring changes with events, 151
sample application. See sample betting application
security, 223–224
smart property extending, 42–46
trade finance (supply chain) use case, 40–41
trust problem with, 46–48
using Ethereum for, 23–24
validating, 142–143
smart contracts, best practices
debugging, 164–165
interaction with uses/enterprise applications, 164
life cycle/migration, 163–164
validation, 165–169
smart contracts, legal use cases
as beginning of autonomous law, 82–83
benefits of, 84
blockchain as evidence/digital signatures, 87–88
challenges of, 85
components, 83–84
design example, 88–95
evolution of, 83–84
legal challenges of, 85–87
in practice, 95–96
risks of, 85
smart property, 42–46
Snowden, Edward, 55
Society for Worldwide Interbank Financial Telecommunication (SWIFT), 28–29
software development life cycle (SDLC), and separate ledgers, 173
Solidity compiler, sample betting application, 234–236, 240
Solidity programming language
basics, 126–127
block and transaction properties, 132
contract debugging and interaction, 244
control and flow statements, 127–128
creating killable contract, 238–239
data types, 128–131
defining data structures, 245–247
Ethereum application best practices, 148–149
functions and parameters, 134–137
order of operation, 133
storage layout, 137–138
visibility specifiers, 131
writing smart contracts with, 125
spacecraft, 10
SpaceX Dragon flight system, 10
Split DAO() function, DAO hack, 223–224
SPV (simplified payment verification) nodes, Ethereum scalability, 120
stack, EVM code execution, 117
stack structure, bids, 254–259
stale blocks, using GHOST for, 108–109
state channels, scalability, 228
state, Ethereum and, 105, 107–108
state transition function (STF), Ethereum, 116–117
state transition system, Bitcoin, 16–18
Stellar Consensus Protocol (SCP), 215
Stellar, private blockchain technology, 215
STF (state transition function), Ethereum, 116–117
storage
distributed. See distributed storage systems
Ethereum technology for, 120
EVM code execution, 117
layout in Ethereum, 137–138
variables, sample betting application, 247–248
Storj, distributed storage system, 65–66
supercomputers, 67–69
SWIFT (Society for Worldwide Interbank Financial Telecommunication), 28–29
Sybil attacks, proof-of-work preventing, 16
Symbiont Assembly, private blockchain technology, 215
Szabo, Nick, 82
T
taxation, virtual currencies and, 77–78
technical challenges
bugs in core code, 221–222
denial-of-service attacks, 222–223
scalability, 228–229
security in smart contracts, 223–228
sharding, 229–231
technology
Ethereum. See Ethereum technology
information, 6–8
technology use cases
decentralized communications, 69–72
distributed computation, 66
distributed storage systems. See distributed storage systems
Golem, 67–68
overview of, 55–56
Web 3.0 technology stack, 72–73
Zennet, 68–69
Telehash, 70
testing
full contract, 265–266
Monax tutorial, 202–212
sample appliction deployment, 285–288
smart contract validation, 165–169
smart contracts lagging in automated, 171
TestRPC, Truffle development environment set up, 146
“The Truth About Blockchain,” (Iansiti/Lakhani), 101
throw keyword, 252
time, global blockchain payment technologies and, 41
timestamps, transaction, 12
title searching, blockchain and real estate, 28
tokens
Ethereum using ether, 104
Golem Network Tokens, 68
legal issues on sale of DAO, 96–97
overview of, 36–37
why blockchain works for, 33
tools, Hyperledger, 195–197
TOR (The Onion Router), 70, 80–81
trade finance (supply chain) use case, 40–41
transaction-based state machine, Ethereum as, 105
transaction list, mining in Ethereum, 107–108
transactions
Bitcoin and Merkle tree, 19–20
Bitcoin blocksize and fees for, 218–220
Bitcoin pseudonymous, 78
transactions (cont.)
elements of Bitcoin, 18–19
Ethereum, 110–114
flow of Bitcoin, 16–17
flow of blockchain, 1–2
programming ledger to trigger automatic, 2
properties for Solidity, 132
transferring ownership for smart property, 43–44
transfer function, smart contract life cycle/migration, 163–164
TransferOwnership event, 149–151
transferOwnership function, Solidity, 148–149
transparency
of distributed computation systems, 66
of global blockchain payment technologies, 41
legal challenge of smart contracts, 86
trigger-based oracles, 153–154
trust
Byzantine Generals Problem and, 8–11
smart contracts and, 46–48, 163–164
U.S. cloud industry and, 55
Turing complete language
blockchains supporting dapps and, 234
overview of, 118–119
Solidity is, 126
U
Uber, La`Zooz vs., 27–28
underBids array, sample betting application, 253–255
underflow attacks, smart contracts, 166
United States v. Lizarraga-Tirado, 81
UNIX timestamp, 138
“upload and disappear,” Swarm, 64
use cases
business. See business use cases
legal and governance. See legal and governance use cases
private blockchains, 175–176
technology. See technology use cases
user interface, deploying sample betting contract, 271–273
users
smart contract interaction with, 164
user-specific contracts, 158–160
UTXOs (unspent transaction outputs), Bitcoin, 16–17, 21–22
V
Vagrant installation, Monax tutorial, 198–213
validation
sample betting application, 255
value, concept in EVM environment, 149–150
Value field, Ethereum transactions, 111
variables
sample betting application, 247–248
specifying in function definition, 249
visibility in Solidity, 131
VDice, decentralized gambling platform, 31
vending machines, smart contracts and, 82–83
versioned file systems, IPFS, 62
view transaction, blockchain processing, 1
visibility specifiers, Solidity, 131
Voorhees, Erik, 11–12
VPNs (virtual private networks), 69, 80
vulnerability tests, smart contract validation, 165
W
wallet address
deploying to mainnet by creating, 266
placing bets in betting application, 283–285
seeding data in contract deployment, 268
withdrawing money in betting application, 289
Washington, George, 10–11
WCL (Whisper communication layer), 71–72
Web 3.0
data storage challenges. See distributed storage systems
enabling decentralized web, 138
evolution of Web to, 57–59
solving trust problem, 47
technology stack, 72–73
web3.js, 241–243
while statement, Solidity, 127
Whisper, decentralized communications, 70–72, 120, 148
whitelisted addresses, smart contract design, 155
withdraw.html, sample betting application, 271–273
withdrawing money, sample betting application, 260–261, 288–289
Wright, Craig Steven, 12
X
Y
Yellen, Janet, 76
Z
Zamfir, Vlad, 221
Zennet, 68–69
“zero-client” gateway, 138