Building the Web 3.0 with Node.js

1. O C T O B E R 2 7 , 2 0 1 7
C O N F I D E N T I A L
Node.js and Blockchain
Building the Web 3.0 with Node.js

2. October 27, 2017
Julián Duque
Developer and Educator / Community Organizer / Engineer
@julian_duque

3. October 27, 2017
Julián Duque
Not a Crypto Expert / Not here for Crypto Currencies (or ICOs)
@julian_duque

4. © 2017 NodeSource C O N F I D E N T I A L
What is Blockchain?
📦⛓
4

5. © 2017 NodeSource C O N F I D E N T I A L5
Hashes
hash(‘😀’) = 2a02ea…7b6
hash(‘😃’) = e36f86…028
hash(‘Hola’) = f688ae…22e
hash(‘Hola!’) = 0676dc…06f

6. © 2017 NodeSource C O N F I D E N T I A L6
Merkle Trees
binary hash tree
Image credit: Wikipedia

7. © 2017 NodeSource C O N F I D E N T I A L7
Blockchains
• Continuously growing, append only, list of records
(blocks)
• Distributed Ledger Technology (DLT)
• Linked and secured using cryptography

8. © 2017 NodeSource C O N F I D E N T I A L8
Blockchains
Image credit: Wikipedia

9. © 2017 NodeSource C O N F I D E N T I A L9
Blockchain Immutability
Image credit: edX - Hyperledger Course

10. © 2017 NodeSource C O N F I D E N T I A L10
Reaching Consensus
Proof of Work
• Blocks are added to the ledger gradually
• People (nodes) take turns to add blocks
• Root checksum must start with a number of zeroes (difficulty, conditions)
• Block includes a nonsense (nonce) that can be changed to create new
checksums
• Difficulty is adjusted to target desired time between blocks (control)

11. © 2017 NodeSource C O N F I D E N T I A L11
Reaching Consensus
Incentives
• Miner (node) who find a new block gets a reward
• Reward is used as currency and to pay transaction fees
• Miners also get transaction fees along with the reward
• Encourage miners to process blocks with transactions (Game theory)
• Encourage users to pay transaction fees depending on urgency

12. © 2017 NodeSource C O N F I D E N T I A L
Public vs Private
12

13. C O N F I D E N T I A L© 2017 NodeSource13

14. © 2017 NodeSource C O N F I D E N T I A L14
Bitcoin
• Crypto Currency (BTC)
• Transfer value from address to address (wallet
to wallet)
• Scripting Language - Turing-Incomplete
• Consensus Algorithm: Proof of Work

15. C O N F I D E N T I A L© 2017 NodeSource15

16. © 2017 NodeSource C O N F I D E N T I A L16
Ethereum
• Virtual Machine (EVM)
• Usage is metered by transaction fees (gas)
• Crypto Currency (ether - ETH)
• Transactions manipulate state
• EVM is Turing-Complete
• Consensus Algorithm: Proof of Work, moving to Proof
of Stake

17. C O N F I D E N T I A L© 2017 NodeSource17

18. C O N F I D E N T I A L© 2017 NodeSource18
Hyperledger
• Umbrella of Open Source projects
• Focused on Business / Permissioned Blockchains
• No crypto currency
• Consensus algorithms: Depending of Project (PoET,
PFBT)
• Some projects are EVM compatible, others have they
own VM

19. © 2017 NodeSource C O N F I D E N T I A L
Why Node.js?
19

20. © 2017 NodeSource C O N F I D E N T I A L20
Why Node.js?
• JavaScript: Language of the web
• Great for building tools
• Great as API / Frontend layer

21. © 2017 NodeSource C O N F I D E N T I A L
Develop Blockchain Applications
21

22. © 2017 NodeSource C O N F I D E N T I A L
BitcoinJS
22

23. © 2017 NodeSource C O N F I D E N T I A L23
BitcoinJS
https://bitcoinjs.org
• Create / Interact with Bitcoin wallets
• Transactions
• Crypto operations

24. © 2017 NodeSource C O N F I D E N T I A L
EthereumJS
24

25. © 2017 NodeSource C O N F I D E N T I A L25
EthereumJS
https://ethereumjs.github.io
• Collection of libraries and utilities for
Ethereum
• Always looking for contributors

26. © 2017 NodeSource C O N F I D E N T I A L
Smart Contracts
26

27. © 2017 NodeSource C O N F I D E N T I A L27
Smart Contracts
• Applications that can be deployed to the
Blockchain (Ethereum / Hyperledger)
• Takes care of State in Blockchain
• Defines and enforces the rules and
penalties around an agreement

28. © 2017 NodeSource C O N F I D E N T I A L
Solidity
28

29. © 2017 NodeSource C O N F I D E N T I A L29
Solidity
• High level language to build Smart
Contracts for Ethereum
• Typed Language
• Based on JavaScript
• Compiled to EVM

30. © 2017 NodeSource C O N F I D E N T I A L30
Solidity
pragma solidity ^0.4.11;
contract HelloWorld {
uint public balance;
address public owner;
function HelloWorld() public {
owner = msg.sender;
balance = 0;
}
function update() public payable isOwner() {
balance = msg.value;
}
modifier isOwner() {
require(msg.sender == owner);
_;
}
}

31. © 2017 NodeSource C O N F I D E N T I A L31
Solidity
$ npm install -g solc

32. © 2017 NodeSource C O N F I D E N T I A L32

33. © 2017 NodeSource C O N F I D E N T I A L33
Truffle
• Framework to build, test and deploy
Smart Contracts
• Test Smart Contracts with JavaScript
• Project generators for ĐApps

34. © 2017 NodeSource C O N F I D E N T I A L34
Truffle
$ npm install -g truffle

35. © 2017 NodeSource C O N F I D E N T I A L
ĐApps
35

36. © 2017 NodeSource C O N F I D E N T I A L36
ĐApps
https://www.stateofthedapps.com
• Web 3.0 - Decentralized Applications
• Interact with Smart Contracts using backend-
less JavaScript Applications
• Bitcoin: The first ĐApp

37. © 2017 NodeSource C O N F I D E N T I A L
MetaMask
37

38. © 2017 NodeSource C O N F I D E N T I A L38
MetaMask
https://www.metamask.io
• Brings Ethereum to your Browser
• Perfect for running ĐApps
• No need to have a full node running

39. © 2017 NodeSource C O N F I D E N T I A L
Hyperledger Composer
39

40. © 2017 NodeSource C O N F I D E N T I A L40
Hyperledger Composer
https://hyperledger.github.io/composer/
• Build private Blockchain Applications and Business Networks
• Build Smart Contracts with a model language
• Generate REST APIs
• Node.js modules (composer-client) to interact with your network

41. © 2017 NodeSource C O N F I D E N T I A L41

42. © 2017 NodeSource C O N F I D E N T I A L42
Blockstack
https://blockstack.org
• Build decentralized applications with JavaScript (BlockstackJS)
• Virtualchain: An existing Blockchain extension

43. © 2017 NodeSource C O N F I D E N T I A L
Demo
https://julianduque.github.io/simple-vote/
43

44. C O N F I D E N T I A L
Thank you!
Julián Duque
julian@nodesource.com
@julian_duque