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スマートコントラクトデザイン / Smart Contract Design

スマートコントラクトデザイン / Smart Contract Design

2022年11月7日(月)、慶應義塾大学大学院メディアデザイン研究科「サービスデザインプロジェクト B」2022秋で使用したスライドです。

Kenji Saito
PRO

November 07, 2022
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  1. Service Design, generated by Stable Diffusion B 2022 4 (

    ) B 2022 — 4 — 2022-11-07 – p.1/74
  2. https://speakerdeck.com/ks91 ( ) ( ) Discord Discord ( / /

    ) Zoom URL ( ) ( ) B 2022 — 4 — 2022-11-07 – p.2/74
  3. ( ) 1 10 17 • 2 10 24 •

    3 10 31 • 4 11 7 • 5 11 14 1 6 11 21 2 7 11 28 8 12 5 ( ) 4 ( 3 ) ↓ B 2022 — 4 — 2022-11-07 – p.3/74
  4. Ethereum ( ) (1) : ERC20 (2) : (3) :

    Web3 B 2022 — 4 — 2022-11-07 – p.4/74
  5. Ethereum ( ) macOS (Monterey 12.6) + Homebrew Linux (Ubuntu

    22.04) (x86/AMD64 and ARM) Windows 10/11 + Windows Subsystem for Linux (Ubuntu ) Ethereum solidity brownie B 2022 — 4 — 2022-11-07 – p.5/74
  6. Solidity Ethereum ( ) http://solidity.readthedocs.io/en/latest/installing-solidity.html Linux (on Windows) “sudo apt”,

    macOS “brew” Linux ARM git clone dependencies solc 0.8.17 (10/31 ) $ solc --version brownie py-solc-x solc (dependencies) ( solc py-solc-x ) B 2022 — 4 — 2022-11-07 – p.6/74
  7. Ganache Ethereum RPC npm ( ) macOS https://qiita.com/kyosuke5_20/items/c5f68fc9d89b84c0df09 Linux https://qiita.com/seibe/items/36cef7df85fe2cefa3ea

    npm Ganache $ sudo npm install -g ganache B 2022 — 4 — 2022-11-07 – p.7/74
  8. Python3 macOS $ brew install python3 Python 3.8 Homebrew $

    brew uninstall --ignore-dependencies [email protected] $ brew install [email protected] /usr/local/opt/[email protected]/bin/python3 Linux $ sudo apt update $ sudo apt install python3.8 python3.8-dev python3.8-venv python3.8-tk 16.10 python3(.8) apt (PPA ) python3 python3-dev python3-venv python3-tk B 2022 — 4 — 2022-11-07 – p.8/74
  9. macOS : . . . macOS wget brew dyld: Library

    not loaded: /usr/local/opt/gettext/lib/libintl.8.dylib $ brew uninstall --force gettext $ brew install gettext B 2022 — 4 — 2022-11-07 – p.9/74
  10. Python (venv) macOS (Linux python3 ) ‘python3.8’ ‘python3’ $ python3.8

    -m venv bbc1env $ source bbc1env/bin/activate (bbc1env) $ pip install -U pip (bbc1env) $ pip install wheel bbc1env ( BBc-1 ) ( ) (bbc1env) $ deactivate B 2022 — 4 — 2022-11-07 – p.10/74
  11. Brownie Python Ethereum https://eth-brownie.readthedocs.io Brownie $ pip install eth-brownie version

    1.19.2 (10/31 ) B 2022 — 4 — 2022-11-07 – p.11/74
  12. $ brownie init ( ERC-20 ) $ brownie bake token

    $ cd token B 2022 — 4 — 2022-11-07 – p.12/74
  13. contracts (macOS Linux (x86/AMD64) ) $ brownie compile Linux (ARM)

    (AMD64 ) $ python # >>> import solcx >>> solcx.compile_solc(’0.6.12’) # >>> quit() /tmp ∼/.solcx/solc-v0.6.12 ( ) $ pytest tests B 2022 — 4 — 2022-11-07 – p.13/74
  14. Brownie $ brownie console Python >>> len(accounts) 10 >>> accounts[0].balance()

    100000000000000000000 >>> quit() B 2022 — 4 — 2022-11-07 – p.14/74
  15. ( ) 10 Ethereum Görli 11 B 2022 — 4

    — 2022-11-07 – p.15/74
  16. infura.io Brownie https://infura.io SIGN UP PROJECT ID infura Ethereum API

    infura . . . infura.io PROJECT ID WEB3_INFURA_PROJECT_ID PROJECT ID (∼/.bash_profile ) $ export WEB3_INFURA_PROJECT_ID= PROJECT ID B 2022 — 4 — 2022-11-07 – p.16/74
  17. G¨ orli ETH brownie console Görli >>> network.disconnect() >>> network.connect(’goerli’)

    >>> len(accounts) 0 >>> accounts.add() <LocalAccount object ’ 16 ’> >>> accounts[0].private_key 16 >>> quit() Görli Testnet ETH Faucet ETH https://goerlifaucet.com ( ) ( ) https://metamask.io/ B 2022 — 4 — 2022-11-07 – p.17/74
  18. G¨ orli ETH brownie console Görli ETH >>> network.disconnect() >>>

    network.connect(’goerli’) >>> len(accounts) 0 >>> accounts.add( 16 ) <LocalAccount object ’ 16 ’> >>> accounts[0].balace() ETH >>> quit() ETH >>> accounts[0].transfer(accounts[1], "0.01 ether") B 2022 — 4 — 2022-11-07 – p.18/74
  19. Ethereum ( ) B 2022 — 4 — 2022-11-07 –

    p.19/74
  20. Ethereum Vitalik Buterin, “Ethereum White Paper: A NEXT GENERATION SMART

    CONTRACT & DECENTRALIZED APPLICATION PLATFORM” 12 (= ) = ⇒ → Dapps ( / / ) B 2022 — 4 — 2022-11-07 – p.20/74
  21. ( ) B 2022 — 4 — 2022-11-07 – p.21/74

  22. . . . B 2022 — 4 — 2022-11-07 –

    p.22/74
  23. vs. B 2022 — 4 — 2022-11-07 – p.23/74

  24. = run B 2022 — 4 — 2022-11-07 – p.24/74

  25. Ether Ethereum EOA : Externally-Owned Account ( ) Ether EVM

    EVM B 2022 — 4 — 2022-11-07 – p.25/74
  26. EVM : Ethereum Virtual Machine Gas ( EVM = (

    burn)) . . . B 2022 — 4 — 2022-11-07 – p.26/74
  27. EVM : : ← : Solidity — JavaScript LLL —

    Lisp Vyper — Python Fe — Vyper Rust ← NEW! Solidity Vyper Python B 2022 — 4 — 2022-11-07 – p.27/74
  28. Solidity ( ) pragma solidityˆ0.7.0; contract IndivisibleAsset { /* */

    string public _name; string public _symbol; uint256 public _quantity; address public _owner; constructor(string memory name, string memory symbol, uint256 quantity) public { _name = name; _symbol = symbol; _quantity = quantity; _owner = msg.sender; } function transfer(address to) public returns (bool) { require (_owner == msg.sender); _owner = to; return true; } } B 2022 — 4 — 2022-11-07 – p.28/74
  29. ( , ) (constructor) (deploy) = ( ) ( )

    ETH Trusted Actor Model B 2022 — 4 — 2022-11-07 – p.29/74
  30. Ethereum B 2022 — 4 — 2022-11-07 – p.30/74

  31. (1) : ERC20 $ brownie bake token B 2022 —

    4 — 2022-11-07 – p.31/74
  32. Solidity JavaScript ( , ) (constructor) ( ) ( )

    Ether Ethereum B 2022 — 4 — 2022-11-07 – p.32/74
  33. pragma solidity ˆ0.6.0; /* 0.8.x */ contract Token { (

    ) : (EVM ) : constructor (...) public { /* */ : } function balanceOf(...) { /* ( ) */ : } : } constructor C (/* */ // ) B 2022 — 4 — 2022-11-07 – p.33/74
  34. ERC20 ERC (Ethereum Request for Comment) 20 https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md contract ERC20

    { function totalSupply() constant returns (uint totalSupply); function balanceOf(address _owner) constant returns (uint balance); function transfer(address _to, uint _value) returns (bool success); function transferFrom(address _from, address _to, uint _value) returns (bool success); function approve(address _spender, uint _value) returns (bool success); function allowance(address _owner, address _spender) constant returns (uint remaining); event Transfer(address indexed _from, address indexed _to, uint _value); event Approval(address indexed _owner, address indexed _spender, uint _value); } name/ , symbol/ , decimals/ approve allowance ERC-777 ( ) B 2022 — 4 — 2022-11-07 – p.34/74
  35. ERC20 ERC20 ( ) ⇒ ERC20 ( ERC20 ) ERC20

    ⇒ B 2022 — 4 — 2022-11-07 – p.35/74
  36. (fungible) ERC-20 → ERC-223 (draft) or ERC-777 ( )( )

    (non-fungible) ERC-721 ( ) ERC-1155 ( ) ERC-3525 (SLOT ) B 2022 — 4 — 2022-11-07 – p.36/74
  37. Token ( ) string public symbol; string public name; uint256

    public decimals; uint256 public totalSupply; mapping(address => uint256) balances; . . . name, symbol decimals : 2 100 1.00 mapping balances B 2022 — 4 — 2022-11-07 – p.37/74
  38. Token ( ) event Transfer(address from, address to, uint256 value);

    Token function emit Transfer() ( ) B 2022 — 4 — 2022-11-07 – p.38/74
  39. Token ( ) constructor( string memory _symbol, string memory _name,

    uint256 _decimals, uint256 _totalSupply ) public { symbol = _symbol; name = _name; decimals = _decimals; totalSupply = _totalSupply; balances[msg.sender] = _totalSupply; } msg.sender _totalSupply B 2022 — 4 — 2022-11-07 – p.39/74
  40. Token balanceOf() function balanceOf(address _owner) public view returns (uint256) {

    return balances[_owner]; } B 2022 — 4 — 2022-11-07 – p.40/74
  41. Token transfer() function transfer(address _to, uint256 _value) public returns (bool)

    { balances[msg.sender] = balances[msg.sender].sub(_value); balances[_to] = balances[_to].add(_value); emit Transfer(msg.sender, _to, _value); return true; } ( ↑ ) OpenZeppelin https://openzeppelin.org B 2022 — 4 — 2022-11-07 – p.41/74
  42. (2) : B 2022 — 4 — 2022-11-07 – p.42/74

  43. GitHub git clone $ git clone https://github.com/ks91/sample-smart-contracts.git sample-smart-contracts contracts, scripts

    tests token Token Solidity 0.5 0.6/0.7 (Token ) Solidity B 2022 — 4 — 2022-11-07 – p.43/74
  44. (m2 ) 1 1 B 2022 — 4 — 2022-11-07

    – p.44/74
  45. IndivisibleAsset string public _name_; string public _symbol_; uint256 public _quantity_;

    address public _owner_; _name_ ( ) _symbol_ _quantity_ (m2 ) _owner_ ‘_’ Solidity . . . B 2022 — 4 — 2022-11-07 – p.45/74
  46. IndivisibleAsset event Transfer(address indexed from, address indexed to); from to

    indexed B 2022 — 4 — 2022-11-07 – p.46/74
  47. IndivisibleAsset constructor (string name, string symbol, uint256 quantity) public {

    _name_ = name; _symbol_ = symbol; _quantity_ = quantity; _owner_ = msg.sender; } B 2022 — 4 — 2022-11-07 – p.47/74
  48. IndivisibleAsset getOwner() function getOwner() public view returns (address) { return

    (_owner_); } B 2022 — 4 — 2022-11-07 – p.48/74
  49. IndivisibleAsset transfer() function transfer(address to) public returns (bool) { require(_owner_

    == msg.sender); _owner_ = to; emit Transfer(msg.sender, to); return true; } require (function ) ( ) $ brownie compile B 2022 — 4 — 2022-11-07 – p.49/74
  50. scripts/indivisible asset.py from brownie import * def main(): accounts[0].deploy(IndivisibleAsset, "5322

    Endo, Fujisawa", "mˆ2", 300) SFC (300m2 ) ( ) B 2022 — 4 — 2022-11-07 – p.50/74
  51. from brownie import * import pytest def test_owner_and_transfer(IndivisibleAsset): asset =

    accounts[0].deploy(IndivisibleAsset, "5322 Endo", "mˆ2", 300) assert asset.getOwner() == accounts[0] asset.transfer(accounts[1], {’from’: accounts[0]}) assert asset.getOwner() == accounts[1] try: asset.transfer(accounts[0], {’from’: accounts[0]}) done = 1 except: done = 0 assert done == 0 accounts[0] accounts[1] B 2022 — 4 — 2022-11-07 – p.51/74
  52. $ pytest tests/test_indivisible_asset.py B 2022 — 4 — 2022-11-07 –

    p.52/74
  53. (3) : B 2022 — 4 — 2022-11-07 – p.53/74

  54. transfer settle, retrieve asset, retrieve token 3 B 2022 —

    4 — 2022-11-07 – p.54/74
  55. 1. ( ) 2. ( ) 3. ( ) B

    2022 — 4 — 2022-11-07 – p.55/74
  56. OneTimeEscrow settle() function settle() public returns (bool) { require(_token_.balanceOf(address(this)) >=

    _price_); /* this */ require(_asset_.getOwner() == address(this)); _token_.transfer(_seller_ , _price_); _asset_.transfer(_buyer_); emit Settled(); /* */ return true; } settle() transfer ( / ) $ brownie compile B 2022 — 4 — 2022-11-07 – p.56/74
  57. (1) from brownie import * import pytest def test_deploy_and_settle(Token, IndivisibleAsset,

    OneTimeEscrow): asset = accounts[0].deploy(IndivisibleAsset, "5322 Endo", "mˆ2", 300) token = accounts[0].deploy(Token, "Test Token", "TEST", 18, "1000 ether") B 2022 — 4 — 2022-11-07 – p.57/74
  58. (2) token.transfer(accounts[1], 300, {’from’: accounts[0]}) escrow = accounts[0].deploy(OneTimeEscrow, token, accounts[1],

    asset, accounts[0], 300) accounts[0] accounts[1] 300 300 TX accounts[1] accounts[0] 300 bake Token 300 ETH wei B 2022 — 4 — 2022-11-07 – p.58/74
  59. (3) token.transfer(escrow, 300, {’from’: accounts[1]}) asset.transfer(escrow, {’from’: accounts[0]}) assert token.balanceOf(accounts[0])

    == 999999999999999999700 assert token.balanceOf(accounts[1]) == 0 assert token.balanceOf(escrow) == 300 assert asset.getOwner() == escrow accounts[1] ( ) 300 accounts[0] ( ) B 2022 — 4 — 2022-11-07 – p.59/74
  60. (4) escrow.settle({’from’: accounts[0]}) assert token.balanceOf(accounts[0]) == 1000000000000000000000 assert token.balanceOf(accounts[1]) ==

    0 assert token.balanceOf(escrow) == 0 assert asset.getOwner() == accounts[1] settle() accounts[0] OK B 2022 — 4 — 2022-11-07 – p.60/74
  61. $ pytest tests/test_one_time_escrow.py : settle() ⇒ Discord B 2022 —

    4 — 2022-11-07 – p.61/74
  62. B 2022 — 4 — 2022-11-07 – p.62/74

  63. 1. (1) (2) Ethereum 2022 11 5 ( ) 23:59

    JST B 2022 — 4 — 2022-11-07 – p.63/74
  64. . . . . . . 6 2 ( )

    ( ) (← ) ( ) B 2022 — 4 — 2022-11-07 – p.64/74
  65. M Ethereum ⇒ 20 Discord . . . B 2022

    — 4 — 2022-11-07 – p.65/74
  66. M VR ⇒ B 2022 — 4 — 2022-11-07 –

    p.66/74
  67. T ⇒ B 2022 — 4 — 2022-11-07 – p.67/74

  68. T ( ?) ( ) ⇒ ( ) B 2022

    — 4 — 2022-11-07 – p.68/74
  69. Web3 Web3 HTTPS B 2022 — 4 — 2022-11-07 –

    p.69/74
  70. ↑ B 2022 — 4 — 2022-11-07 – p.70/74

  71. miro ( ) ( ) B 2022 — 4 —

    2022-11-07 – p.71/74
  72. B 2022 — 4 — 2022-11-07 – p.72/74

  73. 2. API (1) ( ) (2) Web API 2022 11

    12 ( ) 23:59 JST B 2022 — 4 — 2022-11-07 – p.73/74
  74. B 2022 — 4 — 2022-11-07 – p.74/74