スマートコントラクトプログラミング / Smart Contract Programming

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」2025秋 第3回にて使用したスライドです。

Transcript

1. generated by Stable Image Ultra B 2025 3 ( ) B 2025 — 3 — 2025-10-20 – p.1/66
2. https://speakerdeck.com/ks91/collections/service-design-project-b-2025-fall ( ) ( ) Discord Discord ( / / ) Zoom URL ( ) B 2025 — 3 — 2025-10-20 – p.2/66
3. ( ) 1 10 6 • 2 10 13 • 3 10 20 • 4 10 27 2 5 11 10 1 6 11 24 2 7 12 1 8 12 8 ( ) Discord B 2025 — 3 — 2025-10-20 – p.3/66
4. 1. Ethereum ( ) 2. ( ) 3. Ethereum (1) : ERC20 (2) : (3) : B 2025 — 3 — 2025-10-20 – p.4/66
5. 1. Ethereum ( ) macOS (Tahoe 26.0.1) + Homebrew Linux (Ubuntu 24.04) (x86/AMD64 and ARM) Windows 11 + Windows Subsystem for Linux (Ubuntu ) Ethereum solidity brownie Lima on macOS B 2025 — 3 — 2025-10-20 – p.5/66
6. macOS : Homebrew (Apple macOS ) UNIX macOS Lima Homebrew brew Apple brew ( ) brew Rosetta brew brew https://github.com/homebrew/install Path : https://zenn.dev/tet0h/articles/a92651d52bd82460aefb $ which brew /opt/homebrew/bin/brew B 2025 — 3 — 2025-10-20 – p.6/66
7. macOS : Rosetta 2 Apple x86/AMD64 ( ) $ softwareupdate --install-rosetta lima Rosetta 2 lima B 2025 — 3 — 2025-10-20 – p.7/66
8. macOS : Lima macOS Linux ( ) https://github.com/lima-vm/lima QEMU ( ) Rosetta 2 Apple x86/AMD64 brew (lima-additional-guestagents ) $ brew install lima Ubuntu 24.04 (x86/AMD64) “kmd.yaml” $ limactl start kmd.yaml B 2025 — 3 — 2025-10-20 – p.8/66
9. macOS : Lima Linux (Ubuntu) x86_64 $ limactl list Linux (exit ) $ limactl shell kmd Linux limactl list STATUS Stopped limactl start kmd “.lima” diffdisk 100GB B 2025 — 3 — 2025-10-20 – p.9/66
10. Solidity Ethereum ( ) http://solidity.readthedocs.io/en/latest/installing-solidity.html Linux (on Windows) “sudo apt”, macOS “brew” Linux ARM git clone dependencies solc 0.8.30 (10/4 ) $ solc --version brownie py-solc-x solc (dependencies) ( solc py-solc-x ) B 2025 — 3 — 2025-10-20 – p.10/66
11. 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 2025 — 3 — 2025-10-20 – p.11/66
12. Python3 macOS $ brew install python3 Python 3.8 Homebrew $ brew uninstall --ignore-dependencies python@3.9 $ brew install python@3.8 /usr/local/opt/python@3.8/bin/python3 Linux ( python3.12.3 OK) $ sudo apt update $ sudo apt install python3-dev python3-venv python3-tk 16.10 python3(.8) apt (PPA ) python3 python3-dev python3-venv python3-tk B 2025 — 3 — 2025-10-20 – p.12/66
13. macOS : . . . macOS wget brew dyld: Library not loaded: /usr/local/opt/gettext/lib/libintl.8.dylib $ brew uninstall --force gettext $ brew install gettext B 2025 — 3 — 2025-10-20 – p.13/66
14. Python (venv) macOS (Linux python3 ) OK Python $ python3 -m venv bbc2env $ source bbc2env/bin/activate (bbc2env) $ pip install -U pip bbc2env ( BBc-2 ) ( ) (bbc2env) $ deactivate B 2025 — 3 — 2025-10-20 – p.14/66
15. Brownie Python Ethereum https://eth-brownie.readthedocs.io Brownie $ pip install eth-brownie version 1.21.0 (10/4 ) $ pip install setuptools setuptools B 2025 — 3 — 2025-10-20 – p.15/66
16. $ brownie init ( ERC-20 ) $ brownie bake token $ cd token B 2025 — 3 — 2025-10-20 – p.16/66
17. 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 2025 — 3 — 2025-10-20 – p.17/66
18. Brownie $ brownie console Python >>> len(accounts) 10 >>> accounts[0].balance() 100000000000000000000 >>> quit() B 2025 — 3 — 2025-10-20 – p.18/66
19. 2. ( ) Ethereum Sepolia B 2025 — 3 — 2025-10-20 – p.19/66
20. 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 2025 — 3 — 2025-10-20 – p.20/66
21. Sepolia ETH brownie console Sepolia >>> network.disconnect() >>> network.connect(’sepolia’) >>> len(accounts) 0 >>> accounts.add() <LocalAccount object ’ 16 ’> >>> accounts[0].private_key 16 >>> quit() Sepolia Testnet ETH Faucet ETH https://sepoliafaucet.com ( ) ( ) . . . Ethereum 0.001 ETH 0.1 Sepolia ETH B 2025 — 3 — 2025-10-20 – p.21/66
22. Sepolia ETH brownie console Sepolia ETH >>> network.disconnect() >>> network.connect(’sepolia’) >>> len(accounts) 0 >>> accounts.add( 16 ) <LocalAccount object ’ 16 ’> >>> accounts[0].balace() ETH >>> quit() ETH >>> accounts[0].transfer(accounts[1], "0.01 ether") B 2025 — 3 — 2025-10-20 – p.22/66
23. 3. Ethereum B 2025 — 3 — 2025-10-20 – p.23/66
24. Ethereum Vitalik Buterin, “Ethereum White Paper: A NEXT GENERATION SMART CONTRACT & DECENTRALIZED APPLICATION PLATFORM” 12 (= ) = ⇒ → Dapps ( / / ) B 2025 — 3 — 2025-10-20 – p.24/66
25. ( ) B 2025 — 3 — 2025-10-20 – p.25/66
26. B 2025 — 3 — 2025-10-20 – p.26/66
27. = run B 2025 — 3 — 2025-10-20 – p.27/66
28. Ether Ethereum EOA : Externally-Owned Account ( ) Ether EVM EVM B 2025 — 3 — 2025-10-20 – p.28/66
29. EVM : Ethereum Virtual Machine ঢ়ଶ ֎෦ΞΫλʔ ΞΧ΢ϯτ &7. ίʔυ &UIFS
    ˠ
    (BT ىಈ ίϯτϥΫτ ϝοηʔδ
    ͔ɺ৽͍ࣗ͠ಈΦϒδΣΫτ ΞΧ΢ϯτؒͰ΍ΓऔΓ͞ΕΔσʔλ΍
    &UIFS ετϨʔδ ঢ়ଶ` τϥϯβΫγϣϯ ηοτ σδλϧॺ໊ &7. ਓؒͱ͔ ࣗಈ ΦϒδΣΫτ Gas ( EVM = ( burn)) . . . B 2025 — 3 — 2025-10-20 – p.29/66
30. EVM : : ← : Solidity — JavaScript LLL — Lisp Vyper — Python Fe — Vyper Rust ← NEW! Solidity Vyper Python B 2025 — 3 — 2025-10-20 – p.30/66
31. 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 2025 — 3 — 2025-10-20 – p.31/66
32. ( , ) (constructor) (deploy) = ( ) ( ) ETH Trusted Actor Model B 2025 — 3 — 2025-10-20 – p.32/66
33. Ethereum B 2025 — 3 — 2025-10-20 – p.33/66
34. (1) : ERC20 $ brownie bake token B 2025 — 3 — 2025-10-20 – p.34/66
35. pragma solidity ˆ0.6.0; /* 0.8.x */ contract Token { ( ) : (EVM ) : constructor (...) public { /* */ : } function balanceOf(...) { /* ( ) */ : } : } constructor C (/* */ // ) B 2025 — 3 — 2025-10-20 – p.35/66
36. ERC-20 ERC (Ethereum Request for Comments) 20 https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md (EIP: Ethereum Improvement Proposal) ← EIP ( ) 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 2025 — 3 — 2025-10-20 – p.36/66
37. ERC20 ERC20 ( ) ⇒ ERC20 ( ERC20 ) ERC20 ⇒ B 2025 — 3 — 2025-10-20 – p.37/66
38. (fungible) ERC-20 → ERC-223 (draft) or ERC-777 ( )( ) (non-fungible) ERC-721 ( ) ERC-1155 ( ) ERC-3525 (SLOT ) B 2025 — 3 — 2025-10-20 – p.38/66
39. 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 2025 — 3 — 2025-10-20 – p.39/66
40. Token ( ) event Transfer(address from, address to, uint256 value); Token function emit Transfer() ( ) B 2025 — 3 — 2025-10-20 – p.40/66
41. 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 2025 — 3 — 2025-10-20 – p.41/66
42. Token balanceOf() function balanceOf(address _owner) public view returns (uint256) { return balances[_owner]; } B 2025 — 3 — 2025-10-20 – p.42/66
43. 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 2025 — 3 — 2025-10-20 – p.43/66
44. (2) : B 2025 — 3 — 2025-10-20 – p.44/66
45. 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 2025 — 3 — 2025-10-20 – p.45/66
46. (m2 ) 1 1 B 2025 — 3 — 2025-10-20 – p.46/66
47. IndivisibleAsset string public _name_; string public _symbol_; uint256 public _quantity_; address public _owner_; _name_ ( ) _symbol_ _quantity_ (m2 ) _owner_ ‘_’ Solidity . . . B 2025 — 3 — 2025-10-20 – p.47/66
48. IndivisibleAsset event Transfer(address indexed from, address indexed to); from to indexed B 2025 — 3 — 2025-10-20 – p.48/66
49. IndivisibleAsset constructor (string name, string symbol, uint256 quantity) public { _name_ = name; _symbol_ = symbol; _quantity_ = quantity; _owner_ = msg.sender; } B 2025 — 3 — 2025-10-20 – p.49/66
50. IndivisibleAsset getOwner() function getOwner() public view returns (address) { return (_owner_); } B 2025 — 3 — 2025-10-20 – p.50/66
51. 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 2025 — 3 — 2025-10-20 – p.51/66
52. scripts/indivisible asset.py from brownie import * def main(): accounts[0].deploy(IndivisibleAsset, "5322 Endo, Fujisawa", "mˆ2", 300) SFC (300m2 ) ( ) B 2025 — 3 — 2025-10-20 – p.52/66
53. 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 2025 — 3 — 2025-10-20 – p.53/66
54. $ pytest tests/test_indivisible_asset.py B 2025 — 3 — 2025-10-20 – p.54/66
55. (3) : B 2025 — 3 — 2025-10-20 – p.55/66
56. transfer settle, retrieve asset, retrieve token 3 B 2025 — 3 — 2025-10-20 – p.56/66
57. 1. ( ) 2. ( ) 3. ( ) B 2025 — 3 — 2025-10-20 – p.57/66
58. 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 2025 — 3 — 2025-10-20 – p.58/66
59. (1) from brownie import * import pytest seller = accounts[0] buyer = accounts[1] 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 2025 — 3 — 2025-10-20 – p.59/66
60. (2) token.transfer(buyer, 300, {’from’: accounts[0]}) escrow = accounts[0].deploy(OneTimeEscrow, token, buyer, asset, seller, 300) accounts[0]/seller accounts[1]/buyer 300 300 TX buyer seller 300 bake Token 300 ETH wei B 2025 — 3 — 2025-10-20 – p.60/66
61. (3) token.transfer(escrow, 300, {’from’: buyer}) asset.transfer(escrow, {’from’: seller}) assert token.balanceOf(seller) == 999999999999999999700 assert token.balanceOf(buyer) == 0 assert token.balanceOf(escrow) == 300 assert asset.getOwner() == escrow buyer ( ) 300 seller ( ) B 2025 — 3 — 2025-10-20 – p.61/66
62. (4) escrow.settle({’from’: seller}) assert token.balanceOf(seller) == 1000000000000000000000 assert token.balanceOf(buyer) == 0 assert token.balanceOf(escrow) == 0 assert asset.getOwner() == buyer settle() seller OK B 2025 — 3 — 2025-10-20 – p.62/66
63. $ pytest tests/test_one_time_escrow.py : settle() ⇒ Discord B 2025 — 3 — 2025-10-20 – p.63/66
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65. 1. (1) (2) Ethereum 2025 10 25 ( ) 23:59 JST B 2025 — 3 — 2025-10-20 – p.65/66
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