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

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 4 ( ) B 2025 — 4 — 2025-10-27 – p.1/30
2. https://speakerdeck.com/ks91/collections/service-design-project-b-2025-fall ( ) ( ) Discord Discord ( / / ) Zoom URL ( ) B 2025 — 4 — 2025-10-27 – p.2/30
3. ( ) 1 10 6 • 2 10 13 • 3 10 20 • 4 10 27 • 5 11 10 1 6 11 24 2 7 12 1 8 12 8 ( ) ( ) 4 ( 3 ) ↓ B 2025 — 4 — 2025-10-27 – p.3/30
4. ( ) — (3) : Web3 B 2025 — 4 — 2025-10-27 – p.4/30
5. ( ) — Ethereum Sepolia B 2025 — 4 — 2025-10-27 – p.5/30
6. infura.io Brownie https://infura.io SIGN UP PROJECT ID infura Ethereum API infura . . . infura.io Amazon infura.io PROJECT ID WEB3_INFURA_PROJECT_ID PROJECT ID (∼/.bash_profile ) $ export WEB3_INFURA_PROJECT_ID= PROJECT ID B 2025 — 4 — 2025-10-27 – p.6/30
7. 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 — 4 — 2025-10-27 – p.7/30
8. 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 — 4 — 2025-10-27 – p.8/30
9. (3) : B 2025 — 4 — 2025-10-27 – p.9/30
10. transfer settle, retrieve asset, retrieve token 3 B 2025 — 4 — 2025-10-27 – p.10/30
11. 1. ( ) 2. ( ) 3. ( ) B 2025 — 4 — 2025-10-27 – p.11/30
12. 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 — 4 — 2025-10-27 – p.12/30
13. (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 — 4 — 2025-10-27 – p.13/30
14. (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 — 4 — 2025-10-27 – p.14/30
15. (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 — 4 — 2025-10-27 – p.15/30
16. (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 — 4 — 2025-10-27 – p.16/30
17. $ pytest tests/test_one_time_escrow.py : settle() ⇒ Discord B 2025 — 4 — 2025-10-27 – p.17/30
18. B 2025 — 4 — 2025-10-27 – p.18/30
19. 1. (1) (2) Ethereum 2025 10 25 ( ) 23:59 JST B 2025 — 4 — 2025-10-27 – p.19/30
20. . . . . . . 3 1 ( ) ( ) ( ) B 2025 — 4 — 2025-10-27 – p.20/30
21. A ⇒ B 2025 — 4 — 2025-10-27 – p.21/30
22. A Ethereum NFT NFT NFT B 2025 — 4 — 2025-10-27 – p.22/30
23. A — NFT NFT NFT ⇒ ( ) B 2025 — 4 — 2025-10-27 – p.23/30
24. ⇒ 20 Discord . . . ( ) B 2025 — 4 — 2025-10-27 – p.24/30
25. Web3 Web3 HTTPS B 2025 — 4 — 2025-10-27 – p.25/30
26. B 2025 — 4 — 2025-10-27 – p.26/30
27. miro ( ) ( ) B 2025 — 4 — 2025-10-27 – p.27/30
28. B 2025 — 4 — 2025-10-27 – p.28/30
29. 2. API (1) ( ) (2) Web API 2025 11 8 ( ) 23:59 JST B 2025 — 4 — 2025-10-27 – p.29/30
30. B 2025 — 4 — 2025-10-27 – p.30/30