---
id: wiki-2026-0508-blockchain
title: Blockchain
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [블록체인, distributed ledger, smart contract, Ethereum, Bitcoin, web3, ZK proof, rollup]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [blockchain, ethereum, bitcoin, smart-contract, web3, zk-rollup, defi, nft, ai-blockchain]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: Solidity / Rust
  framework: Ethereum / Solana / Cosmos
---

# Blockchain

## 📌 한 줄 통찰
> **"매 신뢰 의 technical implementation"**. 매 central authority X — 매 distributed + 매 cryptographic verification. 매 currency 의 base. 매 smart contract → 매 programmable trust. 매 modern: 매 ZK rollup + AI provenance.

## 📖 핵심

### 매 핵심 mechanism
1. **Decentralization**: 매 single server X.
2. **Immutability**: 매 hash chain 의 변경 의 X.
3. **Consensus**: 매 누가 매 next block.
4. **Cryptographic verification**: 매 transaction 의 sign.
5. **Transparency**: 매 public ledger.

### Consensus algorithm
| Algorithm | 매 사용 |
|---|---|
| Proof of Work (PoW) | Bitcoin, 매 energy ↑ |
| Proof of Stake (PoS) | Ethereum 2.0, 매 energy ↓ |
| Delegated PoS (DPoS) | EOS, Tron |
| Proof of Authority (PoA) | private chain |
| BFT (PBFT, Tendermint) | Cosmos, Hyperledger |
| Avalanche | Avalanche L1 |

### 매 evolution
1. **Bitcoin** (2009): 매 digital currency.
2. **Ethereum** (2015): 매 smart contract.
3. **L2 / Rollup** (2021+): 매 scale.
4. **ZK Rollup** (2023+): 매 zero-knowledge.
5. **Modular** (2024+): 매 Celestia 등 의 specialization.

### 매 stack (Ethereum)
- **L1**: Ethereum mainnet.
- **L2 Optimistic**: Arbitrum, Optimism, Base.
- **L2 ZK**: zkSync, StarkNet, Polygon zkEVM, Scroll.
- **L3**: app-specific rollup.
- **Bridge**: 매 cross-chain.
- **Oracle**: Chainlink, Pyth.

### 매 EVM 대 alternative
- **EVM** (Solidity): 매 dominant.
- **Solana** (Rust + Sealevel): 매 high TPS.
- **Aptos / Sui** (Move): 매 secure 모음.
- **Cosmos** (Tendermint): 매 sovereignty.
- **Near**: 매 sharded.

### 매 application
- **DeFi**: lending, DEX (Uniswap), derivatives.
- **NFT**: art, gaming, identity.
- **DAO**: governance.
- **Stablecoin**: USDC, USDT, DAI.
- **Gaming**: 매 ownership.
- **Identity**: 매 self-sovereign.
- **Provenance**: 매 supply chain, art.

### AI × Blockchain
1. **Provenance**: 매 training data 의 source.
2. **Royalty**: 매 contributor 의 보상.
3. **Decentralized inference**: 매 Bittensor.
4. **Compute marketplace**: 매 Render, Akash.
5. **AI agent payment**: 매 X402, 매 micropayment.
6. **Verifiable inference** (ZK-ML): 매 proof.

### 매 modern issue
1. **Energy** (PoW): 매 Bitcoin 의 GW-scale.
2. **Scaling**: 매 L1 의 limit.
3. **UX**: 매 wallet, 매 gas, 매 seed phrase.
4. **Regulation**: 매 SEC vs CFTC, 매 EU MiCA.
5. **Hack**: 매 매 year 의 Billion-scale theft.
6. **Speculation**: 매 utility ≠ 매 price.

### 매 ZK proof (modern)
- **zk-SNARK** (Groth16, Plonk): 매 succinct.
- **zk-STARK**: 매 transparent (no trusted setup), 매 post-quantum.
- 매 응용: 매 rollup, 매 privacy, 매 ML inference verify.

## 💻 패턴

### Solidity (smart contract)
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract SimpleStorage {
    uint256 private value;
    address public owner;
    
    event ValueChanged(uint256 newValue, address indexed setter);
    
    constructor() {
        owner = msg.sender;
    }
    
    modifier onlyOwner() {
        require(msg.sender == owner, "Not owner");
        _;
    }
    
    function set(uint256 _value) external onlyOwner {
        value = _value;
        emit ValueChanged(_value, msg.sender);
    }
    
    function get() external view returns (uint256) {
        return value;
    }
}
```

### Hardhat (Ethereum dev)
```js
// hardhat.config.js
module.exports = {
  solidity: '0.8.20',
  networks: {
    sepolia: { url: process.env.SEPOLIA_RPC, accounts: [process.env.PRIVATE_KEY] },
    mainnet: { url: process.env.MAINNET_RPC, accounts: [process.env.PRIVATE_KEY] },
  },
};

// scripts/deploy.js
const hre = require('hardhat');

async function main() {
  const Storage = await hre.ethers.getContractFactory('SimpleStorage');
  const storage = await Storage.deploy();
  await storage.waitForDeployment();
  console.log('Deployed to:', await storage.getAddress());
}

main().catch(console.error);
```

### viem (frontend interaction)
```ts
import { createPublicClient, createWalletClient, http, parseAbi } from 'viem';
import { mainnet } from 'viem/chains';

const client = createPublicClient({ chain: mainnet, transport: http() });

const abi = parseAbi(['function get() view returns (uint256)']);
const value = await client.readContract({
  address: '0x...',
  abi,
  functionName: 'get',
});
```

### NFT (ERC-721)
```solidity
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract MyNFT is ERC721 {
    uint256 public nextTokenId;
    
    constructor() ERC721("MyNFT", "MNFT") {}
    
    function mint(address to) external {
        _safeMint(to, nextTokenId++);
    }
    
    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        return string(abi.encodePacked('ipfs://my-cid/', _toString(tokenId), '.json'));
    }
}
```

### DAO governance (Snapshot)
```ts
// 매 token holder 의 vote
const proposal = {
  title: 'Increase treasury allocation',
  choices: ['For', 'Against', 'Abstain'],
  start: Date.now(),
  end: Date.now() + 7 * 86400 * 1000,
  snapshot: latestBlock,
  network: '1',
  strategies: [
    { name: 'erc20-balance-of', params: { address: tokenAddress, decimals: 18 } },
  ],
};
// 매 IPFS 의 post + 매 sign.
```

### ZK-ML proof (verify inference)
```python
# 매 EZKL 의 ONNX 의 ZK proof 로 변환
import ezkl
import torch

# 매 model export
torch.onnx.export(model, dummy_input, 'model.onnx')

# 매 setup
ezkl.gen_settings('model.onnx', 'settings.json')
ezkl.compile_circuit('model.onnx', 'circuit.ezkl', 'settings.json')

# 매 prove
ezkl.prove('input.json', 'circuit.ezkl', 'pk.key', 'proof.json')

# 매 verify (on-chain or off-chain)
ezkl.verify('proof.json', 'settings.json', 'vk.key')
```

→ 매 inference correctness 의 zero-knowledge.

### Provenance (content authenticity)
```solidity
contract ContentProvenance {
    struct Record {
        string contentHash;     // keccak256 of content
        address creator;
        uint256 timestamp;
        string metadataURI;     // ipfs://...
    }
    
    mapping(bytes32 => Record) public records;
    
    function register(string calldata contentHash, string calldata metadataURI) external {
        bytes32 id = keccak256(abi.encodePacked(contentHash, msg.sender));
        records[id] = Record(contentHash, msg.sender, block.timestamp, metadataURI);
    }
}
```

## 🤔 결정 기준
| 응용 | Chain |
|---|---|
| DeFi (max liquidity) | Ethereum L1 |
| Cheap UX | L2 (Base, Arbitrum) |
| High TPS | Solana |
| Privacy | zkSync, StarkNet, Aztec |
| Gaming | L2 / sidechain |
| Enterprise / consortium | Hyperledger / Polygon CDK |
| AI inference | Bittensor, EZKL |
| Stablecoin | Ethereum + L2 |

**기본값**: L2 (Base / Arbitrum) 의 entry. 매 use case 의 specific chain.

## 🔗 Graph
- 부모: [[Distributed-Systems]] · [[Practical-Cryptography|Cryptography]] · [[Web3]]
- 변형: [[Bitcoin]] · [[Ethereum]] · [[Cosmos]]
- 응용: [[DAO]] · [[Smart-Contract]]
- AI 결합: [[Content-Provenance]] · [[C2PA]]
- Adjacent: [[Anarchism]] · [[Authenticity]]

## 🤖 LLM 활용
**언제**: 매 web3 system design. 매 smart contract review. 매 AI 의 provenance / royalty.
**언제 X**: 매 simple problem (centralized 의 enough). 매 high TPS + low latency 의 strict.

## ❌ 안티패턴
- **Centralized 의 force on blockchain**: 매 cost ↑, 매 benefit X.
- **No audit (smart contract)**: 매 hack risk.
- **Unchecked external call**: 매 reentrancy.
- **On-chain large data**: 매 cost (use IPFS).
- **No upgrade plan**: 매 immutable bug.
- **Speculation 의 only**: 매 utility X.
- **PoW 의 default**: 매 energy 의 unjustified.

## 🧪 검증 / 중복
- Verified (Ethereum yellow paper, Solana whitepaper, zk-rollup papers).
- 신뢰도 A.
- Related: [[Smart-Contract]] · [[ZK-ML]] · [[DAO]] · [[Authenticity]] · [[Anarchism]].

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — consensus + L2 + AI×Blockchain + 매 Solidity / viem / EZKL code |