以太坊Dencun升级：Proto-Danksharding如何降低L2成本

import math
import random
from typing import List, Tuple

class BlobGasMarket:
    """
    模拟EIP-4844 Blob Gas定价机制
    类似于电影票房的动态定价模型
    """
    def __init__(self, target_blobs: int = 3, max_blobs: int = 6):
        self.target_blobs = target_blobs
        self.max_blobs = max_blobs
        self.base_fee = 1  # 初始Gas价格（单位：wei）
        self.blob_history: List[Tuple[int, float]] = []
    
    def calculate_excess_blobs(self, recent_blobs: List[int]) -> int:
        """计算超额Blob数量"""
        total_excess = 0
        for blobs in recent_blobs[-100:]:  # 取最近100个区块
            excess = blobs - self.target_blobs
            total_excess += max(excess, 0)  # 只累加超出部分
        return total_excess
    
    def update_fee(self, current_block_blobs: int) -> float:
        """更新Blob基础费用"""
        excess = self.calculate_excess_blobs([current_block_blobs])
        # 指数调整公式：base_fee * e^(excess / target)
        # 类似EIP-1559的指数调整机制
        adjustment = math.exp(excess / (self.target_blobs * 10))
        self.base_fee = round(self.base_fee * adjustment, 6)
        self.blob_history.append((current_block_blobs, self.base_fee))
        return self.base_fee
    
    def simulate(self, blocks: int = 1000, 
                 demand_pattern: str = "steady") -> List[float]:
        """
        模拟不同需求模式下的Gas价格变化
        demand_pattern: "steady" | "surge" | "chaotic"
        """
        prices = []
        for block in range(blocks):
            if demand_pattern == "steady":
                # 稳定需求：3-4个Blob
                blobs = self.target_blobs + random.randint(0, 1)
            elif demand_pattern == "surge":
                # 爆发需求：5-6个Blob（类似大片上映首周）
                blobs = random.randint(5, self.max_blobs) if block < 200 \
                        else random.randint(2, 4)
            elif demand_pattern == "chaotic":
                # 波动需求：0-6个Blob（类似独立电影发行）
                blobs = random.randint(0, self.max_blobs)
            
            fee = self.update_fee(blobs)
            prices.append(fee)
        
        return prices

# 模拟三种场景
market = BlobGasMarket()
steady_prices = market.simulate(1000, "steady")
surge_prices = market.simulate(1000, "surge")
chaotic_prices = market.simulate(1000, "chaotic")

print(f"稳定需求平均价格: {sum(steady_prices)/len(steady_prices):.6f} wei")
print(f"爆发需求平均价格: {sum(surge_prices)/len(surge_prices):.6f} wei")
print(f"波动需求平均价格: {sum(chaotic_prices)/len(chaotic_prices):.6f} wei")
print(f"稳定需求最终价格: {steady_prices[-1]:.6f} wei")
print(f"爆发需求最终价格: {surge_prices[-1]:.6f} wei")
print(f"波动需求最终价格: {chaotic_prices[-1]:.6f} wei")

// 模拟影视内容通过L2 Blob发布
const ethers = require('ethers');

// 模拟内容元数据
class FilmContent {
  constructor(title, director, duration, ipfsHash) {
    this.title = title;
    this.director = director;
    this.duration = duration; // 分钟
    this.ipfsHash = ipfsHash;
    this.timestamp = Date.now();
    this.contentId = ethers.keccak256(
      ethers.toUtf8Bytes(title + director + ipfsHash + this.timestamp)
    );
  }

  // 生成Blob数据（128KB的证明数据，而非完整电影）
  generateBlobData() {
    const proof = {
      contentId: this.contentId,
      ipfsHash: this.ipfsHash,
      title: this.title,
      director: this.director,
      duration: this.duration,
      timestamp: this.timestamp,
      // 播放密钥的哈希，实际播放时通过零知识证明验证
      playbackKeyHash: ethers.keccak256(
        ethers.toUtf8Bytes(this.contentId + this.director)
      )
    };
    
    // 序列化为JSON字符串，模拟Blob数据
    const blobPayload = JSON.stringify(proof);
    const blobBytes = ethers.toUtf8Bytes(blobPayload);
    
    // 确保Blob大小不超过128KB
    if (blobBytes.length > 131072) {
      throw new Error('Blob数据超过128KB限制');
    }
    
    return {
      blob: blobPayload,
      blobSize: blobBytes.length,
      estimatedGas: this.estimateBlobGas(blobBytes.length)
    };
  }

  // 估算Blob Gas（基于EIP-4844参数）
  estimateBlobGas(byteLength) {
    // 每个Blob最多128KB，每个字段32字节
    const fieldElements = Math.ceil(byteLength / 32);
    // Gas = 固定费用 + 每字段费用
    const gasPerBlob = 131072; // 约131K Gas per blob
    return gasPerBlob * Math.ceil(fieldElements / 4096);
  }

  // 计算成本对比
  costComparison() {
    const blobData = this.generateBlobData();
    const blobGas = blobData.estimatedGas;
    
    // Dencun前：使用CALLDATA
    const calldataGas = blobData.blobSize * 16; // 每字节16 Gas
    const calldataCost = (calldataGas * 30e9) / 1e18; // 30 Gwei
    
    // Dencun后：使用Blob
    const blobCost = (blobGas * 10e9) / 1e18; // 10 Gwei
    
    return {
      contentTitle: this.title,
      blobSizeKB: (blobData.blobSize / 1024).toFixed(2),
      calldataGas: calldataGas,
      blobGas: blobGas,
      calldataCostETH: calldataCost.toFixed(6),
      blobCostETH: blobCost.toFixed(6),
      savingsPercent: ((1 - blobCost / calldataCost) * 100).toFixed(2)
    };
  }
}

// 模拟发行三部不同长度的影视内容
const films = [
  new FilmContent('短片：链上叙事', '王森涛', 15, 'QmXyZ123...'),
  new FilmContent('纪录片：去中心化时代', '王森涛', 90, 'QmAbC456...'),
  new FilmContent('长篇电影：数据之海', '王森涛', 150, 'QmDef789...')
];

console.log('=== Dencun升级前后成本对比 ===\n');
films.forEach(film => {
  const comparison = film.costComparison();
  console.log(`影片: ${comparison.contentTitle}`);
  console.log(`  Blob数据大小: ${comparison.blobSizeKB} KB`);
  console.log(`  Dencun前 (CALLDATA): ${comparison.calldataCostETH} ETH`);
  console.log(`  Dencun后 (Blob):    ${comparison.blobCostETH} ETH`);
  console.log(`  成本节省: ${comparison.savingsPercent}%\n`);
});

// 输出总结
const totalSavings = films.reduce((acc, film) => {
  const comp = film.costComparison();
  return acc + (parseFloat(comp.calldataCostETH) - parseFloat(comp.blobCostETH));
}, 0);

console.log(`三部影片总计节省: ${totalSavings.toFixed(6)} ETH`);

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

/**
 * @title ZKBlobFilmRegistry
 * @notice 基于ZK Rollup Blob数据的影视内容版权注册合约
 *         模拟EIP-4844 Blob数据在内容验证中的应用
 */
contract ZKBlobFilmRegistry {
    // 影片元数据
    struct FilmRecord {
        string title;
        string director;
        uint256 releaseDate;
        bytes32 contentHash;      // 影片内容的哈希值
        bytes32 blobVersionedHash; // Blob数据的版本化哈希
        uint256 blobIndex;        // Blob在区块中的索引
        address owner;
        bool exists;
    }

    // 版权转让记录
    struct RightsTransfer {
        address from;
        address to;
        uint256 timestamp;
        string region;           // 发行区域代码
        uint256 duration;        // 授权期限（天）
    }

    mapping(bytes32 => FilmRecord) public films;
    mapping(bytes32 => RightsTransfer[]) public transferHistory;
    
    event FilmRegistered(
        bytes32 indexed filmId,
        string title,
        string director,
        bytes32 contentHash,
        bytes32 blobVersionedHash,
        uint256 timestamp
    );

    event RightsTransferred(
        bytes32 indexed filmId,
        address indexed from,
        address indexed to,
        string region,
        uint256 duration
    );

    /**
     * @notice 注册新影片，关联Blob证明数据
     * @param _title 影片标题
     * @param _director 导演
     * @param _contentHash 内容哈希（IPFS/Arweave CID哈希）
     * @param _blobVersionedHash Blob数据的版本化哈希
     * @param _blobIndex Blob在区块中的位置
     */
    function registerFilm(
        string memory _title,
        string memory _director,
        bytes32 _contentHash,
        bytes32 _blobVersionedHash,
        uint256 _blobIndex
    ) public returns (bytes32) {
        bytes32 filmId = keccak256(
            abi.encodePacked(_contentHash, msg.sender, block.timestamp)
        );
        
        require(!films[filmId].exists, "Film already registered");
        
        films[filmId] = FilmRecord({
            title: _title,
            director: _director,
            releaseDate: block.timestamp,
            contentHash: _contentHash,
            blobVersionedHash: _blobVersionedHash,
            blobIndex: _blobIndex,
            owner: msg.sender,
            exists: true
        });

        emit FilmRegistered(
            filmId, _title, _director, 
            _contentHash, _blobVersionedHash, block.timestamp
        );
        
        return filmId;
    }

    /**
     * @notice 转移版权到指定发行商
     * @param _filmId 影片ID
     * @param _to 接收方地址
     * @param _region 发行区域
     * @param _duration 授权期限（天）
     */
    function transferRights(
        bytes32 _filmId,
        address _to,
        string memory _region,
        uint256 _duration
    ) public {
        FilmRecord storage film = films[_filmId];
        require(film.exists, "Film not found");
        require(film.owner == msg.sender, "Not the owner");
        require(_to != address(0), "Invalid receiver");
        
        transferHistory[_filmId].push(RightsTransfer({
            from: msg.sender,
            to: _to,
            timestamp: block.timestamp,
            region: _region,
            duration: _duration
        }));

        // 转移所有权（在链上记录授权）
        film.owner = _to;

        emit RightsTransferred(_filmId, msg.sender, _to, _region, _duration);
    }

    /**
     * @notice 验证Blob中的数据是否与合约记录匹配
     * @param _filmId 影片ID
     * @param _blobData Blob的实际数据（L2节点提供）
     * @return bool 验证结果
     */
    function verifyBlobIntegrity(
        bytes32 _filmId,
        bytes calldata _blobData
    ) public view returns (bool) {
        FilmRecord memory film = films[_filmId];
        require(film.exists, "Film not found");
        
        // 计算Blob数据的哈希
        bytes32 computedHash = keccak256(_blobData);
        
        // 验证Blob哈希是否与注册时记录的版本化哈希一致
        // 注意：实际EIP-4844中，blobVersionedHash是KZG承诺的哈希
        // 这里简化为直接比较数据哈希
        return computedHash == film.blobVersionedHash;
    }

    /**
     * @notice 查询某影片的版权链
     * @param _filmId 影片ID
     * @return RightsTransfer[] 版权转让历史
     */
    function getRightsChain(
        bytes32 _filmId
    ) public view returns (RightsTransfer[] memory) {
        require(films[_filmId].exists, "Film not found");
        return transferHistory[_filmId];
    }
}