如何在C++中实现区块链核心_分布式账本原理

#include <iostream>
#include <string>
#include <vector>
#include <ctime>
#include <sstream>
#include <iomanip>
#include "sha256.h" // 假设你已经有了SHA256哈希算法的实现

class Block {
public:
    time_t timestamp;
    std::string data;
    std::string previousHash;
    std::string hash;
    int nonce; // 用于工作量证明

    Block(std::string data, std::string previousHash) : data(data), previousHash(previousHash) {
        timestamp = time(0);
        nonce = 0;
        hash = calculateHash();
    }

    std::string calculateHash() {
        std::stringstream ss;
        ss << timestamp << data << previousHash << nonce;
        return sha256(ss.str());
    }

    void mineBlock(int difficulty) {
        std::string target(difficulty, '0');
        while (hash.substr(0, difficulty) != target) {
            nonce++;
            hash = calculateHash();
        }
        std::cout << "Block Mined: " << hash << std::endl;
    }
};

class Blockchain {
public:
    std::vector<Block> chain;

    Blockchain() {
        // 创建创世区块
        chain.emplace_back(Block("Genesis Block", "0"));
    }

    void addBlock(Block newBlock) {
        newBlock.previousHash = getLatestBlock().hash;
        newBlock.mineBlock(4); // 难度值为4，可以调整
        chain.push_back(newBlock);
    }

    Block getLatestBlock() {
        return chain.back();
    }

    bool isChainValid() {
        for (size_t i = 1; i < chain.size(); i++) {
            const Block& currentBlock = chain[i];
            const Block& previousBlock = chain[i - 1];

            if (currentBlock.hash != currentBlock.calculateHash()) {
                return false;
            }

            if (currentBlock.previousHash != previousBlock.hash) {
                return false;
            }
        }
        return true;
    }
};

class Transaction {
public:
    std::string senderAddress;
    std::string receiverAddress;
    double amount;
    time_t timestamp;
    std::string signature;

    Transaction(std::string sender, std::string receiver, double amount) : senderAddress(sender), receiverAddress(receiver), amount(amount) {
        timestamp = time(0);
    }

    std::string calculateHash() {
        std::stringstream ss;
        ss << senderAddress << receiverAddress << amount << timestamp;
        return sha256(ss.str());
    }

    void signTransaction(std::string privateKey) {
        // 使用私钥对交易哈希进行签名
        // 这里需要集成一个加密库，例如OpenSSL
        signature = "TODO: Implement signature with private key";
    }

    bool isValidTransaction() {
        if (senderAddress.empty()) {
            return true; // Coinbase transaction
        }

        if (signature.empty()) {
            return false; // Invalid transaction
        }

        // 验证签名
        // 这里需要集成一个加密库，例如OpenSSL
        return true; // TODO: Implement signature verification
    }
};