Python如何构建区块链？基本数据结构实现

import hashlib
import time

class Block:
    def __init__(self, index, timestamp, data, previous_hash, nonce=0):
        self.index = index
        self.timestamp = timestamp
        self.data = data
        self.previous_hash = previous_hash
        self.nonce = nonce
        self.hash = self.calculate_hash() # 初始哈希，可能在PoW后更新

    def calculate_hash(self):
        # 确保所有数据都被编码成字节串
        block_string = f"{self.index}{self.timestamp}{self.data}{self.previous_hash}{self.nonce}".encode('utf-8')
        return hashlib.sha256(block_string).hexdigest()

    def calculate_hash(self):
        # 确保所有数据都被编码成字节串
        block_string = f"{self.index}{self.timestamp}{self.data}{self.previous_hash}{self.nonce}".encode('utf-8')
        return hashlib.sha256(block_string).hexdigest()

f-string

encode()

new_block

class Blockchain:
    def __init__(self):
        self.chain = []
        self.difficulty = 2 # 比如，哈希值前两位必须是'00'
        self.create_genesis_block()

    def create_genesis_block(self):
        # 创世区块没有前一个哈希，通常设为'0'或空字符串
        self.chain.append(Block(0, time.time(), "Genesis Block", "0"))

    def get_last_block(self):
        return self.chain[-1]

    def proof_of_work(self, index, timestamp, data, previous_hash):
        nonce = 0
        while True:
            # 构建一个临时的字符串来计算哈希，模拟新区块的结构
            test_string = f"{index}{timestamp}{data}{previous_hash}{nonce}".encode('utf-8')
            current_hash = hashlib.sha256(test_string).hexdigest()

            if current_hash.startswith('0' * self.difficulty):
                return nonce, current_hash # 返回找到的nonce和对应的哈希
            nonce += 1

    def new_block(self, data):
        last_block = self.get_last_block()
        index = last_block.index + 1
        timestamp = time.time()
        previous_hash = last_block.hash

        # 执行工作量证明，找到有效的nonce和哈希
        nonce, current_hash = self.proof_of_work(index, timestamp, data, previous_hash)

        # 创建新区块，并直接赋值计算好的哈希
        block = Block(index, timestamp, data, previous_hash, nonce)
        block.hash = current_hash 
        self.chain.append(block)
        return block