# 导入必要的库
import hashlib
import JSON

# 定义一个函数来计算哈希值
def calculate_hash(data):
"""
计算数据的哈希值

:param data: 要计算哈希值的数据
:return: 数据的哈希值
"""
# 创建一个SHA256哈希对象
hasher = hashlib.sha256()

# 将数据转换为字节数组
data_bytes = data.encode("utf-8")

# 将数据字节数组更新到哈希对象中
hasher.update(data_bytes)

# 获取hash值
hash_value = hasher.hexdigest()

# 返回hash值
return hash_value

# 定义一个函数来创建区块
def create_block(index, timestamp, data, previous_hash):
"""
创建一个区块

:param index: 区块的索引
:param timestamp: 区块的时间戳
:param data: 区块的数据
:param previous_hash: 上一个区块的哈希值
:return: 一个区块
"""
# 创建一个区块
block = {
"index": index,
"timestamp": timestamp,
"data": data,
"previous_hash": previous_hash
}

# 计算区块的哈希值
block["hash"] = calculate_hash(json.dumps(block))

# 返回区块
return block

# 创建创世区块
genesis_block = create_block(0, "2023-03-08 12:00:00", "创世区块", "0")

# 创建第二个区块
second_block = create_block(1, "2023-03-08 12:01:00", "第二个区块", genesis_block["hash"])

# 创建第三个区块
third_block = create_block(2, "2023-03-08 12:02:00", "第三个区块", second_block["hash"])

# 打印区块链
blockchain = [genesis_block, second_block, third_block]
print(json.dumps(blockchain, indent=4))