بلاک‌چین چطور کار می‌کند؟ یک زنجیرهٔ کوچک با پایتون بساز

@dataclass(frozen=True)
class Block:
    index: int
    data: str
    previous_hash: str

def append(chain, data):
    previous = digest(chain[-1]) if chain else "0" * 64
    chain.append(Block(len(chain), data, previous))

def digest(block):
    payload = json.dumps(
        {"index": block.index, "data": block.data,
         "previous_hash": block.previous_hash},
        sort_keys=True, separators=(",", ":"), ensure_ascii=False,
    ).encode("utf-8")
    return sha256(payload).hexdigest()

def valid(chain):
    previous = "0" * 64
    for index, block in enumerate(chain):
        if block.index != index or block.previous_hash != previous:
            return False
        previous = digest(block)
    return True

python3 toy_chain.py
# Toy chain: all checks passed