区块链技术与应用 第三章：分布式账本

22v区块链(Blockchain)本质上是一个数据库33…44……66……88融账本基础v交易(Transaction)v在区块链账本系统中，一条记录(Item)通常为一条交易 99融账本基础v账本(Ledger)v在区块链账本系统中，一个账本(Ledger)即为一个区块链 v区块(Block)相当于为账本的分页(Page)布式账本特点v又称共享账本(SharedLedger)、分散式账本技术(Distributed布式账本特点布式账本特点布式账本特点v成本低(Cheap)v可信度高(Trustworthy)v匿名(Anonymous)/wp-content/uploads/2020/04/Python-Cheat-Sheet.pdfhttps://perso.limsi.fr/pointal/_media/python:cours:mementopython3-english.pdfimporthashlibfromwrenchbox.objectimportDict2StrSafeclassBase(Dict2StrSafe):defhash(self):returnhashlib.sha1(str(self.__dict__).encode()).hexdigest()/3/library/hashlib.importhashlibfromwrenchbox.objectimportDict2StrSafeclassBase(Dict2StrSafe):defhash(self):returnhashlib.sha1(str(self.__dict__).encode()).hexdigest()ox/object.pyclassA:def__init__(self):self.x=1classB:def__init__(self):self.a=A()b=B()print(b)fromwrenchbox.objectimportDict2StrSafeclassA1(Dict2StrSafe):def__init__(self):self.x=1classB1(Dict2StrSafe):def__init__(self):self.a=A1()b=B1()print(b)importhashlibfromwrenchbox.objectimportDict2StrSafeclassBase(Dict2StrSafe):defhash(self):returnhashlib.sha1(str(self.__dict__).encode()).hexdigest()fromdatetimeimportdatetimefromuuidimportUUIDfrom.basicimportBaseclassTransaction(Base):def__init__(self,sender:str,receiver:str,amount:int,t:float=None,prev_hash:str=None):classTransaction(Base):def__init__(self,…):assertUUID(sender,version=4)assertUUID(receiver,version=4)self.sender=senderself.receiver=receiverself.t=tiftisnotNoneelsedatetime.now().timestamp()self.prev_hash=prev_hashfrom.basicimportBaseclassBlock(Base):def__init__(self,prev_hash:str=None):self.items=[]self.prev_hash=prev_hash…classBlock(Base):…defadd(self,item):item.prev_hash=self.items[-1].hash()iflen(self.items)elseNoneself.items.append(item)…classBlock(Base):…defvalidate(self):foriinrange(len(self.items)):asserti==0orself.items[i].prev_hash==self.items[i-1].hash()classBlockchain(Base):def__init__(self):self.blocks=[]defadd(self,block):block.prev_hash=self.blocks[-1].hash()iflen(self.blocks)elseNoneself.blocks.append(block)…classBlockchain(Base):…defvalidate(self):foriinrange(len(self.blocks)):asserti==0orself.blocks[i].prev_hash==self.blocks[i-1].hash()self.blocks[i].validate()账本importjsonfromuuidimportuuid4fromfoxchain.blockchainimportBlockchain,Blockfromfoxchain.transactionimportTransactionchain=Blockchain()…账本…chain=Blockchain()foriinrange(3):block=Block()forjinrange(10):transaction=Transaction(sender=str(uuid4()),receiver=str(uuid4()),t)block.add(transaction)chain.add(block)…账本……print(json.dumps(json.loads(str(chain)),indent=4,sort_keys=True))print(chain.validate())…账本……chain.blocks[0].i