def test_transaction_verify_transaction_signature_too_large_signature(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
transaction.add_signature("3379cc2f08e4cde5d24af02611c32693b18f406d4b58fbcd2bbd0acc67b1d")
verify = transaction.verify_transaction_signature()
self.assertFalse(verify)
def test_transaction_verify_transaction_signature(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
signature = wallet.sign_transaction(transaction)
transaction.add_signature(signature)
verify = transaction.verify_transaction_signature()
self.assertTrue(verify)
def add_new_transaction(self, transaction: Transaction) -> bool:
'''
add a new transaction to the block
after checking balance
'''
if transaction.verify_transaction_signature():
# Check balance and fee before confirming a transaction
total_charge = float(transaction.value) + float(transaction.fee)
if transaction.sender != "Block_Reward" and \
self.check_balance(transaction.sender) >= total_charge:
self.unconfirmed_transactions.append(transaction.to_json())
return True
return False
def valid_chain(self, chain: List[str]) -> bool:
'''check if a blockchain (all blocks) is valid'''
current_index = 0
chain = json.loads(chain)
# load and check every block from the blockchain
while current_index < len(chain):
block = json.loads(chain[current_index])
current_block = Block(block['index'], block['transaction'],
block['timestamp'], block['previous_hash'])
current_block.merkle_root = block['merkle_root']
current_block.nonce = block['nonce']
current_block.difficulty = block['difficulty']
# if the current block is NOT the last block
if current_index + 1 < len(chain):
# if the hash value of the current block != previous block's hash value of the next block, then reject
if current_block.compute_hash() != json.loads(
chain[current_index + 1])['previous_hash']:
return False
# check if the current block is an instance from the list of chain
if isinstance(current_block.transaction, list):
for transaction in current_block.transaction:
transaction = json.loads(transaction)
# Skip block reward because it does not have signature
if transaction['sender'] == 'Block_Reward':
continue
current_transaction = Transaction(transaction['sender'],
transaction['recipient'],
transaction['value'])
current_transaction.signature = transaction['signature']
# check if digital signature of each transaction is valid, if not then reject
if not current_transaction.verify_transaction_signature():
return False
# check if hash value of the current block is not valid, if yes then reject
if not self.is_valid_proof(current_block, block['hash']):
return False
current_index += 1
return True
def test_transaction_verify_transaction_signature_no_signature(self):
wallet = Wallet()
transaction = Transaction(wallet.pubkey, "CityU", 1)
verify = transaction.verify_transaction_signature()
self.assertFalse(verify)
