def proof_of_work():
last_block = blockchain[-1]
last_hash = get_hash_of_block(last_block)
proof = 0
while not is_valid_proof(open_transactions, last_hash, proof):
proof += 1
return proof
def mine_block():
last_block = blockchain[-1]
hash_of_block = get_hash_of_block(last_block)
proof = proof_of_work()
# we are excluding the reward_transaction from proof_of_work()
# reward_transaction = {
# 'sender': 'MINING',
# 'recipient': owner,
# 'amount': MINIG_REWARD
# }
reward_transaction = OrderedDict([('sender', 'MINING'),
('recipient', owner),
('amount', MINIG_REWARD)])
# Copying open transaction just in case the open transaction fails, we should not loose open transactions chain
copied_transactions = open_transactions[:]
copied_transactions.append(reward_transaction)
block = {
'previous_hash': hash_of_block,
'index': len(blockchain),
'transactions': copied_transactions,
'proof': proof
}
blockchain.append(block)
save_data()
return True
def verify_chain():
print(blockchain)
for (index, block) in enumerate(blockchain):
if index == 0:
continue
print(block)
if block['previous_hash'] != get_hash_of_block(blockchain[index - 1]):
return False
if not is_valid_proof(block['transactions'][:-1],
block['previous_hash'], block['proof']):
print('proof of work is invalid')
return False
return True