def validate_block(bigchain, block):
"""Validate a block.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
block (dict): block to validate.
Returns:
The block if the block is valid else it raises an exception
describing the reason why the block is invalid.
Raises:
InvalidHash: if the hash of the block is wrong.
"""
# Check if current hash is correct
calculated_hash = crypto.hash_data(util.serialize(block['block']))
if calculated_hash != block['id']:
raise exceptions.InvalidHash()
# Check if the block was created by a federation node
if block['block']['node_pubkey'] not in (bigchain.nodes_except_me +
[bigchain.me]):
raise exceptions.OperationError(
'Only federation nodes can create blocks')
# Check if block signature is valid
verifying_key = crypto.VerifyingKey(block['block']['node_pubkey'])
if not verifying_key.verify(util.serialize(block['block']),
block['signature']):
raise exceptions.InvalidSignature('Invalid block signature')
return block
def check_hash_and_signature(transaction):
# Check hash of the transaction
calculated_hash = get_hash_data(transaction)
if calculated_hash != transaction['id']:
raise exceptions.InvalidHash()
# Check signature
if not validate_fulfillments(transaction):
raise exceptions.InvalidSignature()
def check_hash_and_signature(transaction):
# Check hash of the transaction
calculated_hash = hash_data(serialize(transaction['transaction']))
if calculated_hash != transaction['id']:
raise exceptions.InvalidHash()
# Check signature
if not verify_signature(transaction):
raise exceptions.InvalidSignature()
def validate_block(bigchain, block):
"""Validate a block.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
block (dict): block to validate.
Returns:
The block if the block is valid else it raises an exception
describing the reason why the block is invalid.
Raises:
InvalidHash: if the hash of the block is wrong.
"""
# Check if current hash is correct
calculated_hash = crypto.hash_data(util.serialize(block['block']))
if calculated_hash != block['id']:
raise exceptions.InvalidHash()
return block
def validate_block(self, block):
"""Validate a block.
Args:
block (dict): block to validate.
Returns:
The block if the block is valid else it raises and exception
describing the reason why the block is invalid.
"""
# 1. Check if current hash is correct
calculated_hash = crypto.hash_data(util.serialize(block['block']))
if calculated_hash != block['id']:
raise exceptions.InvalidHash()
# 2. Validate all transactions in the block
for transaction in block['block']['transactions']:
if not self.is_valid_transaction(transaction):
# this will raise the exception
self.validate_transaction(transaction)
return block
def validate_transaction(bigchain, transaction):
"""Validate a transaction.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
transaction (dict): transaction to validate.
Returns:
The transaction if the transaction is valid else it raises an
exception describing the reason why the transaction is invalid.
Raises:
OperationError: if the transaction operation is not supported
TransactionDoesNotExist: if the input of the transaction is not found
TransactionOwnerError: if the new transaction is using an input it doesn't own
DoubleSpend: if the transaction is a double spend
InvalidHash: if the hash of the transaction is wrong
InvalidSignature: if the signature of the transaction is wrong
"""
# If the operation is CREATE the transaction should have no inputs and
# should be signed by a federation node
if transaction['transaction']['operation'] == 'CREATE':
if transaction['transaction']['input']:
raise ValueError('A CREATE operation has no inputs')
if transaction['transaction']['current_owner'] not in (
bigchain.federation_nodes + [bigchain.me]):
raise exceptions.OperationError(
'Only federation nodes can use the operation `CREATE`')
else:
# check if the input exists, is owned by the current_owner
if not transaction['transaction']['input']:
raise ValueError(
'Only `CREATE` transactions can have null inputs')
tx_input = bigchain.get_transaction(
transaction['transaction']['input'])
if not tx_input:
raise exceptions.TransactionDoesNotExist(
'input `{}` does not exist in the bigchain'.format(
transaction['transaction']['input']))
if (tx_input['transaction']['new_owner'] !=
transaction['transaction']['current_owner']):
raise exceptions.TransactionOwnerError(
'current_owner `{}` does not own the input `{}`'.format(
transaction['transaction']['current_owner'],
transaction['transaction']['input']))
# check if the input was already spent by a transaction other than
# this one.
spent = bigchain.get_spent(tx_input['id'])
if spent and spent['id'] != transaction['id']:
raise exceptions.DoubleSpend(
'input `{}` was already spent'.format(
transaction['transaction']['input']))
# Check hash of the transaction
calculated_hash = crypto.hash_data(
util.serialize(transaction['transaction']))
if calculated_hash != transaction['id']:
raise exceptions.InvalidHash()
# Check signature
if not util.verify_signature(transaction):
raise exceptions.InvalidSignature()
return transaction
def validate_transaction(bigchain, transaction):
"""Validate a transaction.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
transaction (dict): transaction to validate.
Returns:
The transaction if the transaction is valid else it raises an
exception describing the reason why the transaction is invalid.
Raises:
OperationError: if the transaction operation is not supported
TransactionDoesNotExist: if the input of the transaction is not found
TransactionOwnerError: if the new transaction is using an input it doesn't own
DoubleSpend: if the transaction is a double spend
InvalidHash: if the hash of the transaction is wrong
InvalidSignature: if the signature of the transaction is wrong
"""
# If the operation is CREATE the transaction should have no inputs and
# should be signed by a federation node
if transaction['transaction']['operation'] == 'CREATE':
# TODO: for now lets assume a CREATE transaction only has one fulfillment
if transaction['transaction']['fulfillments'][0]['input']:
raise ValueError('A CREATE operation has no inputs')
# TODO: for now lets assume a CREATE transaction only has one current_owner
if transaction['transaction']['fulfillments'][0]['current_owners'][
0] not in (bigchain.nodes_except_me + [bigchain.me]):
raise exceptions.OperationError(
'Only federation nodes can use the operation `CREATE`')
else:
# check if the input exists, is owned by the current_owner
if not transaction['transaction']['fulfillments']:
raise ValueError('Transaction contains no fulfillments')
# check inputs
for fulfillment in transaction['transaction']['fulfillments']:
if not fulfillment['input']:
raise ValueError(
'Only `CREATE` transactions can have null inputs')
tx_input = bigchain.get_transaction(
fulfillment['input']['txid'])
if not tx_input:
raise exceptions.TransactionDoesNotExist(
'input `{}` does not exist in the bigchain'.format(
fulfillment['input']['txid']))
# TODO: check if current owners own tx_input (maybe checked by InvalidSignature)
# check if the input was already spent by a transaction other than
# this one.
spent = bigchain.get_spent(fulfillment['input'])
if spent and spent['id'] != transaction['id']:
raise exceptions.DoubleSpend(
'input `{}` was already spent'.format(
fulfillment['input']))
# Check hash of the transaction
calculated_hash = util.get_hash_data(transaction)
if calculated_hash != transaction['id']:
raise exceptions.InvalidHash()
# Check fulfillments
if not util.validate_fulfillments(transaction):
raise exceptions.InvalidSignature()
return transaction
