def random_block_generator(genesis, initial_leaf_number, block_number):
"""
Randomly generates blocks according to the given parameters.
"""
max_initial_leaf_number = initial_leaf_number
max_block_number = block_number
all_blocks = set()
all_blocks.add(hash(genesis))
leaves = set()
block_counter = 1
yield genesis
while block_counter <= max_block_number:
if block_counter <= max_initial_leaf_number + 1:
parents = {hash(genesis)}
else:
parents = frozenset(
sample(leaves, randint(1, max(1, round(len(leaves) / 5)))))
cur_block = Block(block_counter, parents)
leaves -= cur_block.get_parents()
leaves.add(hash(cur_block))
all_blocks.add(hash(cur_block))
block_counter += 1
yield cur_block
def add(self, block: Block, is_malicious: bool = False):
super().add(block)
global_id = hash(block)
if is_malicious:
self._malicious_blocks_to_add_to_honest_dag.append(global_id)
if self.did_attack_fail():
self._first_parallel_block_gid = global_id
# The malicious attack generates a chain, so the new tip is the current block
self._competing_chain_tip_gid = global_id
self._competing_chain_tip_antipast -= self._G.node[global_id][self._BLUE_DIFF_PAST_ORDER_KEY].keys()
self._competing_chain_tip_antipast -= self._G.node[global_id][self._RED_DIFF_PAST_ORDER_KEY].keys()
# Because we are under the assumption that a selfish miner has zero network latency and the
# simulation design, the assumption is that no new blocks are mined between the moment a new
# selfish block is mined and the moment it is added to the DAG
self._virtual_competing_chain_block_parents = \
self._get_competing_chain_tip_parents(global_id,
self._competing_chain_tip_antipast,
block.get_parents())
else:
# Add malicious blocks to the honest DAG as soon as possible
if self.did_attack_fail():
self._add_malicious_blocks_to_honest_dag()
# This is possible because this is a competing chain attack,
# where the honest chain doesn't include any malicious blocks
self._honest_dag.add(block)
if self.did_attack_succeed():
self._add_malicious_blocks_to_honest_dag()
if not self.did_attack_fail():
# need to update the data structure only if in the middle of a (seemingly) successful attack
self._competing_chain_tip_antipast.add(global_id)
if global_id == self._competing_chain_tip_gid or \
self._is_a_bluer_than_b(self._competing_chain_tip_gid, global_id):
self._virtual_competing_chain_block_parents -= block.get_parents()
self._virtual_competing_chain_block_parents.add(global_id)
elif not self._is_attack_viable():
self._stop_attack()
def add(self, block: Block):
global_id = hash(block)
parents = block.get_parents()
# add the block to the phantom
self._G.add_node(global_id)
self._G.node[global_id][self._BLOCK_DATA_KEY] = block
for parent in parents:
self._G.add_edge(global_id, parent)
# update the leaves
self._leaves -= parents
self._leaves.add(global_id)
# update the coloring of the graph and everything related (the blue anticones and the topological order too)
self._update_coloring_incrementally(global_id)
self._update_topological_order_incrementally(global_id)