def collude_and_recover(num_players, reconstruction_threshold, max_secret_length, shares_subset, num_collude):
'''
Args:
num_players, the number of players that were shared across
reconstruction_threshold, the threshold for reconstruction
max_secret_length, the maximum length of the secret that was shared
shares_subset, a dictionary of a subset of players to json robust shares
num_corrupt, the number of players that will collude
Returns:
the result of robust reconstruction
'''
max_secret_length = len(secret)
colluders = {player: rss._deserialize_robust_share(share) for player, share in shares_subset.items()[:num_collude]}
for player, player_dict in colluders.items():
player_dict["share"] /= 2
for verifier, verifier_dict in colluders.items():
new_key, new_vector = authentication.generate_check_vector(player_dict["share"], max_secret_length)
verifier_dict["keys"][player] = new_key
player_dict["vectors"][verifier] = new_vector
# assert that these players do in fact collude
for verifier, verifier_dict in colluders.items():
for player, player_dict in colluders.items():
assert authentication.validate(verifier_dict["keys"][player], player_dict["vectors"][verifier],
player_dict["share"], max_secret_length) is True
shares = combine_testing_dictionaries(shares_subset, jsonify_dict(colluders))
return rss.reconstruct_authenticated_secret(num_players, reconstruction_threshold, max_secret_length, shares)
def test_generate_batch_validate_single():
message = 112358132134
max_length = len(str(message))
num_macs = 55
keys, vectors = authentication.generate_batch(num_macs, message, max_length)
for key, vector in zip(keys, vectors):
assert authentication.validate(key, vector, message, max_length) is True
def test_check_vector_b():
message = 112358132134
max_length = len(str(message))
for i in range(1000):
key, vector = authentication.generate_check_vector(message, max_length)
if (vector[0] == 0): # verify that b is never zero for many cases
assert False
else:
assert authentication.validate(key, vector, message, max_length) and vector[0] != 0
def test_check_vector_large():
message = ('123456789012345678901234567890123456789012345678901234567890'
'123456789012345678901234567890123456789012345678901234567890'
'123456789012345678901234567890123456789012345678901234567890'
'123456789012345678901234567890123456789012345678901234567890'
'123456789012345678901234567890123456789012345678901234567890'
'123456789012345678901234567890123456789012345678901234567890'
'12345678901234567890')
max_length = len(message)
message = int(message)
key, vector = authentication.generate_check_vector(message, max_length)
assert authentication.validate(key, vector, message, max_length) is True
def _get_player_to_verifies_map(shares_map, keys_for_players, vectors_from_players, max_secret_length):
'''
Args:
shares_map, a mapping of player string ids to integer shares
keys_for_players, a mapping of player string ids to maps of keys to associate with other players
vectors_from_players, a mapping of player string ids to maps of vectors associated with this player's share
max_secret_length, the max length of the share if it were represented as a bytestring
Returns:
a mapping from player string id (verifier) to a tuple of players verified by the verifier
'''
verifies = defaultdict(list)
for verifier in shares_map.keys():
for player, share in shares_map.items():
if authentication.validate(keys_for_players[verifier][player], vectors_from_players[player][verifier], share, max_secret_length + 1):
verifies[verifier].append(player)
# return a dictionary that can be inverted - the value is a tuple (hashable) and sorted (in preparation for equality checks)
return {verifier: tuple(sorted(players)) for verifier, players in verifies.items()}
def test_check_vector_standard():
message = 112358132134
max_length = len(str(message))
key, vector = authentication.generate_check_vector(message, max_length)
assert authentication.validate(key, vector, message, max_length) is True
