def test_invalid_mpc_pointer(get_clients) -> None:
parties = get_clients(3)
session = Session(parties=parties)
SessionManager.setup_mpc(session)
x = MPCTensor(secret=1, session=session)
# passing sharetensor pointer
with pytest.raises(ValueError):
ABY3.truncate(x, session, 2**32, None)
def test_bit_injection_exception(get_clients) -> None:
parties = get_clients(3)
falcon = Falcon()
session = Session(parties=parties, protocol=falcon)
SessionManager.setup_mpc(session)
x = MPCTensor(secret=1, session=session)
with pytest.raises(ValueError):
ABY3.bit_injection(x, session, 2**64)
def test_eq():
falcon = Falcon()
aby1 = ABY3(security_type="malicious")
aby2 = ABY3()
other2 = falcon
# Test equal protocol:
assert falcon == other2
# Test different protocol security type
assert falcon != aby1
# Test different protocol objects
assert falcon != aby2
def private_compare(x: List[MPCTensor], r: torch.Tensor) -> MPCTensor:
"""Falcon Private Compare functionality which computes(x>r).
Args:
x (List[MPCTensor]) : shares of bits of x in Zp.
r (torch.Tensor) : Public value r.
Returns:
result (MPCTensor): Returns shares of bits of the operation.
Raises:
ValueError: If input shares is not a list.
ValueError: If input public value is not a tensor.
(if (x>=r) returns 1 else returns 0)
"""
if not isinstance(x, list):
raise ValueError(
f"Input shares for Private Compare: {x} must be a list")
if not isinstance(r, torch.Tensor):
raise ValueError(
f"Value r:{r} must be a torch tensor for private compare")
shape = x[0].shape
session = x[0].session
ptr_list: List[ReplicatedSharedTensor] = [
session_ptr.prrs_generate_random_share(shape=shape, ring_size="2")
for session_ptr in session.session_ptrs
]
beta_2 = MPCTensor(shares=ptr_list, session=session,
shape=shape) # shares of random bit
beta_p = ABY3.bit_injection(
beta_2, session, PRIME_NUMBER) # shares of random bit in Zp.
m = Falcon._random_prime_group(session, shape)
nr_shares = len(x)
u = [0] * nr_shares
c = [0] * nr_shares
w = 0
for i in range(len(x) - 1, -1, -1):
r_i = (r >> i) & 1 # bit at ith position
u[i] = (1 - 2 * beta_p) * (x[i] - r_i)
c[i] = u[i] + 1 + w
w += x[i] ^ r_i
d = m * math.prod(c)
d_val = d.reconstruct(decode=False) # plaintext d.
d_val[d_val != 0] = 1 # making all non zero values as 1.
beta_prime = d_val
return beta_2 + beta_prime
def test_private_compare(get_clients, security) -> None:
parties = get_clients(3)
falcon = Falcon(security_type=security)
session = Session(parties=parties, protocol=falcon)
SessionManager.setup_mpc(session)
base = session.config.encoder_base
precision = session.config.encoder_precision
fp_encoder = FixedPointEncoder(base=base, precision=precision)
secret = torch.tensor([[358.85, 79.29], [67.78, 2415.50]])
r = torch.tensor([[357.05, 90], [145.32, 2400.54]])
r = fp_encoder.encode(r)
x = MPCTensor(secret=secret, session=session)
x_b = ABY3.bit_decomposition_ttp(x, session) # bit shares
x_p = [] # prime ring shares
for share in x_b:
x_p.append(ABY3.bit_injection(share, session, PRIME_NUMBER))
tensor_type = get_type_from_ring(session.ring_size)
result = Falcon.private_compare(x_p, r.type(tensor_type))
expected_res = torch.tensor([[1, 0], [0, 1]], dtype=torch.bool)
assert (result.reconstruct(decode=False) == expected_res).all()
def test_eq():
aby = ABY3()
falcon1 = Falcon(security_type="malicious")
falcon2 = Falcon()
other2 = aby
# Test equal protocol:
assert aby == other2
# Test different protocol security type
assert aby != falcon1
# Test different protocol objects
assert aby != falcon2
def select_shares(x: MPCTensor, y: MPCTensor, b: MPCTensor) -> MPCTensor:
"""Returns either x or y based on bit b.
Args:
x (MPCTensor): input tensor
y (MPCTensor): input tensor
b (MPCTensor): input tensor which is shares of a bit used as selector bit.
Returns:
z (MPCTensor):Returns x (if b==0) or y (if b==1).
Raises:
ValueError: If the selector bit tensor is not of ring size "2".
"""
ring_size = int(b.share_ptrs[0].get_ring_size().get_copy())
shape = b.shape
if ring_size != 2:
raise ValueError(
f"Invalid {ring_size} for selector bit,must be of ring size 2")
if shape is None:
raise ValueError(
"The selector bit tensor must have a valid shape.")
session = x.session
# TODO: Should be made to generate with CryptoProvider in Preprocessing stage.
c_ptrs: List[ReplicatedSharedTensor] = []
for session_ptr in session.session_ptrs:
c_ptrs.append(
session_ptr.prrs_generate_random_share(
shape=shape, ring_size=str(ring_size)))
c = MPCTensor(shares=c_ptrs, session=session,
shape=shape) # bit random share
c_r = ABY3.bit_injection(
c, session, session.ring_size) # bit random share in session ring.
tensor_type = get_type_from_ring(session.ring_size)
mask = (b ^ c).reconstruct(decode=False).type(tensor_type)
d = (mask - (c_r * mask)) + (c_r * (mask ^ 1))
# Order placed carefully to prevent re-encoding,should not be changed.
z = x + (d * (y - x))
return z
def mul_master(
x: MPCTensor,
y: MPCTensor,
session: Session,
op_str: str,
kwargs_: Dict[Any, Any],
) -> MPCTensor:
"""Master method for multiplication.
Args:
x (MPCTensor): Secret
y (MPCTensor): Another secret
session (Session): Session the tensors belong to
op_str (str): Operation string.
kwargs_ (Dict[Any, Any]): Kwargs for some operations like conv2d
Returns:
result (MPCTensor): Result of the operation.
Raises:
ValueError: Raised when number of parties are not three.
ValueError : Raised when invalid security_type is provided.
"""
if len(session.parties) != 3:
raise ValueError("Falcon requires 3 parties")
result = None
ring_size = int(x.share_ptrs[0].get_ring_size().get_copy())
conf_dict = x.share_ptrs[0].get_config().get_copy()
config = Config(**conf_dict)
if session.protocol.security_type == "semi-honest":
result = Falcon.mul_semi_honest(x, y, session, op_str, ring_size,
config, **kwargs_)
elif session.protocol.security_type == "malicious":
result = Falcon.mul_malicious(x, y, session, op_str, ring_size,
config, **kwargs_)
else:
raise ValueError("Invalid security_type for Falcon multiplication")
result = ABY3.truncate(result, session, ring_size, config)
return result
def test_truncation_algorithm1(get_clients, base, precision) -> None:
parties = get_clients(3)
falcon = Falcon("semi-honest")
config = Config(encoder_base=base, encoder_precision=precision)
session = Session(parties=parties, protocol=falcon, config=config)
SessionManager.setup_mpc(session)
x = torch.tensor([[1.24, 4.51, 6.87], [7.87, 1301, 541]])
x_mpc = MPCTensor(secret=x, session=session)
result = ABY3.truncate(x_mpc, session, session.ring_size, session.config)
fp_encoder = FixedPointEncoder(base=session.config.encoder_base,
precision=session.config.encoder_precision)
expected_res = x_mpc.reconstruct(decode=False) // fp_encoder.scale
expected_res = fp_encoder.decode(expected_res)
assert np.allclose(result.reconstruct(), expected_res, atol=1e-3)
def test_bit_decomposition_ttp(get_clients, security_type) -> None:
parties = get_clients(3)
falcon = Falcon(security_type=security_type)
session = Session(parties=parties, protocol=falcon)
SessionManager.setup_mpc(session)
secret = torch.tensor([[-1, 12], [-32, 45], [98, -5624]])
x = MPCTensor(secret=secret, session=session)
b_sh = ABY3.bit_decomposition_ttp(x, session)
ring_size = x.session.ring_size
tensor_type = x.session.tensor_type
ring_bits = get_nr_bits(ring_size)
result = torch.zeros(size=x.shape, dtype=tensor_type)
for i in range(ring_bits):
result |= b_sh[i].reconstruct(decode=False).type(tensor_type) << i
exp_res = torch.tensor([[-65536, 786432], [-2097152, 2949120],
[6422528, -368574464]])
assert (result == exp_res).all()
def test_bit_injection_prime(get_clients, security_type) -> None:
parties = get_clients(3)
falcon = Falcon(security_type=security_type)
session = Session(parties=parties, protocol=falcon)
SessionManager.setup_mpc(session)
ring_size = PRIME_NUMBER
bin_sh = torch.tensor([[1, 1], [0, 0]], dtype=torch.bool)
shares = [bin_sh, bin_sh, bin_sh]
ptr_lst = ReplicatedSharedTensor.distribute_shares(shares,
session,
ring_size=2)
x = MPCTensor(shares=ptr_lst, session=session, shape=bin_sh.shape)
xbit = ABY3.bit_injection(x, session, ring_size)
ring0 = int(xbit.share_ptrs[0].get_ring_size().get_copy())
result = xbit.reconstruct(decode=False)
exp_res = bin_sh.type(torch.uint8)
assert (result == exp_res).all()
assert ring_size == ring0
def truncate(self, input_tensor: "MPCTensor", op_str: str,
is_private: bool) -> "MPCTensor":
"""Checks if operation requires truncation and performs it if required.
Args:
input_tensor (MPCTensor): Result of operation
op_str (str): Operation name
is_private (bool): If operation is private
Returns:
result (MPCTensor): Truncated result
"""
from sympc.protocol import ABY3
from sympc.tensor import ReplicatedSharedTensor
result = None
if (op_str in TRUNCATED_OPS
and (not is_private or self.session.nr_parties > 2)
and self.session.protocol.share_class == ShareTensor):
# For private op we do the division in the mul_parties function from spdz
scale = (self.session.config.encoder_base**
self.session.config.encoder_precision)
result = input_tensor.truediv(scale)
elif (op_str in TRUNCATED_OPS and (not is_private)
and self.session.protocol.share_class == ReplicatedSharedTensor):
ring_size = int(self.share_ptrs[0].get_ring_size().get_copy())
conf_dict = self.share_ptrs[0].get_config().get_copy()
config = Config(**conf_dict)
result = ABY3.truncate(input_tensor, self.session, ring_size,
config)
else:
result = input_tensor
return result
def test_invalid_parties_trunc(get_clients) -> None:
parties = get_clients(2)
session = Session(parties=parties)
with pytest.raises(ValueError):
ABY3.truncate(None, session, 2**32, None)
def test_invalid_security_type():
with pytest.raises(ValueError):
ABY3(security_type="covert")
def test_session() -> None:
protocol = ABY3("semi-honest")
session = Session(protocol=protocol)
assert type(session.protocol) == ABY3
def test_local_decomposition_exception() -> None:
x = ReplicatedSharedTensor()
with pytest.raises(ValueError):
ABY3.local_decomposition(x, "2")
