MPC controller

Attributes

Classes

MPCController 

MPCController(tmp_dir, component_type, component_id)

Parameters:

Name Type Description Default
tmp_dir str

directory use as basedir for temporary files

 required
component_type ComponentType

type of component (researcher or node) this

 required
component_id str

unique ID of this component

 required

Raises:

Type Description
FedbiomedMPCControllerError

cannot create directory for temporary files or MPC files
Source code in fedbiomed/common/mpc_controller.py 
def __init__(
        self,
        tmp_dir: str,
        component_type: ComponentType,
        component_id: str,
) -> None:
    """Multi Party Computation for negotiating cryptographic material with other parties.

    Args:
        tmp_dir: directory use as basedir for temporary files
        component_type: type of component (researcher or node) this
        component_id: unique ID of this component

    Raises:
        FedbiomedMPCControllerError: cannot create directory for temporary files or MPC files
    """

    # Get root directory of fedbiomed
    self._root = ROOT_DIR
    self._component_type = component_type

    mpc_controller_id = str(uuid.uuid4())

    # Use tmp dir to write files
    self._tmp_dir = os.path.join(tmp_dir, 'MPC', component_id, mpc_controller_id)

    # Create TMP dir for MPC logs if it is not existing
    if not os.path.isdir(self._tmp_dir):
        try:
            os.makedirs(self._tmp_dir)
        except Exception as e:
            raise FedbiomedMPCControllerError(
                f"{ErrorNumbers.FB620.value}: Cannot create directory for MPC temporary files : {e}"
            )

    self._mpc_script = os.path.join(self._root, 'scripts', 'fedbiomed_mpc')
    self._mpc_dir = os.path.join(self._tmp_dir, 'MP-SPDZ')
    self._mpc_data_dir = os.path.join(self._mpc_dir , 'Player-Data')

    if not os.path.isdir(self._mpc_data_dir):
        try:
            os.makedirs(self._mpc_data_dir)
        except Exception as e:
            raise FedbiomedMPCControllerError(
                f"{ErrorNumbers.FB620.value}: Cannot create directory for MPC config data : {e}"
            )

    self._process = None

Attributes

mpc_data_dir property 
mpc_data_dir

Getter for MPC config data directory

Returns:

Type Description
str

directory for MPC config data directory
tmp_dir property 
tmp_dir

Getter for MPC temporary files directory

Returns:

Type Description
str

directory for MPC temporary files directory

Functions

exec_shamir 
exec_shamir(party_number, num_parties, ip_addresses)

Executes shamir protocol

Parameters:

Name Type Description Default
party_number int

The party number whose executing the protocol

 required
num_parties int

NUm of total parties participating to multi party computation

 required
ip_addresses str

The file path where IP addresses of the parties. This file is supposed to respect the order of parties.

 required

Returns:

Type Description
str

Path to the file where the input value (key-share) of the parties or output value of the server(server key) is written by the protocol.

Raises:

Type Description
FedbiomedMPCControllerError

MPC computation error, or bad parameters
Source code in fedbiomed/common/mpc_controller.py 
def exec_shamir(
        self,
        party_number: int,
        num_parties: int,
        ip_addresses: str,
) -> str:
    """Executes shamir protocol

    Args:
        party_number: The party number whose executing the protocol
        num_parties: NUm of total parties participating to multi party computation
        ip_addresses: The file path where IP addresses of the parties. This file is supposed
            to respect the order of parties.

    Returns:
        Path to the file where the input value (key-share) of the parties or output value of the server(server key)
            is written by the protocol.

    Raises:
        FedbiomedMPCControllerError: MPC computation error, or bad parameters
    """

    output_file = os.path.join(self._tmp_dir, "Output")
    input_file = os.path.join(self._tmp_dir, "Input")

    i_f_command = ["-if", input_file] if party_number != 0 else []
    o_f_command = ["-of", output_file] if party_number == 0 else []

    command = [self._component_type.name.lower(),
               self._mpc_dir,
               "shamir-server-key",
               "-pn", str(party_number),
               "-nop", str(num_parties),
               *i_f_command, *o_f_command,
               "-aip", ip_addresses, "--compile"]
    status, output = self._exec(command=command)

    if not status:
        error_message = f"{ErrorNumbers.FB620.value}: MPC computation for {self._component_type.name} " \
            "is not successful."
        logger.debug(f"{error_message}. Details: {output}")
        raise FedbiomedMPCControllerError(error_message)

    return f"{output_file}-P{party_number}-0" if party_number == 0 else \
        f"{input_file}-P{party_number}-0"
kill 
kill()

Kills running MP-SPDZ process

Source code in fedbiomed/common/mpc_controller.py 
def kill(self):
    """Kills running MP-SPDZ process"""

    if self._process:
        parent = psutil.Process(self._process.pid)
        for child in parent.children(recursive=True):
            child.kill()
        parent.kill()