Interactive Programs

We define an interactive Cicada program as one that prompts a human for secret input to be used in a computation. Because handling secret interactive input can be tricky, Cicada includes the cicada.interactive.secret_input() function, which prompts one player for input from a console, which could then be secret-shared with the group. You can use it for simple demos and as a starting-point for more sophisticated interaction. Here are some examples:

Tip

These programs can’t be run in a notebook, they need to be run in separate windows using the cicada command … see Running Cicada Programs for some helpful examples of how to run interactive programs.

Here’s a minimal program that prompts player 0 for a secret. Note that the startup timeout for the communicator has been increased to five minutes (300 seconds) to allow enough time to manually start all of the player processes:

import logging

from cicada.additive import AdditiveProtocolSuite
from cicada.communicator import SocketCommunicator
from cicada.interactive import secret_input
from cicada.logging import Logger

logging.basicConfig(level=logging.INFO)

with SocketCommunicator.connect(startup_timeout=300) as communicator:
    log = Logger(logging.getLogger(), communicator)
    protocol = AdditiveProtocolSuite(communicator)

    secret = secret_input(communicator=communicator, src=0)
    log.info(f"Player {communicator.rank} secret: {secret}")

    secret_share = protocol.share(src=0, secret=secret, shape=())
    log.info(f"Player {communicator.rank} share: {secret_share}")

In this example, every player provides a secret, and the group computes the sum:

import logging

import numpy

from cicada.additive import AdditiveProtocolSuite
from cicada.communicator import SocketCommunicator
from cicada.interactive import secret_input
from cicada.logging import Logger

logging.basicConfig(level=logging.INFO, format="{message}", style="{")

with SocketCommunicator.connect(startup_timeout=300) as communicator:
    log = Logger(logging.getLogger(), communicator)
    protocol = AdditiveProtocolSuite(communicator)

    total = protocol.share(src=0, secret=numpy.zeros(shape=()), shape=())
    for i in range(communicator.world_size):
        secret = secret_input(communicator=communicator, src=i)
        share = protocol.share(src=i, secret=secret, shape=())
        total = protocol.add(total, share)

    total = protocol.reveal(total)
    log.info(f"Player {communicator.rank} total: {total}")

Finally, the following is an interactive version of the millionaire’s dilemma … every player provides a secret, and the group determines which person entered the largest value:

import logging

import numpy

from cicada.additive import AdditiveProtocolSuite
from cicada.communicator import SocketCommunicator
from cicada.encoding import Boolean
from cicada.interactive import secret_input
from cicada.logging import Logger

logging.basicConfig(level=logging.INFO, format="{message}", style="{")

with SocketCommunicator.connect(startup_timeout=300) as communicator:
    log = Logger(logging.getLogger(), communicator)
    protocol = AdditiveProtocolSuite(communicator)

    winner = None
    winning_share = protocol.share(src=0, secret=numpy.zeros(shape=()), shape=())

    for rank in communicator.ranks:
        fortune = secret_input(communicator=communicator, src=rank, prompt=f"Player {communicator.rank} fortune: ")
        fortune_share = protocol.share(src=rank, secret=fortune, shape=())
        less_share = protocol.less(fortune_share, winning_share)
        less = protocol.reveal(less_share, encoding=Boolean())
        if not less:
            winner = rank
            winning_share = fortune_share

    log.info(f"Winner: player {winner}")