nucypher/examples/finnegans_wake_demo/finnegans-wake-concise-demo.py

145 lines
4.8 KiB
Python

import datetime
import os
import shutil
import maya
from twisted.logger import globalLogPublisher
from nucypher.characters.lawful import Alice, Bob, Ursula
from nucypher.data_sources import DataSource as Enrico
from nucypher.network.middleware import RestMiddleware
from nucypher.utilities.logging import simpleObserver
from umbral.keys import UmbralPublicKey
######################
# Boring setup stuff #
######################
# Execute the download script (download_finnegans_wake.sh) to retrieve the book
BOOK_PATH = os.path.join('.', 'finnegans-wake.txt')
# Twisted Logger
globalLogPublisher.addObserver(simpleObserver)
# Temporary file storage
TEMP_FILES_DIR = "{}/examples-runtime-cruft".format(os.path.dirname(os.path.abspath(__file__)))
TEMP_DEMO_DIR = "{}/finnegans-wake-demo".format(TEMP_FILES_DIR)
TEMP_CERTIFICATE_DIR = "{}/certs".format(TEMP_DEMO_DIR)
# Remove previous demo files and create new ones
shutil.rmtree(TEMP_FILES_DIR, ignore_errors=True)
os.mkdir(TEMP_FILES_DIR)
os.mkdir(TEMP_DEMO_DIR)
os.mkdir(TEMP_CERTIFICATE_DIR)
#######################################
# Finnegan's Wake on NuCypher Testnet #
# (will fail with bad connection) #####
#######################################
TESTNET_LOAD_BALANCER = "eu-federated-balancer-40be4480ec380cd7.elb.eu-central-1.amazonaws.com"
##############################################
# Ursula, the Untrusted Re-Encryption Proxy #
##############################################
ursula = Ursula.from_seed_and_stake_info(host=TESTNET_LOAD_BALANCER,
certificates_directory=TEMP_CERTIFICATE_DIR,
federated_only=True,
minimum_stake=0)
# Here are our Policy details.
policy_end_datetime = maya.now() + datetime.timedelta(days=5)
m, n = 2, 3
label = b"secret/files/and/stuff"
######################################
# Alice, the Authority of the Policy #
######################################
ALICE = Alice(network_middleware=RestMiddleware(),
known_nodes=[ursula],
learn_on_same_thread=True,
federated_only=True,
known_certificates_dir=TEMP_CERTIFICATE_DIR)
BOB = Bob(
known_nodes=[ursula],
network_middleware=RestMiddleware(),
federated_only=True,
start_learning_now=True,
learn_on_same_thread=True,
known_certificates_dir=TEMP_CERTIFICATE_DIR)
ALICE.start_learning_loop(now=True)
policy = ALICE.grant(BOB,
label,
m=m, n=n,
expiration=policy_end_datetime)
# Alice puts her public key somewhere for Bob to find later...
alices_pubkey_bytes_saved_for_posterity = bytes(ALICE.stamp)
# ...and then disappears from the internet.
del ALICE
#####################
# some time passes. #
# ... #
# #
# ... #
# And now for Bob. #
#####################
#####################
# Bob the BUIDLer ##
#####################
BOB.join_policy(label, alices_pubkey_bytes_saved_for_posterity)
# Now that Bob has joined the Policy, let's show how Enrico the Encryptor
# can share data with the members of this Policy and then how Bob retrieves it.
with open(BOOK_PATH, 'rb') as file:
finnegans_wake = file.readlines()
print()
print("**************James Joyce's Finnegan's Wake**************")
print()
print("---------------------------------------------------------")
for counter, plaintext in enumerate(finnegans_wake):
#########################
# Enrico, the Encryptor #
#########################
enciro = Enrico(policy_pubkey_enc=policy.public_key)
# In this case, the plaintext is a
# single passage from James Joyce's Finnegan's Wake.
# The matter of whether encryption makes the passage more or less readable
# is left to the reader to determine.
single_passage_ciphertext, _signature = enciro.encrypt_message(plaintext)
data_source_public_key = bytes(enciro.stamp)
del enciro
###############
# Back to Bob #
###############
enrico_as_understood_by_bob = Enrico.from_public_keys(
policy_public_key=policy.public_key,
datasource_public_key=data_source_public_key,
label=label
)
# Now Bob can retrieve the original message.
alice_pubkey_restored_from_ancient_scroll = UmbralPublicKey.from_bytes(alices_pubkey_bytes_saved_for_posterity)
delivered_cleartexts = BOB.retrieve(message_kit=single_passage_ciphertext,
data_source=enrico_as_understood_by_bob,
alice_verifying_key=alice_pubkey_restored_from_ancient_scroll)
# We show that indeed this is the passage originally encrypted by Enrico.
assert plaintext == delivered_cleartexts[0]
print("Retrieved: {}".format(delivered_cleartexts[0]))