nucypher/tests/unit/test_character_sign_and_ver...

109 lines
3.6 KiB
Python

import pytest
from nucypher.characters.lawful import Alice, Character
from nucypher.config.constants import TEMPORARY_DOMAIN_NAME
from nucypher.crypto.powers import CryptoPower, NoSigningPower, SigningPower
from nucypher.crypto.signing import InvalidSignature
from nucypher.policy.payment import FreeReencryptions
from tests.constants import MOCK_ETH_PROVIDER_URI, TEMPORARY_DOMAIN
"""
Chapter 1: SIGNING
"""
def test_actor_without_signing_power_cannot_sign():
"""
We can create a Character with no real CryptoPower to speak of.
This Character can't even sign a message.
"""
cannot_sign = CryptoPower(power_ups=[])
non_signer = Character(
crypto_power=cannot_sign,
start_learning_now=False,
domain=TEMPORARY_DOMAIN,
eth_endpoint=MOCK_ETH_PROVIDER_URI,
)
# The non-signer's stamp doesn't work for signing...
with pytest.raises(NoSigningPower):
non_signer.stamp("something")
# ...or as a way to cast the (non-existent) public key to bytes.
with pytest.raises(NoSigningPower):
bytes(non_signer.stamp)
def test_actor_with_signing_power_can_sign():
"""
However, simply giving that character a PowerUp bestows the power to sign.
Instead of having a Character verify the signature, we'll use the lower level API.
"""
message = b"Llamas."
signer = Character(
crypto_power_ups=[SigningPower],
is_me=True,
start_learning_now=False,
domain=TEMPORARY_DOMAIN,
eth_endpoint=MOCK_ETH_PROVIDER_URI,
)
stamp_of_the_signer = signer.stamp
# We can use the signer's stamp to sign a message (since the signer is_me)...
signature = stamp_of_the_signer(message)
# ...or to get the signer's public key for verification purposes.
# (note: we verify directly using Umbral API, skipping Character)
verification = signature.verify(stamp_of_the_signer.as_umbral_pubkey(), message)
assert verification is True
def test_anybody_can_verify(random_address):
"""
In the last example, we used the lower-level Crypto API to verify the signature.
Here, we show that anybody can do it without needing to directly access Crypto.
"""
# Alice can sign by default, by dint of her _default_crypto_powerups.
alice = Alice(
start_learning_now=False,
domain=TEMPORARY_DOMAIN_NAME,
checksum_address=random_address,
pre_payment_method=FreeReencryptions(),
eth_endpoint=MOCK_ETH_PROVIDER_URI,
)
# So, our story is fairly simple: an everyman meets Alice.
somebody = Character(
start_learning_now=False,
domain=TEMPORARY_DOMAIN_NAME,
eth_endpoint=MOCK_ETH_PROVIDER_URI,
)
# Alice signs a message.
message = b"A message for all my friends who can only verify and not sign. You know who you are."
signature = alice.stamp(message)
# Our everyman can verify it.
somebody.verify_from(alice, message, signature)
# Of course, verification fails with any fake message
with pytest.raises(InvalidSignature):
fake = b"McLovin 892 Momona St. Honolulu, HI 96820"
somebody.verify_from(alice, fake, signature)
# Signature verification also works when Alice is not living with our
# everyman in the same process, and he only knows her by her public key
alice_pubkey_bytes = bytes(alice.stamp)
hearsay_alice = Character.from_public_keys({SigningPower: alice_pubkey_bytes})
somebody.verify_from(hearsay_alice, message, signature)
hearsay_alice = Character.from_public_keys(verifying_key=alice_pubkey_bytes)
somebody.verify_from(hearsay_alice, message, signature)
alice.disenchant()