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Properly delivering Alice's signature in the case that she signs the cleartext and includes it in the ciphertext.

pull/129/head
jMyles 2017-11-21 22:02:26 -08:00
parent 2f7bdecc3a
commit 1e67468013
1 changed files with 18 additions and 7 deletions
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25
nkms/characters.py
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@ -14,6 +14,8 @@ from nkms.crypto import api as API
from nkms.crypto.api import secure_random, keccak_digest
from nkms.crypto.constants import NOT_SIGNED, NO_DECRYPTION_PERFORMED
from nkms.crypto.powers import CryptoPower, SigningPower, EncryptingPower
from nkms.crypto.signature import Signature
from nkms.crypto.utils import BytestringSplitter
from nkms.keystore.keypairs import Keypair
from nkms.network import blockchain_client
from nkms.network.protocols import dht_value_splitter
@ -117,20 +119,24 @@ class Character(object):
"""
actor = self._lookup_actor(recipient)
ciphertext = self._crypto_power.encrypt_for(actor.public_key(EncryptingPower),
cleartext)
if sign:
if sign_cleartext:
signature = self.seal(cleartext)
ciphertext = self._crypto_power.encrypt_for(actor.public_key(EncryptingPower),
signature + cleartext)
else:
ciphertext = self._crypto_power.encrypt_for(actor.public_key(EncryptingPower),
cleartext)
signature = self.seal(ciphertext)
else:
signature = NOT_SIGNED
ciphertext = self._crypto_power.encrypt_for(actor.public_key(EncryptingPower),
cleartext)
return ciphertext, signature
def verify_from(self, actor_whom_sender_claims_to_be: "Character", signature: bytes,
message: bytes, decrypt=False,
def verify_from(self, actor_whom_sender_claims_to_be: "Character", message: bytes, signature: Signature = None,
decrypt=False,
signature_is_on_cleartext=False) -> tuple:
"""
Inverse of encrypt_for.
@ -141,11 +147,15 @@ class Character(object):
:param signature_is_on_cleartext: True if we expect the signature to be on the cleartext. Otherwise, we presume that the ciphertext is what is signed.
:return: (Whether or not the signature is valid, the decrypted plaintext or NO_DECRYPTION_PERFORMED)
"""
if not signature and not signature_is_on_cleartext:
raise ValueError("You need to either provide the Signature or decrypt and find it on the cleartext.")
cleartext = NO_DECRYPTION_PERFORMED
if signature_is_on_cleartext:
if decrypt:
cleartext = self._crypto_power.decrypt(message)
message = cleartext
signature, message = BytestringSplitter(Signature)(cleartext, return_remainder=True)
else:
raise ValueError(
"Can't look for a signature on the cleartext if we're not decrypting.")
@ -244,7 +254,7 @@ class Bob(Character):
self._ursulas[ursula_interface_id] = Ursula.as_discovered_on_network(port=port, interface=interface,
pubkey_sig_bytes=ursula_pubkey_sig)
def get_treasure_map(self, policy_group, signature):
def get_treasure_map(self, policy_group):
dht_key = policy_group.treasure_map_dht_key()
@ -253,8 +263,9 @@ class Bob(Character):
packed_encrypted_treasure_map = event_loop.run_until_complete(ursula_coro)
_signature_for_ursula, pubkey_sig_alice, hrac, encrypted_treasure_map = dht_value_splitter(
packed_encrypted_treasure_map[5::], msgpack_remainder=True)
verified, packed_node_list = self.verify_from(self.alice, signature, encrypted_treasure_map,
verified, cleartext = self.verify_from(self.alice, encrypted_treasure_map,
signature_is_on_cleartext=True, decrypt=True)
alices_signature, packed_node_list = BytestringSplitter(Signature)(cleartext, return_remainder=True)
if not verified:
return NOT_FROM_ALICE
else: