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New test for kfrags signed without correctness keys. Test fails

pull/220/head
David Núñez 2018-10-01 13:10:36 +02:00
parent 21c50eb575
commit f535f926b9
3 changed files with 49 additions and 24 deletions
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63
tests/functional/test_correctness.py
View File

@ -21,15 +21,16 @@ import pytest
from umbral import pre
from umbral.point import Point
from umbral.signing import Signer
def test_cheating_ursula_replays_old_reencryption(alices_keys, bobs_keys,
def test_cheating_ursula_replays_old_reencryption(alices_keys, bobs_keys,
kfrags, prepared_capsule):
delegating_privkey, signing_privkey = alices_keys
delegating_pubkey = delegating_privkey.get_pubkey()
receiving_privkey, receiving_pubkey = bobs_keys
capsule_alice1 = prepared_capsule
_unused_key2, capsule_alice2 = pre._encapsulate(delegating_pubkey)
@ -53,8 +54,7 @@ def test_cheating_ursula_replays_old_reencryption(alices_keys, bobs_keys,
cfrags.append(cfrag)
# CFrag 0 is not valid ...
#  CFrag 0 is not valid ...
assert not cfrags[0].verify_correctness(capsule_alice1)
# ... and trying to attach it raises an error.
@ -71,11 +71,11 @@ def test_cheating_ursula_replays_old_reencryption(alices_keys, bobs_keys,
assert cfrag_i.verify_correctness(capsule_alice1)
capsule_alice1.attach_cfrag(cfrag_i)
correct_cases += 1
assert correct_cases == len(cfrags[1:])
def test_cheating_ursula_sends_garbage(kfrags, prepared_capsule):
capsule_alice = prepared_capsule
cfrags = []
@ -91,7 +91,7 @@ def test_cheating_ursula_sends_garbage(kfrags, prepared_capsule):
cfrags[0]._point_e1 = Point.gen_rand()
cfrags[0]._point_v1 = Point.gen_rand()
# Of course, this CFrag is not valid ...
#  Of course, this CFrag is not valid ...
assert not cfrags[0].verify_correctness(capsule_alice)
# ... and trying to attach it raises an error.
@ -103,14 +103,13 @@ def test_cheating_ursula_sends_garbage(kfrags, prepared_capsule):
assert len(correctness_error.offending_cfrags) == 1
# The response of cheating Ursula is in cfrags[0],
# so the rest of CFrags chould be correct:
# so the rest of CFrags should be correct:
for cfrag_i in cfrags[1:]:
assert cfrag_i.verify_correctness(capsule_alice)
capsule_alice.attach_cfrag(cfrag_i)
def test_cfrag_with_missing_proof_cannot_be_attached(kfrags, prepared_capsule):
capsule = prepared_capsule
cfrags = []
@ -119,7 +118,7 @@ def test_cfrag_with_missing_proof_cannot_be_attached(kfrags, prepared_capsule):
cfrags.append(cfrag)
# If the proof is lost (e.g., it is chopped off a serialized CFrag or similar),
# then the CFrag cannot be attached.
#  then the CFrag cannot be attached.
cfrags[0].proof = None
with pytest.raises(cfrag.NoProofProvided):
capsule.attach_cfrag(cfrags[0])
@ -130,7 +129,6 @@ def test_cfrag_with_missing_proof_cannot_be_attached(kfrags, prepared_capsule):
def test_inconsistent_cfrags(bobs_keys, kfrags, prepared_capsule):
receiving_privkey, receiving_pubkey = bobs_keys
capsule = prepared_capsule
@ -139,20 +137,47 @@ def test_inconsistent_cfrags(bobs_keys, kfrags, prepared_capsule):
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag, capsule)
cfrags.append(cfrag)
# For all cfrags that belong to the same policy, the values
# For all cfrags that belong to the same policy, the values
# cfrag._point_noninteractive and cfrag._point_noninteractive
# must be the same. If we swap them, it shouldn't be possible
# to attach the cfrag to the capsule. Let's mangle the first CFrag
# must be the same. If we swap them, it shouldn't be possible
# to attach the cfrag to the capsule. Let's mangle the first CFrag
cfrags[0]._point_noninteractive, cfrags[0]._point_xcoord = cfrags[0]._point_xcoord, cfrags[0]._point_noninteractive
with pytest.raises(pre.UmbralCorrectnessError):
capsule.attach_cfrag(cfrags[0])
# The remaining M cfrags should be fine.
for cfrag in cfrags[1:]:
#  The remaining M cfrags should be fine.
for cfrag in cfrags[1:]:
capsule.attach_cfrag(cfrag)
# Just for fun, let's try to reconstruct the capsule with them:
capsule._reconstruct_shamirs_secret(receiving_privkey)
def test_kfrags_signed_without_correctness_keys(alices_keys, bobs_keys, capsule):
delegating_privkey, signing_privkey = alices_keys
delegating_pubkey = delegating_privkey.get_pubkey()
verifying_key = signing_privkey.get_pubkey()
receiving_privkey, receiving_pubkey = bobs_keys
kfrags = pre.split_rekey(delegating_privkey=delegating_privkey,
signer=Signer(signing_privkey),
receiving_pubkey=receiving_pubkey,
threshold=6,
N=10,
sign_delegating_key=False,
sign_receiving_key=False)
for kfrag in kfrags:
# You can verify the KFrag specifying only the verifying key
assert kfrag.verify(signing_pubkey=verifying_key)
# ... or if it is set in the capsule, using the capsule
capsule.set_correctness_keys(verifying=verifying_key)
assert kfrag.verify_for_capsule(capsule)
# It should even work when other keys are set in the capsule
assert kfrag.verify(signing_pubkey=verifying_key,
delegating_pubkey=delegating_pubkey,
receiving_pubkey=receiving_pubkey)

6
tests/unit/test_kfrags.py
View File

@ -20,7 +20,6 @@ along with pyUmbral. If not, see <https://www.gnu.org/licenses/>.
from umbral.fragments import KFrag
def test_kfrag_serialization(alices_keys, bobs_keys, kfrags):
delegating_privkey, signing_privkey = alices_keys
@ -43,6 +42,7 @@ def test_kfrag_serialization(alices_keys, bobs_keys, kfrags):
assert new_kfrag == kfrag
def test_kfrag_verify_for_capsule(prepared_capsule, kfrags):
for kfrag in kfrags:
assert kfrag.verify_for_capsule(prepared_capsule)
@ -51,14 +51,14 @@ def test_kfrag_verify_for_capsule(prepared_capsule, kfrags):
previous_id, kfrag._id = kfrag._id, bytes(32)
assert not kfrag.verify_for_capsule(prepared_capsule)
# Let's restore the KFrag, and alter the re-encryption key instead
# Let's restore the KFrag, and alter the re-encryption key instead
kfrag._id = previous_id
kfrag._bn_key += kfrag._bn_key
assert not kfrag.verify_for_capsule(prepared_capsule)
def test_kfrag_as_dict_key(kfrags):
dict_with_kfrags_as_keys = {}
dict_with_kfrags_as_keys = dict()
dict_with_kfrags_as_keys[kfrags[0]] = "Some llamas. Definitely some llamas."
dict_with_kfrags_as_keys[kfrags[1]] = "No llamas here. Definitely not."

4
umbral/fragments.py
View File

@ -97,8 +97,8 @@ class KFrag(object):
def verify(self,
signing_pubkey: UmbralPublicKey,
delegating_pubkey: UmbralPublicKey,
receiving_pubkey: UmbralPublicKey,
delegating_pubkey: UmbralPublicKey = None,
receiving_pubkey: UmbralPublicKey = None,
params: Optional[UmbralParameters] = None,
) -> bool: