def test_capsule_as_dict_key(alices_keys):
priv_key_alice, pub_key_alice = alices_keys
plain_data = b'peace at dawn'
ciphertext, capsule = pre.encrypt(pub_key_alice, plain_data)
# We can use the capsule as a key, and successfully lookup using it.
some_dict = {capsule: "Thing that Bob wants to try per-Capsule"}
assert some_dict[capsule] == "Thing that Bob wants to try per-Capsule"
kfrags = pre.split_rekey(alices_keys.priv, alices_keys.pub, 1, 2)
cfrag = pre.reencrypt(kfrags[0], capsule)
capsule.attach_cfrag(cfrag)
cfrag = pre.reencrypt(kfrags[1], capsule)
capsule.attach_cfrag(cfrag)
# Even if we activate the capsule, it still serves as the same key.
cleartext = pre.decrypt(ciphertext, capsule, alices_keys.priv,
alices_keys.pub)
assert some_dict[capsule] == "Thing that Bob wants to try per-Capsule"
assert cleartext == plain_data
# And if we change the value for this key, all is still well.
some_dict[capsule] = "Bob has changed his mind."
assert some_dict[capsule] == "Bob has changed his mind."
assert len(some_dict.keys()) == 1
def test_cheating_ursula_replays_old_reencryption(N, M):
priv_key_alice = keys.UmbralPrivateKey.gen_key()
pub_key_alice = priv_key_alice.get_pubkey()
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
sym_key_alice1, capsule_alice1 = pre._encapsulate(pub_key_alice.point_key)
sym_key_alice2, capsule_alice2 = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
cfrags, metadata = [], []
for i, kfrag in enumerate(kfrags):
# Example of potential metadata to describe the re-encryption request
metadata_i = "This is an example of metadata for re-encryption request #{}"
metadata_i = metadata_i.format(i).encode()
if i == 0:
# Let's put the re-encryption of a different Alice ciphertext
cfrag = pre.reencrypt(kfrag, capsule_alice2, metadata=metadata_i)
else:
cfrag = pre.reencrypt(kfrag, capsule_alice1, metadata=metadata_i)
capsule_alice1.attach_cfrag(cfrag)
cfrags.append(cfrag)
# Let's activate the capsule
capsule_alice1._reconstruct_shamirs_secret(pub_key_alice, priv_key_bob)
with pytest.raises(pre.GenericUmbralError):
sym_key = pre._decapsulate_reencrypted(pub_key_bob.point_key,
priv_key_bob.bn_key,
pub_key_alice.point_key,
capsule_alice1)
assert not cfrags[0].verify_correctness(
capsule_alice1,
pub_key_alice,
pub_key_bob,
)
# The response of cheating Ursula is in cfrags[0],
# so the rest of CFrags should be correct:
for cfrag_i, metadata_i in zip(cfrags[1:], metadata[1:]):
assert cfrag_i.verify_correctness(
capsule_alice1,
pub_key_alice,
pub_key_bob,
)
# Alternatively, we can try to open the capsule directly.
# We should get an exception with an attached list of incorrect cfrags
with pytest.raises(pre.UmbralCorrectnessError) as exception_info:
_ = pre._open_capsule(capsule_alice1, priv_key_bob, pub_key_alice)
correctness_error = exception_info.value
assert cfrags[0] in correctness_error.offending_cfrags
assert len(correctness_error.offending_cfrags) == 1
def test_cheating_ursula_replays_old_reencryption(N, M):
priv_key_alice = keys.UmbralPrivateKey.gen_key()
pub_key_alice = priv_key_alice.get_pubkey()
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
sym_key_alice1, capsule_alice1 = pre._encapsulate(pub_key_alice.point_key)
sym_key_alice2, capsule_alice2 = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
cfrags, challenges = [], []
for index, kfrag in enumerate(kfrags):
if index == 0:
# Let's put the re-encryption of a different Alice ciphertext
cfrag = pre.reencrypt(kfrag, capsule_alice2)
else:
cfrag = pre.reencrypt(kfrag, capsule_alice1)
metadata = ("Challenge metadata: index {}".format(index)).encode()
challenge = pre._challenge(kfrag, capsule_alice1, cfrag, metadata)
capsule_alice1.attach_cfrag(cfrag)
challenges.append(challenge)
cfrags.append(cfrag)
# Let's activate the capsule
capsule_alice1._reconstruct_shamirs_secret(pub_key_alice, priv_key_bob)
with pytest.raises(pre.GenericUmbralError):
sym_key = pre._decapsulate_reencrypted(pub_key_bob.point_key,
priv_key_bob.bn_key,
pub_key_alice.point_key,
capsule_alice1)
metadata = b"Challenge metadata: index 0"
assert not pre._check_challenge(capsule_alice1,
cfrags[0],
challenges[0],
pub_key_alice.point_key,
pub_key_bob.point_key,
metadata
)
# The response of cheating Ursula is in capsules[0],
# so the rest of challenges chould be correct:
for i, challenge in enumerate(challenges[1:], 1):
cfrag = cfrags[i]
metadata = ("Challenge metadata: index {}".format(i)).encode()
assert pre._check_challenge(capsule_alice1,
cfrag,
challenge,
pub_key_alice.point_key,
pub_key_bob.point_key,
metadata
)
def test_cheating_ursula_replays_old_reencryption(N, M):
priv_key_alice = keys.UmbralPrivateKey.gen_key()
pub_key_alice = priv_key_alice.get_pubkey()
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
sym_key_alice1, capsule_alice1 = pre._encapsulate(pub_key_alice.point_key)
sym_key_alice2, capsule_alice2 = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
cfrags, challenges, metadata = [], [], []
for i, kfrag in enumerate(kfrags):
if i == 0:
# Let's put the re-encryption of a different Alice ciphertext
cfrag = pre.reencrypt(kfrag, capsule_alice2)
else:
cfrag = pre.reencrypt(kfrag, capsule_alice1)
# Example of potential metadata to describe the challenge request
metadata_i = {
'ursula_id': i,
'timestamp': time.time(),
'capsule': bytes(capsule_alice1),
'cfrag': bytes(cfrag)
}
metadata.append(str(metadata_i).encode())
challenge = pre._challenge(kfrag, capsule_alice1, cfrag, metadata[i])
capsule_alice1.attach_cfrag(cfrag)
challenges.append(challenge)
cfrags.append(cfrag)
# Let's activate the capsule
capsule_alice1._reconstruct_shamirs_secret(pub_key_alice, priv_key_bob)
with pytest.raises(pre.GenericUmbralError):
sym_key = pre._decapsulate_reencrypted(pub_key_bob.point_key,
priv_key_bob.bn_key,
pub_key_alice.point_key,
capsule_alice1)
assert not pre._check_challenge(capsule_alice1, cfrags[0], challenges[0],
pub_key_alice.point_key,
pub_key_bob.point_key, metadata[0])
# The response of cheating Ursula is in capsules[0],
# so the rest of challenges should be correct:
for i, challenge in enumerate(challenges[1:], 1):
cfrag = cfrags[i]
assert pre._check_challenge(capsule_alice1, cfrag, challenge,
pub_key_alice.point_key,
pub_key_bob.point_key, metadata[i])
def test_bad_capsule_fails_reencryption(kfrags):
params = default_params()
bollocks_capsule = Capsule(params,
point_e=Point.gen_rand(),
point_v=Point.gen_rand(),
bn_sig=CurveBN.gen_rand())
for kfrag in kfrags:
with pytest.raises(Capsule.NotValid):
pre.reencrypt(kfrag, bollocks_capsule)
def test_bad_capsule_fails_reencryption(alices_keys):
priv_key_alice, pub_key_alice = alices_keys
kfrags = pre.split_rekey(priv_key_alice, pub_key_alice, 1, 2)
bollocks_capsule = Capsule(point_e=Point.gen_rand(),
point_v=Point.gen_rand(),
bn_sig=CurveBN.gen_rand())
with pytest.raises(Capsule.NotValid):
pre.reencrypt(kfrags[0], bollocks_capsule)
def test_cheating_ursula_replays_old_reencryption(N, M):
priv_key_alice = keys.UmbralPrivateKey.gen_key()
pub_key_alice = priv_key_alice.get_pubkey()
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
sym_key_alice1, capsule_alice1 = pre._encapsulate(pub_key_alice.point_key)
sym_key_alice2, capsule_alice2 = pre._encapsulate(pub_key_alice.point_key)
k_frags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
c_frags, challenges = [], []
for index, k_frag in enumerate(k_frags):
if index == 0:
# Let's put the re-encryption of a different Alice ciphertext
c_frag = pre.reencrypt(k_frag, capsule_alice2)
else:
c_frag = pre.reencrypt(k_frag, capsule_alice1)
challenge = pre.challenge(k_frag, capsule_alice1, c_frag)
capsule_alice1.attach_cfrag(c_frag)
challenges.append(challenge)
c_frags.append(c_frag)
capsule_alice1._reconstruct_shamirs_secret() # activate capsule
with pytest.raises(pre.GenericUmbralError):
sym_key = pre.decapsulate_reencrypted(pub_key_bob.point_key,
priv_key_bob.bn_key,
pub_key_alice.point_key,
capsule_alice1)
assert not sym_key == sym_key_alice1
assert not pre.check_challenge(
capsule_alice1,
c_frags[0],
challenges[0],
pub_key_alice.point_key,
pub_key_bob.point_key,
)
# The response of cheating Ursula is in capsules[0],
# so the rest of challenges chould be correct:
for (c_frag, ch) in zip(c_frags[1:], challenges[1:]):
assert pre.check_challenge(
capsule_alice1,
c_frag,
ch,
pub_key_alice.point_key,
pub_key_bob.point_key,
)
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)
capsule_alice2.set_correctness_keys(delegating=delegating_pubkey,
receiving=receiving_pubkey,
verifying=signing_privkey.get_pubkey())
cfrags = []
for i, kfrag in enumerate(kfrags):
# Example of potential metadata to describe the re-encryption request
metadata_i = "This is an example of metadata for re-encryption request #{}"
metadata_i = metadata_i.format(i).encode()
if i == 0:
# Let's put the re-encryption of a different Alice ciphertext
cfrag = pre.reencrypt(kfrag, capsule_alice2, metadata=metadata_i)
else:
cfrag = pre.reencrypt(kfrag, capsule_alice1, metadata=metadata_i)
cfrags.append(cfrag)
# CFrag 0 is not valid ...
assert not cfrags[0].verify_correctness(capsule_alice1)
# ... and trying to attach it raises an error.
with pytest.raises(pre.UmbralCorrectnessError) as exception_info:
capsule_alice1.attach_cfrag(cfrags[0])
correctness_error = exception_info.value
assert cfrags[0] in correctness_error.offending_cfrags
assert len(correctness_error.offending_cfrags) == 1
# The rest of CFrags should be correct:
correct_cases = 0
for cfrag_i in cfrags[1:]:
assert cfrag_i.verify_correctness(capsule_alice1)
capsule_alice1.attach_cfrag(cfrag_i)
correct_cases += 1
assert correct_cases == len(cfrags[1:])
def test_bad_capsule_fails_reencryption(alices_keys, bobs_keys):
delegating_privkey, _signing_privkey = alices_keys
signer_alice = Signer(_signing_privkey)
_receiving_privkey, receiving_pubkey = bobs_keys
kfrags = pre.split_rekey(delegating_privkey, signer_alice,
receiving_pubkey, 1, 2)
bollocks_capsule = Capsule(point_e=Point.gen_rand(),
point_v=Point.gen_rand(),
bn_sig=CurveBN.gen_rand())
with pytest.raises(Capsule.NotValid):
pre.reencrypt(kfrags[0], bollocks_capsule)
def test_m_of_n(N, M, alices_keys, bobs_keys):
priv_key_alice, pub_key_alice = alices_keys
priv_key_bob, pub_key_bob = bobs_keys
sym_key, capsule = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
for kfrag in kfrags:
assert kfrag.verify(pub_key_alice.point_key, pub_key_bob.point_key)
for i, kfrag in enumerate(kfrags[:M]):
# Example of potential metadata to describe the re-encryption request
metadata = "This is an example of metadata for re-encryption request #{}"
metadata = metadata.format(i).encode()
cfrag = pre.reencrypt(kfrag, capsule, metadata=metadata)
capsule.attach_cfrag(cfrag)
assert pre._verify_correctness(
capsule,
cfrag,
pub_key_alice.point_key,
pub_key_bob.point_key,
)
# assert capsule.is_openable_by_bob() # TODO: Is it possible to check here if >= m cFrags have been attached?
sym_key_from_capsule = pre._open_capsule(capsule, priv_key_bob,
pub_key_alice)
assert sym_key == sym_key_from_capsule
def test_cheating_ursula_sends_garbage(N, M):
priv_key_alice = keys.UmbralPrivateKey.gen_key()
pub_key_alice = priv_key_alice.get_pubkey()
# Bob
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
sym_key, capsule_alice = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
cfrags, metadata = [], []
for i, kfrag in enumerate(kfrags[:M]):
# Example of potential metadata to describe the re-encryption request
metadata_i = "This is an example of metadata for re-encryption request #{}"
metadata_i = metadata_i.format(i).encode()
cfrag = pre.reencrypt(kfrag, capsule_alice, metadata=metadata_i)
capsule_alice.attach_cfrag(cfrag)
cfrags.append(cfrag)
# Let's put random garbage in one of the cfrags
cfrags[0]._point_e1 = Point.gen_rand()
cfrags[0]._point_v1 = Point.gen_rand()
capsule_alice._reconstruct_shamirs_secret(pub_key_alice,
priv_key_bob) # activate capsule
with pytest.raises(pre.GenericUmbralError):
_unused_key = pre._decapsulate_reencrypted(pub_key_bob.point_key,
priv_key_bob.bn_key,
pub_key_alice.point_key,
capsule_alice)
assert not pre._verify_correctness(
capsule_alice,
cfrags[0],
pub_key_alice.point_key,
pub_key_bob.point_key,
)
# The response of cheating Ursula is in cfrags[0],
# so the rest of CFrags chould be correct:
for cfrag_i, metadata_i in zip(cfrags[1:], metadata[1:]):
assert pre._verify_correctness(
capsule_alice,
cfrag_i,
pub_key_alice.point_key,
pub_key_bob.point_key,
)
# Alternatively, we can try to open the capsule directly.
# We should get an exception with an attached list of incorrect cfrags
with pytest.raises(pre.UmbralCorrectnessError) as exception_info:
_ = pre._open_capsule(capsule_alice, priv_key_bob, pub_key_alice)
correctness_error = exception_info.value
assert cfrags[0] in correctness_error.offending_cfrags
assert len(correctness_error.offending_cfrags) == 1
def test_correctness_proof_serialization():
priv_key_alice = keys.UmbralPrivateKey.gen_key()
pub_key_alice = priv_key_alice.get_pubkey()
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
_unused_key, capsule = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, 1, 2)
# Example of potential metadata to describe the re-encryption request
metadata = b"This is an example of metadata for re-encryption request"
cfrag = pre.reencrypt(kfrags[0], capsule, metadata=metadata)
capsule.attach_cfrag(cfrag)
proof = cfrag.proof
proof_bytes = proof.to_bytes()
# A CorrectnessProof can be represented as
# the 228 total bytes of four Points (33 each) and three BigNums (32 each).
# TODO: Figure out final size for CorrectnessProofs
# assert len(proof_bytes) == (33 * 4) + (32 * 3) == 228
new_proof = CorrectnessProof.from_bytes(proof_bytes)
assert new_proof._point_e2 == proof._point_e2
assert new_proof._point_v2 == proof._point_v2
assert new_proof._point_kfrag_commitment == proof._point_kfrag_commitment
assert new_proof._point_kfrag_pok == proof._point_kfrag_pok
assert new_proof._bn_kfrag_sig1 == proof._bn_kfrag_sig1
assert new_proof._bn_kfrag_sig2 == proof._bn_kfrag_sig2
assert new_proof._bn_sig == proof._bn_sig
assert new_proof.metadata == proof.metadata
def test_cheating_ursula_sends_garbage(kfrags, prepared_capsule):
capsule_alice = prepared_capsule
cfrags = []
for i, kfrag in enumerate(kfrags):
# Example of potential metadata to describe the re-encryption request
metadata_i = "This is an example of metadata for re-encryption request #{}"
metadata_i = metadata_i.format(i).encode()
cfrag = pre.reencrypt(kfrag, capsule_alice, metadata=metadata_i)
cfrags.append(cfrag)
# Let's put random garbage in one of the cfrags
cfrags[0]._point_e1 = Point.gen_rand()
cfrags[0]._point_v1 = Point.gen_rand()
# Of course, this CFrag is not valid ...
assert not cfrags[0].verify_correctness(capsule_alice)
# ... and trying to attach it raises an error.
with pytest.raises(pre.UmbralCorrectnessError) as exception_info:
capsule_alice.attach_cfrag(cfrags[0])
correctness_error = exception_info.value
assert cfrags[0] in correctness_error.offending_cfrags
assert len(correctness_error.offending_cfrags) == 1
# The response of cheating Ursula is in cfrags[0],
# 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_simple_api(N, M, curve=default_curve()):
"""Manually injects umbralparameters for multi-curve testing."""
params = UmbralParameters(curve=curve)
priv_key_alice = keys.UmbralPrivateKey.gen_key(params=params)
pub_key_alice = priv_key_alice.get_pubkey()
priv_key_bob = keys.UmbralPrivateKey.gen_key(params=params)
pub_key_bob = priv_key_bob.get_pubkey()
plain_data = b'peace at dawn'
ciphertext, capsule = pre.encrypt(pub_key_alice, plain_data, params=params)
cleartext = pre.decrypt(ciphertext, capsule, priv_key_alice, params=params)
assert cleartext == plain_data
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N, params=params)
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag, capsule, params=params)
capsule.attach_cfrag(cfrag)
reenc_cleartext = pre.decrypt(ciphertext,
capsule,
priv_key_bob,
pub_key_alice,
params=params)
assert reenc_cleartext == plain_data
def reencrypt_via_rest(id_as_hex):
from nucypher.policy.models import WorkOrder # Avoid circular import
arrangement_id = binascii.unhexlify(id_as_hex)
work_order = WorkOrder.from_rest_payload(arrangement_id, request.data)
log.info("Work Order from {}, signed {}".format(work_order.bob, work_order.receipt_signature))
with ThreadedSession(db_engine) as session:
policy_arrangement = datastore.get_policy_arrangement(arrangement_id=id_as_hex.encode(),
session=session)
kfrag_bytes = policy_arrangement.kfrag # Careful! :-)
verifying_key_bytes = policy_arrangement.alice_pubkey_sig.key_data
# TODO: Push this to a lower level.
kfrag = KFrag.from_bytes(kfrag_bytes)
alices_verifying_key = UmbralPublicKey.from_bytes(verifying_key_bytes)
cfrag_byte_stream = b""
for capsule, capsule_signature in zip(work_order.capsules, work_order.capsule_signatures):
# This is the capsule signed by Bob
capsule_signature = bytes(capsule_signature)
# Ursula signs on top of it. Now both are committed to the same capsule.
capsule_signed_by_both = bytes(stamp(capsule_signature))
capsule.set_correctness_keys(verifying=alices_verifying_key)
cfrag = pre.reencrypt(kfrag, capsule, metadata=capsule_signed_by_both)
log.info("Re-encrypting for {}, made {}.".format(capsule, cfrag))
signature = stamp(bytes(cfrag) + bytes(capsule))
cfrag_byte_stream += VariableLengthBytestring(cfrag) + signature
# TODO: Put this in Ursula's datastore
work_order_tracker.append(work_order)
headers = {'Content-Type': 'application/octet-stream'}
return Response(response=cfrag_byte_stream, headers=headers)
def test_m_of_n(N, M, alices_keys, bobs_keys):
delegating_privkey, signing_privkey = alices_keys
delegating_pubkey = delegating_privkey.get_pubkey()
signer = Signer(signing_privkey)
priv_key_bob, pub_key_bob = bobs_keys
params = delegating_privkey.params
sym_key, capsule = pre._encapsulate(delegating_pubkey)
capsule.set_correctness_keys(delegating=delegating_privkey.get_pubkey(),
receiving=pub_key_bob,
verifying=signing_privkey.get_pubkey())
kfrags = pre.split_rekey(delegating_privkey, signer, pub_key_bob, M, N)
for kfrag in kfrags:
assert kfrag.verify(signing_privkey.get_pubkey(), delegating_privkey.get_pubkey(), pub_key_bob)
for i, kfrag in enumerate(kfrags[:M]):
# Example of potential metadata to describe the re-encryption request
metadata = "This is an example of metadata for re-encryption request #{}"
metadata = metadata.format(i).encode()
cfrag = pre.reencrypt(kfrag, capsule, metadata=metadata)
capsule.attach_cfrag(cfrag)
assert cfrag.verify_correctness(capsule)
sym_key_from_capsule = pre._open_capsule(capsule, priv_key_bob)
assert sym_key == sym_key_from_capsule
def test_cfrag_serialization_with_proof_but_no_metadata(
prepared_capsule, kfrags):
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag, prepared_capsule, provide_proof=True)
cfrag_bytes = cfrag.to_bytes()
proof = cfrag.proof
assert proof is not None
assert proof.metadata is None
# A CFrag can be represented as the 131 total bytes of three Points (33 each) and a CurveBN (32).
# TODO: Figure out final size for CFrags with proofs
# assert len(cfrag_bytes) == 33 + 33 + 33 + 32 == 131
new_cfrag = CapsuleFrag.from_bytes(cfrag_bytes)
assert new_cfrag.point_e1 == cfrag.point_e1
assert new_cfrag.point_v1 == cfrag.point_v1
assert new_cfrag.kfrag_id == cfrag.kfrag_id
assert new_cfrag.point_precursor == cfrag.point_precursor
new_proof = new_cfrag.proof
assert new_proof is not None
assert new_proof.point_e2 == proof.point_e2
assert new_proof.point_v2 == proof.point_v2
assert new_proof.point_kfrag_commitment == proof.point_kfrag_commitment
assert new_proof.point_kfrag_pok == proof.point_kfrag_pok
assert new_proof.bn_sig == proof.bn_sig
assert new_proof.metadata is None
def test_m_of_n(N, M, alices_keys, bobs_keys):
priv_key_alice, pub_key_alice = alices_keys
priv_key_bob, pub_key_bob = bobs_keys
sym_key, capsule = pre._encapsulate(pub_key_alice.point_key)
kfrags = pre.split_rekey(priv_key_alice, pub_key_bob, M, N)
for kfrag in kfrags:
assert kfrag.verify(pub_key_alice.point_key, pub_key_bob.point_key)
for kfrag in kfrags[:M]:
cfrag = pre.reencrypt(kfrag, capsule)
capsule.attach_cfrag(cfrag)
ch = pre.challenge(kfrag, capsule, cfrag)
assert pre.check_challenge(capsule, cfrag, ch, pub_key_alice.point_key,
pub_key_bob.point_key)
# assert capsule.is_openable_by_bob() # TODO: Is it possible to check here if >= m cFrags have been attached?
# capsule.open(pub_bob, priv_bob, pub_alice)
capsule._reconstruct_shamirs_secret()
sym_key_from_capsule = pre.decapsulate_reencrypted(pub_key_bob.point_key,
priv_key_bob.bn_key,
pub_key_alice.point_key,
capsule)
assert sym_key == sym_key_from_capsule
def test_simple_api(N, M, curve=default_curve()):
"""Manually injects umbralparameters for multi-curve testing."""
params = UmbralParameters(curve=curve)
delegating_privkey = UmbralPrivateKey.gen_key(params=params)
delegating_pubkey = delegating_privkey.get_pubkey()
signing_privkey = UmbralPrivateKey.gen_key(params=params)
signing_pubkey = signing_privkey.get_pubkey()
signer = Signer(signing_privkey)
receiving_privkey = UmbralPrivateKey.gen_key(params=params)
receiving_pubkey = receiving_privkey.get_pubkey()
plain_data = b'peace at dawn'
ciphertext, capsule = pre.encrypt(delegating_pubkey, plain_data)
cleartext = pre.decrypt(ciphertext, capsule, delegating_privkey)
assert cleartext == plain_data
capsule.set_correctness_keys(delegating=delegating_pubkey,
receiving=receiving_pubkey,
verifying=signing_pubkey)
kfrags = pre.split_rekey(delegating_privkey, signer, receiving_pubkey, M, N)
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag, capsule)
capsule.attach_cfrag(cfrag)
reenc_cleartext = pre.decrypt(ciphertext, capsule, receiving_privkey)
assert reenc_cleartext == plain_data
def test_activated_capsule_serialization():
priv_key = pre.gen_priv()
pub_key = pre.priv2pub(priv_key)
_unused_key, capsule = pre._encapsulate(pub_key)
kfrags = pre.split_rekey(priv_key, pub_key, 1, 2)
cfrag = pre.reencrypt(kfrags[0], capsule)
capsule.attach_cfrag(cfrag)
capsule._reconstruct_shamirs_secret()
rec_capsule_bytes = capsule.to_bytes()
# An activated Capsule is:
# three points, representable as 33 bytes each (the original), and
# two points and a bignum (32 bytes) (the activated components), for 197 total.
assert len(rec_capsule_bytes) == (33 * 3) + (33 + 33 + 32)
new_rec_capsule = pre.Capsule.from_bytes(rec_capsule_bytes)
# Again, the same three perspectives on equality.
assert new_rec_capsule == capsule
assert new_rec_capsule.activated_components(
) == capsule.activated_components()
assert new_rec_capsule._point_eph_e_prime == capsule._point_eph_e_prime
assert new_rec_capsule._point_eph_v_prime == capsule._point_eph_v_prime
assert new_rec_capsule._point_noninteractive == capsule._point_noninteractive
def reencrypt_via_rest(self, id_as_hex, request: http.Request):
from nucypher.policy.models import WorkOrder # Avoid circular import
id = binascii.unhexlify(id_as_hex)
work_order = WorkOrder.from_rest_payload(id, request.body)
self.log.info("Work Order from {}, signed {}".format(
work_order.bob, work_order.receipt_signature))
with ThreadedSession(self.db_engine) as session:
kfrag_bytes = self.datastore.get_policy_arrangement(
id.hex().encode(), session=session).k_frag # Careful! :-)
# TODO: Push this to a lower level.
kfrag = KFrag.from_bytes(kfrag_bytes)
cfrag_byte_stream = b""
for capsule in work_order.capsules:
# TODO: Sign the result of this. See #141.
cfrag = pre.reencrypt(kfrag, capsule)
self.log.info(
"Re-encrypting for Capsule {}, made CFrag {}.".format(
capsule, cfrag))
cfrag_byte_stream += VariableLengthBytestring(cfrag)
# TODO: Put this in Ursula's datastore
self._work_orders.append(work_order)
headers = {'Content-Type': 'application/octet-stream'}
return Response(content=cfrag_byte_stream, headers=headers)
def test_correctness_proof_serialization(prepared_capsule, kfrags):
# Example of potential metadata to describe the re-encryption request
metadata = b"This is an example of metadata for re-encryption request"
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag, prepared_capsule, metadata=metadata)
proof = cfrag.proof
proof_bytes = proof.to_bytes()
# A CorrectnessProof can be represented as
# the 228 total bytes of four Points (33 each) and three BigNums (32 each).
# TODO: Figure out final size for CorrectnessProofs
# assert len(proof_bytes) == (33 * 4) + (32 * 3) == 228
new_proof = CorrectnessProof.from_bytes(proof_bytes)
assert new_proof.point_e2 == proof.point_e2
assert new_proof.point_v2 == proof.point_v2
assert new_proof.point_kfrag_commitment == proof.point_kfrag_commitment
assert new_proof.point_kfrag_pok == proof.point_kfrag_pok
assert new_proof.bn_sig == proof.bn_sig
assert new_proof.kfrag_signature == proof.kfrag_signature
assert new_proof.metadata == proof.metadata
def test_capsule_length(prepared_capsule, kfrags):
capsule = prepared_capsule
for counter, kfrag in enumerate(kfrags):
assert len(capsule) == counter
cfrag = pre.reencrypt(kfrag, capsule)
capsule.attach_cfrag(cfrag)
def reencrypt(self, policy_id: str, capsule: pre.Capsule,
M: int) -> List[fragments.CapsuleFrag]:
"""
Re-encrypts the given capsule 'M' number of times and returns a list
of CapsuleFrags (CFrags) to be attached to the original Capsule.
:param policy_id: Policy ID to access re-encryption.
:param capsule: The Umbral capsule to re-encrypt.
:param M: The number of times to re-encrypt the capsule for the minimum
number of CFrags needed.
:return: List of CFrags (CapsuleFrags).
"""
try:
kfrags = self.db[policy_id]
except KeyError:
raise ValueError("No Policy found for {}".format(policy_id))
if M > len(kfrags):
raise ValueError(
"Not enough KFrags to re-encrypt {} times!".format(M))
cfrags = []
# TODO: using web3py check if is dead?
data = requests.get("http://172.16.21.223:3000/api/platform/isAlive/")
res = json.loads(data.text)
if bool(res["result"]) == True:
m_kfrags = random.sample(kfrags, M)
for kfrag in m_kfrags:
cfrags.append(pre.reencrypt(kfrag, capsule))
return cfrags
def test_cfrag_serialization_with_proof_and_metadata(prepared_capsule, kfrags):
# Example of potential metadata to describe the re-encryption request
metadata = b'This is an example of metadata for re-encryption request'
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag,
prepared_capsule,
provide_proof=True,
metadata=metadata)
cfrag_bytes = cfrag.to_bytes()
proof = cfrag.proof
assert proof is not None
assert proof.metadata is not None
new_cfrag = CapsuleFrag.from_bytes(cfrag_bytes)
assert new_cfrag.point_e1 == cfrag.point_e1
assert new_cfrag.point_v1 == cfrag.point_v1
assert new_cfrag.kfrag_id == cfrag.kfrag_id
assert new_cfrag.point_precursor == cfrag.point_precursor
new_proof = new_cfrag.proof
assert new_proof is not None
assert new_proof.point_e2 == proof.point_e2
assert new_proof.point_v2 == proof.point_v2
assert new_proof.point_kfrag_commitment == proof.point_kfrag_commitment
assert new_proof.point_kfrag_pok == proof.point_kfrag_pok
assert new_proof.bn_sig == proof.bn_sig
assert new_proof.metadata == metadata
assert new_proof.metadata == proof.metadata
def reencrypt(self, policy_id: str, capsule: pre.Capsule,
M: int) -> List[fragments.CapsuleFrag]:
"""
Re-encrypts the given capsule 'M' number of times and returns a list
of CapsuleFrags (CFrags) to be attached to the original Capsule.
:param policy_id: Policy ID to access re-encryption.
:param capsule: The Umbral capsule to re-encrypt.
:param M: The number of times to re-encrypt the capsule for the minimum
number of CFrags needed.
:return: List of CFrags (CapsuleFrags).
"""
try:
kfrags = self.db[policy_id]
except KeyError:
raise ValueError("No Policy found for {}".format(policy_id))
if M > len(kfrags):
raise ValueError(
"Not enough KFrags to re-encrypt {} times!".format(M))
cfrags = []
m_kfrags = random.sample(kfrags, M)
for kfrag in m_kfrags:
cfrags.append(pre.reencrypt(kfrag, capsule))
return cfrags
def test_decryption_fails_when_it_expects_a_proof_and_there_isnt(N, M, alices_keys, bobs_keys):
"""Manually injects umbralparameters for multi-curve testing."""
delegating_privkey, signing_privkey = alices_keys
delegating_pubkey = delegating_privkey.get_pubkey()
signer = Signer(signing_privkey)
priv_key_bob, pub_key_bob = bobs_keys
plain_data = b'peace at dawn'
ciphertext, capsule = pre.encrypt(delegating_privkey.get_pubkey(), plain_data)
kfrags = pre.split_rekey(delegating_privkey, signer, pub_key_bob, M, N)
capsule.set_correctness_keys(delegating=delegating_privkey.get_pubkey(),
receiving=pub_key_bob,
verifying=signing_privkey.get_pubkey())
for kfrag in kfrags[:M]:
cfrag = pre.reencrypt(kfrag, capsule)
capsule.attach_cfrag(cfrag)
# Even thought we can successfully attach a CFrag, if the proof is lost
# (for example, it is chopped off a serialized CFrag or similar), then decrypt
# will still fail.
cfrag.proof = None
with pytest.raises(cfrag.NoProofProvided):
_cleartext = pre.decrypt(ciphertext, capsule, priv_key_bob)
def test_challenge_response_serialization():
priv_key = pre.gen_priv()
pub_key = pre.priv2pub(priv_key)
_unused_key, capsule = pre._encapsulate(pub_key)
kfrags = pre.split_rekey(priv_key, pub_key, 1, 2)
cfrag = pre.reencrypt(kfrags[0], capsule)
capsule.attach_cfrag(cfrag)
ch_resp = pre.challenge(kfrags[0], capsule, cfrag)
ch_resp_bytes = ch_resp.to_bytes()
# A ChallengeResponse can be represented as
# the 228 total bytes of four Points (33 each) and three BigNums (32 each).
assert len(ch_resp_bytes) == (33 * 4) + (32 * 3) == 228
new_ch_resp = pre.ChallengeResponse.from_bytes(ch_resp_bytes)
assert new_ch_resp.point_eph_e2 == ch_resp.point_eph_e2
assert new_ch_resp.point_eph_v2 == ch_resp.point_eph_v2
assert new_ch_resp.point_kfrag_commitment == ch_resp.point_kfrag_commitment
assert new_ch_resp.point_kfrag_pok == ch_resp.point_kfrag_pok
assert new_ch_resp.bn_kfrag_sig1 == ch_resp.bn_kfrag_sig1
assert new_ch_resp.bn_kfrag_sig2 == ch_resp.bn_kfrag_sig2
assert new_ch_resp.bn_sig == ch_resp.bn_sig
def test_correctness_proof_serialization(alices_keys):
delegating_privkey, signing_privkey = alices_keys
delegating_pubkey = delegating_privkey.get_pubkey()
signer = Signer(signing_privkey)
priv_key_bob = keys.UmbralPrivateKey.gen_key()
pub_key_bob = priv_key_bob.get_pubkey()
params = delegating_privkey.params
_unused_key, capsule = pre._encapsulate(delegating_pubkey)
kfrags = pre.split_rekey(delegating_privkey, signer, pub_key_bob, 1, 2)
# Example of potential metadata to describe the re-encryption request
metadata = b"This is an example of metadata for re-encryption request"
cfrag = pre.reencrypt(kfrags[0], capsule, metadata=metadata)
proof = cfrag.proof
proof_bytes = proof.to_bytes()
# A CorrectnessProof can be represented as
# the 228 total bytes of four Points (33 each) and three BigNums (32 each).
# TODO: Figure out final size for CorrectnessProofs
# assert len(proof_bytes) == (33 * 4) + (32 * 3) == 228
new_proof = CorrectnessProof.from_bytes(proof_bytes)
assert new_proof._point_e2 == proof._point_e2
assert new_proof._point_v2 == proof._point_v2
assert new_proof._point_kfrag_commitment == proof._point_kfrag_commitment
assert new_proof._point_kfrag_pok == proof._point_kfrag_pok
assert new_proof.bn_sig == proof.bn_sig
assert new_proof.kfrag_signature == proof.kfrag_signature
assert new_proof.metadata == proof.metadata
def test_cfrag_serialization_no_proof_no_metadata(alices_keys, bobs_keys):
delegating_privkey, signing_privkey = alices_keys
delegating_pubkey = delegating_privkey.get_pubkey()
_receiving_privkey, receiving_pubkey = bobs_keys
signer_alice = Signer(signing_privkey)
_unused_key, capsule = pre._encapsulate(delegating_pubkey.point_key)
kfrags = pre.split_rekey(delegating_privkey, signer_alice,
receiving_pubkey, 1, 2)
cfrag = pre.reencrypt(kfrags[0], capsule, provide_proof=False)
cfrag_bytes = cfrag.to_bytes()
proof = cfrag.proof
assert proof is None
curve = default_curve()
assert len(cfrag_bytes) == CapsuleFrag.expected_bytes_length(curve)
new_cfrag = pre.CapsuleFrag.from_bytes(cfrag_bytes)
assert new_cfrag._point_e1 == cfrag._point_e1
assert new_cfrag._point_v1 == cfrag._point_v1
assert new_cfrag._kfrag_id == cfrag._kfrag_id
assert new_cfrag._point_noninteractive == cfrag._point_noninteractive
new_proof = new_cfrag.proof
assert new_proof is None
