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_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 test_cfrags():
vector_file = os.path.join('vectors', 'vectors_cfrags.json')
try:
with open(vector_file) as f:
vector_suite = json.load(f)
except OSError:
raise
params = default_params()
capsule = pre.Capsule.from_bytes(bytes.fromhex(vector_suite['capsule']),
params=params)
verifying_key = UmbralPublicKey.from_bytes(
bytes.fromhex(vector_suite['verifying_key']))
delegating_key = UmbralPublicKey.from_bytes(
bytes.fromhex(vector_suite['delegating_key']))
receiving_key = UmbralPublicKey.from_bytes(
bytes.fromhex(vector_suite['receiving_key']))
kfrags_n_cfrags = [
(KFrag.from_bytes(bytes.fromhex(json_kfrag['kfrag'])),
CapsuleFrag.from_bytes(bytes.fromhex(json_kfrag['cfrag'])))
for json_kfrag in vector_suite['vectors']
]
capsule.set_correctness_keys(delegating=delegating_key,
receiving=receiving_key,
verifying=verifying_key)
for kfrag, cfrag in kfrags_n_cfrags:
assert kfrag.verify(signing_pubkey=verifying_key,
delegating_pubkey=delegating_key,
receiving_pubkey=receiving_key), \
'Invalid KFrag {}'.format(kfrag.to_bytes().hex())
new_cfrag = pre.reencrypt(kfrag, capsule, provide_proof=False)
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
assert new_cfrag._point_xcoord == cfrag._point_xcoord
assert new_cfrag.proof is None
assert cfrag.to_bytes() == new_cfrag.to_bytes()
def test_cfrag_serialization_no_proof_no_metadata(prepared_capsule, kfrags):
for kfrag in kfrags:
cfrag = pre.reencrypt(kfrag, prepared_capsule, provide_proof=False)
cfrag_bytes = cfrag.to_bytes()
proof = cfrag.proof
assert proof is None
assert len(cfrag_bytes) == CapsuleFrag.expected_bytes_length()
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 None
def test_lifecycle_with_serialization(N,
M,
signing_mode,
curve=default_curve()):
"""
This test is a variant of test_simple_api, but with intermediate
serialization/deserialization steps, modeling how pyUmbral artifacts
(such as keys, ciphertexts, etc) will actually be used.
These intermediate steps are in between the different 'usage domains'
in NuCypher, namely, key generation, delegation, encryption, decryption by
Alice, re-encryption by Ursula, and decryption by Bob.
Manually injects UmbralParameters for multi-curve testing.
"""
# Convenience method to avoid replicating key generation code
def new_keypair_bytes():
privkey = UmbralPrivateKey.gen_key(params=params)
return privkey.to_bytes(), privkey.get_pubkey().to_bytes()
## SETUP
params = UmbralParameters(curve=curve)
delegating_privkey_bytes, delegating_pubkey_bytes = new_keypair_bytes()
signing_privkey_bytes, signing_pubkey_bytes = new_keypair_bytes()
receiving_privkey_bytes, receiving_pubkey_bytes = new_keypair_bytes()
## DELEGATION DOMAIN:
## Alice delegates decryption rights to some Bob by generating a set of
## KFrags, using her delegating private key and Bob's receiving public key
delegating_privkey = UmbralPrivateKey.from_bytes(delegating_privkey_bytes,
params)
signing_privkey = UmbralPrivateKey.from_bytes(signing_privkey_bytes,
params)
receiving_pubkey = UmbralPublicKey.from_bytes(receiving_pubkey_bytes,
params)
signer = Signer(signing_privkey)
sign_delegating_key, sign_receiving_key = signing_mode
kfrags = pre.generate_kfrags(delegating_privkey=delegating_privkey,
receiving_pubkey=receiving_pubkey,
threshold=M,
N=N,
signer=signer,
sign_delegating_key=sign_delegating_key,
sign_receiving_key=sign_receiving_key)
kfrags_bytes = tuple(map(bytes, kfrags))
del kfrags
del signer
del delegating_privkey
del signing_privkey
del receiving_pubkey
del params
## ENCRYPTION DOMAIN ##
params = UmbralParameters(curve=curve)
delegating_pubkey = UmbralPublicKey.from_bytes(delegating_pubkey_bytes,
params)
plain_data = b'peace at dawn'
ciphertext, capsule = pre.encrypt(delegating_pubkey, plain_data)
capsule_bytes = bytes(capsule)
del capsule
del delegating_pubkey
del params
## DECRYPTION BY ALICE ##
params = UmbralParameters(curve=curve)
delegating_privkey = UmbralPrivateKey.from_bytes(delegating_privkey_bytes,
params)
capsule = pre.Capsule.from_bytes(capsule_bytes, params)
cleartext = pre.decrypt(ciphertext, capsule, delegating_privkey)
assert cleartext == plain_data
del delegating_privkey
del capsule
del params
## RE-ENCRYPTION DOMAIN (i.e., Ursula's side)
cfrags_bytes = list()
for kfrag_bytes in kfrags_bytes:
params = UmbralParameters(curve=curve)
delegating_pubkey = UmbralPublicKey.from_bytes(delegating_pubkey_bytes,
params)
signing_pubkey = UmbralPublicKey.from_bytes(signing_pubkey_bytes,
params)
receiving_pubkey = UmbralPublicKey.from_bytes(receiving_pubkey_bytes,
params)
capsule = pre.Capsule.from_bytes(capsule_bytes, params)
capsule.set_correctness_keys(delegating=delegating_pubkey,
receiving=receiving_pubkey,
verifying=signing_pubkey)
# TODO: use params instead of curve?
kfrag = KFrag.from_bytes(kfrag_bytes, params.curve)
assert kfrag.verify(signing_pubkey, delegating_pubkey,
receiving_pubkey, params)
cfrag_bytes = bytes(pre.reencrypt(kfrag, capsule))
cfrags_bytes.append(cfrag_bytes)
del capsule
del kfrag
del params
del delegating_pubkey
del signing_pubkey
del receiving_pubkey
## DECRYPTION DOMAIN (i.e., Bob's side)
params = UmbralParameters(curve=curve)
capsule = pre.Capsule.from_bytes(capsule_bytes, params)
delegating_pubkey = UmbralPublicKey.from_bytes(delegating_pubkey_bytes,
params)
signing_pubkey = UmbralPublicKey.from_bytes(signing_pubkey_bytes, params)
receiving_privkey = UmbralPrivateKey.from_bytes(receiving_privkey_bytes,
params)
receiving_pubkey = receiving_privkey.get_pubkey()
capsule.set_correctness_keys(delegating=delegating_pubkey,
receiving=receiving_pubkey,
verifying=signing_pubkey)
for cfrag_bytes in cfrags_bytes:
# TODO: use params instead of curve?
cfrag = CapsuleFrag.from_bytes(cfrag_bytes, params.curve)
capsule.attach_cfrag(cfrag)
reenc_cleartext = pre.decrypt(ciphertext, capsule, receiving_privkey)
assert reenc_cleartext == plain_data
