def test_key_length(self, backend):
kdf = KBKDFHMAC(hashes.SHA1(), Mode.CounterMode, 85899345920, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
with pytest.raises(ValueError):
kdf.derive(b'material')
def test_buffer_protocol(self, backend):
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 10, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
key = kdf.derive(bytearray(b"material"))
assert key == b'\xb7\x01\x05\x98\xf5\x1a\x12L\xc7.'
def test_invalid_key(self, backend):
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 32, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
key = kdf.derive(b"material")
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 32, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
with pytest.raises(InvalidKey):
kdf.verify(b"material2", key)
def kbkdf_counter_mode_test(backend, params):
supported_algorithms = {
'hmac_sha1': hashes.SHA1,
'hmac_sha224': hashes.SHA224,
'hmac_sha256': hashes.SHA256,
'hmac_sha384': hashes.SHA384,
'hmac_sha512': hashes.SHA512,
}
supported_counter_locations = {
"before_fixed": CounterLocation.BeforeFixed,
"after_fixed": CounterLocation.AfterFixed,
}
algorithm = supported_algorithms.get(params.get('prf'))
if algorithm is None or not backend.hmac_supported(algorithm()):
pytest.skip("KBKDF does not support algorithm: {}".format(
params.get('prf')
))
ctr_loc = supported_counter_locations.get(params.get("ctrlocation"))
if ctr_loc is None or not isinstance(ctr_loc, CounterLocation):
pytest.skip("Does not support counter location: {}".format(
params.get('ctrlocation')
))
ctrkdf = KBKDFHMAC(
algorithm(),
Mode.CounterMode,
params['l'] // 8,
params['rlen'] // 8,
None,
ctr_loc,
None,
None,
binascii.unhexlify(params['fixedinputdata']),
backend=backend)
ko = ctrkdf.derive(binascii.unhexlify(params['ki']))
assert binascii.hexlify(ko) == params["ko"]
def test_unicode_error_context(self, backend):
with pytest.raises(TypeError):
KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
"context", # type: ignore[arg-type]
None,
backend=backend,
)
def test_invalid_backend(self, backend):
with raises_unsupported_algorithm(_Reasons.BACKEND_MISSING_INTERFACE):
KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=object(),
)
def test_l(self, backend):
with pytest.raises(ValueError):
KBKDFHMAC(
hashes.SHA1(),
Mode.CounterMode,
32,
4,
None,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
def test_unsupported_mode(self, backend):
with pytest.raises(TypeError):
KBKDFHMAC(
hashes.SHA256(),
None, # type: ignore[arg-type]
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
def test_unsupported_location(self, backend):
with pytest.raises(TypeError):
KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
None, # type: ignore[arg-type]
b"label",
b"context",
None,
backend=backend,
)
def test_unsupported_parameters(self, backend):
with pytest.raises(ValueError):
KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
b"fixed",
backend=backend,
)
def test_unsupported_hash(self, backend):
with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_HASH):
KBKDFHMAC(
object(), # type: ignore[arg-type]
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
def test_l_type(self, backend):
with pytest.raises(TypeError):
KBKDFHMAC(
hashes.SHA1(),
Mode.CounterMode,
32,
4,
b"l", # type: ignore[arg-type]
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
def test_unsupported_algorithm(self, backend):
with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_HASH):
KBKDFHMAC(
DummyHashAlgorithm(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
def kbkdf_counter_mode_test(backend, params):
supported_algorithms = {
'hmac_sha1': hashes.SHA1,
'hmac_sha224': hashes.SHA224,
'hmac_sha256': hashes.SHA256,
'hmac_sha384': hashes.SHA384,
'hmac_sha512': hashes.SHA512,
}
supported_counter_locations = {
"before_fixed": CounterLocation.BeforeFixed,
"after_fixed": CounterLocation.AfterFixed,
}
algorithm = supported_algorithms.get(params.get('prf'))
if algorithm is None or not backend.hmac_supported(algorithm()):
pytest.skip("KBKDF does not support algorithm: {0}".format(
params.get('prf')))
ctr_loc = supported_counter_locations.get(params.get("ctrlocation"))
if ctr_loc is None or not isinstance(ctr_loc, CounterLocation):
pytest.skip("Does not support counter location: {0}".format(
params.get('ctrlocation')))
ctrkdf = KBKDFHMAC(algorithm(),
Mode.CounterMode,
params['l'] // 8,
params['rlen'] // 8,
None,
ctr_loc,
None,
None,
binascii.unhexlify(params['fixedinputdata']),
backend=backend)
ko = ctrkdf.derive(binascii.unhexlify(params['ki']))
assert binascii.hexlify(ko) == params["ko"]
def _smb3kdf(self, ki, label, context):
"""
See SMB 3.x key derivation function
https://blogs.msdn.microsoft.com/openspecification/2017/05/26/smb-2-and-smb-3-security-in-windows-10-the-anatomy-of-signing-and-cryptographic-keys/
:param ki: The session key is the KDK used as an input to the KDF
:param label: The purpose of this derived key as bytes string
:param context: The context information of this derived key as bytes
string
:return: Key derived by the KDF as specified by [SP800-108] 5.1
"""
kdf = KBKDFHMAC(
algorithm=hashes.SHA256(),
mode=Mode.CounterMode,
length=16,
rlen=4,
llen=4,
location=CounterLocation.BeforeFixed,
label=label,
context=context,
fixed=None,
backend=default_backend()
)
return kdf.derive(ki)
def test_already_finalized(self):
kdf = KBKDFHMAC(hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b'label',
b'context',
None,
backend=default_backend())
kdf.derive(b'material')
with pytest.raises(AlreadyFinalized):
kdf.derive(b'material2')
kdf = KBKDFHMAC(hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b'label',
b'context',
None,
backend=default_backend())
key = kdf.derive(b'material')
with pytest.raises(AlreadyFinalized):
kdf.verify(b'material', key)
kdf = KBKDFHMAC(hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b'label',
b'context',
None,
backend=default_backend())
kdf.verify(b'material', key)
with pytest.raises(AlreadyFinalized):
kdf.verify(b"material", key)
def test_already_finalized(self, backend):
kdf = KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
kdf.derive(b"material")
with pytest.raises(AlreadyFinalized):
kdf.derive(b"material2")
kdf = KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
key = kdf.derive(b"material")
with pytest.raises(AlreadyFinalized):
kdf.verify(b"material", key)
kdf = KBKDFHMAC(
hashes.SHA256(),
Mode.CounterMode,
32,
4,
4,
CounterLocation.BeforeFixed,
b"label",
b"context",
None,
backend=backend,
)
kdf.verify(b"material", key)
with pytest.raises(AlreadyFinalized):
kdf.verify(b"material", key)
def test_unicode_error_key_material(self, backend):
with pytest.raises(TypeError):
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 32, 4, 4,
CounterLocation.BeforeFixed, b'label',
b'context', None, backend=backend)
kdf.derive(u'material')
def test_already_finalized(self, backend):
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 32, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
kdf.derive(b'material')
with pytest.raises(AlreadyFinalized):
kdf.derive(b'material2')
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 32, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
key = kdf.derive(b'material')
with pytest.raises(AlreadyFinalized):
kdf.verify(b'material', key)
kdf = KBKDFHMAC(hashes.SHA256(), Mode.CounterMode, 32, 4, 4,
CounterLocation.BeforeFixed, b'label', b'context',
None, backend=backend)
kdf.verify(b'material', key)
with pytest.raises(AlreadyFinalized):
kdf.verify(b"material", key)
backend=backend) # An instance of PBKDF2HMACBackend
else:
# The KBKDF (Key Based Key Derivation Function) used here is defined by the NIST SP 800-108 document, to be used
# to derive additional keys from a key that has been established through an automated key-establishment scheme
label = b'KBKDF HMAC Label'
context = b'KBKDF HMAC Context'
kdf = KBKDFHMAC(
algorithm=hash_algo, # An instance of HashAlgorithm
mode=Mode.
CounterMode, # The desired mode of the PRF.A value from the Mode enum
length=32, # The desired length of the derived key in bytes
rlen=
4, # An integer that indicates the length of the counter in bytes
llen=
4, # An integer that indicates the length of the length in bytes
location=CounterLocation.
BeforeFixed, # The desired location of the counter
label=
label, # Application specific label information. Byte string or None
context=
context, # Application specific context information. Byte string or None
fixed=
None, # Instead of specifying label and context, supply your own fixed data
backend=backend) # A cryptography backend HashBackend instance
# Derive a new key from the shared secret
derived_key = kdf.derive(password)
# Make sure shared keys agree
print(Fore.GREEN + '\nDerived AES key ({} bits): {}'.format(
len(derived_key) * 8,
def _derive_urlsafe_key(*, label, context):
backend = default_backend()
kdf = KBKDFHMAC(algorithm=hashes.SHA256(), mode=Mode.CounterMode, length=32, rlen=4, llen=4,
location=CounterLocation.BeforeFixed, label=label, context=context, fixed=None, backend=backend)
key = kdf.derive(settings.SECRET_KEY.encode())
return urlsafe_b64encode(key)
