def test_unwrap_invalid_wrapped_key_length(self, backend):
# Keys to unwrap must be at least 24 bytes
with pytest.raises(ValueError):
keywrap.aes_key_unwrap(b"sixteen_byte_key", b"\x00" * 16, backend)
# Keys to unwrap must be a multiple of 8 bytes
with pytest.raises(ValueError):
keywrap.aes_key_unwrap(b"sixteen_byte_key", b"\x00" * 27, backend)
def test_unwrap_invalid_wrapped_key_length(self, backend):
# Keys to unwrap must be at least 24 bytes
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(b"sixteen_byte_key", b"\x00" * 16, backend)
# Keys to unwrap must be a multiple of 8 bytes
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(b"sixteen_byte_key", b"\x00" * 27, backend)
def test_unwrap(self, backend, params):
wrapping_key = binascii.unhexlify(params["k"])
wrapped_key = binascii.unhexlify(params["c"])
if params.get("fail") is True:
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(wrapping_key, wrapped_key, backend)
else:
unwrapped_key = keywrap.aes_key_unwrap(wrapping_key, wrapped_key, backend)
assert params["p"] == binascii.hexlify(unwrapped_key)
def test_unwrap(self, backend, params):
wrapping_key = binascii.unhexlify(params["k"])
wrapped_key = binascii.unhexlify(params["c"])
if params.get("fail") is True:
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(wrapping_key, wrapped_key, backend)
else:
unwrapped_key = keywrap.aes_key_unwrap(wrapping_key, wrapped_key,
backend)
assert params["p"] == binascii.hexlify(unwrapped_key)
def decrypt(self, token, key=None, cek=None):
logger.debug('SYM decrypt')
if not key and not cek:
raise MissingKey("On of key or cek must be specified")
if isinstance(token, JWEnc):
jwe = token
else:
jwe = JWEnc().unpack(token)
if len(jwe) != 5:
raise WrongNumberOfParts(len(jwe))
if not cek:
jek = jwe.encrypted_key()
if isinstance(key, SYMKey):
try:
key = key.key.encode('utf8')
except AttributeError:
key = key.key
# The iv for this function must be 64 bit
cek = aes_key_unwrap(key, jek, default_backend())
auth_data = jwe.b64_protected_header()
msg = self._decrypt(
jwe.headers["enc"], cek, jwe.ciphertext(),
auth_data=auth_data,
iv=jwe.initialization_vector(), tag=jwe.authentication_tag())
if "zip" in self and self["zip"] == "DEF":
msg = zlib.decompress(msg)
return msg
def unwrap_key(self, wrapped_key):
wrapped_key = six.ensure_binary(wrapped_key)
try:
plain_text = aes_key_unwrap(self._key, wrapped_key, default_backend())
except InvalidUnwrap as cause:
raise JWEError(cause)
return plain_text
def unwrap(self, enc_alg, ek, headers, key):
op_key = key.get_op_key('unwrapKey')
self._check_key(op_key)
cek = aes_key_unwrap(op_key, ek, default_backend())
if len(cek) * 8 != enc_alg.CEK_SIZE:
raise ValueError('Invalid "cek" length')
return cek
def unwrap(self, key, bitsize, ek, headers):
rk = self._get_key(key, 'decrypt')
cek = aes_key_unwrap(rk, ek, default_backend())
if _bitsize(cek) != bitsize:
raise InvalidJWEKeyLength(bitsize, _bitsize(cek))
return cek
def decode_cipher_value(content):
"""Get user from ACS service response.
Args:
content (bytes): response.content
Returns:
tuple: first_name, last_name, DOB, PESEL
"""
tree = fromstring(content)
PUBLIC_KEY = tree.find('.//{http://www.w3.org/2009/xmldsig11#}PublicKey').text
CIPHER_VALUE = tree.find('.//{http://www.w3.org/2001/04/xmlenc#}CipherValue').text
USER_ATTRS = tree.find('.//{http://www.w3.org/2001/04/xmlenc#}EncryptedData/{http://www.w3.org/2001/04/xmlenc#}CipherData/{http://www.w3.org/2001/04/xmlenc#}CipherValue').text
concatKDFParams = tree.find('.//{http://www.w3.org/2009/xmlenc11#}ConcatKDFParams')
with open(settings.LOGINGOVPL_ENC_KEY, 'rb') as f:
server_private_key = load_pem_private_key(
f.read(), None, default_backend(),
)
public_key_bytes = base64.b64decode(PUBLIC_KEY)
curve = ec.SECP256R1()
peer_public_key = ec.EllipticCurvePublicKey.from_encoded_point(curve, public_key_bytes)
peer_public_key_pem = peer_public_key.public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo,
)
logger.debug('peer public key:\n%s', peer_public_key_pem.decode())
shared_key = server_private_key.exchange(
ec.ECDH(), peer_public_key)
logger.debug('shared key: %s', shared_key)
otherinfo = get_otherinfo(concatKDFParams)
logger.debug('otherinfo: %s', otherinfo)
ckdf = ConcatKDFHash(
algorithm=hashes.SHA256(),
length=32,
otherinfo=binascii.unhexlify(otherinfo.encode()),
backend=default_backend()
)
cipher_bytes = base64.b64decode(CIPHER_VALUE)
wrapping_key = ckdf.derive(shared_key)
logger.debug('wrapping key: %s', wrapping_key)
session_key = aes_key_unwrap(wrapping_key, cipher_bytes, default_backend())
user_attr_bytes = base64.b64decode(USER_ATTRS)
nonce, tag = user_attr_bytes[:12], user_attr_bytes[-16:]
cipher = AES.new(session_key, AES.MODE_GCM, nonce)
decoded_saml = cipher.decrypt_and_verify(user_attr_bytes[12:-16], tag)
logger.debug(decoded_saml)
return decoded_saml
def wrap_unwrap(key_1, key_2): # Function to wrap and unwrap keys
backend = default_backend()
wrapped_key = keywrap.aes_key_wrap(
key_2, key_1, backend=backend) # Wrap key 1 with key 2
unwrapped_key = keywrap.aes_key_unwrap(
key_2, wrapped_key,
backend=backend) # Unwrapped the wrapped key with the key 2
return wrapped_key, unwrapped_key
def aes_key_unwrap(self, kek: bytes, wrapped_key: bytes) -> bytes:
"""Unwraps a key using a key-encrypting key (KEK).
:param kek: The key-encrypting key
:param wrapped_key: Encrypted data
:return: Un-wrapped key
"""
return keywrap.aes_key_unwrap(kek, wrapped_key, default_backend())
def test_keywrap(backend, wycheproof):
wrapping_key = binascii.unhexlify(wycheproof.testcase["key"])
key_to_wrap = binascii.unhexlify(wycheproof.testcase["msg"])
expected = binascii.unhexlify(wycheproof.testcase["ct"])
if (wycheproof.valid or
(wycheproof.acceptable
and wycheproof.testcase["comment"] != "invalid size of wrapped key")):
result = keywrap.aes_key_wrap(wrapping_key, key_to_wrap, backend)
assert result == expected
if wycheproof.valid or wycheproof.acceptable:
result = keywrap.aes_key_unwrap(wrapping_key, expected, backend)
assert result == key_to_wrap
else:
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(wrapping_key, expected, backend)
def unwrap_key(security_control: SecurityControlField, wrapping_key: bytes,
wrapped_key: bytes):
"""
Simple function to unwrap a key received.
"""
validate_key(security_control.security_suite, wrapping_key)
validate_key(security_control.security_suite, wrapped_key)
unwrapped_key = aes_key_unwrap(wrapping_key, wrapped_key)
return unwrapped_key
def test_unwrap(self, backend, subtests):
params = _load_all_params(
os.path.join("keywrap", "kwtestvectors"),
["KW_AD_128.txt", "KW_AD_192.txt", "KW_AD_256.txt"],
load_nist_vectors,
)
for param in params:
with subtests.test():
wrapping_key = binascii.unhexlify(param["k"])
wrapped_key = binascii.unhexlify(param["c"])
if param.get("fail") is True:
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(wrapping_key, wrapped_key,
backend)
else:
unwrapped_key = keywrap.aes_key_unwrap(
wrapping_key, wrapped_key, backend)
assert param["p"] == binascii.hexlify(unwrapped_key)
def test_keywrap(backend, wycheproof):
wrapping_key = binascii.unhexlify(wycheproof.testcase["key"])
key_to_wrap = binascii.unhexlify(wycheproof.testcase["msg"])
expected = binascii.unhexlify(wycheproof.testcase["ct"])
if (
wycheproof.valid or (
wycheproof.acceptable and
wycheproof.testcase["comment"] != "invalid size of wrapped key"
)
):
result = keywrap.aes_key_wrap(wrapping_key, key_to_wrap, backend)
assert result == expected
if wycheproof.valid or wycheproof.acceptable:
result = keywrap.aes_key_unwrap(wrapping_key, expected, backend)
assert result == key_to_wrap
else:
with pytest.raises(keywrap.InvalidUnwrap):
keywrap.aes_key_unwrap(wrapping_key, expected, backend)
def unwrap_key_aes(key_to_unwrap, wrapping_key):
""" Unwraps a key using the AES key wrapping mode of operation as specified in
https://www.ietf.org/rfc/rfc3394.txt
:param key_to_unwrap: the wrapped result of a previous wrap operation. I.e. the key
to be unwrapped
:param wrapping_key: the key used to unwrap = KEK. This must be the same key used
to wrap
:return: the unwrapped key
"""
return keywrap.aes_key_unwrap(wrapping_key, key_to_unwrap,
default_backend())
def dec_setup(self, token, key=None, **kwargs):
"""
:param token: signed JSON Web token
:param key: Private Elliptic Curve Key
:param kwargs:
:return:
"""
self.headers = token.headers
self.iv = token.initialization_vector()
self.ctxt = token.ciphertext()
self.tag = token.authentication_tag()
# Handle EPK / Curve
if "epk" not in self.headers or "crv" not in self.headers["epk"]:
raise Exception("Ephemeral Public Key Missing in ECDH-ES Computation")
epubkey = ECKey(**self.headers["epk"])
apu = apv = ""
if "apu" in self.headers:
apu = b64d(self.headers["apu"].encode())
if "apv" in self.headers:
apv = b64d(self.headers["apv"].encode())
if self.headers["alg"] == "ECDH-ES":
try:
dk_len = KEY_LEN[self.headers["enc"]]
except KeyError:
raise Exception("Unknown key length for algorithm")
self.cek = ecdh_derive_key(
key,
epubkey.pub_key,
apu,
apv,
str(self.headers["enc"]).encode(),
dk_len,
)
elif self.headers["alg"] in [
"ECDH-ES+A128KW",
"ECDH-ES+A192KW",
"ECDH-ES+A256KW",
]:
_pre, _post = self.headers["alg"].split("+")
klen = int(_post[1:4])
kek = ecdh_derive_key(key, epubkey.pub_key, apu, apv, str(_post).encode(), klen)
self.cek = aes_key_unwrap(kek, token.encrypted_key(), default_backend())
else:
raise Exception("Unsupported algorithm %s" % self.headers["alg"])
return self.cek
def decrypt(self, pk, *args):
km = pk.keymaterial
# assemble the public component of ephemeral key v
v = ec.EllipticCurvePublicNumbers(self.p.x, self.p.y, km.oid.curve()).public_key(default_backend())
# compute s using the inverse of how it was derived during encryption
s = km.__privkey__().exchange(ec.ECDH(), v)
# derive the wrapping key
z = km.kdf.derive_key(s, km.oid, PubKeyAlgorithm.ECDH, pk.fingerprint)
# unwrap and unpad m
_m = aes_key_unwrap(z, self.c, default_backend())
padder = PKCS7(64).unpadder()
return padder.update(_m) + padder.finalize()
def decrypt(self, pk, *args):
km = pk.keymaterial
# assemble the public component of ephemeral key v
v = ec.EllipticCurvePublicNumbers(self.vX, self.vY, km.oid.curve()).public_key(default_backend())
# compute s using the inverse of how it was derived during encryption
s = km.__privkey__().exchange(ec.ECDH(), v)
# derive the wrapping key
z = km.kdf.derive_key(s, km.oid, PubKeyAlgorithm.ECDH, pk.fingerprint)
# unwrap and unpad m
_m = aes_key_unwrap(z, self.c, default_backend())
padder = PKCS7(64).unpadder()
return padder.update(_m) + padder.finalize()
def key_unwrap(self, mechanism, data, wrapping_key, nonce_iv):
"""
:param mechanism key wrapping mechanism
:param data: data to unwrap
:param wrapping_key: AES key used to wrap data
:param nonce_iv Nonce data
:return: unwrapped data
Unwrap the encrypted data which has been wrapped using a
KeyWrap mechanism.
"""
if mechanism == WRAP_AES_CBC_PAD or mechanism == WRAP_DES3_CBC_PAD:
return self.symmetric_unwrap(data, wrapping_key, nonce_iv=nonce_iv)
if mechanism == WRAP_AES_KEY_WRAP:
return keywrap.aes_key_unwrap(wrapping_key, data, self.backend)
raise ValueError("Unsupported key wrap algorithm: " + mechanism)
def unwrap(self, wrapping_key, wrapped_key):
# type: (bytes, bytes) -> bytes
"""Unwrap key using AES keywrap.
:param bytes wrapping_key: Loaded key with which to unwrap
:param bytes wrapped_key: Wrapped key to unwrap
:returns: Unwrapped key
:rtype: bytes
"""
if self.java_name not in ("AES", "AESWrap"):
raise NotImplementedError('"unwrap" is not supported by this cipher')
try:
return keywrap.aes_key_unwrap(wrapping_key=wrapping_key, wrapped_key=wrapped_key, backend=default_backend())
except Exception:
error_message = "Key unwrap failed"
_LOGGER.exception(error_message)
raise UnwrappingError(error_message)
def unwrap_key(self, key, algorithm):
if algorithm == 'A256KW':
return aes_key_unwrap(self.kek, key, self.backend)
raise ValueError('Unknown key wrap algorithm.')
def decrypt(self, encrypted_data_key) -> bytes:
data_key = aes_key_unwrap(
wrapping_key=self._key_bytes,
wrapped_key=encrypted_data_key,
)
return data_key
def key_unwrap(cls, kek: 'SK', data: bytes):
if cls.get_key_length() != len(kek.k):
raise ValueError("Key has the wrong length")
return aes_key_unwrap(wrapping_key=kek.k, wrapped_key=data, backend=default_backend())
def test_unwrap_invalid_key_length(self, backend):
with pytest.raises(ValueError):
keywrap.aes_key_unwrap(b"badkey", b"\x00" * 24, backend)
def unwrap(self, ek, headers, key):
op_key = key.get_op_key('unwrapKey')
self._check_key(op_key)
cek = aes_key_unwrap(op_key, ek, default_backend())
return cek
def unwrap_key(self, key, algorithm):
if algorithm == 'A256KW':
return aes_key_unwrap(self.kek, key, self.backend)
else:
raise ValueError(_ERROR_UNKNOWN_KEY_WRAP_ALGORITHM)
def unwrap_key(self, key, algorithm):
if algorithm == 'A256KW':
return aes_key_unwrap(self.kek, key, self.backend)
else:
raise ValueError(_ERROR_UNKNOWN_KEY_WRAP_ALGORITHM)
def transform(self, data):
aes_key_unwrap(self._key, data, default_backend())
def unwrap_key(self, wrapping_key, key_to_unwrap):
try:
return aes_key_unwrap(wrapping_key, key_to_unwrap, default_backend())
except InvalidUnwrap:
raise WrongPassword("Password is incorrect.")
def unwrap(self, ek, headers, key):
self._check_key(key)
cek = aes_key_unwrap(key, ek, default_backend())
return cek
def unwrap_data_key(self, wrapped_data_key: bytes) -> bytes:
return aes_key_unwrap(
wrapping_key=self._wrapping_key,
wrapped_key=wrapped_data_key,
)
def AESKeyWrap():
print("\n\n\n===========================================")
print("Welcome to Key Wrap (KW) Mode of Operation")
print("===========================================")
print(" ")
print(
"Key wrapping and un-wrapping requires 3 parameters in order to function correctly:\n"
)
print(
"\n1) The key encrytion key or 'the wrapping key', which must be of 16, 24 or 32 bytes in value in order for AES to function."
)
print(
"2) The key that is to be wrapped 'key to wrap', this is also of 16, 24 or 32 bytes in value."
)
print(
"3) Finally, the wrapped key, this is the encrypted value of the key which is also used in the unwrapping process."
)
print(
"\nFor simplicity's sake, we have already defined a value for the key encryption key to be b'1234567890123456'."
)
wrappingKey = b'1234567890123456' # Must be 16,24,32 bytes
userYN = input("Do you wish to change this value?(y/n):")
if (userYN == "y"):
wrappingKey = input(
"Enter a new value for the wrapping key(MUST BE OF 16, 24 OR 32 BYTES):"
)
wrappingKey = wrappingKey.encode('utf-8')
while (True):
if ((len(wrappingKey) % 8 == 0) and len(wrappingKey) >= 16
and len(wrappingKey) <= 32):
break
print("The wrapping key must be a valid AES key length")
wrappingKey = input(
"Enter a new value for the wrapping key.(MUST BE OF 16, 24 OR 32 BYTES):"
)
wrappingKey = wrappingKey.encode('utf-8')
print(
"\nAnd again, for simplicity's sake we've defined the key that is to be wrapped to be b'wow-this-is-fun!'"
)
keyToWrap = b'wow-this-is-fun!' # Must be 16,24,32 bytes
userYN = input("Do you wish to change this value?(y/n):")
if (userYN == "y"):
keyToWrap = input(
"Enter a new value for key to be wrapped.(MUST BE OF 16, 24 OR 32 BYTES):"
)
keyToWrap = keyToWrap.encode('utf-8')
while (True):
if ((len(keyToWrap) % 8 == 0) and len(keyToWrap) >= 16
and len(keyToWrap) <= 32):
break
print("The wrapping key must be a valid AES key length")
keyToWrap = input(
"Enter a new value for the wrapping key(MUST BE OF 16, 24 OR 32 BYTES):"
)
keyToWrap = keyToWrap.encode('utf-8')
wrappedKey = keywrap.aes_key_wrap(wrappingKey,
keyToWrap,
backend=default_backend())
print("\nThe encrypted value for the wrapped key is:", wrappedKey)
input("Press Enter to see how we computed the wrapped key value...")
print("\nWhat just happened?")
print("-------------------------------------")
print(
"\nSo to go over how we got the encrypted value, lets take a moment to recall all the components involved."
)
print(
"First off, when the program asked about setting a key encryption key, this key value is what's going to remain constant in both wrapping and un-wrapping the new key (Defaulted to b'1234567890123456' if no input)."
)
print(
"The 'new key' is essentially the symmetric key we are wrapping so that we have a safe transfer of keys from the sender side to the receiver."
)
print(
"This 'new key', we will dub it as the 'keyToWrap' value and this is the second value the program asked for your input. It was defaulted to b'wow-this-is-fun!' if there was no input."
)
print("\nSo now we have the following: ")
print(
"1) Key Encryption Key 'wrappinKey' = b'1234567890123456' or whatever you inputted."
)
print(
"2) New Symmetric Key 'keyToWrap' = b'wow-this-is-fun!' or whatever you inputted."
)
print(
"\nFinally, the program used the 'wrappingKey' to encrypt the 'keyToWrap' and that's how we got our 'WrappedKey' value."
)
print("To clarify, the wrapped key is:", wrappedKey)
input(
"Press Enter to see how we can return back to our 'keyToWrap' value..."
)
print("\nWhat about un-wrapping?")
print("-------------------------------------")
print(
"\nNow if we wanted to get back our 'keyToWrap' which would be the symmetric key we wanted to exchange, it is actually quite simple given the parameters and values."
)
print(
"This is most helpful when trying to decrypt the wrapped key as the receiver of the new symmetric key."
)
print(
"\nJust like what we stated above when figuring out our wrapped key value, lets see what we have:"
)
print(
"1) Key Encrytion key 'wrappingKey' = b'1234567890123456' or whatever it was you inputted. (REMEMBER THIS PARAMETER REMAINS CONSTANT FOR BOTH OPERATIONS)"
)
print("2) 'wrappedKey' = ", wrappedKey)
print(
"\nJust like before, using the two values and then decrypting using AES, we get back our 'keyToWrap' value"
)
c = keywrap.aes_key_unwrap(wrappingKey,
wrappedKey,
backend=default_backend())
print(
"After decrypting we end up with the symmetric key that was to be exchanged between sender and receiver:",
c)
def key_unwrap(wrapping_key, wrapped_key):
return aes_key_unwrap(wrapping_key, wrapped_key, _BACKEND)
def test_unwrap_invalid_key_length(self, backend):
with pytest.raises(ValueError):
keywrap.aes_key_unwrap(b"badkey", b"\x00" * 24, backend)
def unwrap_key(self, wrapping_key, key_to_unwrap):
try:
return aes_key_unwrap(wrapping_key, key_to_unwrap, default_backend())
except InvalidUnwrap:
raise WrongPassword("Password is incorrect.")
def unwrap_key(self, wrapped_key: bytes) -> bytes:
try:
return aes_key_unwrap(self._key, wrapped_key)
except Exception as err:
raise DecodeError("Failed to unwrap key.") from err
