def aes_key_unwrap_with_padding(wrapping_key, wrapped_key, backend=None):
backend = _get_backend(backend)
if len(wrapped_key) < 16:
raise InvalidUnwrap("Must be at least 16 bytes")
if len(wrapping_key) not in [16, 24, 32]:
raise ValueError("The wrapping key must be a valid AES key length")
if len(wrapped_key) == 16:
# RFC 5649 - 4.2 - exactly two 64-bit blocks
decryptor = Cipher(AES(wrapping_key), ECB(), backend).decryptor()
b = decryptor.update(wrapped_key)
assert decryptor.finalize() == b""
a = b[:8]
data = b[8:]
n = 1
else:
r = [wrapped_key[i:i + 8] for i in range(0, len(wrapped_key), 8)]
encrypted_aiv = r.pop(0)
n = len(r)
a, r = _unwrap_core(wrapping_key, encrypted_aiv, r, backend)
data = b"".join(r)
# 1) Check that MSB(32,A) = A65959A6.
# 2) Check that 8*(n-1) < LSB(32,A) <= 8*n. If so, let
# MLI = LSB(32,A).
# 3) Let b = (8*n)-MLI, and then check that the rightmost b octets of
# the output data are zero.
(mli, ) = struct.unpack(">I", a[4:])
b = (8 * n) - mli
if (not bytes_eq(a[:4], b"\xa6\x59\x59\xa6")
or not 8 * (n - 1) < mli <= 8 * n
or (b != 0 and not bytes_eq(data[-b:], b"\x00" * b))):
raise InvalidUnwrap()
if b == 0:
return data
else:
return data[:-b]
def aes_key_unwrap(wrapping_key, wrapped_key, backend=None):
backend = _get_backend(backend)
if len(wrapped_key) < 24:
raise InvalidUnwrap("Must be at least 24 bytes")
if len(wrapped_key) % 8 != 0:
raise InvalidUnwrap("The wrapped key must be a multiple of 8 bytes")
if len(wrapping_key) not in [16, 24, 32]:
raise ValueError("The wrapping key must be a valid AES key length")
aiv = b"\xa6\xa6\xa6\xa6\xa6\xa6\xa6\xa6"
r = [wrapped_key[i:i + 8] for i in range(0, len(wrapped_key), 8)]
a = r.pop(0)
a, r = _unwrap_core(wrapping_key, a, r, backend)
if not bytes_eq(a, aiv):
raise InvalidUnwrap()
return b"".join(r)
def verify(self, totp, time):
if not constant_time.bytes_eq(self.generate(time), totp):
raise InvalidToken("Supplied TOTP value does not match.")
def verify(self, key_material, expected_key):
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey
def verify(self, tag):
mac = self.finalize()
if not constant_time.bytes_eq(mac, tag):
raise InvalidSignature("Value did not match computed tag.")
def verify(self, key_material, expected_key):
derived_key = self.derive(key_material)
if not constant_time.bytes_eq(derived_key, expected_key):
raise InvalidKey("Keys do not match.")
def verify(self, hotp, counter):
if not constant_time.bytes_eq(self.generate(counter), hotp):
raise InvalidToken("Supplied HOTP value does not match.")
def verify(self, signature):
digest = self.finalize()
if not constant_time.bytes_eq(digest, signature):
raise InvalidSignature("Signature did not match digest.")