def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
sharedinfo: typing.Optional[bytes],
backend=None,
):
backend = _get_backend(backend)
max_len = algorithm.digest_size * (2**32 - 1)
if length > max_len:
raise ValueError(
"Can not derive keys larger than {} bits.".format(max_len))
if sharedinfo is not None:
utils._check_bytes("sharedinfo", sharedinfo)
self._algorithm = algorithm
self._length = length
self._sharedinfo = sharedinfo
if not isinstance(backend, HashBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HashBackend.",
_Reasons.BACKEND_MISSING_INTERFACE,
)
self._backend = backend
self._used = False
def verify(self, tag: bytes) -> None:
utils._check_bytes("tag", tag)
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
ctx, self._ctx = self._ctx, None
ctx.verify(tag)
def verify(self, tag):
utils._check_bytes("tag", tag)
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
ctx, self._ctx = self._ctx, None
ctx.verify(tag)
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
info: typing.Optional[bytes],
backend: typing.Any = None,
):
self._algorithm = algorithm
max_length = 255 * algorithm.digest_size
if length > max_length:
raise ValueError(
"Cannot derive keys larger than {} octets.".format(max_length))
self._length = length
if info is None:
info = b""
else:
utils._check_bytes("info", info)
self._info = info
self._used = False
def __init__(
self,
salt: bytes,
length: int,
n: int,
r: int,
p: int,
backend: typing.Any = None,
):
from cryptography.hazmat.backends.openssl.backend import (
backend as ossl, )
if not ossl.scrypt_supported():
raise UnsupportedAlgorithm(
"This version of OpenSSL does not support scrypt")
self._length = length
utils._check_bytes("salt", salt)
if n < 2 or (n & (n - 1)) != 0:
raise ValueError("n must be greater than 1 and be a power of 2.")
if r < 1:
raise ValueError("r must be greater than or equal to 1.")
if p < 1:
raise ValueError("p must be greater than or equal to 1.")
self._used = False
self._salt = salt
self._n = n
self._r = r
self._p = p
def _check_params(self, nonce: bytes, data: bytes,
associated_data: bytes) -> None:
utils._check_byteslike("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if len(nonce) != 12:
raise ValueError("Nonce must be 12 bytes")
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: bytes,
iterations: int,
backend: typing.Any = None,
):
from cryptography.hazmat.backends.openssl.backend import (
backend as ossl,
)
if not ossl.pbkdf2_hmac_supported(algorithm):
raise UnsupportedAlgorithm(
"{} is not supported for PBKDF2 by this backend.".format(
algorithm.name
),
_Reasons.UNSUPPORTED_HASH,
)
self._used = False
self._algorithm = algorithm
self._length = length
utils._check_bytes("salt", salt)
self._salt = salt
self._iterations = iterations
def __init__(self, algorithm, length, info, backend):
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
self._algorithm = algorithm
self._backend = backend
max_length = 255 * algorithm.digest_size
if length > max_length:
raise ValueError(
"Can not derive keys larger than {} octets.".format(
max_length
))
self._length = length
if info is None:
info = b""
else:
utils._check_bytes("info", info)
self._info = info
self._used = False
def __init__(
self,
salt: bytes,
length: int,
n: int,
r: int,
p: int,
backend: typing.Optional[Backend] = None,
):
backend = _get_backend(backend)
if not isinstance(backend, ScryptBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement ScryptBackend.",
_Reasons.BACKEND_MISSING_INTERFACE,
)
self._length = length
utils._check_bytes("salt", salt)
if n < 2 or (n & (n - 1)) != 0:
raise ValueError("n must be greater than 1 and be a power of 2.")
if r < 1:
raise ValueError("r must be greater than or equal to 1.")
if p < 1:
raise ValueError("p must be greater than or equal to 1.")
self._used = False
self._salt = salt
self._n = n
self._r = r
self._p = p
self._backend = backend
def verify(self, signature):
utils._check_bytes("signature", signature)
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
ctx, self._ctx = self._ctx, None
ctx.verify(signature)
def _common_args_checks(algorithm, length, otherinfo):
max_length = algorithm.digest_size * (2**32 - 1)
if length > max_length:
raise ValueError(
"Can not derive keys larger than {0} bits.".format(max_length))
if otherinfo is not None:
utils._check_bytes("otherinfo", otherinfo)
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: typing.Optional[bytes],
info: typing.Optional[bytes],
backend=None,
):
backend = _get_backend(backend)
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE,
)
self._algorithm = algorithm
if salt is None:
salt = b"\x00" * self._algorithm.digest_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
self._backend = backend
self._hkdf_expand = HKDFExpand(self._algorithm, length, info, backend)
def _check_params(self, nonce: bytes, data: bytes,
associated_data: bytes) -> None:
utils._check_byteslike("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if len(nonce) < 8 or len(nonce) > 128:
raise ValueError("Nonce must be between 8 and 128 bytes")
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: typing.Optional[bytes],
otherinfo: typing.Optional[bytes],
backend: typing.Any = None,
):
_common_args_checks(algorithm, length, otherinfo)
self._algorithm = algorithm
self._length = length
self._otherinfo: bytes = otherinfo if otherinfo is not None else b""
if algorithm.block_size is None:
raise TypeError("{} is unsupported for ConcatKDF".format(
algorithm.name))
if salt is None:
salt = b"\x00" * algorithm.block_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
self._used = False
def _check_params(self, nonce: bytes, data: bytes,
associated_data: bytes) -> None:
utils._check_byteslike("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if not 7 <= len(nonce) <= 13:
raise ValueError("Nonce must be between 7 and 13 bytes")
def derive(self, key_material):
if self._used:
raise AlreadyFinalized
utils._check_bytes("key_material", key_material)
self._used = True
# inverse floor division (equivalent to ceiling)
rounds = -(-self._length // self._algorithm.digest_size)
output = [b'']
# For counter mode, the number of iterations shall not be
# larger than 2^r-1, where r <= 32 is the binary length of the counter
# This ensures that the counter values used as an input to the
# PRF will not repeat during a particular call to the KDF function.
r_bin = utils.int_to_bytes(1, self._rlen)
if rounds > pow(2, len(r_bin) * 8) - 1:
raise ValueError('There are too many iterations.')
for i in range(1, rounds + 1):
h = hmac.HMAC(key_material, self._algorithm, backend=self._backend)
counter = utils.int_to_bytes(i, self._rlen)
if self._location == CounterLocation.BeforeFixed:
h.update(counter)
h.update(self._generate_fixed_input())
if self._location == CounterLocation.AfterFixed:
h.update(counter)
output.append(h.finalize())
return b''.join(output)[:self._length]
def verifier(self, signature, signature_algorithm):
_warn_sign_verify_deprecated()
utils._check_bytes("signature", signature)
_check_not_prehashed(signature_algorithm)
return _DSAVerificationContext(self._backend, self, signature,
signature_algorithm)
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
info: typing.Optional[bytes],
backend=None,
):
backend = _get_backend(backend)
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE,
)
self._algorithm = algorithm
self._backend = backend
max_length = 255 * algorithm.digest_size
if length > max_length:
raise ValueError(
"Can not derive keys larger than {} octets.".format(
max_length))
self._length = length
if info is None:
info = b""
else:
utils._check_bytes("info", info)
self._info = info
self._used = False
def verify(self, signature):
utils._check_bytes("signature", signature)
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
ctx, self._ctx = self._ctx, None
ctx.verify(signature)
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: typing.Optional[bytes],
otherinfo: typing.Optional[bytes],
backend: typing.Optional[Backend] = None,
):
backend = _get_backend(backend)
_common_args_checks(algorithm, length, otherinfo)
self._algorithm = algorithm
self._length = length
self._otherinfo: bytes = otherinfo if otherinfo is not None else b""
if algorithm.block_size is None:
raise TypeError("{} is unsupported for ConcatKDF".format(
algorithm.name))
if salt is None:
salt = b"\x00" * algorithm.block_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE,
)
self._backend = backend
self._used = False
def derive(self, key_material):
utils._check_bytes("key_material", key_material)
if self._used:
raise AlreadyFinalized
self._used = True
return self._expand(key_material)
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: bytes,
iterations: int,
backend: typing.Optional[Backend] = None,
):
backend = _get_backend(backend)
if not isinstance(backend, PBKDF2HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement PBKDF2HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE,
)
if not backend.pbkdf2_hmac_supported(algorithm):
raise UnsupportedAlgorithm(
"{} is not supported for PBKDF2 by this backend.".format(
algorithm.name),
_Reasons.UNSUPPORTED_HASH,
)
self._used = False
self._algorithm = algorithm
self._length = length
utils._check_bytes("salt", salt)
self._salt = salt
self._iterations = iterations
self._backend = backend
def _common_args_checks(algorithm: hashes.HashAlgorithm, length: int,
otherinfo: typing.Optional[bytes]):
max_length = algorithm.digest_size * (2**32 - 1)
if length > max_length:
raise ValueError(
"Can not derive keys larger than {} bits.".format(max_length))
if otherinfo is not None:
utils._check_bytes("otherinfo", otherinfo)
def __init__(self, algorithm, mode, length, rlen, llen,
location, label, context, fixed, backend):
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
if not isinstance(algorithm, hashes.HashAlgorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported hash algorithm.",
_Reasons.UNSUPPORTED_HASH
)
if not backend.hmac_supported(algorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported hmac algorithm.",
_Reasons.UNSUPPORTED_HASH
)
if not isinstance(mode, Mode):
raise TypeError("mode must be of type Mode")
if not isinstance(location, CounterLocation):
raise TypeError("location must be of type CounterLocation")
if (label or context) and fixed:
raise ValueError("When supplying fixed data, "
"label and context are ignored.")
if rlen is None or not self._valid_byte_length(rlen):
raise ValueError("rlen must be between 1 and 4")
if llen is None and fixed is None:
raise ValueError("Please specify an llen")
if llen is not None and not isinstance(llen, int):
raise TypeError("llen must be an integer")
if label is None:
label = b''
if context is None:
context = b''
utils._check_bytes("label", label)
utils._check_bytes("context", context)
self._algorithm = algorithm
self._mode = mode
self._length = length
self._rlen = rlen
self._llen = llen
self._location = location
self._label = label
self._context = context
self._backend = backend
self._used = False
self._fixed_data = fixed
def __init__(self, algorithm, mode, length, rlen, llen,
location, label, context, fixed, backend):
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
if not isinstance(algorithm, hashes.HashAlgorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported hash algorithm.",
_Reasons.UNSUPPORTED_HASH
)
if not backend.hmac_supported(algorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported hmac algorithm.",
_Reasons.UNSUPPORTED_HASH
)
if not isinstance(mode, Mode):
raise TypeError("mode must be of type Mode")
if not isinstance(location, CounterLocation):
raise TypeError("location must be of type CounterLocation")
if (label or context) and fixed:
raise ValueError("When supplying fixed data, "
"label and context are ignored.")
if rlen is None or not self._valid_byte_length(rlen):
raise ValueError("rlen must be between 1 and 4")
if llen is None and fixed is None:
raise ValueError("Please specify an llen")
if llen is not None and not isinstance(llen, int):
raise TypeError("llen must be an integer")
if label is None:
label = b''
if context is None:
context = b''
utils._check_bytes("label", label)
utils._check_bytes("context", context)
self._algorithm = algorithm
self._mode = mode
self._length = length
self._rlen = rlen
self._llen = llen
self._location = location
self._label = label
self._context = context
self._backend = backend
self._used = False
self._fixed_data = fixed
def derive(self, key_material):
if self._used:
raise AlreadyFinalized("Scrypt instances can only be used once.")
self._used = True
utils._check_bytes("key_material", key_material)
return self._backend.derive_scrypt(
key_material, self._salt, self._length, self._n, self._r, self._p
)
def verifier(self, signature, signature_algorithm):
_warn_sign_verify_deprecated()
utils._check_bytes("signature", signature)
_check_signature_algorithm(signature_algorithm)
_check_not_prehashed(signature_algorithm.algorithm)
return _ECDSAVerificationContext(
self._backend, self, signature, signature_algorithm.algorithm
)
def _check_params(
self,
data: bytes,
associated_data: typing.List,
) -> None:
utils._check_bytes("data", data)
if not isinstance(associated_data, list) or not all(
isinstance(x, bytes) for x in associated_data):
raise TypeError("associated_data must be a list of bytes or None")
def _common_args_checks(algorithm, length, otherinfo):
max_length = algorithm.digest_size * (2 ** 32 - 1)
if length > max_length:
raise ValueError(
"Can not derive keys larger than {} bits.".format(
max_length
))
if otherinfo is not None:
utils._check_bytes("otherinfo", otherinfo)
def _verify_key_size(algorithm, key):
# Verify that the key is instance of bytes
utils._check_bytes("key", key)
# Verify that the key size matches the expected key size
if len(key) * 8 not in algorithm.key_sizes:
raise ValueError("Invalid key size ({0}) for {1}.".format(
len(key) * 8, algorithm.name))
return key
def derive(self, key_material):
if self._used:
raise AlreadyFinalized("PBKDF2 instances can only be used once.")
self._used = True
utils._check_bytes("key_material", key_material)
return self._backend.derive_pbkdf2_hmac(self._algorithm, self._length,
self._salt, self._iterations,
key_material)
def from_encoded_point(cls, curve, data):
utils._check_bytes("data", data)
if not isinstance(curve, EllipticCurve):
raise TypeError("curve must be an EllipticCurve instance")
if six.indexbytes(data, 0) not in [0x02, 0x03, 0x04]:
raise ValueError("Unsupported elliptic curve point type")
from cryptography.hazmat.backends.openssl.backend import backend
return backend.load_elliptic_curve_public_bytes(curve, data)
def __init__(self, key):
if not backend.aead_cipher_supported(self):
raise exceptions.UnsupportedAlgorithm(
"ChaCha20Poly1305 is not supported by this version of OpenSSL",
exceptions._Reasons.UNSUPPORTED_CIPHER)
utils._check_bytes("key", key)
if len(key) != 32:
raise ValueError("ChaCha20Poly1305 key must be 32 bytes.")
self._key = key
def verifier(
self,
signature: bytes,
signature_algorithm: hashes.HashAlgorithm,
) -> AsymmetricVerificationContext:
_warn_sign_verify_deprecated()
utils._check_bytes("signature", signature)
_check_not_prehashed(signature_algorithm)
return _DSAVerificationContext(self._backend, self, signature,
signature_algorithm)
def __init__(self, key):
if not backend.aead_cipher_supported(self):
raise exceptions.UnsupportedAlgorithm(
"ChaCha20Poly1305 is not supported by this version of OpenSSL",
exceptions._Reasons.UNSUPPORTED_CIPHER
)
utils._check_bytes("key", key)
if len(key) != 32:
raise ValueError("ChaCha20Poly1305 key must be 32 bytes.")
self._key = key
def verifier(
self, signature: bytes,
signature_algorithm: ec.EllipticCurveSignatureAlgorithm
) -> AsymmetricVerificationContext:
_warn_sign_verify_deprecated()
utils._check_bytes("signature", signature)
_check_signature_algorithm(signature_algorithm)
_check_not_prehashed(signature_algorithm.algorithm)
# This assert is to help mypy realize what type this object holds
assert isinstance(signature_algorithm.algorithm, hashes.HashAlgorithm)
return _ECDSAVerificationContext(self._backend, self, signature,
signature_algorithm.algorithm)
def __init__(
self,
prf: typing.Callable,
mode: Mode,
length: int,
rlen: int,
llen: typing.Optional[int],
location: CounterLocation,
label: typing.Optional[bytes],
context: typing.Optional[bytes],
fixed: typing.Optional[bytes],
):
assert callable(prf)
if not isinstance(mode, Mode):
raise TypeError("mode must be of type Mode")
if not isinstance(location, CounterLocation):
raise TypeError("location must be of type CounterLocation")
if (label or context) and fixed:
raise ValueError("When supplying fixed data, "
"label and context are ignored.")
if rlen is None or not self._valid_byte_length(rlen):
raise ValueError("rlen must be between 1 and 4")
if llen is None and fixed is None:
raise ValueError("Please specify an llen")
if llen is not None and not isinstance(llen, int):
raise TypeError("llen must be an integer")
if label is None:
label = b""
if context is None:
context = b""
utils._check_bytes("label", label)
utils._check_bytes("context", context)
self._prf = prf
self._mode = mode
self._length = length
self._rlen = rlen
self._llen = llen
self._location = location
self._label = label
self._context = context
self._used = False
self._fixed_data = fixed
def from_encoded_point(cls, curve, data):
utils._check_bytes("data", data)
if not isinstance(curve, EllipticCurve):
raise TypeError("curve must be an EllipticCurve instance")
if len(data) == 0:
raise ValueError("data must not be an empty byte string")
if six.indexbytes(data, 0) not in [0x02, 0x03, 0x04]:
raise ValueError("Unsupported elliptic curve point type")
from cryptography.hazmat.backends.openssl.backend import backend
return backend.load_elliptic_curve_public_bytes(curve, data)
def _byte_unpadding_update(buffer_, data, block_size):
if buffer_ is None:
raise AlreadyFinalized("Context was already finalized.")
utils._check_bytes("data", data)
buffer_ += data
finished_blocks = max(len(buffer_) // (block_size // 8) - 1, 0)
result = buffer_[:finished_blocks * (block_size // 8)]
buffer_ = buffer_[finished_blocks * (block_size // 8):]
return buffer_, result
def _get_unverified_token_data(token):
utils._check_bytes("token", token)
try:
data = base64.urlsafe_b64decode(token)
except (TypeError, binascii.Error):
raise InvalidToken
if not data or six.indexbytes(data, 0) != 0x80:
raise InvalidToken
try:
timestamp, = struct.unpack(">Q", data[1:9])
except struct.error:
raise InvalidToken
return timestamp, data
def _encrypt_from_parts(self, data, current_time, iv):
utils._check_bytes("data", data)
padder = padding.PKCS7(algorithms.AES.block_size).padder()
padded_data = padder.update(data) + padder.finalize()
encryptor = Cipher(
algorithms.AES(self._encryption_key), modes.CBC(iv), self._backend
).encryptor()
ciphertext = encryptor.update(padded_data) + encryptor.finalize()
basic_parts = (
b"\x80" + struct.pack(">Q", current_time) + iv + ciphertext
)
h = HMAC(self._signing_key, hashes.SHA256(), backend=self._backend)
h.update(basic_parts)
hmac = h.finalize()
return base64.urlsafe_b64encode(basic_parts + hmac)
def __init__(self, algorithm, length, salt, info, backend):
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
self._algorithm = algorithm
if salt is None:
salt = b"\x00" * self._algorithm.digest_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
self._backend = backend
self._hkdf_expand = HKDFExpand(self._algorithm, length, info, backend)
def __init__(self, initialization_vector, tag=None, min_tag_length=16):
# len(initialization_vector) must in [1, 2 ** 64), but it's impossible
# to actually construct a bytes object that large, so we don't check
# for it
utils._check_byteslike("initialization_vector", initialization_vector)
if len(initialization_vector) == 0:
raise ValueError("initialization_vector must be at least 1 byte")
self._initialization_vector = initialization_vector
if tag is not None:
utils._check_bytes("tag", tag)
if min_tag_length < 4:
raise ValueError("min_tag_length must be >= 4")
if len(tag) < min_tag_length:
raise ValueError(
"Authentication tag must be {} bytes or longer.".format(
min_tag_length)
)
self._tag = tag
self._min_tag_length = min_tag_length
def __init__(self, key, tag_length=16):
utils._check_bytes("key", key)
if len(key) not in (16, 24, 32):
raise ValueError("AESCCM key must be 128, 192, or 256 bits.")
self._key = key
if not isinstance(tag_length, int):
raise TypeError("tag_length must be an integer")
if tag_length not in (4, 6, 8, 12, 14, 16):
raise ValueError("Invalid tag_length")
self._tag_length = tag_length
if not backend.aead_cipher_supported(self):
raise exceptions.UnsupportedAlgorithm(
"AESCCM is not supported by this version of OpenSSL",
exceptions._Reasons.UNSUPPORTED_CIPHER
)
def __init__(self, algorithm, length, salt, iterations, backend):
if not isinstance(backend, PBKDF2HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement PBKDF2HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
if not backend.pbkdf2_hmac_supported(algorithm):
raise UnsupportedAlgorithm(
"{0} is not supported for PBKDF2 by this backend.".format(
algorithm.name),
_Reasons.UNSUPPORTED_HASH
)
self._used = False
self._algorithm = algorithm
self._length = length
utils._check_bytes("salt", salt)
self._salt = salt
self._iterations = iterations
self._backend = backend
def __init__(self, algorithm, length, sharedinfo, backend):
max_len = algorithm.digest_size * (2 ** 32 - 1)
if length > max_len:
raise ValueError(
"Can not derive keys larger than {0} bits.".format(max_len))
if sharedinfo is not None:
utils._check_bytes("sharedinfo", sharedinfo)
self._algorithm = algorithm
self._length = length
self._sharedinfo = sharedinfo
if not isinstance(backend, HashBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HashBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
self._backend = backend
self._used = False
def __init__(self, algorithm, length, salt, otherinfo, backend):
_common_args_checks(algorithm, length, otherinfo)
self._algorithm = algorithm
self._length = length
self._otherinfo = otherinfo
if self._otherinfo is None:
self._otherinfo = b""
if salt is None:
salt = b"\x00" * algorithm.block_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
if not isinstance(backend, HMACBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement HMACBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
self._backend = backend
self._used = False
def __init__(self, salt, length, n, r, p, backend):
if not isinstance(backend, ScryptBackend):
raise UnsupportedAlgorithm(
"Backend object does not implement ScryptBackend.",
_Reasons.BACKEND_MISSING_INTERFACE
)
self._length = length
utils._check_bytes("salt", salt)
if n < 2 or (n & (n - 1)) != 0:
raise ValueError("n must be greater than 1 and be a power of 2.")
if r < 1:
raise ValueError("r must be greater than or equal to 1.")
if p < 1:
raise ValueError("p must be greater than or equal to 1.")
self._used = False
self._salt = salt
self._n = n
self._r = r
self._p = p
self._backend = backend
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if len(nonce) == 0:
raise ValueError("Nonce must be at least 1 byte")
def update(self, data):
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
utils._check_bytes("data", data)
self._ctx.update(data)
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if not 7 <= len(nonce) <= 13:
raise ValueError("Nonce must be between 7 and 13 bytes")
def __init__(self, key):
utils._check_bytes("key", key)
if len(key) not in (16, 24, 32):
raise ValueError("AESGCM key must be 128, 192, or 256 bits.")
self._key = key
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if len(nonce) != 12:
raise ValueError("Nonce must be 12 bytes")
