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commit b9c99befab
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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import abc
class KeyDerivationFunction(metaclass=abc.ABCMeta):
@abc.abstractmethod
def derive(self, key_material: bytes) -> bytes:
"""
Deterministically generates and returns a new key based on the existing
key material.
"""
@abc.abstractmethod
def verify(self, key_material: bytes, expected_key: bytes) -> None:
"""
Checks whether the key generated by the key material matches the
expected derived key. Raises an exception if they do not match.
"""

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
from cryptography.hazmat.bindings._rust import openssl as rust_openssl
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
Argon2id = rust_openssl.kdf.Argon2id
KeyDerivationFunction.register(Argon2id)
__all__ = ["Argon2id"]

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import typing
from cryptography import utils
from cryptography.exceptions import AlreadyFinalized, InvalidKey
from cryptography.hazmat.primitives import constant_time, hashes, hmac
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
def _int_to_u32be(n: int) -> bytes:
return n.to_bytes(length=4, byteorder="big")
def _common_args_checks(
algorithm: hashes.HashAlgorithm,
length: int,
otherinfo: bytes | None,
) -> None:
max_length = algorithm.digest_size * (2**32 - 1)
if length > max_length:
raise ValueError(f"Cannot derive keys larger than {max_length} bits.")
if otherinfo is not None:
utils._check_bytes("otherinfo", otherinfo)
def _concatkdf_derive(
key_material: bytes,
length: int,
auxfn: typing.Callable[[], hashes.HashContext],
otherinfo: bytes,
) -> bytes:
utils._check_byteslike("key_material", key_material)
output = [b""]
outlen = 0
counter = 1
while length > outlen:
h = auxfn()
h.update(_int_to_u32be(counter))
h.update(key_material)
h.update(otherinfo)
output.append(h.finalize())
outlen += len(output[-1])
counter += 1
return b"".join(output)[:length]
class ConcatKDFHash(KeyDerivationFunction):
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
otherinfo: bytes | None,
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""
self._used = False
def _hash(self) -> hashes.Hash:
return hashes.Hash(self._algorithm)
def derive(self, key_material: bytes) -> bytes:
if self._used:
raise AlreadyFinalized
self._used = True
return _concatkdf_derive(
key_material, self._length, self._hash, self._otherinfo
)
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey
class ConcatKDFHMAC(KeyDerivationFunction):
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: bytes | None,
otherinfo: bytes | None,
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(f"{algorithm.name} is unsupported for ConcatKDF")
if salt is None:
salt = b"\x00" * algorithm.block_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
self._used = False
def _hmac(self) -> hmac.HMAC:
return hmac.HMAC(self._salt, self._algorithm)
def derive(self, key_material: bytes) -> bytes:
if self._used:
raise AlreadyFinalized
self._used = True
return _concatkdf_derive(
key_material, self._length, self._hmac, self._otherinfo
)
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import typing
from cryptography import utils
from cryptography.exceptions import AlreadyFinalized, InvalidKey
from cryptography.hazmat.primitives import constant_time, hashes, hmac
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
class HKDF(KeyDerivationFunction):
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
salt: bytes | None,
info: bytes | None,
backend: typing.Any = None,
):
self._algorithm = algorithm
if salt is None:
salt = b"\x00" * self._algorithm.digest_size
else:
utils._check_bytes("salt", salt)
self._salt = salt
self._hkdf_expand = HKDFExpand(self._algorithm, length, info)
def _extract(self, key_material: bytes) -> bytes:
h = hmac.HMAC(self._salt, self._algorithm)
h.update(key_material)
return h.finalize()
def derive(self, key_material: bytes) -> bytes:
utils._check_byteslike("key_material", key_material)
return self._hkdf_expand.derive(self._extract(key_material))
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey
class HKDFExpand(KeyDerivationFunction):
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
info: bytes | None,
backend: typing.Any = None,
):
self._algorithm = algorithm
max_length = 255 * algorithm.digest_size
if length > max_length:
raise ValueError(
f"Cannot derive keys larger than {max_length} octets."
)
self._length = length
if info is None:
info = b""
else:
utils._check_bytes("info", info)
self._info = info
self._used = False
def _expand(self, key_material: bytes) -> bytes:
output = [b""]
counter = 1
while self._algorithm.digest_size * (len(output) - 1) < self._length:
h = hmac.HMAC(key_material, self._algorithm)
h.update(output[-1])
h.update(self._info)
h.update(bytes([counter]))
output.append(h.finalize())
counter += 1
return b"".join(output)[: self._length]
def derive(self, key_material: bytes) -> bytes:
utils._check_byteslike("key_material", key_material)
if self._used:
raise AlreadyFinalized
self._used = True
return self._expand(key_material)
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import typing
from cryptography import utils
from cryptography.exceptions import (
AlreadyFinalized,
InvalidKey,
UnsupportedAlgorithm,
_Reasons,
)
from cryptography.hazmat.primitives import (
ciphers,
cmac,
constant_time,
hashes,
hmac,
)
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
class Mode(utils.Enum):
CounterMode = "ctr"
class CounterLocation(utils.Enum):
BeforeFixed = "before_fixed"
AfterFixed = "after_fixed"
MiddleFixed = "middle_fixed"
class _KBKDFDeriver:
def __init__(
self,
prf: typing.Callable,
mode: Mode,
length: int,
rlen: int,
llen: int | None,
location: CounterLocation,
break_location: int | None,
label: bytes | None,
context: bytes | None,
fixed: bytes | None,
):
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 break_location is None and location is CounterLocation.MiddleFixed:
raise ValueError("Please specify a break_location")
if (
break_location is not None
and location != CounterLocation.MiddleFixed
):
raise ValueError(
"break_location is ignored when location is not"
" CounterLocation.MiddleFixed"
)
if break_location is not None and not isinstance(break_location, int):
raise TypeError("break_location must be an integer")
if break_location is not None and break_location < 0:
raise ValueError("break_location must be a positive integer")
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 llen == 0:
raise ValueError("llen must be non-zero")
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._break_location = break_location
self._label = label
self._context = context
self._used = False
self._fixed_data = fixed
@staticmethod
def _valid_byte_length(value: int) -> bool:
if not isinstance(value, int):
raise TypeError("value must be of type int")
value_bin = utils.int_to_bytes(1, value)
if not 1 <= len(value_bin) <= 4:
return False
return True
def derive(self, key_material: bytes, prf_output_size: int) -> bytes:
if self._used:
raise AlreadyFinalized
utils._check_byteslike("key_material", key_material)
self._used = True
# inverse floor division (equivalent to ceiling)
rounds = -(-self._length // prf_output_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.")
fixed = self._generate_fixed_input()
if self._location == CounterLocation.BeforeFixed:
data_before_ctr = b""
data_after_ctr = fixed
elif self._location == CounterLocation.AfterFixed:
data_before_ctr = fixed
data_after_ctr = b""
else:
if isinstance(
self._break_location, int
) and self._break_location > len(fixed):
raise ValueError("break_location offset > len(fixed)")
data_before_ctr = fixed[: self._break_location]
data_after_ctr = fixed[self._break_location :]
for i in range(1, rounds + 1):
h = self._prf(key_material)
counter = utils.int_to_bytes(i, self._rlen)
input_data = data_before_ctr + counter + data_after_ctr
h.update(input_data)
output.append(h.finalize())
return b"".join(output)[: self._length]
def _generate_fixed_input(self) -> bytes:
if self._fixed_data and isinstance(self._fixed_data, bytes):
return self._fixed_data
l_val = utils.int_to_bytes(self._length * 8, self._llen)
return b"".join([self._label, b"\x00", self._context, l_val])
class KBKDFHMAC(KeyDerivationFunction):
def __init__(
self,
algorithm: hashes.HashAlgorithm,
mode: Mode,
length: int,
rlen: int,
llen: int | None,
location: CounterLocation,
label: bytes | None,
context: bytes | None,
fixed: bytes | None,
backend: typing.Any = None,
*,
break_location: int | None = None,
):
if not isinstance(algorithm, hashes.HashAlgorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported hash algorithm.",
_Reasons.UNSUPPORTED_HASH,
)
from cryptography.hazmat.backends.openssl.backend import (
backend as ossl,
)
if not ossl.hmac_supported(algorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported hmac algorithm.",
_Reasons.UNSUPPORTED_HASH,
)
self._algorithm = algorithm
self._deriver = _KBKDFDeriver(
self._prf,
mode,
length,
rlen,
llen,
location,
break_location,
label,
context,
fixed,
)
def _prf(self, key_material: bytes) -> hmac.HMAC:
return hmac.HMAC(key_material, self._algorithm)
def derive(self, key_material: bytes) -> bytes:
return self._deriver.derive(key_material, self._algorithm.digest_size)
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey
class KBKDFCMAC(KeyDerivationFunction):
def __init__(
self,
algorithm,
mode: Mode,
length: int,
rlen: int,
llen: int | None,
location: CounterLocation,
label: bytes | None,
context: bytes | None,
fixed: bytes | None,
backend: typing.Any = None,
*,
break_location: int | None = None,
):
if not issubclass(
algorithm, ciphers.BlockCipherAlgorithm
) or not issubclass(algorithm, ciphers.CipherAlgorithm):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported cipher algorithm.",
_Reasons.UNSUPPORTED_CIPHER,
)
self._algorithm = algorithm
self._cipher: ciphers.BlockCipherAlgorithm | None = None
self._deriver = _KBKDFDeriver(
self._prf,
mode,
length,
rlen,
llen,
location,
break_location,
label,
context,
fixed,
)
def _prf(self, _: bytes) -> cmac.CMAC:
assert self._cipher is not None
return cmac.CMAC(self._cipher)
def derive(self, key_material: bytes) -> bytes:
self._cipher = self._algorithm(key_material)
assert self._cipher is not None
from cryptography.hazmat.backends.openssl.backend import (
backend as ossl,
)
if not ossl.cmac_algorithm_supported(self._cipher):
raise UnsupportedAlgorithm(
"Algorithm supplied is not a supported cipher algorithm.",
_Reasons.UNSUPPORTED_CIPHER,
)
return self._deriver.derive(key_material, self._cipher.block_size // 8)
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import typing
from cryptography import utils
from cryptography.exceptions import (
AlreadyFinalized,
InvalidKey,
UnsupportedAlgorithm,
_Reasons,
)
from cryptography.hazmat.bindings._rust import openssl as rust_openssl
from cryptography.hazmat.primitives import constant_time, hashes
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
class PBKDF2HMAC(KeyDerivationFunction):
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(
f"{algorithm.name} is not supported for PBKDF2.",
_Reasons.UNSUPPORTED_HASH,
)
self._used = False
self._algorithm = algorithm
self._length = length
utils._check_bytes("salt", salt)
self._salt = salt
self._iterations = iterations
def derive(self, key_material: bytes) -> bytes:
if self._used:
raise AlreadyFinalized("PBKDF2 instances can only be used once.")
self._used = True
return rust_openssl.kdf.derive_pbkdf2_hmac(
key_material,
self._algorithm,
self._salt,
self._iterations,
self._length,
)
def verify(self, key_material: bytes, expected_key: bytes) -> None:
derived_key = self.derive(key_material)
if not constant_time.bytes_eq(derived_key, expected_key):
raise InvalidKey("Keys do not match.")

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import sys
from cryptography.hazmat.bindings._rust import openssl as rust_openssl
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
# This is used by the scrypt tests to skip tests that require more memory
# than the MEM_LIMIT
_MEM_LIMIT = sys.maxsize // 2
Scrypt = rust_openssl.kdf.Scrypt
KeyDerivationFunction.register(Scrypt)
__all__ = ["Scrypt"]

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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import annotations
import typing
from cryptography import utils
from cryptography.exceptions import AlreadyFinalized, InvalidKey
from cryptography.hazmat.primitives import constant_time, hashes
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
def _int_to_u32be(n: int) -> bytes:
return n.to_bytes(length=4, byteorder="big")
class X963KDF(KeyDerivationFunction):
def __init__(
self,
algorithm: hashes.HashAlgorithm,
length: int,
sharedinfo: bytes | None,
backend: typing.Any = None,
):
max_len = algorithm.digest_size * (2**32 - 1)
if length > max_len:
raise ValueError(f"Cannot derive keys larger than {max_len} bits.")
if sharedinfo is not None:
utils._check_bytes("sharedinfo", sharedinfo)
self._algorithm = algorithm
self._length = length
self._sharedinfo = sharedinfo
self._used = False
def derive(self, key_material: bytes) -> bytes:
if self._used:
raise AlreadyFinalized
self._used = True
utils._check_byteslike("key_material", key_material)
output = [b""]
outlen = 0
counter = 1
while self._length > outlen:
h = hashes.Hash(self._algorithm)
h.update(key_material)
h.update(_int_to_u32be(counter))
if self._sharedinfo is not None:
h.update(self._sharedinfo)
output.append(h.finalize())
outlen += len(output[-1])
counter += 1
return b"".join(output)[: self._length]
def verify(self, key_material: bytes, expected_key: bytes) -> None:
if not constant_time.bytes_eq(self.derive(key_material), expected_key):
raise InvalidKey