moving to scripts

asq-env/lib/python3.9/site-packages/cryptography/hazmat/primitives/kdf/pbkdf2.py

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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.
+
+
+import typing
+
+from cryptography import utils
+from cryptography.exceptions import (
+    AlreadyFinalized,
+    InvalidKey,
+    UnsupportedAlgorithm,
+    _Reasons,
+)
+from cryptography.hazmat.backends import _get_backend
+from cryptography.hazmat.backends.interfaces import Backend, PBKDF2HMACBackend
+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.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 derive(self, key_material: bytes) -> bytes:
+        if self._used:
+            raise AlreadyFinalized("PBKDF2 instances can only be used once.")
+        self._used = True
+
+        utils._check_byteslike("key_material", key_material)
+        return self._backend.derive_pbkdf2_hmac(
+            self._algorithm,
+            self._length,
+            self._salt,
+            self._iterations,
+            key_material,
+        )
+
+    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.")