Merge pull request #1468 from dstufft/move-to-src

Move the cryptography package into a src/ subdirectory

1 files changed, 66 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/primitives/kdf/pbkdf2.py b/src/cryptography/hazmat/primitives/kdf/pbkdf2.py
new file mode 100644
index 00000000..97b6408c
--- /dev/null
+++ b/src/cryptography/hazmat/primitives/kdf/pbkdf2.py
@@ -0,0 +1,66 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
+from cryptography import utils
+from cryptography.exceptions import (
+    AlreadyFinalized, InvalidKey, UnsupportedAlgorithm, _Reasons
+)
+from cryptography.hazmat.backends.interfaces import PBKDF2HMACBackend
+from cryptography.hazmat.primitives import constant_time, interfaces
+
+
+@utils.register_interface(interfaces.KeyDerivationFunction)
+class PBKDF2HMAC(object):
+    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
+        if not isinstance(salt, bytes):
+            raise TypeError("salt must be bytes.")
+        self._salt = salt
+        self._iterations = iterations
+        self._backend = backend
+
+    def derive(self, key_material):
+        if self._used:
+            raise AlreadyFinalized("PBKDF2 instances can only be used once.")
+        self._used = True
+
+        if not isinstance(key_material, bytes):
+            raise TypeError("key_material must be bytes.")
+        return self._backend.derive_pbkdf2_hmac(
+            self._algorithm,
+            self._length,
+            self._salt,
+            self._iterations,
+            key_material
+        )
+
+    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.")